(a) What is meant by breathing? What happens to the rate of breathing during vigorous exercise and why?
(b) Define translocation with respect to transport in plants. Why is it essential for plants? Where in plants are the following synthesised?
(i) Sugar (iii) Hormone
(a) The process of taking in of oxygen from air in to the lungs and expulsion of carbon dioxide out of the lungs is called breathing. The rate of breathing during vigorous exercise increases by about 20 to 25 times per minute. It is because, during vigorous exercise the demand for oxygen increases. Breathing occurs involuntarily but its rate is controlled by the respiratory center of the brain.
(b) Translocation is the transport of food from the leaves to other parts of the plant and occurs in the part of the vascular tissue known as phloem.
It is essential for plants because every part of the plant needs food for obtaining energy for building its parts and maintaining its life.
(i) Sugar is synthesised in the leaves of the plant.
(ii) Hormones are synthesised at the tips of roots and stems of a plant.
Name the green dot like structures in some cells observed by a student when a leaf peel was viewed under a microscope. What is this green colour due to?
(a) Name the pigment in leaves which absorbs sunlight energy.
(b) What is the colour of this pigment ?
What is the name of those cells in the leaf of a plant which control the opening and closing of stomata?
Name the enzyme present in human saliva. What type of food material is digested by this enzyme ?
In addition to carbon dioxide and water, state two other conditions necessary for the process of photosynthesis to take place.
Apart from sunlight and chlorophyll, what other things are required to make food by photosynthesis ?
Name the following :
(a) The process in plants which converts light energy into chemical energy.
(b) Organisms that cannot prepare their own food.
(c) Organisms that can prepare their own food.
(d) The cell organelle where photosynthesis occurs.
(e) The cells which surround a stomatal pore.
(f) An enzyme secreted by gastric glands in stomach which acts on proteins.
Draw a neat diagram of excretory system of human beings and label the following:
(i) Kidney
(ii) Ureter
(iii) Urinary Bladder
(iv) Urethra
In the experiment "Light is essential for photosynthesis", why does the uncovered part of the leaf turn blue-black after putting iodine solution?
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
a) How do plants obtain food ?
(b) Why do plants need nitrogen ? How do plants obtain nitrogen ?
(a) What is the role of hydrochloric acid in our stomach ?
(b) What is the function of enzymes in the human digestive system ?
(a) Which part of the body secretes bile ? Where is bile stored ? What is the function of bile ?
(b) What is trypsin ? What is its function ?
(a) Name the main organs of the human digestive system. Also name the associated glands.
(b) How do carbohydrates, fats and proteins get digested in human beings ?
Name one substance which is produced in anaerobic respiration by an organism but not in aerobic respiration.
Explain why, when air is taken in and let out during breathing, the lungs always contain a residual volume of air.
Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.
a) Leaves of a healthy potted plant were coated with vaseline to block the stomata. Will this plant remain healthy for long? State three reasons for your answer.
(b) State any two differences between autotrophic nutrition and heterotrophic nutrition.
A Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :