Question : Which of the following structures is characteristic of members of phylum Arthropoda?

Jointed appendages

Water vascular system

Flame cells

Radula

Correct Answer : Jointed appendages

Question : In cockroach, the respiratory system consists of

Gills

Tracheae

Book lungs

Skin

Correct Answer : Tracheae

Question : Which type of symmetry is exhibited by adult echinoderms?

Bilateral symmetry

Radial symmetry

Asymmetrical

Spherical symmetry

Correct Answer : Radial symmetry

Question : The excretory organs of earthworm are

Malpighian tubules

Nephridia

Flame cells

Green glands

Correct Answer : Nephridia

Question : Which of the following correctly represents the sequence of major taxonomic categories from higher to lower rank?

Kingdom → Class → Phylum → Order → Family → Genus → Species

Kingdom → Phylum → Class → Order → Family → Genus → Species

Kingdom → Phylum → Order → Class → Family → Genus → Species

Kingdom → Class → Order → Phylum → Family → Species → Genus

Correct Answer : Kingdom → Phylum → Class → Order → Family → Genus → Species

Question : In a diploblastic animal, the body wall is formed by

Only ectoderm

Only endoderm

Ectoderm and endoderm with mesoglea between them

Ectoderm, mesoderm and endoderm

Correct Answer : Ectoderm and endoderm with mesoglea between them

Question : Which of the following is correctly matched?

Sycon — Asconoid canal system

Obelia — Ctenophora

Taenia — Annelida

Aurelia — Platyhelminthes

Correct Answer : Sycon — Asconoid canal system

Question : In humans, the part of the brain primarily responsible for maintaining posture and equilibrium is

Medulla oblongata

Cerebellum

Hypothalamus

Corpus callosum

Correct Answer : Cerebellum

Question : During muscle contraction, which region of a sarcomere remains essentially unchanged in length?

I band

H zone

A band

Actin filament

Correct Answer : A band

Question : A person with blood group AB can receive blood from all ABO blood groups because their plasma

Contains both anti-A and anti-B antibodies

Lacks both anti-A and anti-B antibodies

Contains only anti-A antibodies

Contains only anti-B antibodies

Correct Answer : Lacks both anti-A and anti-B antibodies

Question : Which hormone is primarily responsible for the reabsorption of water in the distal tubules and collecting ducts of the nephron?

Aldosterone

Antidiuretic hormone

Atrial natriuretic factor

Thyroxine

Correct Answer : Antidiuretic hormone

Question : Which of the following correctly describes the mechanism of inspiration in a normal human?

Diaphragm relaxes and becomes dome-shaped

External intercostal muscles relax, decreasing thoracic volume

Diaphragm contracts and flattens, increasing thoracic volume

Internal intercostal muscles contract to increase thoracic volume

Correct Answer : Diaphragm contracts and flattens, increasing thoracic volume

Question : If the glomerular filtration rate is approximately 125 mL/min, the approximate volume of filtrate formed in the kidneys in 24 hours is

18 litres

90 litres

180 litres

300 litres

Correct Answer : 180 litres

Question : Which of the following events occurs immediately after the binding of acetylcholine to receptors on the motor end plate?

Release of acetylcholine from the synaptic vesicles

Generation of an action potential in the sarcolemma

Release of calcium ions from the sarcoplasmic reticulum

Binding of myosin to actin

Correct Answer : Generation of an action potential in the sarcolemma

Question : In the human female reproductive cycle, the surge of which hormone triggers ovulation?

FSH

LH

Progesterone

Prolactin

Correct Answer : LH

Question : Which embryonic structure gives rise to the notochord in chordates?

Ectoderm

Endoderm

Mesoderm

Neural crest

Correct Answer : Mesoderm

Question : A man with blood group A and a woman with blood group B have a child with blood group O. What are the probable genotypes of the parents?

IAIA and IBIB

IAi and IBi

IAIA and IBi

IAi and IBIB

Correct Answer : IAi and IBi

Question : In a population under Hardy-Weinberg equilibrium, the frequency of an autosomal recessive disease allele is 0.2. What is the expected frequency of heterozygous individuals?

0.04

0.16

0.32

0.64

Correct Answer : 0.32

Question : Which of the following statements about the human menstrual cycle is correct?

Progesterone concentration is highest during the proliferative phase

Ovulation occurs immediately after the menstrual phase

The corpus luteum mainly secretes progesterone during the luteal phase

FSH reaches its maximum concentration only during the luteal phase

Correct Answer : The corpus luteum mainly secretes progesterone during the luteal phase

Question : A normal human male has 46 chromosomes in each somatic cell. How many chromosomes and chromatids are present in a primary spermatocyte at the end of S phase?

46 chromosomes and 46 chromatids

46 chromosomes and 92 chromatids

92 chromosomes and 92 chromatids

92 chromosomes and 46 chromatids

Correct Answer : 46 chromosomes and 92 chromatids

Question : Which of the following pairs is correctly matched with respect to the type of immunity?

Antibody transfer through colostrum — Artificial active immunity

Vaccination — Natural passive immunity

Antibodies received through antiserum injection — Artificial passive immunity

Recovery from an infection — Artificial passive immunity

Correct Answer : Antibodies received through antiserum injection — Artificial passive immunity

Question : Which of the following is a characteristic feature of phylum Cnidaria?

Triploblastic organisation

Presence of cnidoblasts

Organ-system level of organisation

Bilateral symmetry in all members

Correct Answer : Presence of cnidoblasts

Question : The body cavity of members of phylum Aschelminthes is

Acoelomate

Pseudocoelomate

Coelomate

Haemocoel

Correct Answer : Pseudocoelomate

Question : Which of the following animals possesses a water vascular system?

Pheretima

Asterias

Hirudinaria

Nereis

Correct Answer : Asterias

Question : In an earthworm, the structure primarily responsible for grinding food is

Pharynx

Gizzard

Crop

Typhlosole

Correct Answer : Gizzard

Question : Which of the following is an example of a hermaphrodite animal?

Ascaris

Cockroach

Earthworm

Prawn

Correct Answer : Earthworm

Question : The larva of a frog undergoes metamorphosis under the influence of

Thyroxine

Insulin

Adrenaline

Glucagon

Correct Answer : Thyroxine

Question : Which part of the human nephron is impermeable to water and actively transports electrolytes?

Descending limb of loop of Henle

Ascending limb of loop of Henle

Collecting duct

Proximal convoluted tubule

Correct Answer : Ascending limb of loop of Henle

Question : The counter-current mechanism in the mammalian kidney primarily involves

PCT and DCT

Loop of Henle and vasa recta

Bowman's capsule and glomerulus

Collecting duct and ureter

Correct Answer : Loop of Henle and vasa recta

Question : Which of the following conditions would most directly increase the secretion of antidiuretic hormone?

A decrease in blood osmolarity

An increase in blood osmolarity

An increase in urine volume due to excess water intake

A decrease in plasma sodium concentration

Correct Answer : An increase in blood osmolarity

Question : Which blood vessel carries oxygenated blood from the lungs to the heart?

Pulmonary artery

Pulmonary vein

Superior vena cava

Inferior vena cava

Correct Answer : Pulmonary vein

Question : The first heart sound, commonly described as "lub", is associated with closure of

Semilunar valves

Aortic valve only

Atrioventricular valves

Pulmonary valve only

Correct Answer : Atrioventricular valves

Question : Which component of blood is primarily responsible for the transport of oxygen?

Plasma proteins

Erythrocytes

Platelets

Leucocytes

Correct Answer : Erythrocytes

Question : A decrease in blood calcium level stimulates the secretion of

Calcitonin

Parathyroid hormone

Thymosin

Aldosterone

Correct Answer : Parathyroid hormone

Question : Which hormone promotes milk production in mammary glands after childbirth?

Oxytocin

Prolactin

FSH

Estrogen

Correct Answer : Prolactin

Question : Oxytocin released during childbirth produces its effect mainly by causing

Contraction of uterine muscles

Development of ovarian follicles

Secretion of thyroid hormones

Inhibition of milk ejection

Correct Answer : Contraction of uterine muscles

Question : Which part of the human brain acts as an important centre for regulating body temperature, hunger and thirst?

Cerebellum

Hypothalamus

Medulla oblongata

Pons

Correct Answer : Hypothalamus

Question : The corpus callosum in the human brain primarily connects

Cerebellum with medulla

The two cerebral hemispheres

Spinal cord with cerebellum

Hypothalamus with pituitary gland

Correct Answer : The two cerebral hemispheres

Question : Which type of synapse generally permits transmission of impulses in both directions?

Chemical synapse

Electrical synapse

Neuromuscular junction

Neuroglandular junction

Correct Answer : Electrical synapse

Question : During the propagation of an action potential, depolarisation of the neuronal membrane is mainly caused by

Efflux of Na⁺

Influx of Na⁺

Influx of K⁺

Efflux of Ca²⁺

Correct Answer : Influx of Na⁺

Question : Which of the following correctly describes the role of calcium ions during skeletal muscle contraction?

Calcium binds directly to myosin and releases ATP

Calcium binds to troponin, causing tropomyosin to move away from active sites

Calcium breaks down actin filaments

Calcium inhibits interaction between actin and myosin

Correct Answer : Calcium binds to troponin, causing tropomyosin to move away from active sites

Question : Which region of the human sperm contains enzymes that facilitate penetration of the ovum?

Middle piece

Acrosome

Tail

Nucleus

Correct Answer : Acrosome

Question : The hormone responsible for maintaining the endometrium during pregnancy is primarily

Progesterone

FSH

LH

Melatonin

Correct Answer : Progesterone

Question : Implantation of the human embryo normally occurs in the

Myometrium

Endometrium

Perimetrium

Cervix

Correct Answer : Endometrium

Question : Which extra-embryonic membrane is primarily involved in the formation of the placenta in humans?

Amnion

Chorion

Yolk sac

Allantois

Correct Answer : Chorion

Question : If a carrier woman for haemophilia marries a normal man, what is the probability that a male child will be haemophilic?

0%

25%

50%

100%

Correct Answer : 50%

Question : A woman with normal vision whose father was colour-blind marries a normal-visioned man with no family history of colour blindness. What is the probability of having a colour-blind son?

0%

25%

50%

75%

Correct Answer : 25%

Question : In a dihybrid cross AaBb × AaBb, the probability of obtaining an offspring with genotype aaBb is

1/16

2/16

3/16

4/16

Correct Answer : 2/16

Question : Which of the following is an example of a sex-linked recessive disorder in humans?

Phenylketonuria

Haemophilia

Sickle-cell anaemia

Thalassemia

Correct Answer : Haemophilia

Question : According to Hardy-Weinberg principle, if the frequency of allele A in a population is 0.7, the expected frequency of heterozygous individuals is

0.09

0.21

0.42

0.49

Correct Answer : 0.42

Question : Which of the following correctly represents the evolutionary relationship among humans and the great apes?

Humans evolved directly from modern chimpanzees

Humans and chimpanzees share a common ancestor

Gorillas are the direct ancestors of humans

Modern apes evolved from modern humans

Correct Answer : Humans and chimpanzees share a common ancestor

Question : Which of the following animals belongs to phylum Mollusca?

Pila

Hirudinaria

Asterias

Ascaris

Correct Answer : Pila

Question : The excretory structures in cockroach are

Nephridia

Malpighian tubules

Flame cells

Green glands

Correct Answer : Malpighian tubules

Question : Which of the following is a defining characteristic of phylum Porifera?

Presence of true tissues

Canal system with numerous pores

Organ-system level of organisation

Closed circulatory system

Correct Answer : Canal system with numerous pores

Question : The body of an adult tapeworm is divided into repeated segments called

Setae

Proglottids

Scoli

Nephridia

Correct Answer : Proglottids

Question : Which of the following is correctly matched?

Nereis — Annelida

Sycon — Cnidaria

Fasciola — Aschelminthes

Balanoglossus — Echinodermata

Correct Answer : Nereis — Annelida

Question : In humans, which part of the alimentary canal is the major site of absorption of digested nutrients?

Stomach

Small intestine

Large intestine

Rectum

Correct Answer : Small intestine

Question : Which enzyme is responsible for the digestion of proteins in the stomach?

Trypsin

Pepsin

Lipase

Amylase

Correct Answer : Pepsin

Question : Bile salts facilitate digestion of fats mainly by

Hydrolysing triglycerides directly

Emulsifying fats into smaller droplets

Converting proteins into amino acids

Activating salivary amylase

Correct Answer : Emulsifying fats into smaller droplets

Question : Which structure prevents food from entering the trachea during swallowing?

Glottis

Epiglottis

Uvula

Larynx

Correct Answer : Epiglottis

Question : The oxygen-carrying pigment in human erythrocytes is

Haemocyanin

Haemoglobin

Myoglobin

Bilirubin

Correct Answer : Haemoglobin

Question : Which of the following is the correct sequence of blood flow through the pulmonary circulation?

Right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium

Left ventricle → pulmonary artery → lungs → pulmonary vein → right atrium

Right atrium → pulmonary vein → lungs → pulmonary artery → left ventricle

Left atrium → pulmonary artery → lungs → pulmonary vein → right ventricle

Correct Answer : Right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium

Question : Which leukocytes are primarily associated with antibody production?

Neutrophils

B-lymphocytes

Eosinophils

Basophils

Correct Answer : B-lymphocytes

Question : The pacemaker of the human heart is

Atrioventricular node

Sinoatrial node

Bundle of His

Purkinje fibres

Correct Answer : Sinoatrial node

Question : Which hormone decreases blood glucose concentration?

Glucagon

Insulin

Adrenaline

Cortisol

Correct Answer : Insulin

Question : Iodine is essential for the synthesis of

Insulin

Thyroxine

Adrenaline

Growth hormone

Correct Answer : Thyroxine

Question : Which endocrine gland is commonly referred to as the master gland?

Thyroid

Pituitary

Adrenal

Pineal

Correct Answer : Pituitary

Question : Which part of the nephron is primarily responsible for selective reabsorption of glucose, amino acids, and much of the water and electrolytes from the filtrate?

Proximal convoluted tubule

Loop of Henle

Distal convoluted tubule

Collecting duct

Correct Answer : Proximal convoluted tubule

Question : The juxtaglomerular apparatus contributes to the regulation of blood pressure by releasing

Renin

Insulin

Thyroxine

Erythropoietin

Correct Answer : Renin

Question : During a normal cardiac cycle, ventricular systole begins with

Closure of atrioventricular valves

Opening of atrioventricular valves

Opening of semilunar valves

Closure of semilunar valves

Correct Answer : Closure of atrioventricular valves

Question : Which of the following is an example of a reflex action mediated primarily through the spinal cord?

Thinking

Withdrawal of hand from a hot object

Reading

Voluntary movement of the arm

Correct Answer : Withdrawal of hand from a hot object

Question : Which part of the eye controls the amount of light entering the eye?

Cornea

Iris

Retina

Lens

Correct Answer : Iris

Question : The blind spot in the human eye is the region where

Only cones are present

Only rods are present

The optic nerve leaves the eyeball

The lens is attached to the iris

Correct Answer : The optic nerve leaves the eyeball

Question : Which of the following hormones is secreted by the adrenal medulla?

Cortisol

Aldosterone

Adrenaline

Glucagon

Correct Answer : Adrenaline

Question : In human spermatogenesis, meiosis I produces

Two primary spermatocytes

Two secondary spermatocytes

Four spermatids

One spermatozoon

Correct Answer : Two secondary spermatocytes

Question : The acrosome of a sperm is derived from the

Mitochondria

Golgi apparatus

Endoplasmic reticulum

Centrosome

Correct Answer : Golgi apparatus

Question : Which hormone is secreted by the corpus luteum and helps maintain the uterine endometrium?

FSH

Progesterone

Oxytocin

Prolactin

Correct Answer : Progesterone

Question : Fertilisation in humans normally occurs in the

Uterus

Cervix

Ampullary-isthmic junction of the fallopian tube

Vagina

Correct Answer : Ampullary-isthmic junction of the fallopian tube

Question : If nondisjunction of homologous chromosomes occurs during meiosis I, the resulting gametes are expected to contain

All normal chromosome numbers

Two gametes with n + 1 and two with n − 1 chromosomes

One gamete with n + 1, one with n − 1, and two normal gametes

Four gametes with n + 1 chromosomes

Correct Answer : Two gametes with n + 1 and two with n − 1 chromosomes

Question : In a cross between a heterozygous tall pea plant and a dwarf pea plant, the expected phenotypic ratio is

3 tall : 1 dwarf

1 tall : 1 dwarf

1 tall : 3 dwarf

All tall

Correct Answer : 1 tall : 1 dwarf

Question : A DNA molecule contains 30% adenine. What percentage of its bases would be guanine?

20%

30%

40%

70%

Correct Answer : 20%

Question : Which of the following animals is diploblastic and radially symmetrical?

Hydra

Earthworm

Cockroach

Planaria

Correct Answer : Hydra

Question : The specialised cells responsible for locomotion and food capture in ctenophores are

Cnidoblasts

Colloblasts

Choanocytes

Flame cells

Correct Answer : Colloblasts

Question : Which of the following is a characteristic feature of Platyhelminthes?

True coelom

Pseudocoelom

Dorsoventrally flattened body

Metameric segmentation

Correct Answer : Dorsoventrally flattened body

Question : Which of the following structures is absent in members of phylum Echinodermata?

Water vascular system

Tube feet

Jointed appendages

Calcareous endoskeleton

Correct Answer : Jointed appendages

Question : In a typical chordate, the notochord is located

Dorsal to the nerve cord

Ventral to the nerve cord

Dorsal to the alimentary canal

Between the nerve cord and alimentary canal

Correct Answer : Between the nerve cord and alimentary canal

Question : Which of the following is correctly matched?

Petromyzon — Jawless vertebrate

Scoliodon — Bony fish

Rana — Reptilia

Columba — Mammalia

Correct Answer : Petromyzon — Jawless vertebrate

Question : The respiratory organs of fishes are primarily

Lungs

Tracheae

Gills

Skin

Correct Answer : Gills

Question : Which feature distinguishes mammals from most other vertebrates?

Presence of a vertebral column

Presence of a four-chambered heart

Presence of mammary glands

Presence of paired appendages

Correct Answer : Presence of mammary glands

Question : The enzyme that initiates protein digestion in the small intestine by converting trypsinogen into trypsin is

Enterokinase

Pepsin

Pepsinogen

Carboxypeptidase

Correct Answer : Enterokinase

Question : Which of the following is absorbed predominantly into the lymphatic vessels of intestinal villi?

Glucose

Amino acids

Long-chain fatty acids

Mineral salts

Correct Answer : Long-chain fatty acids

Question : A deficiency of intrinsic factor would most directly impair the absorption of

Vitamin B12

Vitamin C

Vitamin D

Vitamin K

Correct Answer : Vitamin B12

Question : Which region of the alimentary canal contains numerous villi and microvilli to maximise absorptive surface area?

Stomach

Small intestine

Large intestine

Oesophagus

Correct Answer : Small intestine

Question : During normal expiration, the diaphragm

Contracts and flattens

Relaxes and becomes dome-shaped

Contracts and becomes dome-shaped

Remains completely stationary

Correct Answer : Relaxes and becomes dome-shaped

Question : Most carbon dioxide in human blood is transported in the form of

Dissolved CO2

Carbaminohaemoglobin

Bicarbonate ions

Carbonic acid

Correct Answer : Bicarbonate ions

Question : The Bohr effect facilitates oxygen unloading from haemoglobin when

CO2 concentration decreases and pH increases

CO2 concentration increases and pH decreases

Temperature decreases and pH increases

CO2 concentration decreases and temperature decreases

Correct Answer : CO2 concentration increases and pH decreases

Question : Which part of the respiratory system is the principal site of gaseous exchange in humans?

Trachea

Bronchi

Alveoli

Larynx

Correct Answer : Alveoli

Question : If the tidal volume of a person is 500 mL and the respiratory rate is 12 breaths per minute, the approximate minute ventilation is

600 mL

6 L

12 L

60 L

Correct Answer : 6 L

Question : Which of the following combinations correctly represents the components of the conducting part of the human respiratory system?

Nasal chamber, trachea, bronchi and bronchioles

Alveoli, alveolar ducts and respiratory bronchioles only

Nasal chamber and alveoli only

Lungs and pleural cavity only

Correct Answer : Nasal chamber, trachea, bronchi and bronchioles

Question : Which of the following statements about haemoglobin is correct?

Each haemoglobin molecule can bind irreversibly to four oxygen molecules

Oxygen binds to the iron atom of the haem group

Haemoglobin is present only in plasma

Haemoglobin transports only carbon dioxide

Correct Answer : Oxygen binds to the iron atom of the haem group

Question : The filtration membrane of the renal corpuscle includes

Only the walls of Bowman's capsule

Glomerular capillary endothelium, basement membrane and podocytes

Only the basement membrane

Only the podocytes

Correct Answer : Glomerular capillary endothelium, basement membrane and podocytes

Question : Which hormone increases sodium reabsorption in the distal parts of the nephron?

ADH

Aldosterone

ANF

Calcitonin

Correct Answer : Aldosterone

Question : A person produces a very large volume of dilute urine due to inadequate secretion of

ADH

Aldosterone

Renin

Atrial natriuretic factor

Correct Answer : ADH

Question : Which of the following correctly describes the role of atrial natriuretic factor?

It increases blood pressure by increasing sodium reabsorption

It decreases blood pressure by promoting sodium and water excretion

It increases glucose reabsorption in the nephron

It stimulates secretion of thyroxine

Correct Answer : It decreases blood pressure by promoting sodium and water excretion

Question : The resting membrane potential of a neuron is mainly maintained by

Only calcium channels

Sodium-potassium pump and selective permeability of the membrane

Only sodium-potassium pump without ion leakage

Continuous opening of voltage-gated sodium channels

Correct Answer : Sodium-potassium pump and selective permeability of the membrane

Question : Which neurotransmitter is released at the neuromuscular junction of skeletal muscles?

Acetylcholine

Thyroxine

Insulin

Dopamine

Correct Answer : Acetylcholine

Question : Damage to the cerebellum would most likely affect

Vision

Balance and coordination

Hearing

Hormonal secretion by the thyroid

Correct Answer : Balance and coordination

Question : Which of the following represents a correct example of negative feedback in endocrine regulation?

Oxytocin increasing uterine contractions during childbirth

High thyroxine levels suppressing secretion of TSH

Insulin increasing blood glucose concentration

ADH increasing urine volume

Correct Answer : High thyroxine levels suppressing secretion of TSH

Question : In humans, the secondary oocyte released during ovulation is arrested at

Prophase I

Metaphase I

Metaphase II

Prophase II

Correct Answer : Metaphase II

Question : Which of the following chromosomal conditions results from the presence of an additional X chromosome in a male?

Turner syndrome

Klinefelter syndrome

Down syndrome

Edward syndrome

Correct Answer : Klinefelter syndrome

Question : Which of the following is the characteristic feature of phylum Annelida?

Radial symmetry and diploblastic organisation

Metameric segmentation and true coelom

Pseudocoelom and unsegmented body

Water vascular system and tube feet

Correct Answer : Metameric segmentation and true coelom

Question : In members of phylum Arthropoda, the body cavity is primarily represented by

Coelom

Pseudocoelom

Haemocoel

Gastrovascular cavity

Correct Answer : Haemocoel

Question : Which of the following animals possesses a closed circulatory system?

Cockroach

Earthworm

Prawn

Starfish

Correct Answer : Earthworm

Question : The excretory organ of prawn is

Malpighian tubule

Green gland

Nephridium

Flame cell

Correct Answer : Green gland

Question : Which of the following is a characteristic feature of class Amphibia?

Dry, cornified skin

Respiration exclusively through lungs

Life restricted entirely to water

Larval stages generally possess gills

Correct Answer : Larval stages generally possess gills

Question : Which of the following animals is correctly associated with a four-chambered heart?

Frog

Lizard

Crocodile

Shark

Correct Answer : Crocodile

Question : The structural and functional unit of the human kidney is

Renal corpuscle

Nephron

Glomerulus

Collecting duct

Correct Answer : Nephron

Question : Which part of the nephron is responsible for maintaining the osmotic gradient in the renal medulla through counter-current multiplication?

Loop of Henle

Proximal convoluted tubule

Distal convoluted tubule

Bowman's capsule

Correct Answer : Loop of Henle

Question : If the concentration of glucose in the filtrate exceeds the renal threshold, glucose begins to appear in urine because

Glomerular filtration stops

Tubular reabsorptive capacity is exceeded

ADH secretion completely stops

Glucose cannot enter the renal tubule

Correct Answer : Tubular reabsorptive capacity is exceeded

Question : Which of the following substances is normally absent or present only in negligible amounts in the urine of a healthy person?

Urea

Uric acid

Creatinine

Glucose

Correct Answer : Glucose

Question : The normal pacemaker activity of the heart originates in the

AV node

SA node

Bundle of His

Purkinje fibres

Correct Answer : SA node

Question : Which component of the cardiac conduction system delays the transmission of the impulse before it reaches the ventricles?

SA node

AV node

Purkinje fibres

Bundle branches

Correct Answer : AV node

Question : A person with severe deficiency of platelets is most likely to experience

Impaired oxygen transport

Excessive bleeding

Increased antibody production

Reduced blood glucose

Correct Answer : Excessive bleeding

Question : Which plasma protein is mainly involved in blood clotting?

Albumin

Globulin

Fibrinogen

Haemoglobin

Correct Answer : Fibrinogen

Question : The lymphatic system is important for the absorption and transport of

Amino acids from the stomach

Long-chain fatty acids from the intestine

Glucose from the liver

Oxygen from the lungs

Correct Answer : Long-chain fatty acids from the intestine

Question : Which hormone is secreted by the posterior pituitary after synthesis in the hypothalamus?

Growth hormone

ADH

TSH

ACTH

Correct Answer : ADH

Question : Excess secretion of growth hormone in adults results in

Dwarfism

Acromegaly

Cretinism

Myxoedema

Correct Answer : Acromegaly

Question : Which endocrine disorder is associated with hypersecretion of cortisol?

Diabetes insipidus

Addison's disease

Cushing's syndrome

Graves' disease

Correct Answer : Cushing's syndrome

Question : Which hormone is primarily responsible for the "fight-or-flight" response?

Insulin

Adrenaline

Progesterone

Melatonin

Correct Answer : Adrenaline

Question : A decrease in blood glucose concentration directly stimulates the pancreas to secrete

Insulin

Glucagon

Somatostatin only

Thyroxine

Correct Answer : Glucagon

Question : The functional unit of skeletal muscle contraction is

Myofibril

Sarcomere

Sarcoplasm

Tendon

Correct Answer : Sarcomere

Question : During muscle contraction, which of the following changes occurs?

The actin filaments shorten

The myosin filaments shorten

The Z-lines move closer together

The A-band disappears

Correct Answer : The Z-lines move closer together

Question : Which protein forms the thick filament of a skeletal muscle sarcomere?

Actin

Myosin

Troponin

Tropomyosin

Correct Answer : Myosin

Question : Which part of the human ear contains the organ of Corti?

Middle ear

Cochlea

Semicircular canals

Eustachian tube

Correct Answer : Cochlea

Question : The semicircular canals are primarily associated with

Hearing

Static balance only

Dynamic equilibrium

Smell

Correct Answer : Dynamic equilibrium

Question : Which photoreceptor cells are responsible for vision in dim light?

Cones

Rods

Bipolar cells

Ganglion cells

Correct Answer : Rods

Question : In the human eye, the image formed on the retina is

Virtual, erect and magnified

Real, inverted and diminished

Virtual, inverted and diminished

Real, erect and magnified

Correct Answer : Real, inverted and diminished

Question : If a normal woman who is a carrier of an X-linked recessive disorder marries a normal man, what proportion of their daughters is expected to be carriers?

0%

25%

50%

100%

Correct Answer : 50%

Question : In a monohybrid cross between two heterozygous individuals, the probability of obtaining a homozygous recessive offspring is

1/2

1/4

1/8

3/4

Correct Answer : 1/4

Question : Which of the following represents a case of incomplete dominance?

AB blood group in humans

Flower colour in Snapdragon

Haemophilia in humans

Albinism in humans

Correct Answer : Flower colour in Snapdragon

Question : Which of the following is a defining feature of phylum Ctenophora?

Cnidoblasts for prey capture

Comb plates for locomotion

Jointed appendages

Flame cells for excretion

Correct Answer : Comb plates for locomotion

Question : Which of the following animals exhibits organ-system level of organisation and is acoelomate?

Sycon

Hydra

Planaria

Ascaris

Correct Answer : Planaria

Question : In a sponge, the cells that generate water currents and trap food particles are

Cnidoblasts

Choanocytes

Colloblasts

Flame cells

Correct Answer : Choanocytes

Question : Which of the following is correctly matched with its locomotory structure?

Starfish — Tube feet

Earthworm — Parapodia

Cockroach — Setae

Prawn — Cilia

Correct Answer : Starfish — Tube feet

Question : Which of the following organisms is a connecting link between chordates and non-chordates in classical zoological classification?

Balanoglossus

Pila

Asterias

Ascaris

Correct Answer : Balanoglossus

Question : Which type of epithelial tissue is specialised for rapid diffusion and is found lining the alveoli of lungs?

Cuboidal epithelium

Columnar epithelium

Simple squamous epithelium

Stratified squamous epithelium

Correct Answer : Simple squamous epithelium

Question : Which connective tissue connects muscle to bone?

Ligament

Tendon

Cartilage

Areolar tissue

Correct Answer : Tendon

Question : The intervertebral discs in the human vertebral column are primarily composed of

Elastic cartilage

Fibrocartilage

Hyaline cartilage

Bone

Correct Answer : Fibrocartilage

Question : Which of the following muscles is involuntary and striated?

Skeletal muscle

Smooth muscle

Cardiac muscle

Voluntary muscle

Correct Answer : Cardiac muscle

Question : The functional unit of the nervous system is

Nephron

Neuron

Sarcomere

Osteon

Correct Answer : Neuron

Question : Which part of a neuron receives signals from other neurons?

Axon

Dendrites

Synaptic vesicles

Myelin sheath

Correct Answer : Dendrites

Question : The myelin sheath around axons in the peripheral nervous system is formed by

Astrocytes

Schwann cells

Microglia

Oligodendrocytes

Correct Answer : Schwann cells

Question : Which of the following correctly describes saltatory conduction?

Impulse travels continuously along the entire axonal membrane

Impulse jumps from one node of Ranvier to the next

Impulse travels only through the dendrites

Impulse occurs without ion movement

Correct Answer : Impulse jumps from one node of Ranvier to the next

Question : The hormone that promotes calcium deposition in bones and lowers blood calcium concentration is

Parathyroid hormone

Calcitonin

Aldosterone

Glucagon

Correct Answer : Calcitonin

Question : Which of the following hormones is secreted by the pineal gland?

Melatonin

Thymosin

Oxytocin

Cortisol

Correct Answer : Melatonin

Question : The thymus gland plays an important role in

Maturation of T-lymphocytes

Production of erythrocytes in adults

Secretion of insulin

Formation of bile

Correct Answer : Maturation of T-lymphocytes

Question : Which of the following is an example of innate immunity?

Antibody production following vaccination

Skin acting as a physical barrier

Formation of memory cells after infection

Antibody production after exposure to a pathogen

Correct Answer : Skin acting as a physical barrier

Question : The antibody that is most abundant in human blood and can cross the placenta is

IgA

IgE

IgG

IgM

Correct Answer : IgG

Question : Which immunoglobulin is mainly associated with allergic reactions?

IgG

IgA

IgE

IgM

Correct Answer : IgE

Question : HIV primarily attacks which cells of the human immune system?

B-lymphocytes

Helper T-lymphocytes

Erythrocytes

Neutrophils

Correct Answer : Helper T-lymphocytes

Question : Which of the following is a characteristic feature of secondary immune response?

It is slower and weaker than the primary response

It occurs only in the absence of memory cells

It is faster and stronger due to memory cells

It does not involve lymphocytes

Correct Answer : It is faster and stronger due to memory cells

Question : Which hormone is essential for the development of female secondary sexual characteristics?

Testosterone

Estrogen

Adrenaline

Glucagon

Correct Answer : Estrogen

Question : In a healthy human female, the average duration of the menstrual cycle is approximately

14 days

21 days

28 days

40 days

Correct Answer : 28 days

Question : Which hormone causes the development of the corpus luteum after ovulation?

FSH

LH

Prolactin

Oxytocin

Correct Answer : LH

Question : Which structure in the female reproductive system receives the ovulated secondary oocyte?

Uterus

Fallopian tube

Cervix

Vagina

Correct Answer : Fallopian tube

Question : The process by which spermatids transform into mature spermatozoa is called

Spermatogenesis

Spermiation

Spermiogenesis

Oogenesis

Correct Answer : Spermiogenesis

Question : Which of the following cells in the testis provides nourishment to developing germ cells?

Leydig cells

Sertoli cells

Spermatogonia

Primary spermatocytes

Correct Answer : Sertoli cells

Question : Leydig cells in the testes primarily secrete

FSH

Testosterone

Progesterone

Estrogen

Correct Answer : Testosterone

Question : In humans, the diploid chromosome number is restored at

Gametogenesis

Meiosis I

Fertilisation

Implantation

Correct Answer : Fertilisation

Question : A man with genotype IAi and a woman with genotype IBi have a child. What is the probability that the child will have blood group AB?

0%

25%

50%

75%

Correct Answer : 25%

Question : Which of the following is a characteristic feature of phylum Hemichordata?

Presence of a true notochord

Body divided into proboscis, collar and trunk

Presence of jointed appendages

Presence of tube feet

Correct Answer : Body divided into proboscis, collar and trunk

Question : Which of the following animals belongs to class Cephalopoda?

Pila

Unio

Sepia

Asterias

Correct Answer : Sepia

Question : The radula in molluscs is primarily used for

Respiration

Excretion

Scraping and feeding

Locomotion

Correct Answer : Scraping and feeding

Question : Which of the following is correctly matched?

Hirudinaria — Suckers

Pheretima — Parapodia

Nereis — Setae absent

Ascaris — Flame cells

Correct Answer : Hirudinaria — Suckers

Question : In cockroach, the compound eyes are made up of numerous visual units called

Ommatidia

Nephridia

Ocelli

Statocysts

Correct Answer : Ommatidia

Question : Which structure in cockroach functions as a grinding organ of the alimentary canal?

Crop

Gizzard

Ileum

Rectum

Correct Answer : Gizzard

Question : Which of the following is an example of a diploblastic animal?

Earthworm

Hydra

Ascaris

Cockroach

Correct Answer : Hydra

Question : The presence of a pseudocoelom is characteristic of

Platyhelminthes

Aschelminthes

Annelida

Mollusca

Correct Answer : Aschelminthes

Question : Which of the following is a correct feature of mammals?

They are cold-blooded vertebrates

They possess mammary glands

They have a three-chambered heart

They respire only through gills

Correct Answer : They possess mammary glands

Question : The enzyme present in saliva that begins the digestion of starch is

Pepsin

Trypsin

Salivary amylase

Lipase

Correct Answer : Salivary amylase

Question : Which of the following substances is required for the absorption of vitamin B12 from the small intestine?

Bile salts

Intrinsic factor

Trypsin

Pepsin

Correct Answer : Intrinsic factor

Question : The hormone secreted by the gastric mucosa that stimulates secretion of gastric juice is

Secretin

Gastrin

Cholecystokinin

Enterogastrone

Correct Answer : Gastrin

Question : Which part of the small intestine receives bile and pancreatic juice?

Duodenum

Jejunum

Ileum

Caecum

Correct Answer : Duodenum

Question : Which enzyme converts angiotensinogen into angiotensin I?

Renin

ACE

Pepsin

Trypsin

Correct Answer : Renin

Question : Which of the following statements about the glomerulus is correct?

It reabsorbs glucose from urine

It is a network of capillaries involved in ultrafiltration

It secretes ADH

It stores urine

Correct Answer : It is a network of capillaries involved in ultrafiltration

Question : The maximum amount of glucose reabsorption in the nephron normally occurs in the

Proximal convoluted tubule

Loop of Henle

Distal convoluted tubule

Collecting duct

Correct Answer : Proximal convoluted tubule

Question : Which condition results from inadequate secretion of ADH?

Diabetes mellitus

Diabetes insipidus

Addison's disease

Cushing's syndrome

Correct Answer : Diabetes insipidus

Question : Which of the following is the correct sequence of events in a reflex arc?

Receptor → sensory neuron → CNS → motor neuron → effector

Effector → sensory neuron → CNS → receptor → motor neuron

Receptor → motor neuron → CNS → sensory neuron → effector

CNS → receptor → sensory neuron → motor neuron → effector

Correct Answer : Receptor → sensory neuron → CNS → motor neuron → effector

Question : Which part of the brain regulates respiration and cardiovascular reflexes?

Cerebrum

Medulla oblongata

Cerebellum

Hypothalamus

Correct Answer : Medulla oblongata

Question : Which of the following hormones is released during stress and increases blood glucose availability?

Insulin

Adrenaline

Calcitonin

Melatonin

Correct Answer : Adrenaline

Question : Which hormone stimulates the growth of ovarian follicles during the follicular phase?

LH

FSH

Progesterone

Oxytocin

Correct Answer : FSH

Question : The immediate endocrine signal that causes ovulation in the human female is

FSH surge

LH surge

Progesterone surge

Estrogen withdrawal

Correct Answer : LH surge

Question : Which of the following is the correct sequence during human fertilisation?

Sperm entry → cortical reaction → completion of meiosis II → fusion of nuclei

Fusion of nuclei → sperm entry → cortical reaction → meiosis II

Meiosis II → sperm entry → fusion of nuclei → cortical reaction

Cortical reaction → fusion of nuclei → sperm entry → meiosis II

Correct Answer : Sperm entry → cortical reaction → completion of meiosis II → fusion of nuclei

Question : Which embryonic tissue primarily gives rise to the nervous system?

Ectoderm

Mesoderm

Endoderm

Trophoblast

Correct Answer : Ectoderm

Question : A woman with genotype IAi and a man with genotype ii have children. What fraction of their children is expected to have blood group A?

0%

25%

50%

100%

Correct Answer : 50%

Question : In a pedigree, unaffected parents produce an affected child, and the trait occurs in both males and females. Which inheritance pattern is most consistent with this observation?

Autosomal dominant

Autosomal recessive

Y-linked

Mitochondrial only

Correct Answer : Autosomal recessive

Question : In a test cross involving a dihybrid individual AaBb, the expected phenotypic ratio, assuming independent assortment, is

9 : 3 : 3 : 1

3 : 1

1 : 1

1 : 1 : 1 : 1

Correct Answer : 1 : 1 : 1 : 1

Question : A DNA molecule has 800 base pairs, of which 30% are adenine-thymine base pairs. How many guanine-cytosine base pairs are present?

240

320

560

640

Correct Answer : 560

Question : Which enzyme joins Okazaki fragments during DNA replication?

DNA helicase

DNA ligase

DNA polymerase

RNA polymerase

Correct Answer : DNA ligase

Question : If the coding strand of a DNA segment has the sequence 5′-ATGCCT-3′, the corresponding mRNA sequence is

5′-UACGGA-3′

5′-AUGCCU-3′

5′-TACGGA-3′

5′-AUGGCU-3′

Correct Answer : 5′-AUGCCU-3′

Question : Which tissue in plants is primarily responsible for the increase in girth of stems and roots?

Vascular cambium

Apical meristem

Intercalary meristem

Protoderm

Correct Answer : Vascular cambium

Question : In a typical dicot root, the vascular bundles are arranged as:

Conjoint and collateral

Radial with exarch xylem

Conjoint and bicollateral

Radial with endarch xylem

Correct Answer : Radial with exarch xylem

Question : Which of the following is a characteristic feature of sclerenchymatous cells?

They are living and actively dividing

They possess thin primary walls

They have thick, lignified secondary walls

They contain abundant chloroplasts

Correct Answer : They have thick, lignified secondary walls

Question : The Casparian strips in the endodermis of roots are mainly composed of:

Cellulose

Suberin

Pectin

Lignin only

Correct Answer : Suberin

Question : Which of the following correctly represents the sequence of tissues encountered from the outside toward the centre in a typical dicot stem?

Epidermis → cortex → endodermis → pericycle → vascular bundles → pith

Epidermis → cortex → pericycle → endodermis → vascular bundles → pith

Epidermis → endodermis → cortex → pericycle → vascular bundles → pith

Epidermis → cortex → vascular bundles → endodermis → pericycle → pith

Correct Answer : Epidermis → cortex → endodermis → pericycle → vascular bundles → pith

Question : In a dorsiventral leaf, the palisade parenchyma is generally located:

Below the upper epidermis

Below the lower epidermis

Around the vascular bundles only

Between the epidermis and cuticle

Correct Answer : Below the upper epidermis

Question : Which plant hormone promotes cell division and delays senescence of leaves?

Auxin

Gibberellin

Cytokinin

Abscisic acid

Correct Answer : Cytokinin

Question : A plant cell placed in a hypertonic solution undergoes plasmolysis because:

Water enters the cell by endosmosis

Water leaves the cell by exosmosis

Solutes enter the cell by active transport

The cell wall loses its permeability

Correct Answer : Water leaves the cell by exosmosis

Question : Which statement about phloem transport is correct?

It occurs only from roots toward leaves

It is always unidirectional in a plant

Organic solutes can move from source to sink through sieve tubes

It occurs exclusively through xylem vessels

Correct Answer : Organic solutes can move from source to sink through sieve tubes

Question : If a plant is exposed to prolonged water stress, which response is most directly associated with abscisic acid?

Stomatal closure

Promotion of cell division

Breaking of seed dormancy

Increased transpiration

Correct Answer : Stomatal closure

Question : In C4 plants, the initial fixation of atmospheric CO₂ occurs in mesophyll cells, producing:

3-phosphoglyceric acid using RuBisCO

Oxaloacetic acid using PEP carboxylase

Ribulose bisphosphate using PEP carboxylase

Pyruvic acid using RuBisCO

Correct Answer : Oxaloacetic acid using PEP carboxylase

Question : Which of the following combinations is correctly matched?

Chlorophyll a — reaction centre pigment

Carotenoids — primary electron acceptors

RuBisCO — enzyme of glycolysis

Cytochrome oxidase — Calvin cycle enzyme

Correct Answer : Chlorophyll a — reaction centre pigment

Question : During photorespiration in a C3 plant, the initial oxygenation reaction involving RuBisCO results in the formation of:

Two molecules of 3-PGA

One molecule each of 3-PGA and 2-phosphoglycolate

Two molecules of phosphoglycolate

One molecule each of glucose and oxygen

Correct Answer : One molecule each of 3-PGA and 2-phosphoglycolate

Question : Which stage of cellular respiration produces the largest amount of ATP under aerobic conditions?

Glycolysis

Krebs cycle

Oxidative phosphorylation

Fermentation

Correct Answer : Oxidative phosphorylation

Question : A plant has a net gain of 6 molecules of CO₂ fixed through the Calvin cycle. The number of molecules of 3-phosphoglycerate initially formed is:

6

12

18

24

Correct Answer : 12

Question : Which of the following statements about cyclic photophosphorylation is correct?

It involves both photosystems I and II

It results in the photolysis of water

It produces ATP but not NADPH

It produces NADPH but not ATP

Correct Answer : It produces ATP but not NADPH

Question : In the Krebs cycle, substrate-level phosphorylation directly results in the formation of:

ATP or GTP

NADPH

FADH₂ only

Oxygen

Correct Answer : ATP or GTP

Question : Which of the following is an example of a plant showing heterophylly?

Presence of different leaf forms at different stages or conditions

Presence of only compound leaves

Development of leaves exclusively underground

Formation of leaves only during flowering

Correct Answer : Presence of different leaf forms at different stages or conditions

Question : The main function of the root cap is to:

Absorb mineral salts

Protect the root apical meristem

Transport food to the root

Increase the rate of photosynthesis

Correct Answer : Protect the root apical meristem

Question : Which Mendelian ratio is expected in the F₂ generation of a typical dihybrid cross involving two independently assorting genes with complete dominance?

3 : 1

1 : 1

9 : 3 : 3 : 1

1 : 2 : 1

Correct Answer : 9 : 3 : 3 : 1

Question : Which meristem is responsible for the formation of primary tissues in a plant body?

Lateral meristem

Apical meristem

Cork cambium

Vascular cambium

Correct Answer : Apical meristem

Question : In a monocot stem, vascular bundles are generally:

Arranged in a ring and open

Scattered and closed

Arranged in a ring and closed

Scattered and open

Correct Answer : Scattered and closed

Question : Which of the following is a simple permanent tissue?

Xylem

Phloem

Parenchyma

Epidermis

Correct Answer : Parenchyma

Question : Companion cells are associated with:

Tracheids

Vessels

Sieve tube elements

Fibres

Correct Answer : Sieve tube elements

Question : Which component of xylem is mainly responsible for conduction of water and minerals?

Fibres

Parenchyma

Vessels and tracheids

Companion cells

Correct Answer : Vessels and tracheids

Question : Bulliform cells are characteristically found in the:

Lower epidermis of dicot leaves

Upper epidermis of grasses

Pericycle of roots

Cortex of dicot stems

Correct Answer : Upper epidermis of grasses

Question : Which of the following is a xerophytic adaptation that helps reduce water loss?

Large thin leaves

Sunken stomata

Absence of cuticle

Reduced root system

Correct Answer : Sunken stomata

Question : The movement of water through the apoplast pathway occurs mainly through:

Cytoplasm of living cells

Cell walls and intercellular spaces

Plasmodesmata

Vacuoles

Correct Answer : Cell walls and intercellular spaces

Question : Which force is primarily responsible for the ascent of sap in tall trees according to the cohesion-tension theory?

Root pressure alone

Transpiration pull

Osmotic pressure of phloem

Active pumping by xylem cells

Correct Answer : Transpiration pull

Question : Guttation commonly occurs through specialized structures called:

Lenticels

Hydathodes

Stomata

Trichomes

Correct Answer : Hydathodes

Question : Which plant growth regulator is most closely associated with fruit ripening?

Auxin

Ethylene

Cytokinin

Abscisic acid

Correct Answer : Ethylene

Question : Gibberellins are known to promote:

Stomatal closure

Bolting and internode elongation

Leaf senescence

Fruit ripening exclusively

Correct Answer : Bolting and internode elongation

Question : Which hormone is commonly associated with breaking seed dormancy and promoting germination?

Abscisic acid

Gibberellin

Ethylene

Cytokinin

Correct Answer : Gibberellin

Question : Apical dominance in plants is primarily promoted by:

Auxin

Ethylene

Abscisic acid

Cytokinin

Correct Answer : Auxin

Question : Which of the following is an example of a short-day plant?

Wheat

Spinach

Rice

Pea

Correct Answer : Rice

Question : Photoperiodism refers to the response of plants to:

Intensity of light only

Duration of light and dark periods

Direction of light

Quality of soil

Correct Answer : Duration of light and dark periods

Question : The respiratory quotient for carbohydrates under aerobic conditions is generally:

0.5

1.0

1.5

2.0

Correct Answer : 1.0

Question : During glycolysis, one molecule of glucose is converted into:

Two molecules of pyruvate

Two molecules of acetyl-CoA

One molecule of pyruvate

Four molecules of pyruvate

Correct Answer : Two molecules of pyruvate

Question : In aerobic respiration, pyruvate is converted into acetyl-CoA in the:

Cytoplasm

Mitochondrial matrix

Inner mitochondrial membrane

Chloroplast

Correct Answer : Mitochondrial matrix

Question : Which molecule acts as the primary CO₂ acceptor in the Calvin cycle?

PEP

RuBP

OAA

PGA

Correct Answer : RuBP

Question : The enzyme RuBisCO is located in the:

Thylakoid lumen

Stroma of chloroplast

Outer mitochondrial membrane

Cytoplasm

Correct Answer : Stroma of chloroplast

Question : In the light reaction of photosynthesis, photolysis of water is associated with:

Photosystem I

Photosystem II

Cytochrome complex only

ATP synthase

Correct Answer : Photosystem II

Question : The oxygen released during photosynthesis comes from:

Carbon dioxide

Glucose

Water

RuBP

Correct Answer : Water

Question : Which of the following molecules is directly required for the reduction phase of the Calvin cycle?

NADPH

FAD

O₂

N₂

Correct Answer : NADPH

Question : In a C4 plant, the bundle sheath cells are generally characterized by:

Absence of chloroplasts

Large chloroplasts and little intercellular space

Complete absence of mitochondria

Absence of cell walls

Correct Answer : Large chloroplasts and little intercellular space

Question : Which of the following is a characteristic feature of CAM plants?

Stomata remain open throughout the day

CO₂ is fixed at night and utilized during the day

They lack chlorophyll

They perform only anaerobic respiration

Correct Answer : CO₂ is fixed at night and utilized during the day

Question : In CAM plants, organic acids accumulated during the night are primarily stored in:

Chloroplasts

Vacuoles

Nucleus

Mitochondria

Correct Answer : Vacuoles

Question : Which mineral element is a component of the chlorophyll molecule?

Nitrogen

Magnesium

Potassium

Calcium

Correct Answer : Magnesium

Question : Nitrogen deficiency in plants commonly causes:

Chlorosis of older leaves

Increased chlorophyll synthesis

Enhanced root pressure

Immediate fruit ripening

Correct Answer : Chlorosis of older leaves

Question : Which microorganism is commonly associated with biological nitrogen fixation in leguminous plants?

Rhizobium

Azotobacter only

Nitrosomonas

Pseudomonas

Correct Answer : Rhizobium

Question : Nitrification involves the conversion of:

Nitrate into atmospheric nitrogen

Ammonia into nitrite and then nitrate

Nitrogen gas into ammonia directly by plants

Proteins directly into nitrogen gas

Correct Answer : Ammonia into nitrite and then nitrate

Question : Which of the following is an essential macronutrient for plants?

Molybdenum

Boron

Zinc

Phosphorus

Correct Answer : Phosphorus

Question : The opening and closing of stomata are directly regulated by changes in:

Guard cell turgor

Xylem lignification

Root cap thickness

Phloem fibre length

Correct Answer : Guard cell turgor

Question : During stomatal opening, potassium ions generally:

Move out of guard cells

Accumulate in guard cells

Are converted into glucose

Enter the xylem vessels directly

Correct Answer : Accumulate in guard cells

Question : Which type of cell division produces genetically identical daughter cells and maintains chromosome number?

Meiosis I

Meiosis II

Mitosis

Reduction division

Correct Answer : Mitosis

Question : In flowering plants, meiosis in the microspore mother cell produces:

Two diploid microspores

Four haploid microspores

Four diploid pollen grains

One haploid megaspore

Correct Answer : Four haploid microspores

Question : The functional megaspore in a typical angiosperm develops into:

Endosperm

Embryo sac

Pollen grain

Seed coat

Correct Answer : Embryo sac

Question : A typical mature embryo sac of an angiosperm contains:

Eight cells and seven nuclei

Seven cells and eight nuclei

Eight cells and eight nuclei

Seven cells and seven nuclei

Correct Answer : Seven cells and eight nuclei

Question : Double fertilisation in angiosperms involves:

Syngamy and triple fusion

Two successive syngamy events

Triple fusion only

Pollination and syngamy

Correct Answer : Syngamy and triple fusion

Question : The endosperm formed after triple fusion in a typical angiosperm is initially:

Haploid

Diploid

Triploid

Tetraploid

Correct Answer : Triploid

Question : Which part of the root is mainly responsible for the absorption of water and minerals from the soil?

Root cap

Region of meristematic activity

Region of elongation

Region of maturation

Correct Answer : Region of maturation

Question : In a typical dicot stem, the vascular bundles are described as:

Radial and exarch

Conjoint, collateral and open

Conjoint, bicollateral and closed

Radial and endarch

Correct Answer : Conjoint, collateral and open

Question : Which tissue provides mechanical strength to young growing plant parts?

Parenchyma

Collenchyma

Chlorenchyma

Aerenchyma

Correct Answer : Collenchyma

Question : Which of the following xylem elements is living at maturity?

Vessel

Tracheid

Xylem fibre

Xylem parenchyma

Correct Answer : Xylem parenchyma

Question : The secondary growth in dicot roots is mainly brought about by the activity of:

Apical meristem and protoderm

Vascular cambium and cork cambium

Intercalary meristem and phellogen

Pericycle and epidermis only

Correct Answer : Vascular cambium and cork cambium

Question : Which tissue forms the protective outer covering of young plant organs?

Epidermis

Phloem

Endodermis

Pericycle

Correct Answer : Epidermis

Question : Lenticels are primarily involved in:

Translocation of food

Gaseous exchange

Absorption of minerals

Secondary thickening of roots

Correct Answer : Gaseous exchange

Question : Which of the following is correctly matched with its function?

Xylem — transport of organic food

Phloem — transport of organic solutes

Collenchyma — conduction of water

Sclerenchyma — photosynthesis

Correct Answer : Phloem — transport of organic solutes

Question : If a plant cell has a solute potential of −0.8 MPa and a pressure potential of +0.3 MPa, its water potential is:

−1.1 MPa

−0.5 MPa

+0.5 MPa

+1.1 MPa

Correct Answer : −0.5 MPa

Question : Root pressure is most likely to be observed when:

Transpiration is extremely high

Soil is dry

Transpiration is low and soil water is readily available

Stomata remain permanently open

Correct Answer : Transpiration is low and soil water is readily available

Question : Which phenomenon explains the movement of water molecules through a selectively permeable membrane from higher water potential to lower water potential?

Diffusion

Osmosis

Active transport

Imbibition

Correct Answer : Osmosis

Question : Which statement about transpiration is correct?

It occurs only through stomata

It helps in the ascent of water through the xylem

It always decreases mineral absorption

It occurs only during darkness

Correct Answer : It helps in the ascent of water through the xylem

Question : The proton gradient required for ATP synthesis during photosynthesis is established across the:

Outer chloroplast membrane

Thylakoid membrane

Inner mitochondrial membrane

Nuclear membrane

Correct Answer : Thylakoid membrane

Question : In non-cyclic photophosphorylation, the final electron acceptor is:

Water

Oxygen

NADP⁺

RuBP

Correct Answer : NADP⁺

Question : Which of the following correctly describes the Z-scheme of photosynthetic electron transport?

Electrons move from Photosystem I to water only

Electrons are excited twice during non-cyclic electron flow

Only Photosystem II participates

ATP is formed without electron transport

Correct Answer : Electrons are excited twice during non-cyclic electron flow

Question : If a C3 plant and a C4 plant are exposed to high temperature and intense light, the C4 plant generally shows greater photosynthetic efficiency because it:

Lacks chloroplasts in mesophyll cells

Has a mechanism that concentrates CO₂ around RuBisCO

Uses oxygen as the primary carbon source

Does not require ATP during carbon fixation

Correct Answer : Has a mechanism that concentrates CO₂ around RuBisCO

Question : Which compound is regenerated at the end of the Calvin cycle?

3-phosphoglycerate

Triose phosphate

RuBP

Oxaloacetate

Correct Answer : RuBP

Question : For the fixation of 3 molecules of CO₂ in the Calvin cycle, the number of turns of the cycle required is:

1

2

3

6

Correct Answer : 3

Question : Which of the following is an amphibolic pathway?

Glycolysis

Krebs cycle

Fermentation

Photophosphorylation

Correct Answer : Krebs cycle

Question : Under anaerobic conditions in yeast, pyruvate is converted into:

Lactate only

Ethanol and CO₂

Acetyl-CoA and CO₂

Oxaloacetate and CO₂

Correct Answer : Ethanol and CO₂

Question : During glycolysis, the net gain from one molecule of glucose is:

2 ATP and 2 NADH

4 ATP and 4 NADH

2 ATP and 4 NADH

4 ATP and 2 FADH₂

Correct Answer : 2 ATP and 2 NADH

Question : Which molecule enters the Krebs cycle after oxidative decarboxylation of pyruvate?

Pyruvate

Acetyl-CoA

Oxaloacetate

Lactate

Correct Answer : Acetyl-CoA

Question : The respiratory quotient of an organism utilizing fats as the major respiratory substrate is generally:

Equal to 1

Greater than 1

Less than 1

Always zero

Correct Answer : Less than 1

Question : Which plant growth regulator is associated with stress responses and induction of seed dormancy?

Auxin

Cytokinin

Abscisic acid

Gibberellin

Correct Answer : Abscisic acid

Question : Which hormone is widely used to induce rooting in stem cuttings?

Auxin

Ethylene

Abscisic acid

Cytokinin

Correct Answer : Auxin

Question : Which of the following effects is associated with ethylene?

Promotion of apical dominance

Fruit ripening

Stimulation of cell division in roots

Inhibition of abscission

Correct Answer : Fruit ripening

Question : A plant hormone is applied to a rosette plant and causes rapid elongation of the internodes, resulting in bolting. The hormone is most likely:

Gibberellin

Cytokinin

Abscisic acid

Ethylene

Correct Answer : Gibberellin

Question : The phenomenon in which a plant responds to the relative duration of day and night to initiate flowering is:

Vernalisation

Phototropism

Photoperiodism

Geotropism

Correct Answer : Photoperiodism

Question : Vernalisation is particularly useful in promoting flowering in certain plants by exposure to:

High temperature

Low temperature

Continuous darkness

High salinity

Correct Answer : Low temperature

Question : Which of the following is a major function of cytokinins?

Promotion of cell division

Induction of stomatal closure

Promotion of fruit ripening

Inhibition of cell division

Correct Answer : Promotion of cell division

Question : In a typical angiosperm pollen grain, the generative cell ultimately gives rise to:

One egg cell

Two male gametes

Two synergids

Three antipodal cells

Correct Answer : Two male gametes

Question : Which layer of the anther wall helps in the dehiscence of the anther at maturity?

Epidermis

Endothecium

Middle layers

Tapetum

Correct Answer : Endothecium

Question : The tapetum of the anther is mainly concerned with:

Protection of the ovule

Nutrition of developing pollen grains

Formation of the seed coat

Formation of the embryo

Correct Answer : Nutrition of developing pollen grains

Question : In an angiosperm, the pollen tube usually enters the ovule through the:

Chalaza

Micropyle

Funicle

Integument

Correct Answer : Micropyle

Question : Which cells of the mature embryo sac are located at the micropylar end?

Three antipodals

Two polar nuclei

Egg apparatus

Central cell only

Correct Answer : Egg apparatus

Question : The two polar nuclei present in the central cell of a typical embryo sac are formed by:

Fusion of the two synergids

Fusion of the three antipodals

Fusion of the two polar nuclei after their migration

Division of the egg cell

Correct Answer : Fusion of the two polar nuclei after their migration

Question : Apomixis is best described as:

Formation of fruits without fertilisation

Formation of seeds without fertilisation

Fusion of two male gametes

Development of pollen grains without meiosis

Correct Answer : Formation of seeds without fertilisation

Question : Polyembryony refers to the occurrence of:

More than one embryo in a seed

More than one seed in a fruit

More than one pollen grain in an anther

More than one ovule in an ovary

Correct Answer : More than one embryo in a seed

Question : Which part of a typical dicot seed develops into the seed coat?

Endosperm

Integuments

Nucellus

Embryo

Correct Answer : Integuments

Question : In a monocot seed such as maize, the single cotyledon is called:

Scutellum

Coleoptile

Coleorhiza

Pericarp

Correct Answer : Scutellum

Question : During seed germination, the first structure to emerge from a typical seed is generally the:

Plumule

Radicle

Cotyledon

Hypocotyl

Correct Answer : Radicle

Question : Which of the following is a characteristic feature of meristematic cells?

Large central vacuole

Dense cytoplasm and prominent nucleus

Extensive intercellular spaces

Dead protoplasm

Correct Answer : Dense cytoplasm and prominent nucleus

Question : In a typical monocot root, the number of xylem poles is generally:

Two

Three

Four

More than six

Correct Answer : More than six

Question : Which tissue is responsible for the conduction of organic food in plants?

Xylem

Phloem

Collenchyma

Sclerenchyma

Correct Answer : Phloem

Question : Which of the following is NOT a component of the vascular tissue system?

Xylem

Phloem

Pericycle

Companion cells

Correct Answer : Pericycle

Question : The vascular bundles of a typical monocot stem are:

Open because cambium is present

Closed because cambium is absent

Radial because xylem and phloem alternate

Bicollateral because two cambial strips are present

Correct Answer : Closed because cambium is absent

Question : In a dicot leaf, the vascular bundles are generally surrounded by:

Bundle sheath

Endodermis

Pericycle

Cork

Correct Answer : Bundle sheath

Question : Which modification of roots provides additional support to the stem in maize?

Prop roots

Pneumatophores

Storage roots

Tuberous roots

Correct Answer : Prop roots

Question : Pneumatophores are specialized roots commonly found in plants growing in:

Deserts

Marshy and waterlogged areas

Mountain regions

Freshwater lakes only

Correct Answer : Marshy and waterlogged areas

Question : The tendrils of pea are modifications of:

Roots

Leaves

Stems

Inflorescences

Correct Answer : Leaves

Question : The thorn of Bougainvillea is a modification of:

Leaf

Root

Stem

Stipule

Correct Answer : Stem

Question : Which type of venation is typically found in monocot leaves?

Reticulate

Parallel

Dichotomous

Furcate

Correct Answer : Parallel

Question : In an isobilateral leaf, stomata are generally present:

Only on the upper surface

Only on the lower surface

On both surfaces

Only along the midrib

Correct Answer : On both surfaces

Question : Which of the following is a correct example of a simple leaf?

Neem

Pea

Guava

Acacia

Correct Answer : Guava

Question : In a compound leaf, the axillary bud is present:

At the base of every leaflet

In the axil of the whole leaf

At the tip of every leaflet

Only on the petiole of each leaflet

Correct Answer : In the axil of the whole leaf

Question : Which floral whorl is directly involved in the production of pollen grains?

Calyx

Corolla

Androecium

Gynoecium

Correct Answer : Androecium

Question : A flower having both stamens and carpels is called:

Unisexual

Bisexual

Neuter

Asexual

Correct Answer : Bisexual

Question : A flower in which the gynoecium occupies the highest position while other floral parts are below it is:

Hypogynous

Perigynous

Epigynous

Zygomorphic

Correct Answer : Hypogynous

Question : Which placentation is characteristic of tomato?

Marginal

Axile

Parietal

Basal

Correct Answer : Axile

Question : In marginal placentation, the ovules are borne:

On the central axis

Along the ventral suture of a single carpel

On the inner wall of a multilocular ovary

At the base of the ovary

Correct Answer : Along the ventral suture of a single carpel

Question : Which of the following represents a valvate aestivation?

Petals overlap one another regularly

One margin overlaps the next and so on

Margins of adjacent petals touch but do not overlap

Two petals completely enclose the remaining petals

Correct Answer : Margins of adjacent petals touch but do not overlap

Question : Which part of the flower develops into the fruit after fertilisation?

Ovule

Ovary

Anther

Stigma

Correct Answer : Ovary

Question : Which part of the ovule develops into the seed coat?

Nucellus

Integuments

Embryo sac

Funicle

Correct Answer : Integuments

Question : In most angiosperms, the endosperm develops before:

Pollination

Fertilisation

Embryo development

Formation of pollen grains

Correct Answer : Embryo development

Question : Which of the following is a characteristic feature of a dicot embryo?

One cotyledon

Two cotyledons

No plumule

Absence of radicle

Correct Answer : Two cotyledons

Question : During germination of a hypogeal seed, the cotyledons:

Are carried above the soil surface

Remain below the soil surface

Always become photosynthetic leaves

Develop directly into roots

Correct Answer : Remain below the soil surface

Question : Which process involves the movement of pollen grains from the anther to the stigma of the same flower?

Cross-pollination

Self-pollination

Fertilisation

Apomixis

Correct Answer : Self-pollination

Question : Which adaptation is commonly associated with wind-pollinated flowers?

Large and brightly coloured petals

Production of abundant lightweight pollen

Strong fragrance and nectar

Sticky pollen grains

Correct Answer : Production of abundant lightweight pollen

Question : The phenomenon in which pollen grains of the same species are transferred from one flower to another flower is:

Autogamy

Geitonogamy

Apomixis

Parthenocarpy

Correct Answer : Geitonogamy

Question : Which of the following is an outbreeding device that prevents self-pollination by maturation of anthers and stigma at different times?

Herkogamy

Dichogamy

Self-incompatibility

Monoecy

Correct Answer : Dichogamy

Question : Fusion of one male gamete with the egg cell results in the formation of:

Endosperm

Zygote

Primary endosperm cell

Pollen tube

Correct Answer : Zygote

Question : If the chromosome number of the egg cell is 10, the chromosome number of the primary endosperm nucleus after triple fusion will be:

10

20

30

40

Correct Answer : 30

Question : Which of the following correctly describes triple fusion?

Fusion of two eggs with one male gamete

Fusion of one male gamete with two polar nuclei

Fusion of two male gametes with the egg

Fusion of two synergids with one male gamete

Correct Answer : Fusion of one male gamete with two polar nuclei

Question : Which of the following is an example of a non-endospermic seed at maturity?

Castor

Maize

Pea

Coconut

Correct Answer : Pea

Question : The persistent nucellus found in some seeds is known as:

Perisperm

Pericarp

Testa

Tegmen

Correct Answer : Perisperm

Question : Which of the following is an example of a parthenocarpic fruit?

Seedless banana

Mango

Pea

Gram

Correct Answer : Seedless banana

Question : In tissue culture, the ability of a single plant cell to develop into a complete plant is called:

Plasticity

Totipotency

Ploidy

Heterosis

Correct Answer : Totipotency

Question : Which technique is most directly used for rapid multiplication of genetically identical plants under sterile conditions?

Hybridisation

Micropropagation

Mutation breeding

Cross-pollination

Correct Answer : Micropropagation

Question : In plant breeding, emasculation is performed primarily to:

Remove immature ovules

Prevent unwanted self-pollination

Increase seed dormancy

Induce polyploidy

Correct Answer : Prevent unwanted self-pollination

Question : Which of the following is an example of a biofertiliser?

Rhizobium

Penicillium

Yeast

Agaricus

Correct Answer : Rhizobium

Question : Mycorrhiza represents a symbiotic association between:

Algae and fungi

Fungi and roots

Bacteria and leaves

Viruses and roots

Correct Answer : Fungi and roots

Question : Which of the following is the correct sequence of zones in a root from the root cap toward the mature region?

Zone of maturation → zone of elongation → zone of cell division

Zone of cell division → zone of elongation → zone of maturation

Zone of elongation → zone of maturation → zone of cell division

Zone of maturation → zone of cell division → zone of elongation

Correct Answer : Zone of cell division → zone of elongation → zone of maturation

Question : Which type of meristem is present at the bases of internodes in grasses and enables regrowth after grazing?

Apical meristem

Lateral meristem

Intercalary meristem

Secondary meristem

Correct Answer : Intercalary meristem

Question : Which of the following is a characteristic feature of heartwood?

It is actively involved in water conduction

It is lighter in colour than sapwood

It consists of older, non-functional secondary xylem

It contains abundant living xylem parenchyma

Correct Answer : It consists of older, non-functional secondary xylem

Question : During secondary growth, cork cambium produces:

Secondary xylem inward and secondary phloem outward

Phellem outward and phelloderm inward

Phelloderm outward and phellem inward

Only secondary phloem

Correct Answer : Phellem outward and phelloderm inward

Question : Which of the following statements about stomata is correct?

Guard cells of dicots are generally dumbbell-shaped

Guard cells of grasses are generally kidney-shaped

Guard cells regulate the opening and closing of stomata

Stomata are present only on roots

Correct Answer : Guard cells regulate the opening and closing of stomata

Question : The cohesion between water molecules is mainly due to:

Ionic bonds

Hydrogen bonds

Peptide bonds

Glycosidic bonds

Correct Answer : Hydrogen bonds

Question : Which factor directly decreases the rate of transpiration?

High temperature

High wind velocity

High atmospheric humidity

Low atmospheric humidity

Correct Answer : High atmospheric humidity

Question : Which of the following is a correct distinction between diffusion and active transport?

Diffusion always requires ATP

Active transport occurs only through cell walls

Diffusion occurs down a concentration gradient, whereas active transport can occur against it

Active transport never involves membrane proteins

Correct Answer : Diffusion occurs down a concentration gradient, whereas active transport can occur against it

Question : The first stable product formed during CO₂ fixation in a C4 plant is:

3-phosphoglycerate

Oxaloacetic acid

RuBP

Glucose

Correct Answer : Oxaloacetic acid

Question : Which of the following combinations correctly represents the products of the light-dependent reactions of photosynthesis?

ATP, NADPH and O₂

Glucose, ATP and CO₂

NADP⁺, ADP and O₂

RuBP, NADPH and CO₂

Correct Answer : ATP, NADPH and O₂

Question : If a plant is supplied with radioactive carbon dioxide containing ¹⁴C, the label would first appear in the products of:

Photolysis of water

Carbon fixation

Photophosphorylation

Electron transport

Correct Answer : Carbon fixation

Question : Which of the following statements about photorespiration is correct?

It is highest in C4 plants

It involves chloroplasts, peroxisomes and mitochondria

It produces large amounts of ATP

It occurs only in complete darkness

Correct Answer : It involves chloroplasts, peroxisomes and mitochondria

Question : In mitochondrial oxidative phosphorylation, ATP synthase uses:

A proton gradient

A sodium gradient only

A glucose gradient

An oxygen gradient

Correct Answer : A proton gradient

Question : Which of the following produces carbon dioxide during aerobic respiration?

Glycolysis

Oxidative phosphorylation

Pyruvate oxidation and Krebs cycle

Photophosphorylation

Correct Answer : Pyruvate oxidation and Krebs cycle

Question : If the oxygen supply to a respiring plant cell is suddenly stopped, which process can continue for a short period to generate ATP?

Krebs cycle

Electron transport chain

Glycolysis

Oxidative decarboxylation

Correct Answer : Glycolysis

Question : Which plant hormone is primarily responsible for maintaining apical dominance?

Cytokinin

Auxin

Ethylene

Abscisic acid

Correct Answer : Auxin

Question : A farmer wants to induce seedless fruits without fertilisation. Which phenomenon is most relevant?

Vernalisation

Parthenocarpy

Photoperiodism

Apomixis

Correct Answer : Parthenocarpy

Question : Which plant growth regulator is commonly used to overcome apical dominance and promote lateral bud growth?

Auxin

Cytokinin

Abscisic acid

Ethylene

Correct Answer : Cytokinin

Question : A plant is exposed to a day length that is shorter than its critical photoperiod and flowers only under these conditions. It is most likely a:

Long-day plant

Short-day plant

Day-neutral plant

Long-night insensitive plant

Correct Answer : Short-day plant

Question : Which of the following is an example of a day-neutral plant?

Wheat

Soybean

Tomato

Rice

Correct Answer : Tomato

Question : In a typical angiosperm, the microspore mother cell is:

Haploid

Diploid

Triploid

Tetraploid

Correct Answer : Diploid

Question : Which structure of the pollen grain gives rise to the pollen tube?

Generative cell

Vegetative cell

Endothecium

Tapetum

Correct Answer : Vegetative cell

Question : Self-incompatibility in flowering plants is a mechanism that:

Promotes self-fertilisation

Prevents genetically similar pollen from effecting fertilisation

Prevents formation of pollen grains

Causes seed dormancy

Correct Answer : Prevents genetically similar pollen from effecting fertilisation

Question : Which of the following is NOT a component of the egg apparatus in a typical embryo sac?

Egg cell

Two synergids

Three antipodals

None of the above

Correct Answer : Three antipodals

Question : The ploidy of the cells in the endosperm of a typical angiosperm is:

Haploid

Diploid

Triploid

Tetraploid

Correct Answer : Triploid

Question : Which of the following structures protects the plumule in a monocot embryo?

Coleorhiza

Scutellum

Coleoptile

Endosperm

Correct Answer : Coleoptile

Question : Which of the following is correctly matched?

Perisperm — persistent nucellus

Testa — inner integument only

Scutellum — root cap

Coleoptile — protects radicle

Correct Answer : Perisperm — persistent nucellus

Question : In apomixis, progeny are generally genetically similar to the parent because:

Meiosis is always followed by cross-fertilisation

Seed formation occurs without normal fertilisation

Two genetically unrelated gametes fuse

Only pollen grains undergo mutation

Correct Answer : Seed formation occurs without normal fertilisation

Question : Which of the following is an important advantage of micropropagation?

Production of genetically variable plants only

Rapid multiplication of disease-free plants

Prevention of all mutations

Elimination of photosynthesis

Correct Answer : Rapid multiplication of disease-free plants

Question : A plant breeder removes the anthers from a bisexual flower before they release pollen and then applies pollen from a selected plant. This procedure is:

Bagging only

Emasculation followed by artificial pollination

Apomixis

Vegetative propagation

Correct Answer : Emasculation followed by artificial pollination