iGCSE Biology (0610)-21.3 Genetic modification - iGCSE Style Questions Paper 1

Question

Which statement about non-biodegradable plastics in aquatic environments is correct?

A As non-biodegradable plastics decompose in aquatic environments, they release carbon dioxide.
B Extremely small fragments of non-biodegradable plastics can move up the food chain.
C Non-biodegradable plastics in aquatic environments cause an increase in the growth of producers.
D Non-biodegradable plastics in aquatic environments decompose quickly.

▶️ Answer/Explanation

Detailed solution

The correct answer is B.

Reasoning:
Non-biodegradable plastics do not break down chemically but instead fragment into tiny particles called microplastics.These fragments are frequently ingested by small marine organisms at the base of the food web. Because they cannot be digested, they persist in the gut and are passed to larger predators when eaten. This allows the plastic to accumulate and move up the food chain to higher trophic levels. Unlike organic waste, these materials do not decompose quickly or release $CO_2$ through biological decay, and they often harm producers by blocking sunlight.

Question

A gene is added to the genetic material of an avocado plant. This gene makes the avocado fruits stay ripe for longer before they start to decompose. What is this process an example of?

1 adaptation
2 genetic modification
3 selective breeding

A) 1, 2 and 3
B) 1 and 3 only
C) 2 only
D) 3 only

▶️ Answer/Explanation

Solution

Ans: C

This process is genetic modification (2) because a foreign gene is directly inserted into the avocado’s DNA to alter its characteristics.

It is not adaptation (1), which occurs naturally over generations, nor selective breeding (3), which involves choosing parents with desired traits. Thus, only option C (2 only) is correct.

Question

Which row shows uses of genetic modification?

▶️ Answer/Explanation

Solution

Ans: D

Genetic modification involves directly altering an organism’s DNA. The correct pair is:

Producing insulin – Genetically modified bacteria produce human insulin
Creating pest-resistant crops – Genes from bacteria are inserted into plants

Other options mix genetic modification with traditional methods (selective breeding, cross-pollination) which don’t involve direct DNA manipulation.

iGCSE Biology (0610)-21.3 Genetic modification – iGCSE Style Questions Paper 1

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