(a) What is meant by positive tropism and negative tropism ? Explain with examples.
(b) Define thigmotropism. Give one example of thigmotropism.
(c) What is the difference between thigmotropism and thigmonasty ? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively ?
a) The growth of a plant part in response to a stimulus is called positive tropism and if the growth of a plant part is away from the stimulus, then it is called negative tropism.Example: The roots of a plant go towards earth in response to gravity is an example of positive geotropism whereas stem grows away from earth against gravity is an example of negative geotropism.
(b) The directional growth movement of a plant part in response to the touch of an object is called thigmotropism.Example: Tendrils grow towards any support which they happen to touch and wind around it.
(c)
Tendrils grow towards a stimulus hence it is a directional movement which shows that it is a case of thigmotropism whereas, the folding of leaves in mimosa plant does not depend on the direction of stimulus (touch) which shows that it is an example of thigmonasty.
a) What is the function of our nervous system ?
(b) What are the main organs of the human nervous system ? Draw a labelled diagram to show the main organs of the human nervous system.
(c) How does the human nervous system work ? Explain.
(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?
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?
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 ?
Name the five types of tropisms. How are tropic movements helpful to plants ? Explain with an example.
a) What are the short fibres of a neuron known as ?
What is the long fibre of a neuron known as ?
(a) What is spinal cord ? What is its main function ?
(b) Give the functions of medulla.
Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?
Nervous and hormonal system together perform the function of control and coordination in human beings. Justify the statement.
State how concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light ?
Write one example each of the following tropic movements :
(i) Positive phototropism (ii) Negative phototropism
(iii) Positive geotropism (iv) Negative geotropism
(v) Hydrotropism (vi) Chemotropism
State the structural and the functional unit of the nervous system. Draw its neat labelled diagram and write two functions.
What is chemotropism? Give one example. Name any two plant hormones and mention their functions.
Name and explain the function of the hormone secreted by the pituitary gland in humans.
(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 stimulus in : (a) phototropism ? (b) geotropism ? (c) chemotropism ? (d) hydrotropism ? (e) thigmotropism ?
Name the plant hormones which are responsible for the following effects :
(a) falling of leaves
(b) opening of stomata
(c) bending of stem towards light (d) closing of stomata
Which halogen element is necessary for the making of thyroxine hormone by the thyroid gland ?
Name one gland each :
(a) which acts only as an endocrine gland.
(b) which acts only as an exocrine gland.
(c) which acts both as an endocrine gland as well as an gxocrine gland.
(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) The human brain can be broadly divided into three regions. Name these three regions.
(b) What is cranium ? What is its function ?
What is the function of insulin hormone ? What type of patients are given insulin injections ?
State the functions of the following hormones :
(a) Thyroxine (b) Adrenaline (c) Growth hormone
Explain the difference between each of the following pairs of terms :
(a) receptor and effector (b) cerebrum and cerebellum
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.
Name various plant hormones. Also give their physiological effects on plant growth and development.