How are fats digested in our bodies? Where does this process take place?
The small intestine is the site of the complete digestion of carbohydrates, proteins and fats. It receives the secretions of the liver and pancreas for this purpose. The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. Bile juice from the liver accomplishes this in addition to acting on fats. Fats are present in the intestine in the form of large globules, which make it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action. The pancreas secretes pancreatic juice, which contains enzymes like trypsin for digesting proteins and lipase for breaking down emulsified fats. The walls of the small intestine contain glands, which secrete intestinal juice. The enzymes present in it finally convert the proteins to amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerol.
(a) Name the pigment in leaves which absorbs sunlight energy.
(b) What is the colour of this pigment ?
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?
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 ?
a) How do plants obtain food ?
(b) Why do plants need nitrogen ? How do plants obtain nitrogen ?
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.
Name one substance which is produced in anaerobic respiration by an organism but not in aerobic respiration.
What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.
Write correct sequence of four steps of method for the preparation of temporary mount of a stained leaf peel.
Draw a neat diagram of excretory system of human beings and label the following:
(i) Kidney
(ii) Ureter
(iii) Urinary Bladder
(iv) Urethra
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.
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 scientific name of the animals which are :
(i) only meat eaters ?
(ii) only plant eaters ?
(iii) both, plant and meat eaters ?
Which of the organs perform the following functions in humans ?
(i) Absorption of food
(ii) Absorption of water
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
(a) What is chlorophyll ? What part does chlorophyll play in photosynthesis ?
(b) (i) Which simple food is prepared first in the process of photosynthesis ?
(ii) Name the food which gets stored in plant leaves.
(a) What criteria can be used to decide whether something is alive ?
(b) What is meant by life processes ? Name the basic life processes common to all living organisms which are essential for maintaining life.
(a) What are heterotrophs ? Give one example of heterotrophs.
(b) What is the difference between autotrophic nutrition and heterotrophic nutrition ?
(a) How does carbon dioxide from the air enter the leaves of a plant to be used in photosynthesis ?
(b) How does water from the soil reach the leaves of a plant to be used in photosynthesis ?