GCSE Combined Science Biology

Question 1

Which organelle is responsible for aerobic respiration in animal cells?

Accepted Answer

Mitochondria

Answer

Mitochondria are the site of aerobic respiration, where glucose and oxygen react to release energy (as ATP). They are sometimes called the 'powerhouses' of the cell. Active cells like muscle cells contain more mitochondria.

Question 2

What is the word equation for photosynthesis?

Accepted Answer

Carbon dioxide + water → glucose + oxygen

Answer

Photosynthesis converts carbon dioxide and water into glucose and oxygen, using light energy absorbed by chlorophyll. This process occurs in the chloroplasts of plant cells and is essential for producing food and releasing oxygen.

Question 3

In the human digestive system, where does most absorption of nutrients occur?

Accepted Answer

Small intestine

Answer

The small intestine is the main site of nutrient absorption. Its inner surface has millions of villi, which increase the surface area enormously. Villi have thin walls and a rich blood supply for efficient absorption.

Question 4

What type of cell division produces genetically identical daughter cells?

Accepted Answer

Mitosis

Answer

Mitosis produces two genetically identical daughter cells from one parent cell. It is used for growth, repair, and asexual reproduction. Each daughter cell has the same number of chromosomes as the parent cell.

Question 5

Which of the following best describes the role of white blood cells in the immune system?

Accepted Answer

They defend against pathogens by producing antibodies and engulfing microorganisms

Answer

White blood cells defend the body against infection. Phagocytes engulf and digest pathogens, while lymphocytes produce specific antibodies that lock onto antigens on the surface of pathogens, marking them for destruction.

GCSE Revision Practice Test

GCSE Revision Practice Test

GCSE Combined Science Biology