Q1: The plant hormone which is essential for cell
division is
(a) Ethylene
(b) Auxin
(c) Gibberellin
(d) Cytokinin
Answer: (d) Cytokinin
Q2: The activities of the internal organs are
controlled by the
(a) Central Nervous System
(b) Peripheral Nervous System
(c) Autonomic Nervous System
(d) None of these
Answer: (a) Central Nervous System
Q3: The seat of intelligence and voluntary action in
the brain is
(a) Diencephalon
(b) Cerebrum
(c) Cerebellum
(d) Medulla Oblongata
Answer: (b) Cerebrum
Q4: The gap between two neurons is known as ___ .
(a) synapse
(b) synopsis
(c) impulse
(d) synaptic node
Answer: (a) synapse
Q5: Which of the following is a plant hormone?
(a) Thyroxin
(b) Cytokinin
(c) Insulin
(d) Oestrogen
Answer: (b) Cytokinin
Q6: Tropic movements are
(a) in response to light
(b) in response to gravity
(c) uni-directional
(d) non-directional
Answer: (c) uni-directional
Q7: Artifical ripening of fruit is carried out by
(a) Auxins
(b) Ethylene
(c) Abscisic acid (ABA)
(d) Gibberellins
Answer: (b) Ethylene
Q8: Part of brain that controls respiration,
heartbeat and peristalsis is ____.
(a) Cerebrum
(b) Cerebellum
(c) Pons
(d) Medulla
Answer: (d) Medulla
Q9: The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
Answer: (d) All of the above.
Q10: Which of the following hormone is released by
thyroid?
(a) Insulin
(b) Thyroxin
(c) Trypsin
(d) Pepsin
Answer: (b) Thyroxin
Q11: Which body organ is surrounded by meninges?
(a) Heart and Lungs
(b) Brain & Heart
(c) Brain and Spinal Cord
(d) Spinal Cord and Lungs
Answer: (c) Brain and Spinal Cord
Q12: Part of brain that controls muscular co-
ordination is ____.
(a) Cerebrum
(b) Cerebellum
(c) Pons
(d) Medulla
Answer: (b) Cerebellum
Q13: Growth of the stem is controlled by
(a) gibberellin
(b) auxin
(c) abscisic acid
(d) cytokinin
Answer: (a) gibberellin
Q14: Wilting of leaves is caused by which hormone?
(a) gibberellin
(b) auxin
(c) abscisic acid
(d) cytokinin
Answer: (c) abscisic acid
Q15: Which of the following hormones contains
iodine?
(a) adrenaline
(b) testosterone
(c) thyroxine
(d) insulin
Answer: (c) thyroxine
Q16: Which part of brain controls the posture and
balance of the body?
(a) Cerebrum
(b) Cerebellum
(c) Pons
(d) Medulla
Answer: (b) Cerebellum
Q19: Fill in the blanks.
(a) _____ is the is the structural and functional unit of
the nervous system.
(b) An automatic response to a stimulus which is not
controlled by the brain is called ______.
(c) Chemical messengers which control and coordinate
in plants and animals are called _____.
(d) The movement of a plant part in the direction of
light is called ____.
(e) ________ is the movement of plant part in response
to the availability of water.
(f) ________ is the movement of plant part in response to
the pull of earth’s gravity
(g) The movement of plant part in response to certain
chemicals is called ______.
(h) _________ is the reflex centre of the brain.
(i) __________ is a structure associated with both
nervous system and endocrine system.
Answer:
(a) Neuron or Nerve cell
(b) Reflex Action
(c) Hormones
(d) Phototropism
(e) Hydrotropism
(f) Geotropism
(g) Chemotropism
(h) Medulla Oblongata
(i) Hypothalmus
Q20: What happens at the
synapse between two neurons?
Answer: Synapse is a very small
gap between the last portion of
axon of one neuron and the
dendron of the other neuron. It
acts as a one way valve to transmit
impulses. This is one directional
flow of impulses because the
chemicals are produced only on
one side of the neuron i.e., the
axon’s side. Via axon, the impulses
travel across the synapse to the
dendron of the other neuron.
In toto, synapse performs the following tasks:
1. It allows the information to pass from one neuron to
another.
2. It ensures the passage of nerve impulse in one direction
only.
3. It helps in information processing by combining the
effects of all impulses received.
Watch the you tube video explaining what is the
Synapse structure and how it functions.
Q21: Which part of the brain maintains posture and
equilibrium of the body?
Answer: Cerebellum.
Q22: How do we detect the smell of an agarbatti
(incense stick)?
Answer: The fore-brain is the main thinking part of the
brain. It has regions which receive sensory impulses
from various receptors. Separate areas of the fore-brain
are specialised for hearing, smell, sight and so on.
Olfactoreceptors (present in nose) send the information
about the smell of incense stick to fore-brain. The for-
brain interprets it along with with information received
from other receptors as well as with information that is
already stored in the brain
Q23: List the functions performed by Cerebrum.
Answer: The cerebrum performs the following
functions:
1. It governs our mental abilities like thinking, reasoning,
learning, memorising etc.
2. It controls our feelings, emotions and speech.
3. It controls all involuntary functions.
Q24: Which is the largest and most prominent part
of the brain.
Answer: Cerebrum
Q25: What are the functions of cerebellum?
Answer:
1. Maintains equilibrium or balance of the body.
2. Coordinates muscular movement.
3. Controls posture of the body.
Q26: How brain is protected inside a human body?
Answer: Brain is protected by a bony box called
cranium, within which are present 3 layers of fluid-
filled (called cerebrospinal fluid) membranes (called
meninges) for absorbing shock and buoyancy
Q27: What is the role of the brain in reflex action?
Answer: Brain has no role to play in creation of reflex
action response. Instead spinal cord is the control
centre of a reflex action. In fact brain becomes aware
after the reflex arc has been formed.
Q28: What do you mean by reflex action? Give
examples of reflex actions?
Answer: It is defined as fast, unconscious, immediate,
automatic and involuntary response of the body
(through effectors) to a stimulus. It is monitored
through spinal cord.
Examples of reflex actions:
1. Closing eyes when bright light falls on the eyes.
2. Knee-jerk
3. Withdraw Hands when pricked by a pin.
4. Choking stimulates cough reflex
5. Withdraw hand or leg when it touches an hot object.
6. Women knitting a sweater while watching TV
(conditioned reflex).
Q29: What are the different types of reflexes?
Answer: There are two types of reflexes:
Unconditioned reflexes
Conditioned reflexes
Unconditioned or Unconditional reflexes are those
which are inherited. Our brain does not learn these
reflexes. E.g. when we touch a hot plate, we
immediately moves away our hand.
Conditioned reflexes are those which our brain has
learned by repeating the action number of times. e.g. a
typist is typing a letter without looking at the typewriter
keys.
Q30: What is reflex arc?
Answer: The structural and functional unit that carries
our reflex action is called a reflex arc. It consists of:
A receptor
sensory nerve (afferent)
Spinal Cord and Inter-neuron
motor nerve (efferent)
effector
Q31: What are plant hormones?
Answer: Plant hormones or phytohormones are
naturally-occurring organic substances used as chemical
coordinators in plants. These are synthesized in one
part of the plant body (in minute quantities) and are
translocated to other parts when required.
The five major types of phytohormones are:
auxins: promote cell division, bending of shoot towards
the source of light.
gibberellins : stimulate stem elongation.
cytokinins : promote cell division.
abscisic acid: inhibit growth ,closing of stomata ,seed
dormancy.
ethylene( gas hormone): promotes fruit ripening and
growth.
Q32: Who coined the term phytohormones?
Answer: Thimann in 1948.
Q33: How is the movement of leaves of the
sensitive plant different from the movement of a
shoot towards light?
Answer: The movement of leaves of the sensitive plant,
(e.g. Mimosa pudica or touch-me-not) occurs in
response to touch or contact stimuli. It is a growth
independent movement (nastic movement).
The movement of shoot towards light is called photo-
tropism. This type of movement is directional and is
growth dependent
Q35: What will happen when plant is exposed to
unidirectional light?
Answer: Stem bends towards unidirectional flow of
light. It is called phototropism.
Q36 What is chemotropism?
Answer: Directional movement of a plant/ or its part in
response to chemicals is called chemotropism. e.g.
growth of the pollen tube towards the ovule is a
chemotropic movement due to which fertilization of
flower takers place.
Q37: Give examples of geotropism.
Answer:
1. Roots move in the direction of gravity (positive +ve
getropism)
2. Shoots move (up) against direction of gravity (negative -
v geotropism
I
Q38: Why do mammals like humans need an
endocrinal system?
or
Q: What are the limitations of nervous system in
human body? How it is overcome?
Answer: Nervous system in human body works or
communicates using nerve impulses which are form of
electrical impulses. Electrical impulses are an excellent
means of communication in human body but they have
following limitations:
1. They reach only those cells that are connected by
nervous tissue, not each and every cell
in the animal body.
2. Cells cannot continually create and transmit electrical
impulses. once an electrical impulse is generated in a
cell and transmitted, the cell will take some time to reset
its mechanisms before it can generate and transmit a
new impulse.
Due to above said limitations most multicellular
organisms use another means of communication
between cells, namely, chemical communication i.e.
hormone or endocrine system. It is slower than nerve
cells but potentially reach all cells of the body.
Q39(NCERT): How does chemical coordination take
place in animals?
Answer: Hormones act as chemical coordinators in
animals. Hormone is the chemical messenger that
regulates the physiological processes in living
organisms. It is secreted by ductless glands into blood
stream and reach their target site.
Q40: Who coined the term hormone?
Answer: Bayliss and Starling. Both of discovered the
peptide hormone called secretin in human intestine.
Q41(CBSE 2010): What will happen if intake of
iodine in our diet is low?
or
Q: Why is the use of iodised salt advised?
Answer: It is advised to used iodised salt to prevent
goitre (enlargement of the thyroid gland). Iodine is
required for the proper functioning of thyroid. Iodine
stimulates the thyroid gland to produce thyroxin
hormone. This hormone regulates carbohydrate, fat,
and protein metabolism in our body.
Q42(CBSE 2010): Name the hormone secreted by an
endocrine gland during emergency? Name the
gland which secretes this hormone.
Answer: Adrenaline hormone is secreted by the adrenal
glands. It helps to regulate heart beat, blood pressure,
metabolism in the times of stress or emergency to cope
up with the situation.
Q43: How does adrenaline affects heart during
emergency?
or
Q(NCERT): How does our body respond when
adrenaline is secreted into the blood?
Answer: During emergency situations, adrenaline
hormone is released to blood stream in large quantities.
It increases the heartbeat and hence supplies more
oxygen to the muscles. The increase in breathing rate
also increases due to contractions of diaphragm and rib
muscles. It raises the blood pressure and thus enable
the body to cope up with any stress or emergency.
Q44 : Which hormone is injected to a
diabetic patient and why?
or
Q(NCERT): Why are some patients of diabetes
treated by giving injections of insulin?
Answer: Diabetes is a condition in which sugar level in
blood is very high. Insulin hormone is released by
pancreas glands which regulates the blood sugar level.
In diabetic patients, pancreas has stopped releasing
insulin hormone. If it is not secreted in proper
amounts, the sugar level in the blood rises causing
many harmful effects. Due to this reason diabetic
patients are treated by giving injections of insulin.
Q45 How does our body maintain
blood sugar level?
Answer: The timing and amount of hormone released
are regulated by feedback mechanisms. When the sugar
levels in blood rise, they are detected by the cells of the
pancreas which respond by producing more insulin. As
the blood sugar level falls, insulin secretion is reduced.
Q46: Where adrenal glands are located?
Answer: Adrenal glands are like caps just above the
kidneys.
Q47: What is hyperglycemia?
Answer: Hyperglycemia refers to high sugar level in
blood. In general diabetic patients has hyperglycemia
due to insufficient release of insulin hormone.
Q48: Where thyroid gland is located?
Answer: Thyroid gland is situated in front of the neck
below larynx
Q49: Which endocrine gland is called master
gland? Why?
Answer: Pituitary gland (pea shape, present in mid-
brain) is considered as master endocrine gland. It is
said so because it controls almost all other endocrine
glands.
Q50: Why is pancreas a dual gland?
Answer: Pancreas is a dual gland because it acts as both
endocrine and exocrine gland. As endocrine it secretes
hormones like insulin, glucagen. As an exocrine glands,
it releases enzymes like trypsin, lypase, amylase etc.
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