CBSE Class 10 Science Control and Coordination Assignment Set 04

Question. Phytohormones are
(a) hormones regulating growth from seed to adulthood
(b) hormones regulating secondary growth
(c) growth regulators synthesized by plants and influencing physiological processes
(d) hormones regulating flowering.

Answer: C

Question. The effect of daily light period on flowering is called
(a) photooxidation
(b) phototropism
(c) photoperiodism
(d) photorespiration

Answer: C

Question. The natural plant hormones were first isolated from
(a) cotton fruits, spinach leaves, rice plant
(b) avena coleoptiles, fungus gibberella
(c) corn germ oil, human urine
(d) human urine, rice plant.

Answer: B

Question. Brain stem is formed by the union of
(a) optic lobes
(b) cerebellum with optic lobes
(c) corpora striate
(d) mid brain, ponsvarolli and medulla oblongata

Answer: D

Question. Number of spinal nerves in man are
(a) 11 pairs
(b) 13 pairs
(c) 6 pairs
(d) 31 pairs

Answer: D

Question. If the tip of a seeding is cut off, growth as well as bending ceases because it hampers
(a) perception of light stimulus
(b) transpiration
(c) respiration
(d) photosynthesis.

Answer: A

Question. A plant bends towards the source of light when exposed to the light on only one side. Which of the following is the best explanation of the phenomena ?
(a) It needs light for photosynthesis
(b) The apices of their stems are attracted by light
(c) Some auxin accumulates on the shaded side to induce greater cell elongation on that side
(d) Light stimulates the cells on the illuminated side to increase in
length

Answer: C

Question. Third ventricle occurs in
(a) cerebrum
(b) cerebellum
(c) medulla oblongata
(d) diencephalon

Answer: D

Question. The pineal body is considered as
(a) an endocrine gland
(b) an organ concerned with voluntary actions
(c) an organ concerned with vision
(d) a vestige of third eye and endocrine gland

Answer: D

Question. The movement of plant organs in response to the force of gravity is called
(a) hydrotropism
(b) geotropism
(c) heliotropism
(d) phototropism

Answer: B

Question. A high concentration of synthetic auxins is generally used for
(a) wee control
(b) enhancing root initiation
(c) controlling of cell enlargement
(d) preventing the growth of the lateral buds.

Answer: A

Question. Part of brain involved in interpretation, storage of information and initiation of response on the basis of past experience is
(a) motor area
(b) cerebellum
(c) sensory area
(d) association area

Answer: D

Question. Autonomic nervous system controls
(a) reflex action
(b) sense organs
(c) internal organs
(d) skeletal muscle

Answer: C

Question. Gibberellic acid has been successfully employed to induce flowering
(a) in long day plants under short day conditions
(b) in short day plants under long day conditions
(c) for some plants
(d) none of the above

Answer: A

Question. Cytokinins are known to
(a) inhibit cytoplamic movement
(c) help in retention of chlorophyll
(c) influence water movement
(d) promote abscission layer formation

Answer: B

Question. The study of nervous system and its disorders is called
(a) neurogenesis
(b) hematology
(c) neuroglia
(d) neurology

Answer: D

Question. In reflex action the reflex arc is formed by
(a) brain spinal cord muscles
(b) receptor spinal cord muscles
(c) muscle receptor brain
(d) muscles spinal cord receptor

Answer: B

Question. Ethylene is a
(a) solid hormone
(b) gaseous enzyme
(c) gaseous hormone
(d) liquid gas mixture

Answer: C

Question. Pineapple an be made to flower if off season by
(a) zeatin
(b) ethylene
(c) temperature
(d) short days

Answer: B

Question. The sensation of sight in human brain is perceived by
(a) optic lobe
(b) occipital lobe
(c) frontal lobe
(d) parietal lobe

Answer: B

Question. The sensation of sight in human brain is perceived by
(a) optic lobe
(b) occipital lobe
(c) frontal lobe
(d) parietal lobe

Answer: B

Question. Find out the plant growth inhibitor phytohormone
(a) Auxin
(b) 2,4 D
(c) Cytokinin
(d) Abscisic acid
Answer: (d) Abscisic acid

Question. A deficiency of Iodine may result in the-
(a) Goiter
(b) Scurvey
(c) Beri Beri
(d) All of the options
Answer: (a) Goiter

Question. Testosterone comes under which of the following-
(a) Estrogen
(b) Progesterone
(c) Androgen
(d) Both (a) and (c)
Answer: (c) Androgen

Question. Pancreas is responsible for the secretion of
(a) Pancreatic juice
(b) Pancreatic amylase
(c) Insulin
(d) All of the options
Answer: (d) All of the options

Question. Apical dominance and bolting in plants are due to-
(a) Auxin and gibberellin
(b) Auxin and cytokinin
(c) Auxin and ethylene
(d) Auxin and ABA
Answer: (a) Auxin and gibberellin

Short Answer Type Questions

Question. Name the hormone which helps in the regulation of glucose in the blood.
Answer: Insulin

Question. Name two tissues that provide control and coordination in multicellular animals.
Answer: Nervous tissue and Endocrine tissue

Question. Describe how the cells on the dark side of the shoot grow longer as the concentration of Auxin increases.
Answer: Auxin is a hormone that is found in plants and plays a key role in the growth and development of shoots and roots. Specifically, auxin helps regulate cell elongation, which is the process of cells growing longer as they move away from a source of light. Auxin increases the concentration of molecules in cells on the side of the shoot that is away from the light, which causes the cells to elongate. The increased concentration of auxin molecules signals the cells to grow longer, resulting in the shoot bending toward the light. This process is known as phototropism and is essential for plants to grow in the direction of light. Without auxin, plants would not be able to orient themselves properly and would not be able to survive.

Question. Describe the structure of neurons.
Answer: A neuron is the basic unit of the nervous system. At the core of a neuron is the cell body, which houses the nucleus, the control center of the cell. Extending from the cell body are long, thread-like projections called dendrites, which receive signals from other neurons. The axon is a long, thin projection that transmits signals away from the cell body to other neurons or to effector organs. At the end of the axon are the synaptic terminals, which form connections with other neurons.

Question. When our body receives a sudden stimulus, our body shows a strong reaction. Explain the process.
Answer: Reflex action is a type of involuntary, rapid and automatic response to stimuli. It is a basic physiological process that all animals possess and is characterized by its speed and lack of conscious thought. The reflex action mechanism involves the coordination of the sensory and motor systems and is based on the concept of stimulus and response. When the body receives strong and sudden stimuli like pressure, temperature or chemicals, then the sensory neuron sends a message to the spinal cord. The relay neuron sends the signal to the motor neuron and the latter sends a signal to the effector muscle to respond.

Question. Compare chemotropism and Hydrotropism.
Answer: chemotropism: Movement due to chemicals. E.g.- pollen tube growth on stigma and style. Hydrotropism: Movement due to water. E.g. growth of root toward water

Question. What are endocrine glands? Locate any four endocrine glands of humans by drawing suitable diagram.
Answer: endocrine glands are ductless glands that secrete hormones to control and coordinate body function. Fig 7.7, page124, NCERT

Question. (a) A person is advised by a doctor to take less sugar in his diet. Name the disease from which the man is suffering. For the disease which hormone is responsible?
Name the endocrine gland which secretes growth hormone.
Which glands secrets growth hormone? What will be the consequences of Deficiency and Excess secretion of growth hormone?
Answer: (a)Disease- Diabetes mellitus, Hormone – Insulin, Gland- Pancreas
Gland- Pancreas
Gland- Pituitary Gland, Excess secretion: Gigantism, Deficiency: Dwarfism

Question. How does chemical coordination occur in plants?
Answer: In plants, chemical coordination occurs with the help of plant hormones/ Plant growth regulators. (Phytohormones). Examples- Auxin, Cytokinin, Gibberellin, Abscisic acid, and ethylene. These hormones help to coordinate growth, development, and responses to the environment. Plant hormones are synthesized at different and diffuse to the area where they act.
Auxin promotes cell growth, Gibberellins promote stem elongation, Cytokinin promotes cell division, and Abscisic acid inhibits growth.

Question. What events take place between the synapse of two neurons?
Answer: A synapse is a gap between two neurons. In between synapses, nerve impulses are conducted by a chemical process with the help of neurotransmitters (acetylcholine). within the axon, a nerve impulse travels by an electric signal. When it reached to synapse, the neurotransmitters are released in the synaptic cleft. These neurotransmitters act as stimuli for the next neuron.