(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) ?
(a) A growth movement ofa plant part in response to an external stimulus in which the direction of stimulus determines the direction of response is called tropism. Example – The bending of plant stem towards light is an example of positive phototropism.
(b) Different types of tropisms are:
(i) Phototropism – The movement of a plant part in response to light is called phototropism. Its stimulus is light.
(ii) Geotropism – The movement of a plant part in response to gravity is called geotropism. Its stimulus is gravity.
(iii) Chemotropism – The movement of a plant part in response to a chemical stimulus is called chemotropism. Its stimulus is chemical.
(iv) Hydrotropism – The movement of a plant part in response to a water stimulus is called hydrotropism. Its stimulus is water.
(v) Thigmotropism – The movement of a plant part in response to a touch stimulus is called thigmotropism. Its stimulus is touch.
(c)
Tropisms:
1. These movements are always in the direction of the stimulus.
2. These movements are slow.
3. These movements are exhibited by all parts of a plant.
For example, movement of shoot towards the light and not towards
Nasties:
1. These movements are neither away nor towards the stimulus.
2. These movements are fast.
3. These movements are exhibited by the flat organs (like leaves and petals of flowers) of a plant.
For example, the bending and dropping of leaves in ‘Touch-me-not’ plant.
(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.
(a) Define geotropism. Give one example of geotropism.
(b) What is meant by ‘positive geotropism’ and ‘negative geotropism ? Give one example of each type. Draw a labelled diagram to illustrate your answer indicating the plant part which shows positive geotropism and the plant part which shows negative geotropism.
(c) Name one plant part which exhibits positive thigmotropism.
Which one term in each of the following includes the other three ?
(a) thyroid, ductless gland, thymus, pituitary, ovary
(b) adrenalin, insulin, hormone, thyroxine, estrogen
(a) The human brain can be broadly divided into three regions. Name these three regions.
(b) What is cranium ? What is its function ?
What does CNS stand for ? Which part of CNS : (a) consists of two cerebral hemispheres, and (b) has spinal nerves attached to it ?
What are meanings? What are their functions? Name the fluid, which is filled in between meanings.
(a) How is brain protected from injury and shock?
(b) Name two main parts of hind brain and state the functions of each.
What is chemotropism? Give one example. Name any two plant hormones and mention their functions.
What are 'hormones'? State one function of each of the following hormones:
(i) Thyroxine (ii) Insulin
A potted plant is made to lie horizontally on the ground. Which part of the plant will show
(i) positive geotropism?
(ii) negative geotropism?
Name and explain the function of the hormone secreted by the pituitary gland in humans.
Which one of the following actions on touch is an example of chemical control?
(i) Movement on the touch-sensitive plant.
(ii) Movement in human leg.
(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?
Give one example each of a plant part:
(a) which is positively hydrotropic as well as positively geotropic.
(b) which is positively phototropic but negatively geotropic.
Which of the following is a growth movement and which is not ?
(a) folding up of leaves of sensitive plant on touching with hand.
(b) folding up of petals of dandelion flower when light fades.
Name the plant part :
(a) which bends in the direction of gravity but away from light
(b) which bends towards light but away from the force of gravity
a) What are the short fibres of a neuron known as ?
What is the long fibre of a neuron known as ?
(a) How does chemical coordination take place in human beings ?
(b) Why is the use of iodised salt advisable ?
What is the function of insulin hormone ? What type of patients are given insulin injections ?
(a) What is a reflex action ? Explain with the help of an example.
(b) Define reflex arc. Give the flow chart of a spinal reflex arc.
(c) How are involuntary actions and reflex actions different from each other ?
(a) Name two systems which taken together perform the functions of control and coordination in human beings.
(b) What does the central nervous system in humans consist of ? What is the job of the central nervous system ?
(c) Give the various functions of brain.
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?
State how concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light ?
(i) Name the hormones that are released in human males and females when they reach puberty.
(ii) Name a gland associated with brain. Which problem is caused due to the deficiency of the hormone released by this gland ?