CBSE Class 10 Science Control And Coordination Worksheet Set 09

This is Set 09 of a printable fill-in-the-blanks worksheet for CBSE Class 10 Science Chapter 6, Control and Coordination, with the answer and a Teacher's Note for each item. The blanks test hormones, tropic and nastic movements, brain parts, neurons and synapses, insulin and the thyroid.

Fill in the Blanks

Question 1. A feedback mechanism regulates the action of the ________.
Answer:
Final answer: hormones.
Reason: The timing and the amount of hormone released are regulated by feedback mechanisms, for example insulin and the blood sugar level.
In simple words: Hormone levels are kept steady by feedback.

Teacher's Note:
1. Feedback means the result controls its own production.
2. Think of the insulin example.

Question 2. ________ hormone is applied to cuttings to induce root initiation in horticulture.
Answer:
Final answer: auxin.
Reason: Auxin promotes root formation on stem cuttings.
In simple words: Auxin makes cuttings grow roots.

Teacher's Note:
1. Auxin also helps in cell elongation.
2. Gardeners use rooting powders with auxin.

Question 3. ________ movements are growth movements of plants in response to environmental triggers from a specific direction.
Answer:
Final answer: tropic (tropism).
Reason: Tropic movements are directional and depend on growth. Nastic movements are non-directional.
In simple words: Tropic movements grow towards or away from the stimulus.

Teacher's Note:
1. Tropic means directional growth.
2. Phototropism and geotropism are examples.

Question 4. Receptors are structures which are able to detect ________.
Answer:
Final answer: stimuli (changes in the environment).
Reason: Receptors are present in the sense organs and detect light, sound, smell, taste and temperature.
In simple words: Receptors sense the changes around us.

Teacher's Note:
1. Receptors detect and effectors respond.
2. Name two receptors you know.

Question 5. Hypothalamus stimulates the ________ gland to release growth hormone.
Answer:
Final answer: pituitary.
Reason: The hypothalamus controls the pituitary, which is why it is called the link between the nervous system and the endocrine system.
In simple words: The hypothalamus tells the pituitary to release growth hormone.

Teacher's Note:
1. The pituitary is the master gland.
2. The hypothalamus is a part of the forebrain.

Question 6. Mimosa pudica shows ________ movement.
Answer:
Final answer: nastic (seismonastic).
Reason: The leaves fold on touch without any growth and without regard to the direction of the touch.
In simple words: Mimosa leaves fold without growing.

Teacher's Note:
1. Nastic movements do not depend on the direction of the stimulus.
2. Mimosa is the touch-me-not plant.

Question 7. ________ is the main thinking part of the brain.
Answer:
Final answer: The forebrain (cerebrum).
Reason: The forebrain controls thinking, memory and voluntary actions.
In simple words: The forebrain does the thinking.

Teacher's Note:
1. The hind brain is for balance and involuntary actions.
2. The cerebrum is the largest part of the forebrain.

Question 8. Motor nerves transmit response from the ________ nervous system to ________ organs in the form of impulse.
Answer:
Final answer: central; effector.
Reason: Motor neurons carry impulses away from the brain or spinal cord to the effector organs, the muscles or glands.
In simple words: Motor nerves carry orders from the centre to the effector.

Teacher's Note:
1. Sensory neurons go the other way, from receptors to the central nervous system.
2. Motor neurons end at muscles or glands.

Question 9. A ________ allows delivery of electrical impulses from neurons to other cells.
Answer:
Final answer: synapse.
Reason: The synapse is the gap between two neurons, or between a neuron and a muscle or gland cell, where the message is passed by chemicals.
In simple words: The synapse is the gap where one neuron passes the message to the next.

Teacher's Note:
1. The signal changes from electrical to chemical at the synapse.
2. Synapse works in one direction only.

Question 10. Coordination in plants takes place by means of chemical substances called ________.
Answer:
Final answer: phytohormones (plant hormones).
Reason: Plants have no nervous system, so they use hormones to coordinate their activities.
In simple words: Plants coordinate with hormones.

Teacher's Note:
1. Name five plant hormones.
2. Plant hormones are made in small amounts.

Question 11. Endocrine glands secrete their hormones directly ________.
Answer:
Final answer: into the blood.
Reason: These glands are ductless, so the hormones pass into the blood, which carries them to the target organs.
In simple words: Hormones go straight into the blood.

Teacher's Note:
1. Exocrine glands have ducts.
2. Pancreas has both endocrine and exocrine parts.

Question 12. ________ coordinates the activity of picking up a pencil for writing.
Answer:
Final answer: The cerebellum.
Reason: The cerebellum makes the movements of the muscles precise and balanced while the cerebrum decides to do the action.
In simple words: The cerebellum keeps fine movements precise.

Teacher's Note:
1. Cerebrum decides, cerebellum makes the action precise.
2. The cerebellum is in the hind brain.

Question 13. Positive geotropism of root is due to greater growth on ________ side as compared to ________ side.
Answer:
Final answer: upper; lower.
Reason: The upper side of a horizontal root grows faster, so the root bends downwards towards gravity.
In simple words: The upper side of a root grows more, so the root bends down.

Teacher's Note:
1. Draw a horizontal root and mark the growth.
2. Roots are positively geotropic.

Question 14. ________ promotes senescence and is found in high concentration in ripened fruits.
Answer:
Final answer: Ethylene.
Reason: Ethylene is the gaseous hormone that ripens fruits.
In simple words: Ripe fruits are rich in the ripening gas ethylene.

Teacher's Note:
1. One ripe fruit can ripen others because of ethylene.
2. It is the only gaseous plant hormone.

Question 15. Deficiency of insulin hormone causes ________.
Answer:
Final answer: diabetes mellitus.
Reason: Without enough insulin the blood sugar level stays high.
In simple words: Too little insulin gives diabetes.

Teacher's Note:
1. Insulin is made by the pancreas.
2. Diabetic patients may need insulin injections.

Question 16. If the sugar levels in blood rise, they are detected by the cells of the ________ which respond by producing more insulin.
Answer:
Final answer: pancreas.
Reason: The pancreas secretes more insulin to bring the sugar level down. This is a feedback mechanism.
In simple words: The pancreas senses the sugar and adjusts insulin.

Teacher's Note:
1. The pancreas is both an endocrine and exocrine gland.
2. Insulin is made by the beta cells of the islets.

Question 17. ________ regulates the growth and development of female sex organs.
Answer:
Final answer: The ovary (through oestrogen).
Reason: The ovary secretes oestrogen, which brings about the changes of puberty in girls.
In simple words: The ovary makes the female sex hormone.

Teacher's Note:
1. The corresponding male gland is the testis.
2. Oestrogen is the female sex hormone.

Question 18. When growing plants detect light, a hormone called ________ is synthesised at the shoot tip.
Answer:
Final answer: auxin.
Reason: Auxin diffuses to the shady side and makes the cells there grow longer, so the shoot bends towards light.
In simple words: Auxin turns the shoot towards light.

Teacher's Note:
1. Auxin is made at the shoot tip.
2. Phototropism is controlled by auxin.

Question 19. Plant hormone ________ promotes cell division.
Answer:
Final answer: cytokinin.
Reason: Cytokinins are present in higher amounts in areas of rapid cell division such as fruits and seeds.
In simple words: Cytokinin makes cells divide.

Teacher's Note:
1. Cytokinin also delays leaf ageing.
2. Gibberellin helps the growth of stems.

Question 20. Element ________ is essential for the synthesis of thyroxine.
Answer:
Final answer: iodine.
Reason: Thyroxine contains iodine, which is why iodised salt is advisable.
In simple words: Thyroxine cannot be made without iodine.

Teacher's Note:
1. Deficiency causes goitre.
2. Iodine is a non-metal.