Chapter 7. Control and Coordination

Class 10 Science Chapter 7. Control and Coordination Internal Questions and Answers :

Internal Question :

1. What is the difference between a reflex action and walking?

Answer: A reflex action is an involuntary response to a stimulus, while walking is a voluntary coordinated movement involving the contraction and relaxation of muscles in a deliberate manner.
2. What happens at the synapse between two neurons?

Answer: At the synapse, electrical signals from one neuron are transmitted to another neuron. When an electrical impulse reaches the pre-synaptic terminal, neurotransmitters are released into the synaptic cleft, which bind to receptors on the postsynaptic neuron, allowing the signal to be transmitted.
3. Which part of the brain maintains posture and equilibrium of the body?

Answer: The cerebellum, located in the brain, is responsible for maintaining posture and equilibrium of the body.
4. How do we detect the smell of an agarbatti (incense stick)?

Answer:When we smell an agarbatti (incense stick), odor molecules are released and inhaled. They bind to olfactory receptors in the nose, triggering electrical signals that are transmitted to the brain for perception of the smell.
5. What is the role of the brain in reflex action?

Answer: The brain plays a crucial role in reflex actions by receiving sensory input from the body and coordinating the appropriate motor response. It processes the sensory information and initiates the reflexive motor action without conscious thought.

Internal Question :

1. What are plant hormones?

Answer: Plant hormones, also known as phytohormones, are chemical compounds produced by plants that regulate growth, development, and responses to environmental stimuli. They control various processes such as cell division, elongation, differentiation, and flowering.
2. How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?

Answer: The movement of leaves in the sensitive plant (Mimosa pudica) is a response to touch, known as thigmotropism. When touched, the leaflets fold inward. In contrast, shoot movement towards light, known as phototropism, involves bending of the stem or shoot towards the light source to maximize photosynthesis.
3. Give an example of a plant hormone that promotes growth.

Answer: Gibberellins are an example of plant hormones that promote growth. They stimulate stem elongation, cell division, and seed germination. Gibberellins are involved in various developmental processes, such as internode elongation, fruit growth, and flowering.
4. How do auxins promote the growth of a tendril around a support?

Answer: Auxins promote the growth of a tendril around a support through a process called positive phototropism. Auxins accumulate on the shaded side of the tendril, causing it to elongate more on that side, resulting in curvature and wrapping around the support.
5. Design an experiment to demonstrate hydrotropism.

Answer: The step of experiment are :

(i) Take a potted plant with well-developed roots.

(ii) Ensure that the plant is evenly watered and healthy.

(iii) Prepare a setup where the plant is placed horizontally with the stem lying flat.

(iv) Tilt the pot slightly, so water is available only on one side of the pot.

(v) Observe the plant's growth over several days.

(vi) The roots should show a hydrotropic response by growing more towards the side with water, seeking a water source for the plant's sustenance.

Internal Question :

1. How does chemical coordination take place in animals?

Answer: Chemical coordination in animals occurs through the endocrine system. Endocrine glands release hormones into the bloodstream, which bind to specific receptors on target cells or organs, initiating physiological responses and maintaining overall homeostasis and communication within the body.
2. Why is the use of iodised salt advisable?

Answer: The use of iodized salt is advisable because iodine is an essential nutrient for the proper functioning of the thyroid gland. Iodized salt helps prevent iodine deficiency disorders, such as goiter and mental impairment, promoting overall health.
3. How does our body respond when adrenaline is secreted into the blood?

Answer: When adrenaline is secreted into the blood, the body undergoes several physiological responses. These include increased heart rate, elevated blood pressure, dilation of air passages, heightened alertness, increased energy, and redirection of blood flow to vital organs.
4. Why are some patients of diabetes treated by giving injections of insulin?

Answer: Some patients with diabetes are treated by giving injections of insulin because their bodies either do not produce enough insulin or are unable to effectively use the insulin produced. Insulin injections help regulate blood sugar levels and allow proper utilization of glucose by cells.

Class 10 Science Chapter 7. Control and Coordination Exercises :

1. Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin.

Answer : (d) Cytokinin.

2. The gap between two neurons is called a
(a) dendrite.
(b) synapse.
(c) axon.
(d) impulse.

Answer : (b) synapse.

3. 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.

4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?

Answer: The function of receptors in our body is to detect and respond to various stimuli, such as light, sound, touch, temperature, and chemical signals. When receptors do not work properly, it can lead to sensory impairments or disorders like loss of vision, hearing, or sensation, affecting our ability to perceive and respond to the environment accurately.
5. Draw the structure of a neuron and explain its function.

Answer:  The structure of a neuron :

Neurons function by transmitting electrical impulses, known as action potentials, along their axons. When a neuron receives a signal through its dendrites, it integrates and processes the information. If the signal reaches a threshold, an action potential is generated and travels down the axon, allowing communication with other neurons or target cells, facilitating sensory perception, motor control, memory formation, and overall nervous system function.
6. How does phototropism occur in plants?

Answer:  Phototropism in plants occurs due to the hormone auxin, which accumulates on the shaded side of the plant. When light hits the plant, auxin redistributes, causing elongation of cells on the shaded side, resulting in the plant bending towards the light source.

7. Which signals will get disrupted in case of a spinal cord injury?

Answer: A spinal cord injury can disrupt both sensory and motor signals. Sensory signals, such as touch and pain, may be impaired or lost. Motor signals, controlling muscle movement and coordination, can also be disrupted, resulting in paralysis or weakness.
8. How does chemical coordination occur in plants?

Answer: Chemical coordination in plants occurs through the synthesis, transport, and perception of plant hormones. These hormones, such as auxins, gibberellins, and cytokinins, regulate various physiological processes including growth, development, flowering, and response to environmental stimuli.
9. What is the need for a system of control and coordination in an organism?

Answer: A system of control and coordination in an organism is essential for maintaining homeostasis, coordinating physiological processes, responding to external stimuli, regulating growth and development, and ensuring proper functioning and survival of the organism.
10. How are involuntary actions and reflex actions different from each other?

Answer: Involuntary actions are automatic responses carried out by the body without conscious control, such as heartbeat or digestion. Reflex actions, on the other hand, are rapid and involuntary responses to specific stimuli, mediated by the spinal cord, providing quick protection or withdrawal from potential harm.
11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

Answer: Nervous mechanisms for control and coordination in animals involve rapid transmission of electrical impulses through neurons, allowing for quick and precise responses. Hormonal mechanisms, however, rely on chemical messengers (hormones) released into the bloodstream, resulting in slower but more widespread and long-lasting effects throughout the body.
12. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?

Answer: The movement in a sensitive plant, such as Mimosa pudica, is termed thigmonastic movement and is triggered by touch or physical stimulation. It involves a rapid folding of leaflets. In contrast, movement in our legs involves muscular contractions and is controlled by the nervous system to generate intentional and coordinated locomotion.