IGCSE Biology Paper-4: Specimen Questions with Answers 13 - 16 of 279

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Passage

Enzymes are large biomolecules that are responsible for many chemical reactions that are necessary to sustain life.

Question 13 (3 of 4 Based on Passage)

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Would enzyme activity be affected by pH?

Explanation

Yes. pH is one of the main factor for denaturation of protein so if enzyme is subjected to pH level under which it is denatured , there will be no enzyme activity.

Question 14 (4 of 4 Based on Passage)

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In which condition of pH, enzymes can act better?

Explanation

Many enzymes act better in pH of six and eight.

Question 15

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What are the main negative impacts of monocultures?

Explanation

Crop plants are mainly grown as big area of a single variety. This is called a monoculture. The main negative impacts of monoculture are-

  • There is a high biodiversity found in natural ecosystem but it decreases in monocultures because in a monoculture only a few species are survive where the crop is growing.
  • Monocultures increase in the populations of organisms that are pest of that particular crop. E. g. If a leafhopper use rice plant. it will able to reduce its yields.
  • When insecticides are used to kill the pest many useful insects are also kill by spraying of insecticides.

Passage

Figure shows the blood cell under the light microscope,

Figure Shows the Blood Cell

Question 16 (1 of 2 Based on Passage)

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Identify White and red blood cells.

Explanation

In the Blood Cell

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