In mammals and birds why is it necessary to separate oxygenated and de-oxygenated blood ?
Mammals and birds are warm blooded animals. This means they can control their body temperature and do not have to depend on environment for their body temperature regulation. Because of this birds and mammals require optimum oxidization of glucose which would be possible with good supply of oxygen. So it is required to have separate oxygenated and de-oxygenated blood to supply the required amount of oxygen.
(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 ?
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.
Draw a diagram of human excretory system and label renal artery and urethra.
State in brief the function of :
List the three kinds of blood vessels of human circulatory system and write ¦ their functions in tabular form.