GCSE - Biology

Question 1

The nucleus

Answer 1

Controls all the activities of the cell and is surrounded by the nuclear membrane. It contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or new organisms. The average diameter is around 10 um.

Question 2

The cytoplasm

Answer 2

a liquid gel in which the organelles are suspended and where most of the chemical reactions needed for life take place.

Question 3

The cell membrane

Answer 3

controls the passage of substances such as

glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.

Question 4

The mitochondria

Answer 4

structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell. They are very small: 1-2 um in length and only 0.2-0.7 um in diameter.

Question 5

The ribosomes

Answer 5

where protein synthesis takes place, making all the proteins needed in the cell.