cell structure and organisation

Question 1

what are cells?

Answer 1

cell = unit of life. It consists of a mass of living matter called protoplasm

Question 2

function of cell membrane [made of lipids and proteins]

Answer 2

it has a partially permeable membrane, which controls the movement of substances in and out of the cell

Question 3

functions of cell wall [made of cellulose]

Answer 3

fully permeable which protects the cell from injury, fixed shape

Question 4

functions of cytoplasm

Answer 4

jelly-like substance that fills the cell contains organelles

Question 5

functions of the nucleus

Answer 5

• controls cell activities (cell growth/repair worn out part)
• essential for cell division

Question 6

functions of chromosomes [made up of proteins and deoxyribonucleic acid/DNA]

Answer 6

thread-like structure, found in the nucleus
- condense and shorten to become thick, rod-shaped structures

Question 7

functions of rough endoplasmic reticulum

Answer 7

a network of flattened spaces lined with a membrane
- has ribosomes attached to it
- outer surface of the RER is continuous with the nuclear membrane

Question 8

functions of ribosomes

Answer 8

attached to RER or lie freely in the cytoplasm
- attached to the RER, make proteins that are transported out of the cell
- lying freely, make proteins that are used within the cytoplasm of that cell

Question 9

functions of smooth endoplasmic reticulum

Answer 9

• synthesis substances such as fats and steroids (sex hormones)
• converts harmful substances into harmless substances through a process -detoxification

Question 10

functions of the golgi body (golgi apparatus)

Answer 10

vesicles fuse with one side of the golgi body and pinch off from the opposite side
- chemically modifies substances made by the ER
- stores and packages these substances in vesicles for secretion out of the cell

Question 11

functions of mitochondria

Answer 11

small oval/sausage-shaped organelles
- aerobic respiration occurs in the mitochondria
↳energy can be used for growth and reproduction

Question 12

functions of chloroplasts

Answer 12

oval structures
- green pigment, chlorophyll
- essential for photosynthesis

Question 13

functions of vacuoles

Answer 13

fluid-filled space
plant cells: large central vacuole (cell sap)
↳ sugars, mineral salts, amino acids
animal cells: small vacuoles (temporarily)
↳ contain water and food substances