State the functions of plant hormones. Name four different types of plant hormones.
Plant hormones help to coordinate growth, development and responses in environment.
Four different types of plant hormones are – Auxins, Gibberellins, Cytokinins, Ethylene and Abscisic acid.
(a) How does chemical coordination take place in human beings ?
(b) Why is the use of iodised salt advisable ?
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
A potted plant is made to lie horizontally on the ground. Which part of the plant will show
(i) positive geotropism?
(ii) negative geotropism?
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 ?
What are 'hormones'? State one function of each of the following hormones:
(i) Thyroxine (ii) Insulin
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.
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……………….
A person walks across a room in barefeet and puts his foot on a drawing pin lying on the floor. He lets out a cry. Explain what happens in his nervous system in bringing about this response.
Which part of the brain controls involuntary actions? Write the function of any two regions of it.
Name and explain the function of the hormone secreted by the pituitary gland in humans.
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
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 ?
(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 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 ?
(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 ?
(a) Name the hormone which is released into the blood when its sugar level rises. Explain the need of Chemical communication in multicellular organisms the organ which produces this hormone and its effect on blood sugar level. Also mention the digestive enzymes secreted by this organ with one function of each.
(b) Explain the need of Chemical communication in multicellular organisms.
Name one example of the movement of a plant part which is very quick and can be observed easily.
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.
(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 ?
Name the five types of tropisms. How are tropic movements helpful to plants ? Explain with an example.
State how concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light ?
State the structural and the functional unit of the nervous system. Draw its neat labelled diagram and write two functions.
(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) How is brain protected from injury and shock?
(b) Name two main parts of hind brain and state the functions of each.
Which organ secretes a hormone when bloo’d sugar rises in our body? Name the hormone and name one enzyme released by this organ.