Control and Coordination — Class 10 Science PYQs

(D)/ Axonal end of one neuron to dendritic end of another neuron

(a) The timing and amount of hormone released are regulated by feedback mechanism. For example, if the sugar levels in the 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. (Any other suitable example) (2 Marks)
OR
(b)
* Electrical impulse reaches only those cells that are connected by nervous tissue, not each and every cell in the animal body. (1 Mark)
* Once an electrical impulse is generated in the cell and transmitted, the cell will take some time to reset its mechanism before it can generate and transmit a new impulse. / Transmission of electrical impulses is not a continuous process. (1 Mark)

(a) (i) Electrical impulses will reach only those cells that are connected by nervous tissue, not each and every cell in the animal body. (1 Mark)
(ii) 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 / cell cannot continuously create and transmit electrical impulses. (1 Mark)

(a)
Nephron
Neuron
(i) Filtration/Structural/
(i) Structural/ Functional unit
1
Functional unit of the kidney.
of the nervous system.
(ii) Filters nitrogenous wastes
(ii) Transmits information
from the blood.
from one part of the body
to another.
(any one, any other suitable difference)
(b)
Sensory Nerve
Motor Nerve
(i) Carries impulse from receptors
(i) Carries impulse from
1
to CNS/ Brain and Spinal cord.
CNS/Brain and Spinal cord
to the motor area/ effector
organ.
(any other suitable difference)
(c)
Consumers
Decomposers
(i) Organisms that feed on
(i) Organisms that breakdown
producers and other
dead organic matter into
1
consumers.
simpler inorganic
substances.
(ii) Transfers energy through the
(ii) Recycle nutrients back into
food chain.
the environment.
(any one, any other suitable difference)
3

Chewing of food
i) It is a voluntary action.
ii) It is controlled by forebrain. (1 Mark)
Salivation on sight of food
i) It is a reflex/involuntary action.
ii)It is controlled by medulla in the hind brain. (1 Mark)
(any other suitable difference)

• Reflex action (½ Mark)
• An automatic and quick response to a stimulus which does not involve thinking. (½ Mark)
• Stimulus $\rightarrow$ Receptor $\rightarrow$ sensory neuron $\rightarrow$ relay neuron (spinal cord) $\rightarrow$ Motor neuron $\rightarrow$ effector (muscle) response. (1 Mark)

(B) / Cerebellum (1 Mark)

(a) Actions which are controlled by forebrain / Actions which are under our control and are performed according to our will. (1 Mark)
(b) Cerebellum. (1 Mark)

(a) Actions which are controlled by forebrain / Actions which are under our control and are performed according to our will.
(b) Cerebellum.

(C)/ Hind Brain-Cerebellum

(A) / (i), (ii) and (iii) (1 Mark)

(a) Actions which are controlled by forebrain / Actions which are under our control and are performed according to our will.
(b) Cerebellum.

(A) / (i) and (iii) respectively
1
1

(C) / Chemotropism (1 Mark)

(D)/ Rapid cell division in tendril cells that are away from the support

(b)Tendrils of pea plant are sensitive to touch. When they come in contact with any support, the part of the tendril in contact with the object does not grow as rapidly as the part of the tendril away from the object. This causes the tendril to circle around the object and thus help in climbing the pea plant. (2 Marks)

(A) Promote cell division

(i) Cytokinin (½ Mark)
(ii) Abscisic acid/ ABA (½ Mark)
(iii) Auxin (½ Mark)
(iv) Abscisic acid/ ABA (½ Mark)

(a) Due to hydrotropism, the roots grow towards area of water availability so that they can absorb water and minerals. (1 Mark)
(b) Auxins promote cell elongation / Auxin regulates the tropic responses like bending (growth) of stem towards light. (1 Mark)
(c)
begin{tabular}{|l|l|}
hline
textbf{Movement by sensitive plants} &
textbf{Tropic Movements by plants}
hline
Non-directional & Directional
hline
Fast & Slow
hline
Growth independent movement & Growth related
hline
end{tabular} (Any two points and any other difference) (2 Marks)
(c)
begin{tabular}{|l|l|}
hline
textbf{Movement of Roots} &
textbf{Movement of Shoots}
hline
Gravity: Grows towards gravity / Positive geotropism & Gravity: Grows away from gravity / Negative geotropism
hline
Light: Grows away from light / Negative phototropism & Light: Grows towards light/ Positive phototropism
hline
end{tabular} (2 Marks)

(A)/ Pituitary gland (1 Mark)

(B) / Both A and R are correct but R is not the correct explanation for A (1)

(C)/ Pancreas (1 Mark)

Squirrel shows fight or flight response -Release of adrenaline, heart beats faster, more supply of oxygen to muscles (limb muscles), reduced blood supply to digestive system and skin, contraction of rib muscles and diaphragm, increased breathing rate. (2 Marks)

(a) The timing and amount of hormone released are regulated by feedback mechanism. For example, if the sugar levels in the 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. (Any other suitable example) (2 Marks)
OR
(b)
* Electrical impulse reaches only those cells that are connected by nervous tissue, not each and every cell in the animal body. (1 Mark)
* Once an electrical impulse is generated in the cell and transmitted, the cell will take some time to reset its mechanism before it can generate and transmit a new impulse. / Transmission of electrical impulses is not a continuous process. (1 Mark)

Hormones are chemical messengers produced by endocrine glands that travel through blood stream to regulate various functions of the body.
(1)
(i) Regulates blood-sugar level.
(
frac{1}{2})
(ii) Prepares body for dealing with stress.
(
frac{1}{2})

• As his pancreatic duct is blocked, enzymes for digestion will not be transported to small intestine / The blockage will cause difficulty in digestion of proteins, carbohydrates and fats. (1 Mark)
• Insulin secretion is already affected. (1 Mark)

(a) • Adrenal gland (½ Mark)
• Adrenaline (½ Mark)
(b) Responses (any two):
• Adrenaline acts on the heart and makes the heart beats faster to provide oxygen to the muscles.
• The blood supply to skin and digestive system is reduced due to contraction of muscles of arteries to divert the blood through skeletal muscles.
• Breathing rate increases due to contraction of diaphragm and rib muscles. (1 + 1 Marks)

(a) (i) • Adrenal glands (½ Mark)
• Adrenaline hormone is secreted directly into the blood and carried to different body parts. This makes heart beat fast resulting in supply of more oxygen to our muscles. The breathing rate also increases because of the contractions of the diaphragm and the rib muscles. These responses together enable the animal body to be ready to deal with scary situation. (1½ Marks)
(a) (ii) The blood to the digestive system and skin is reduced due to contraction of muscles around small arteries in these organs to divert the blood to our skeletal muscles for more energy. (2 Marks)
(b) Iodised salt contains iodine which is necessary for the thyroid gland to make thyroxin hormone. (1 Mark)
(c) Because they are suffering from diabetes i.e. having high sugar level in their blood causing harmful effects / Insulin secretion is less. (1 Mark)