Name the five types of tropisms. How are tropic movements helpful to plants ? Explain with an example.
The five types of tropisms are: Phototropism, Geotropism, Chemotropism, Hydrotropism and Thigmotropism. The various types of tropic movements help the plants to survive. Example even if a seed is planted upside down, its root will grow downwards into earth because it is positively geotropic.
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……………….
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.
Nervous and hormonal system together perform the function of control and coordination in human beings. Justify the statement.
Which part of the brain controls involuntary actions? Write the function of any two regions of it.
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?
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.
Which halogen element is necessary for the making of thyroxine hormone by the thyroid gland ?
Write the names of all the major endocrine glands present in the human body. Which of these glands also function as exocrine glands ?
(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 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?
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
What is synapse ? In a neuron cell how is an electrical impulse created and what is the role of synapse in this context ?
(a) Draw the structure of neuron and label cell body and axon.
(b) Name the part of neuron:
(i) where information is acquired
(ii) through which information travels as an electrical impulse.
What is chemotropism? Give one example. Name any two plant hormones and mention their functions.
A potted plant is made to lie horizontally on the ground. Which part of the plant will show
(i) positive geotropism?
(ii) negative geotropism?
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism ?
Name various plant hormones. Also give their physiological effects on plant growth and development.
Smita's father has been advised by a doctor to reduce his sugar intake.
A young green plant receives sunlight from one direction only. What will happen to its shoots ?
Name the plant hormones which help/promote (i) cell division (ii) growth of
the stem and roots?
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?
What is the general name of chemical substances which bring about control and coordination in plants ?
Give one example of the movement of a plant part which is caused by the loss of water (or migration of water).
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……………
(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 ?
Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.
(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) 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.
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
(a) What substances are made by endocrine glands ?
(b) What is the function of receptors and effectors in our body ?
