(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.
(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.
(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.
Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.
(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 the stimulus in : (a) phototropism ? (b) geotropism ? (c) chemotropism ? (d) hydrotropism ? (e) thigmotropism ?
Fill in the following blanks :
(a) A plant’s response to light is called…………..
(b) A plant’s response to gravity is called…………..
(c) Plant shoot grows upward in response to…………….
(d) Plant roots grow downward in response to…………..
(e) Tendrils wind around a support in response to……………
(f) Plant roots grow towards…….. and in the direction of force of……………
(g) A root of a plant grows downward. This is known as…………..
(h) ……….is the hormone that causes phototropism in plants
(i) The response of leaves to the sunlight is called……………
State the structural and the functional unit of the nervous system. Draw its neat labelled diagram and write two functions.
State the functions of any three of the structural and functional unit of nervous system.
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.
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism ?
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 ?
Name the plant hormones which help/promote (i) cell division (ii) growth of
the stem and roots?
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 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) ?
What is the name of in-built ‘arrangement’ in our body which controls the timing and amount of hormones released by various endocrine glands in the body ?
(a) What substances are made by endocrine glands ?
(b) What is the function of receptors and effectors in our body ?
(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 ?
In what ways are puberty and adolescence result of the activity of some glands in the human body ?
When you smell a favourite food your mouth begins to water (that is, you secrete saliva). Write down what the following are examples of :
(a) the smell of the food
(b) the cells in your nasal passages which perceive the smell
(c) the gland which is stimulated to secrete saliva.
(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.
Mention one function for each of these hormones:
(a) Thyroxin (b) Insulin (c) Adrenaline (d) Growth hormone (e) Testosterone.
(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.
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 ?
If we happen to touch a hot object unknowingly, we immediately pull back our hand. What is this type of action known as ?
a) What are the short fibres of a neuron known as ?
What is the long fibre of a neuron known as ?
What are the scientific names for the following receptors in animals ?
(a) receptors for light
(b) receptors for heat
(c) receptors for sound
(d) receptors for smell
(e) receptors for taste