biology MCQs - 12th class Chapter 03 Mcqs

1

The condition in plants grown without light, where they become long and fail to form chlorophyll, is called?

A

Chlorosis

B

Etiolation

C

Callus formation

D

Galls

2

Biorhythms that occur with a periodicity of about 24 hours are known as?

A

Circannual

B

Circadian

C

Endogenous

D

Exogenous

3

Which synthetic auxin is used as a selective weed killer for broad-leaved species?

A

NAA

B

Indole propionic acid

C

IAA

D

2,4 D

4

Which plant hormone promotes 'bolting' in some rosette plants?

A

Auxin

B

Gibberellin

C

Cytokinin

D

Abscisic acid

5

The promotion of stomatal closing under water stress is a function of which hormone?

A

Ethene

B

Cytokinin

C

Abscisic acid

D

Gibberellin

6

Receptors that detect stimuli of touch, pressure, hearing, and equilibrium are called?

A

Chemoreceptors

B

Photoreceptors

C

Thermoreceptors

D

Mechanoreceptors

7

Undifferentiated nerve endings that produce the sensation of pain are known as?

A

Nociceptors

B

Meissner's corpuscles

C

Pacinian corpuscles

D

Thermoreceptors

8

Which cells in the nervous system play a vital role in the nutrition and protection of neurons?

A

Sensory neurons

B

Motor neurons

C

Neuroglia

D

Associative neurons

9

Groups of ribosomes associated with rough ER in a neuron's cell body are called?

A

Dendrites

B

Axons

C

Neurofibrils

D

Nissl's granules

10

The pathway of passage of an impulse during a reflex action is called a?

A

Nerve impulse

B

Synapse

C

Reflex arc

D

Motor pathway

11

In a resting neuron, the concentration of which ion is tenfold higher outside the cell than inside?

A

Potassium (K+)

B

Sodium (Na+)

C

Chloride (Cl-)

D

Calcium (Ca++)

12

The resting membrane potential of a typical neuron is approximately?

A

-50mV

B

+70mV

C

-70mV

D

+50mV

13

During an action potential, the inner membrane surface becomes more positive due to the influx of which ions?

A

Potassium (K+)

B

Sodium (Na+)

C

Chloride (Cl-)

D

Organic ions

14

The jumping of a nerve impulse from one node of Ranvier to another in myelinated neurons is called?

A

Active transport

B

Saltatory impulse

C

Synaptic transmission

D

Resting potential

15

The normal speed of a nerve impulse in humans is about?

A

50 meters per second

B

100 meters per second

C

150 meters per second

D

200 meters per second

16

Which of these is the main neurotransmitter for synapses that lie outside the central nervous system?

A

Dopamine

B

Serotonin

C

Adrenaline

D

Acetylcholine

17

Which animal exhibits a diffused nervous system consisting of a nerve network?

A

Planaria

B

Human

C

Hydra

D

Earthworm

18

The part of the human brain responsible for controlling automatic functions like breathing and heart rate is the?

A

Cerebellum

B

Medulla

C

Thalamus

D

Cerebrum

19

The limbic system in the human brain is primarily involved in producing?

A

Voluntary movements

B

Logical reasoning

C

Emotions and drives

D

Sensory interpretation

20

The part of the brain that plays an important role in the formation of long-term memory is the?

A

Amygdala

B

Hypothalamus

C

Hippocampus

D

Pons

21

The left cerebral hemisphere controls which side of the body?

A

The left side

B

The right side

C

Both sides equally

D

The lower part

22

The cerebellum is best developed in which animal, reflecting its role in complex flight activity?

A

Fish

B

Frog

C

Bird

D

Snake

23

How many pairs of cranial nerves arise from the brain in humans?

A

12

B

24

C

31

D

62

24

The part of the autonomic nervous system associated with 'fight or flight' responses is the?

A

Somatic system

B

Parasympathetic system

C

Sympathetic system

D

Central nervous system

25

Parkinson's disease is believed to be caused by cell death in a brain area that produces which neurotransmitter?

A

Serotonin

B

Acetylcholine

C

Dopamine

D

Adrenaline

26

Which nervous disorder is characterized by abrupt transient symptoms of a motor or sensory nature, often with changes in consciousness?

A

Alzheimer's disease

B

Epilepsy

C

Parkinson's disease

D

Dementia

27

The action of nicotine mimics which neurotransmitter, making it a stimulant of nerve impulse?

A

Dopamine

B

GABA

C

Serotonin

D

Acetylcholine

28

Hormones like insulin and glucagon are chemically classified as?

A

Steroids

B

Amino acid derivatives

C

Polypeptides

D

Proteins

29

Oxytocin and ADH are produced in the hypothalamus and stored in the?

A

Anterior pituitary

B

Median lobe of pituitary

C

Posterior pituitary

D

Thyroid gland

30

Which hormone from the anterior pituitary stimulates milk production?

A

FSH

B

LH

C

Prolactin

D

TSH

31

Excess secretion of MSH (Melanophore stimulating hormone), as in Addison's disease, causes?

A

Lightening of the skin

B

Darkening of the skin

C

Increased hair growth

D

Loss of weight

32

A lack of which hormone causes diabetes insipidus, characterized by dilute urine and great thirst?

A

Insulin

B

ADH (Vasopressin)

C

Glucagon

D

Aldosterone

33

Which disease is caused by excess thyroxine production, leading to exophthalmic goiter?

A

Cretinism

B

Myxoedema

C

Graves' disease

D

Addison's disease

34

Which hormone is antagonistic to parathormone and is involved in calcium metabolism?

A

Thyroxine

B

Calcitonin

C

Insulin

D

Cortisol

35

Failure to produce insulin leads to which condition?

A

Diabetes insipidus

B

Hypoglycaemia

C

Diabetes mellitus

D

Cushing's disease

36

Which hormone is produced by the adrenal medulla and dilates blood vessels in skeletal muscles during stress?

A

Aldosterone

B

Cortisol

C

Noradrenaline

D

Adrenaline

37

Destruction of the adrenal cortex leads to which condition?

A

Cushing's disease

B

Addison's disease

C

Graves' disease

D

Acromegaly

38

Which hormone is produced by the pyloric region of the stomach and stimulates gastric juice secretion?

A

Secretin

B

Gastrin

C

Oestrogen

D

Progesterone

39

Which hormone is a major constituent of birth control pills because it suppresses ovulation?

A

Oestrogen

B

FSH

C

LH

D

Progesterone

40

Testosterone is produced by which cells in the testes?

A

Seminiferous tubules

B

Germinal epithelium

C

Sertoli cells

D

Interstitial cells

41

Behaviour that is predetermined by the inheritance of specific nerve pathways is called?

A

Learned behaviour

B

Innate behaviour

C

Imprinting

D

Habituation

42

A directed movement either towards or away from a stimulus is known as?

A

Kinesis

B

Taxis

C

Reflex

D

Instinct

43

A specific part of a stimulus that elicits an instinctive response, like the red belly of a stickleback fish, is a?

A

Sign stimulus

B

Conditioned stimulus

C

IRM

D

Primary stimulus

44

The simplest form of learning that involves a decrease in response to a repeated stimulus is?

A

Imprinting

B

Habituation

C

Latent learning

D

Insight learning

45

Pavlov's experiments with dogs are a classic example of?

A

Operant conditioning

B

Conditioned reflex type I

C

Imprinting

D

Insight learning

46

Learning that occurs without any obvious reward, such as a rat learning a maze while wandering, is called?

A

Habituation

B

Latent learning

C

Operant conditioning

D

Insight learning

47

The type of learning demonstrated by a chimpanzee stacking boxes to reach fruit is?

A

Insight learning

B

Imprinting

C

Trial and error learning

D

Latent learning

48

The hormone that promotes apical dominance and fruit growth is?

A

Gibberellin

B

Cytokinin

C

Auxin

D

Ethene

49

The corpus callosum connects the?

A

Cerebrum and cerebellum

B

Two cerebral hemispheres

C

Thalamus and hypothalamus

D

Pons and medulla

50

Which part of the nervous system controls involuntary responses by influencing organs and glands?

A

Somatic Nervous System

B

Autonomic Nervous System

C

Central Nervous System

D

Sensory Nervous System