biology - control and coordination

Class 10 - Biology

Control and Coordination

Q&A
Question:

(a) Define phototropism. Give one example of phototropism.
(b) How does phototropism occur in a plant stem (or shoot) ? Explain with the help of labelled diagrams.
(c) What is meant by positive phototropism and negative phototropism ? Give one example of each type.

Answer:

(a) Phototropism – The movement of a plant part in response to light is called phototropism. Example -Stem bends towards the light is positive phototropism.
(b) Phototropism in a plant stem – The bending of a plant stem towards light is an example of phototropism. The plant stem responds to light and bends towards it due to the action of auxin hormone. The auxin hormone is present at the tip of the stem of the growing plant. Auxin prefers to stay in shade away from light so when sunlight falls on the stem from one side, it gets concentrated on the opposite side. Due to more auxin, the shady side of the stem grows to be longer than the side of stem which is facing light, and makes the stem bend towards light.
Control-And-Coordination-Lakhmir-Singh-class-10-Biology-Solutions-34
(c) The movement of a plant part towards light is called positive phototropism. Example ? the stem of the growing bends towards light. The movement of a plant part away from light is called negative phototropism. Example ? The roots of a plant move away from light.



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Questions and Answers


Control and Coordination - Questions
1.

Answer the following:
(a) Name the endocrine gland associated with brain?
(b) Which gland secretes digestive enzymes as well as hormones?
(c) Name the endocrine gland associated with kidneys?
(d) Which endocrine gland is present in males but not in females?


Answer
2.

(a) Explain any three directional movements in plants.
(b) How brain and spinal cord are protected in human ?
(c) Name the master gland present in the brain.


Answer
3.

What are the two parts of the vertebrate nervous system ?


Answer
4.

State whether coughing is a voluntary action or reflex action.


Answer
5.

(a) Write the names of five endocrine glands found in the human body. Name the hormones secreted by each gland.
(b) How do hormones reach the organs they control ?
(c) Name the gland which controls the secretion of hormones from the pituitary.
(d) How does our body respond when adrenaline is secreted in large amounts into the blood ?
(e) Name the disease which occurs in adults due to the deficiency of iodine in the diet. What is the main symptom of this disease ?


Answer
6.

Write the functions of any one part of the hind – brain.


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7.

Name any three endocrine glands in human body and briefly write the function of each of them.


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8.

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


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9.

Name, the two main organs of our central nervous system. Which one of them plays a major role in sending command to muscles to act without involving thinking process? Name the phenomenon involved.


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10.

(a) Name the two main constituents of the Central Nervous System in human beings.
(b) What is the need for a system of control and coordination in human beings?


Answer
11.

Which plant hormone is responsible for the wilting and falling of leaves ?


Answer
12.

What is the scientific name of sensitive plant ?


Answer
13.

(a) What does a stem (or shoot) do in response to gravity ? What is this phenomenon known as ?
(b) What does a root do in response to light ? What is this phenomenon known as ?


Answer
14.

What is a tendril ? Name the two types of tendrils. What does a tendril do in response to the touch of a support ? What is this phenomenon known as ?


Answer
15.

What is a tendril ? Name the two types of tendrils. What does a tendril do in response to the touch of a support ? What is this phenomenon known as ?


Answer
16.

Name the plant organs which are :
(a) positively phototropic (b) positively geotropic
(c) negatively geotropic (d) positively hydrotropic


Answer
17.

(a) What is meant by ‘tropisms’ (or tropic movements) ? Explain with an example.
(b) What are the different types of tropisms ? Define each type of tropism. Write the name of stimulus in each case.
(c) How do tropisms differ from nasties (or nastic movements) ?


Answer
18.

Name the two systems of control and coordination in higher animals.


Answer
19.

State one function each of cerebellum and pons.


Answer
20.

Where are hormones made in the human body ?


Answer
21.

Which gland secretes the growth hormone ?


Answer
22.

Name, the disease caused by the deficiency of thyroxine hormone in the body.


Answer
23.

What part does the diet play in helping us to have a healthy thyroid gland ?


Answer
24.

Name two parts of the body which contain receptors of chemical stimuli.


Answer
25.

Which parts of the body form the central nervous system ?


Answer
26.

Why do you need iodine in your diet ?


Answer
27.

Fill in the following blanks with suitable words :
(a) The two examples of effectors are…………. and………………
(b) Our…………. system allows Us to react to our surroundings. Information from receptors passes
along…………. neurons to our brain. Our brain sends impulses along………… neurons to our muscles.
(c) A neuron which carries an impulse to the brain is called a……………….
(d) The neuron which carries a message for action to a muscle or gland is known as a……………….


Answer
28.

(a) Name the three types of nerves which constitute the peripheral nervous system.
(b) What is the difference between a reflex action and walking ?
(c) How do we detect the smell of an incense stick (agarbatti) ?


Answer
29.

(a) The human brain can be broadly divided into three regions. Name these three regions.
(b) What is cranium ? What is its function ?


Answer
30.

State the functions of the following hormones :
(a) Thyroxine (b) Adrenaline (c) Growth hormone


Answer
31.

Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands ?


Answer
32.

List three ways in which neurons are similar to other cells.


Answer
33.

What is the difference between a voluntary and an involuntary action ? Which kind of action is digestion ? Explain your choice.


Answer
34.

What does CNS stand for ? Which part of CNS : (a) consists of two cerebral hemispheres, and (b) has spinal nerves attached to it ?


Answer
35.

Which hormone :
(a) prepares the body for action ?
(b) controls the amount of glucose in blood ?
(c) gives boys a deep voice ?
(d) gives girls soft skin ?


Answer
36.

a) What is the function of our nervous system ?
(b) What are the main organs of the human nervous system ? Draw a labelled diagram to show the main organs of the human nervous system.
(c) How does the human nervous system work ? Explain.


Answer
37.

How does phototropism occur in plants?


Answer
38.

What is the need for a system of control and coordination in an organism?


Answer
39.

Name the plant hormones responsible for the following:
(a) Elongation of cells.
(b) Growth of stem.
(c) Promotion of cell division.
(d) Falling of senescent leaves.


Answer
40.

What will happen if intake of iodine in our diet is low?


Answer
41.

Mention one function for each of these hormones:
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.


Answer
42.

Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?


Answer
43.

Mention the names of various phytohormones.


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44.

Discuss phototropism.


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45.

Describe the central nervous system in human beings.


Answer
46.

Name the hormones secreted by thyroid, parathyroid and pancreas.


Answer
47.

List the functions of testosterone and estrogen.


Answer
48.

Why is the response of a plant to a stimulus not observed immediately?


Answer
49.

Name any two phytohormones, which are growth promoters.


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50.

What makes a stem bend towards sunlight?


Answer