(a) What is the role of hydrochloric acid in our stomach ?
(b) What is the function of enzymes in the human digestive system ?
(a) Hydrochloric acid: It makes the medium of gastric juice acidic so that the enzyme pepsin can digest the proteins properly and also kills any bacteria that might have entered the stomach with food.
(b) Enzymes help in the breaking down of complex organic food materials into simpler forms.
What is the name of tiny projections on the inner surface of small intestine which help in absorbing the digested food ?
(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 Give one reason why multicellular organisms require special organs for exchange of gases between their body and their environment. :
Name the enzyme present in human saliva. What type of food material is digested by this enzyme ?
Draw a neat diagram of excretory system of human beings and label the following:
(i) Kidney
(ii) Ureter
(iii) Urinary Bladder
(iv) Urethra
(a) Draw a sectional view of the human heart and label on it – Aorta, Right ventricle and Pulmonary veins.
(b) State the functions of the following components of transport system:
(i) Blood (ii) Lymph
In the experiment "Light is essential for photosynthesis", why does the uncovered part of the leaf turn blue-black after putting iodine solution?
Which of the following type of energy is used by living organisms to perform vital life processes ?
Kinetic energy, Chemical energy, Potential energy, Nuclear energy
Which of the organs perform the following functions in humans ?
(i) Absorption of food
(ii) Absorption of water
(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 are autotrophs ? Give one example of autotrophs.
(b) What are the conditions necessary for autotrophic nutrition ?
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.
(a) What would happen if all the green plants disappear from the earth ?
(b) If a plant is releasing carbon dioxide and taking in oxygen during the day, does it mean that there is no photosynthesis occurring ? Justify your answer.
Name the process by which plant parts like roots, stems, and leaves get oxygen required for respiration.
In the lungs :
(a) what substance is taken into the body ?
(b) what substance is removed from the body ?
State whether the following statements are true or false :
(a) During respiration, the plants take C02 and release 02.
(b) Energy can be produced in cells without oxygen.
(c) Fish and earthworm exchange gases during respiration in the same way.
