Advance Biology solved question
ADVANCE BIOLOGY QUESTIONS AND ANSWERS
qn 1. why is its necessary for pepsin to be secreted in and inactive state?
answer✓
~Active pepsin would dogest cells that produce it, there being no mucus barrier within the gastric glands.
qn 2.(a) List the features of the small intestine which increase its surface area.
(b) why is this an advantage?
answers✓
~(a) The fold of the wall of the small intestine, villi and microvilli
~(b) It increase tremendously the surface area for secretion and absorption and makes it very efficient at these processes.
qn 3. What would happen to the activity of the intestinal enzymes if the pH in the small intestine remained at 2?
answer√
~ Rate of enzymes activity would decrease or stop as the enzymes would be denatured by low pH.
qn 4. Suggest on advantage of using active transport in the absorption of monosaccharides, dipeptides and amino acids.
answer✓
~it ensures that even if the soluble food molecules are in concentration lower than those already in the blood , they will still pass into the blood.
qn 5. Why does a mouse require a larger number of joules per unit weight than a human?
answer√
~Because of the continual heat loss from the relativel lager body surface of the mouse.
qn 6. Explain why animals are dependent on light energy.
answer√
~ Ligth energy is needed for photosynthesis. Photosynthetic organisms (mainly plants and algae) are at the beginning of almost all food chains. Animals are therefore dependent on plant . either directly or indirectly for their energy and materials.
qn 7. What is the precise role of oxygen in respiration?
asnswer✓
~ Oxygen is the final hydrogen acceptoe in the respiratory chain.
qn 8. The rate of uptake of oxygen increase immedieately exercise starts. How is the supply of oxygen from the outside the body to the cells inceased during exercise?
answer✓
✓ Oxygen supply is increased by increased rate and depth of breathing, and an increase in the power and rate of heart beat.
qn 9. Why does the lactic acid level in the blood continue to rise after excercise when anaerobic respiration has ceased?
answer✓
✓ Lactic acid is being removed from the muscles by the blood , to be taken to the liver.
qn 10. why should the diameter of mitochondrial remain faily constant when the length is so variables?
answer✓
✓ For the rapid diffusion of molecules between cytoplasm and mitochondrion.
qn 11. Name four chemical substances which are involved in resiration which would enter the mitochondrion from the cytoplasm and four which would leave.
answer✓
✓ material entering- pyruvate, oxygen, reduced hydrogen carrier, ADP, phosphate.
✓ material leaving- carbon dioxide, oxdised hydrogen carrier, ATP, water.
qn 12. Try to explain why blood flowing in the same direction as the water current ( a parallel current system) would be a relatively inefficient mechanism for exchange of gases.
answer✓
✓ When blood and water first meet, the concentration gradient of oxygen between them will be great. However as blood and water flow along together the gradient will decrese until blood shows a percentage saturation for oxygen equal ti that of the water. This would be well below the bloods maximum possible saturation point and therefore inafficient.
qn 13. how many times must a molecules of oxygen diffuse across a cell surface membrane in passing from the inside of an alveolus to haemoglobin.
answer✓
✓Five- into epitheliak cell lining alveolus, out of this cell, into endothelial cell of blood capillary, out of this cell l, and into red cell.
qn 14.The volume of air exchanged in the alveoli is in fact that of the pulmonary ventilation. suggest why this is the case.
answer✓
✓ Because not all the air exchanged reaches the alveoli. Some is in the bronchioles, bronchi and trachea( dead space air).
qn 15. Why smaller mammals like rate have higher metabolic rate.
answer✓
✓ smaller mammals have a larger surface area to volume ratio from which heat can be lost and therfore must use up more oxygen in order to maintain a constant body temperature.
qn 16. Why is the usual RQ for humans between 0.7 and 1.0?
answer✓
✓ Because human generally respire a mixture of carbohydrate and fat.
qn 17. what factors are likely to affect the number and diversity of species reaching an area?
answer✓
✓ Geographical barriers, such as oceans; ecological barriers, such as unfavourable habitats separating areas of favourable habitats; distance over which dispersal must operate; air and water current: size and nature of invasion areas.
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