Class 10 Trendsetter solved CBSE Test paper-02
1. What is a neuron? (1
mark)
Ans: Neuron is the structural
&functional unit of nervous system.
2. Give an example of
plant hormone that promotes growth. (1 mark)
Ans: auxins, gibberellins and
cytokinins
3. What part of the
brain maintains posture and equilibrium of the body? (1 mark)
Ans: Cerebellum controls coordination
and adjustment of movements (equilibrium) and posture
4. Which
parts of the body produce growth regulators? (1 mark)
Ans: Pituitary Gland
5.What is synapse ?
Ans: The junction between neurons is
called synapse.
5. List two functions
performed by ovaries in a human female. (1 mark)
Ans: (a) Produces ova or egg. (b)
Hormones Oestrogen and Progesterone.
6. What does a stem (or
shoot) do in a response to light? (1 mark)
Ans: The stem is positively
phototropic (grown towards light)
7. Name the 2 hormones
secreted by pancreas. Write one function of each hormone. (2 marks)
Ans: (i) Insulin is secreted by the
beta cells and like other hormones, passes directly into the blood. Insulin is required
to convert glucose into glycogen (glycogensesis) and store it in liver.
(ii) The alpha cells of pancreas secrete glucagon, the
metabolic effects of which are opposite to those of insulin. It causes the
breakdown of liver glycogen, thereby releasing glucose into the blood stream.
8. How are involuntary
actions and reflex actions different from each other? (2 marks)
Ans: Reflex actions are rapid automatic
response to a stimulus without the conscious involvement of the
brain. E.g.: Withdrawing the hand from a hot object.
Involuntary actions are controlled by the brain but not by our conscious thinking. E.g.: Beating of the heart, peristaltic movement of the intestines
Involuntary actions are controlled by the brain but not by our conscious thinking. E.g.: Beating of the heart, peristaltic movement of the intestines
9. What is the
difference between a reflex action and walking? (2 marks)
Ans: Reflex action is an involuntary
action and mostly controlled my spinal cord whereas walking is a voluntary
action and it is controlled by brain.
10. What is the need for
a system of control and coordination in an organism? (2 marks)
Ans: (a). Maintain a steady state of stability in
constantly changing environment
(b) For adjustment of the vital
activities of life
(c) To maintain homeostasis.
11. Distinguish between
cerebrum and spinal cord. (2 marks)
Ans:
Cerebrum
|
Spinal cord
|
It is the largest portion of
the brain consisting of two hemispheres
|
Portion of Central nervous
system that conducts impulse to and from the brain
|
In cerebrum grey matter covers
the white matter.
|
In spinal cord white matter
covers the grey matter.
|
Controls different thought and
action such as orientation, recognition, emotions, memory and speech.
|
The spinal cord carries out
sensory, integrative, and motor functions in order to transmit impulses to
the brain.
|
12. Define the following
terms: (i) nerve impulses (ii) axon
(iii) olfactory receptors. (3 marks)
Ans: (i) Nerve impulse : A nerve
impulse is a way of two nerve cells to communicate with one another. Nerve impulses
are mostly electrical signals along the dendrites. Neurons, also known as brain
cells, produce nerve impulses. A nerve impulse is also called an action
potential.
(ii) axon : An
axon also known as a nerve fibre is a
long, slender projection of a nerve cell or neuron that conducts electrical impulses away from
the neuron's cell body. The function of the axon is to transmit information to
different neurons, muscles and glands.
(iii) Olfactory
receptors: These are a pair of small, solid, cube shaped bodies. They are fully
covered by cerebrum. They receive impulse for smell
13. What is the function
of receptors in our body? Think of situations where receptors do not work
properly. What problems are likely to arise? (3 marks)
Ans: Receptors are sensory structures
(organs/tissues or cells) present all over the body. The receptors are
either grouped in case of eye or ear,
or scattered in case of skin.
Functions of receptors:
(i) They sense the external stimuli such
as heat or pain.
(ii) They also trigger an impulse in
the sensory neuron which sends message to the spinal cord.
When the receptors are damaged, the
external stimuli transferring signals to the brain are not felt. For example,
in the case of damaged receptors, if we accidentally touch any hot object, then
our hands might get burnt as damaged receptors cannot perceive the external
stimuli of heat and pain.
14. (a) What are
‘hormones’?
(b) List four characteristics
of hormones.
(c) Name the hormones
required for the following:
(i) Functioning of
memory glands. (ii) Regulation of
calcium and phosphate in blood.
(iii) Lowering of blood
glucose. (iv) Development of
moustache and beard in human male
Ans:(a) Hormones are chemical
substances which are directly poured into the blood stream by the endocrine
glands and have effects on special target organs.
(b) General characteristics of
hormones are as follows:
a)
Hormones
are secreted by endocrine cells.
b)
Hormones
are chemical messengers.
c)
The
are chemical signals that circulate in the body fluids.
d)
The
hormones regulate the behavior of the target cells.
e)
Hormones,
unlike enzymes do not catalyze any reaction.
(c) The hormones required for the following:
(i) Functioning of memory glands. Follicle
stimulating Hormone
(ii) Regulation of calcium and
phosphate in blood.:- parathyroid hormone
(iii) Lowering of blood glucose.- insulin
(iv) Development of moustache and
beard in human male : Testosterone
15. (a) What is autonomic nervous system? Name the subsystem in which it is subdivided? [2]
(b) How do auxins help in bending of stem towards light ? Explain.[3]
Ans:
(a) The autonomic nervous system (ANS) is that part of the peripheral nervous system that largely acts independent of conscious control (involuntarily) and consists of nerves in cardiac muscle, smooth muscle, and exocrine and endocrine glands. It is responsible for maintenance functions (metabolism, cardiovascular activity, temperature regulation, digestion) that have a reputation for being outside of conscious control .
(a) The autonomic nervous system (ANS) is that part of the peripheral nervous system that largely acts independent of conscious control (involuntarily) and consists of nerves in cardiac muscle, smooth muscle, and exocrine and endocrine glands. It is responsible for maintenance functions (metabolism, cardiovascular activity, temperature regulation, digestion) that have a reputation for being outside of conscious control .
The
autonomic nervous system is typically divided into two main subsystems, the
sympathetic nervous system and the parasympathetic nervous system.
(b) When
growing plants detect light a hormone called Auxin, synthesized at the shoot
tip 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 plant appears to bend towards light.