Chapter 3

Question 1

Cell membrane

Answer 1

structure that encloses the contents of a cell and allows the movement of some materials in and out

Question 2

Nucleus

Answer 2

central part of an atom, made up of protons and neutrons. Also roundish structure inside a cell that acts as the control centre for the cell. Plural = nuclei.

Question 3

Cytosol

Answer 3

the fluid found inside cells

Question 4

Cell Wall

Answer 4

a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants. In the algae and higher plants it consists mainly of cellulose.

Question 5

Chloroplasts

Answer 5

oval-shaped organelle found only in plant cells. Chloroplasts contain the pigment chlorophyll. They are the ‘factories’ in which carbon dioxide and water are changed by sunlight and water into food by the process of photosynthesis.

Question 6

Vacuole

Answer 6

sacs within a cell used to store food and wastes. Plant cells usually have one large vacuole. Animal cells have several small vacuoles or none at all.