IGCSE Biology Paper-1: Specimen Questions with Answers 170 - 171 of 208

Question 170

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Question

MCQ▾

Which process depends on energy from respiration?

Choices

Choice (4)
a.Photosynthesis
b.Diffusion
c.Peristalsis
d.Osmosis

Answer

c.

Explanation

The process of peristalsis begins in the esophagus when a bolus of food is swallowed. The strong wave-like motions of the smooth muscle in the esophagus carry the food to the stomach, where it is churned into a liquid mixture called chyme. Digestion converts components of the food we eat into smaller molecules that can be absorbed into the body and utilized for energy needs or as building blocks for making larger molecules in cells.

Motions of the Smooth Muscle

Motions of the Smooth Muscle

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Question 171

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Question

MCQ▾

Four words are shown below.

Alcohol anaerobic sugar yeast

These words can be used in the spaces P, Q, R and S to complete the sentence below. ‘In brewing and bread making, respiration takes place. The micro-organism called ……P…… uses ……Q. …. as a source of food. The product of this ……R…… respiration is ……S……. ‘

Which combination of words correctly completes the sentences?

Choices

Choice (4)
a.P-yeast, Q-sugar, R-alcohol, S- anaerobic
b.P-sugar, Q-yeast, R-sugar, S- anaerobic
c.P-yeast, Q-sugar, R-anaerobic, S-alcohol
d.P-yeast, Q-alcohol, R-sugar, S- anaerobic

Answer

a.

Explanation

  • These words can be used in the spaces P, Q, R and S to complete the sentence below. ‘In brewing and bread making, respiration takes place. The micro-organism called Yeast uses sugar as a source of food. The product of this alcohol respiration is anaerobic’
  • Anaerobic respiration: It occurs in the absence of molecular oxygen and is also called fermentation. In this, the food is only partially oxidized so only a part of energy (5%) is released and of energy remains trapped in the intermediate compounds. It is found in lower organisms like bacteria and yeast. It is also found in certain parasitic worms (Ascaris, Taenia) which live in deficient medium. The organism showing anaerobic respiration, are called anaerobes. These involve one of following reactions.
Part of Energy is Released

Part of Energy is Released

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