IGCSE Biology Paper-2: Specimen Questions with Answers 154 - 155 of 203

Question 154

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Question

MCQ▾

The diagram shows a leaf.

The diagram shows a leaf

The Diagram Shows a Leaf

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Use the key to identify the plant to which the leaf belongs.

Leaf classification

Leaf Classification

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Choices

Choice (4)
a.D
b.A
c.C
d.B

Answer

b.

Explanation

  • Dichotomous keys are used to identify unfamiliar organisms. They simplify the process of identification. Each key is made up of pairs of contrasting features, starting with quite general characteristics and progressing to ones that are more specific. By following the key and making appropriate choices, it is possible to identify the organism correctly.
  • Example of a dichotomous key that could be used to place a plant using types of leaf it bears. In the given figure leaf is only in one piece that is a simple leaf is not their but compound leaf that is leaf lets are shown. Leaf lets have jagged teeth, which provide our appropriate answer.

Question 155

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Question

MCQ▾

The diagram below shows the initial diameter of a plant cell. The plant cell was placed in a hypotonic solution for one hour.

The diagram below shows the initial diameter of a plant

The Diagram below Shows the Initial Diameter of a Plant

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What will be the results after one hour?

Choices

Choice (4)
a.
The results after one hour
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b.
The results after one hour
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c.
The results after one hour
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d.
The results after one hour
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Answer

b.

Explanation

  • When the plant cells are placed in a hypotonic solution (higher water potential or dilute solution as compared to the cytoplasm), water diffuses into the cell causing the cytoplasm to build up a pressure against the wall that is called turgor pressure (TP).
  • The pressure exerted by the protoplasts due to entry of water against the rigid walls is called pressure potential. Because of the rigidity of the cell wall, the cell does not rupture. This turgor pressure is ultimately responsible for enlargement and growth of cells. .
  • The swelling up of a plasmolysed protoplast due to endosmosis under the influence of a hypotonic solution or water is called deplasmolysis.
plant cell placedin Hypotonic solution

Plant Cell Placedin Hypotonic Solution

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