IGCSE Biology Paper-4: Specimen Questions with Answers 201 - 203 of 279

Passage

Soon after starting physical activity the concentration of carbon dioxide in the blood increases.

Question 201 (2 of 3 Based on Passage)

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Name the process inside cells that produces carbon dioxide.

Explanation

Aerobic Respiration

It uses oxygen and completely oxidizes the organic food mainly carbohydrate (Sugars) to carbon dioxide and water. It therefore, releases the entire energy available in glucose and release carbon dioxide.

Question 202 (3 of 3 Based on Passage)

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State the effect on breathing of an increase in carbon dioxide concentration in the blood.

Explanation

When concentration in blood increases, breathing becomes faster and deeper. The effect of rising concentration is due to decrease in affinity of for ​. Thus, the released in the tissues accelerates the delivery of (called Bohr effect) , due to-which breathing becomes faster and deeper.

Question 203

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Shows the different types of human teeth.

The Human Teeth

Describe the functions of the canine and molar teeth.

Explanation

Canines: There is one pointed canine in each maxillary of upper jaw and each dentary of lower jaw next to the incisors. They are meant for piercing, tearing and offence and defense. They are single rooted and monocuspid.

Molars: They have more than two roots and 4 - 5 cuspid. They are meant for crushing, grinding, and chewing.

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