bio chapter 1

Question 1

function of cell surface membrane

Answer 1

selectively permeable membrane that allows only some substances to pass through and controls movement of substances in and out of cell

Question 2

function of cytoplasm

Answer 2

where most cell activities occur + contains organelles

Question 3

function of nucleus

Answer 3

1. controls cell activities such as cell growth and repair of worn-out parts
2. essential for cell division (cells without a nucleus are unable to divide)
3. contains genetic information in form of chromosomes

Question 4

function of rough endoplasmic reticulum

Answer 4

transports proteins made by ribosomes to Golgi body for secretion out of cell

Question 4

function of smooth endoplasmic reticulum

Answer 4

-> synthesizes substances such as fats and steroids
-> converts harmful substances into harmless substances through detoxification

Question 5

function of ribosomes

Answer 5

synthesizes proteins in cell either:
1. attached to membrane of RER and makes proteins that are usually transported out of the cell
2. lie freely in cytoplasm and make proteins that are used within cytoplasm of cell

Question 6

function of Golgi body/apparatus

Answer 6

1. chemically modifies substances made by ER
2. stores and packages these substances in vesicles for secretion out of cell

Question 7

function of mitochondria [singular: mitochondrion]

Answer 7

1. where aerobic respiration occurs
2. during aerobic respiration, food substances are broken down to release energy in the form of adenosine triphosphate
3. this energy may be used by cell to perform cell activities e.g. growth and reproduction

Question 8

function of vacuoles

Answer 8

1. plant cells = large central vacuole
   -> contains cell sap which contains dissolved substances e.g. sugars, mineral salts and amino acids
2. animal cells = small numerous vacuoles
   -> contain water and food substances

Question 9

function of cellulose cell wall

Answer 9

1. protects cell from injury
2. gives plant cell a fixed shape

Question 10

function of chloroplasts

Answer 10

-> contain a green pigment called chlorophyll that is essential for photosynthesis

Question 11

processes in the endomembrane system (RER - protein)

Answer 11

1. nucleus controls synthesis of polypeptide
2. ribosomes attached on outer surface of RER synthesizes polypeptides
3. newly synthesized protein is drawn into lumen of RER
4. vesicles containing polypeptide made by RER pinches off from RER
5. vesicles fuse with the Golgi body releasing the protein molecules made by RER which is then chemically modified
6. Secretory vesicles containing modified protein molecules pinch off from the Golgi body and move towards cell surface membrane
7. Secretory vesicles fuse with the cell surface membrane and their contents exit the cell

Question 12

processes in the endomembrane system (SER - fats/lipids)

Answer 12

1. vesicles containing fats/lipids made by SER pinches off from SER
2. vesicles fuse with the Golgi body releasing the fat molecules made by SER which is then chemically modified
3. Secretory vesicles containing modified fat molecules pinch off from the Golgi body and move towards cell surface membrane
4. Secretory vesicles fuse with the cell surface membrane and their contents exit the cell