(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.
What is the function of insulin hormone ? What type of patients are given insulin injections ?
(a) Which plant hormone is present in greater concentration in the areas of rapid cell division?
(b) Give one example of a plant growth promoter and a plant growth inhibitor.
(a) What does a plant root do in response to water ? What is this phenomenon known as ?
(b) What happens to the moonflower (i) during daytime, and (ii) at night ? What is this phenomenon known as ?
(a) Name the hormones secreted by the following endocrine glands :
(i) Thyroid gland (ii) Parathyroid glands (iii) Pancreas (iv) Adrenal glands
(b) Write the functions of testosterone and oestrogen hormones.
(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 ?
What is the general name of chemical substances which bring about control and coordination in plants ?
Give the scientific terms used to represent the following :
(a) Bending of a shoot towards light.
(b) Growing of roots towards the earth.
(c) Growth of a pollen tube towards ovule.
(d) Bending of roots towards water.
(e) Winding of tendril around a support
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) How is brain protected from injury and shock?
(b) Name two main parts of hind brain and state the functions of each.
Name and explain the function of the hormone secreted by the pituitary gland in humans.
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.
State the functions of the following hormones :
(a) Thyroxine (b) Adrenaline (c) Growth hormone
Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands ?
Explain the difference between each of the following pairs of terms :
(a) receptor and effector (b) cerebrum and cerebellum
(a) Name the structural and functional unit of nervous system.
(b) Draw a flow chart to show the classification of nervous system into various parts.
(c) What is autonomic nervous system ? What is its function ?
(d) What is voluntary nervous system ? Explain the working of voluntary nervous system with an example.
Answer the following:
(a) Which hormone is responsible for the changes noticed in females at puberty?
(b) Dwarfism results due to deficiency of which hormone?
(c) Blood sugar level rises due to deficiency of which hormone?
(d) Iodine is necessary for the synthesis of which hormone?
Mention one function for each of these hormones:
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.
What are meanings? What are their functions? Name the fluid, which is filled in between meanings.
Which organ secretes a hormone when bloo’d sugar rises in our body? Name the hormone and name one enzyme released by this organ.
What is the function of receptors in our body? Think of situation where receptors do not work properly. What problems are likely to arise?
Name one plant hormone that promotes growth and another plant hormone which inhibits growth.
(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 ?
Define chemotropism. Give one example of chemotropism. State whether this example is of positive chemotropism or negative chemotropism.
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism ?
a) What are the short fibres of a neuron known as ?
What is the long fibre of a neuron known as ?