CONTROL AND COORDINATION

Q1.Describe an activity to illustrate the phenomenon of phototropism

and explain why does this occur.
Ans. a.Take a plant and make such an arrangement that it receives the
light coming from a window as shown in the figure and observe it for few
days.
b. Now, turn the flask so that the shoots are away from light and the
roots towards light. Leave it undisturbed in this condition for a few days.
c. Again, observe carefully to find the difference in the movement. d.
When growing plants detect light, auxin, synthesized at the shoot tip,
helps the cells to grow longer. Auxin always diffuses towards the shady
side of the shoot. This concentrations of auxin stimulates the cells to
grow longer on the side of the shoot which is away from light. Thus, the
plant appears to bend towards light.

Q2. (a) Draw the structure of a neuron and label the following on it:
Nucleus, Dendrite, Cell body and Axon. (b) Name the part of neuron (i)
Where information is acquired. (ii) Through which information travels as
an electrical impulse.
Ans: a. DIAGRAM
b. (i) Dendrite (ii) Axon.

Q3. Name the hormone synthesised at the shoot tips. How does it help
the plant to respond to light?
Ans : Auxin is synthesised at the shoot tips when growing plant detects
light and helps the cells to grow longer. When light is coming from one
side of the plant, auxin diffuses towards the shady side of the shoot. This
concentration of auxin stimulates the cells to grow longer on the side of
the shoot which is away from light. Thus, the plant appears to bend
towards light.

Q4. Draw and describe the role of various parts of human brain.
Ans : Human brain has three major parts: a. Fore-Brain contains mainly
cerebrum. b. Mid-brain. c. Hind-brain.
Functions
a. Cerebellum which controls posture, balance of body and accurate
voluntary movements.
b. Pons regulates respiration
c. Medulla oblongata which controls involuntary actions like blood
pressure, salivation, vomiting etc.

Q5. a. Name the hormone which is injected to a diabetic patient. b. Why

should we use iodised salt in our diet? c. If iodine is insufficient in one’s
diet, what might be the deficiency disease and its symptoms?
Ans : a. Insulin. b. Iodine is necessary for the thyroid gland to secrete
thyroxine hormone. Thyroxine regulates carbohydrates, proteins and fat
metabolism in the body, to provide best balance for growth. c. If iodine is
insufficient in one’s diet, iodine deficiency disease called goitre occurs.
Symptom is swollen neck.

Q6. (a) What is reflex arc? (b) What are the components of reflex arc?
(c) How do muscle cells move? Ans : a. The process of detecting the
signal or the input and responding to it by an output action might be
completed quickly. Such a connection is commonly called reflex arc. b.
Stimulus " Receptors " Sensory neurons " Spinal cord " Motor neurons "
Effector.

Q7. Which hormone is secreted during emergency situations like anger

or excitement? How does it help the human body to handle such
situations?
Ans: Adrenaline is secreted during emergency situations. Heart beats
faster, supply of more oxygen to muscles, more blood to skeletal
muscles, increased breathing rate. It provides energy to muscles to act
swiftly.

Q8. Answer the following:

a. Name the endocrine gland associated with brain.
b. Which gland secretes digestive enzymes as well as hormone?
c. Name the endocrine gland associated with kidneys.
d. Which endocrine gland is present in males but not in females?
e. Which hormone is responsible for changes in females during puberty?
f. Iodine is necessary for the synthesis of which hormone?
Ans : a. Pituitary gland, b. Pancreas, c. Adrenal gland,
d. Testes, e. Oestrogen, f. Thyroxine.
Q9. How does chemical coordination occur in plants? Explain with the
help of three examples.
Ans : In plants, chemical coordination occurs through various
phytohormones. a. Auxins secreted by growing tissues. They provide
growth of plants.
b. Gibberelins cause stem elongation, seed germination and flowering.
c. Cytokinins present in areas of actively dividing cells like fruits, seeds.
Promote cell division.
d. Abscisic acid inhibits growth and respond to environmental stress.

Q10. Give two examples of functions in plants that are regulated by light.
Ans: The two functions in plants that are regulated by light are:
a. Seed germination - Breaking of dormancy
b. Photosynthesis – Respiration process

Q11. The neck of a person appears to be swollen.

a. Name the disease this person is suffering from.
Ans: The person is suffering from goitre.
b. Name the mineral whose deficiency in the diet causes this disease.
Ans: Deficiency of iodine in the diet causes this disease.

Q12. Why is the use of iodised salt advisable?

Ans: Iodine is a trace element and a necessary substrate for thyroid
gland hormone synthesis. It is required by the thyroid gland to make
thyroxine hormone. The use of iodised salt is advisable because it
provides iodine needed by the thyroid gland to make sufficient thyroxine
for our body that helps prevent risk of goitre.

LIFE PROCESSES
Q1. What is the fate of glucose molecule in a. Anaerobic respiration in
Yeast and lactobacillus bacteria? b. Aerobic respiration in human cells.
Write chemical equation for each type.

Q2. What are the important features of all respiratory structures in

animals? or How are alveoli designed to maximize the exchange of
gases?
Ans : All respiratory system have some important features. a. Large
surface area. b. Thin and delicate surface for diffusion and exchange of
gases. It is generally located in protected inner part of body. c. Rich
blood supply to respiratory organ. Since all of them are present in alveoli
hence it is perfectly designed for exchange of gases.

Q3. Differentiate between Artery and Veins.

Ans: Arteries carry blood away from the heart (arteriole: small arterial
branch). They have thick and flexible walls to endure higher pressure of
blood. Veins transport blood toward the heart (venue: small vessel that
carries blood from capillaries to veins). They have thinner wall but there
are valves in them at regular distance to prevent back flow of blood
especially when blood is returning back to heart from lower organs.

Q4. How is the small intestine designed to absorb digested food?

Ans : Walls of small intestine has finger like projection called villi to
increase surface area. The food is absorbed by villi and brought into
blood. Fat is brought into lymph vessel.

Q5. Differentiate between auricles and ventricles.

Ans : Auricle -1. Upper thin walled chambers. 2. Receive blood from
veins. 3. Push blood into the ventricles.
Ventricle-1. Lower thick walled chambers. 2. Receive blood from the
auricles. 3. Push blood into the arteries.

Q6. Identify structure A-D in the given figure and write the function of C
& D:

Q7. Give one example of each of saprophytic and parasitic nutrition.

Ans: One example each of saprophytic and parasitic nutrition is as
follows:
Parasitic Nutrition – Plasmodium (Protozoa)
Saprophytic Nutrition – fungi.

Q8. Trachea do not collapse when there is not much air because they
are –
a. thick and muscular
b. having cartilaginous rings
c. have valves
d. supported by the larynx.
Ans: b) having cartilaginous rings.

Q9. Name the red pigment carrying oxygen in the blood.

Ans: The red pigment carrying oxygen in blood Haemoglobin.

Q10. What advantage over an aquatic organism does a terrestrial

organism have with regard to obtaining oxygen for respiration?
Ans: Terrestrial organisms have evolved to be more efficient at
absorbing oxygen from the air than watery organisms. –
i. Increased respiratory surface area.
ii. Very fine and delicate surface for easy exchange of oxygen and
carbon – dioxide.
iii. Placement of respiratory surface within the body for protection.
iv. The mechanism for transporting air into and out of the respiratory
surface, which absorbs oxygen.

Q11. What type of respiration takes place in human muscles during

vigorous exercise and why?
Ans: Anaerobic respiration occurs in human muscles during severe
exercise. During exercise, our energy requirement increases, so our
striated muscles start respiring anaerobically in the lack of oxygen and
produce ATP molecules.

Q12. How is opening and closing of stomata regulated?

Ans: Guard cells control the closure and opening of the stomata. The
stomata open when the guard cells swells up due to the presence of
water .And because of the loss of water, the guard cells shrink and the
stomata close.

Q13. Why is it necessary to separate oxygenated & deoxygenated

blood in mammals & birds?
Ans: The separation of oxygenated and deoxygenated blood allows the
organism to receive adequate oxygen. This mechanism is beneficial to
creatures who demand a lot of energy. Mammals and birds use oxygen
to obtain energy in order to maintain a consistent body temperature.
Q14. Why are the walls of the trachea supported by cartilaginous rings?
Ans: The trachea is held together by cartilaginous rings that keep it
from collapsing even when there isn't much air in it.

Q15. Why is diffusion insufficient to meet the oxygen requirements of

multicellular organisms like humans?
Ans: As all cells in multicellular animals are not in direct contact with the
environment, simple diffusion is insufficient to supply the needs of all
body cells.

Q16. How are the lungs designed in human beings to maximize the
area for exchange of gases?
Ans: Bronchioles end in alveoli, which are balloon-like structures in the
lungs. Alveoli have a network of blood capillaries that increase the
surface area available for gas exchange.

Q17. Why is the rate of breathing much faster in aquatic organisms

than those in terrestrial organisms?
Ans: Aquatic species get their oxygen from dissolved oxygen in the
water. Water has a relatively low oxygen availability as compared to air.
As a result, aquatic organisms must breathe more quickly than terrestrial
organisms.
Q18. What is the role of acids in our stomach?
Ans: HCL plays the following role in our stomach:
a. Make the medium acidic to allow the pepsin enzyme to work.
b. Kills the harmful bacteria present in food
c. Prevents fermentation of food

Q19. Leaves of a healthy potted plant were coated with petroleum jelly.
How will it affect the plant? State two reasons.
Ans: The plant will not remain healthy for long due to the following
reasons:
1. There will be no transpiration.
2. There will be no exchange of gases which will affect the rate of
photosynthesis.

Q20. Draw a labeled diagram of :

1. Digestive system 2. Respiratoty system 3. Double circulation 4.
Excretory system