chapter 1 - cell structure and organisation

Question 1

define what is a cell.

Answer 1

cell is the basic unit of life.

Question 2

what is the function of the cell membrane?

Answer 2

it controls the movement of substances in and out of the cell.

Question 3

what are the two functions of the cell wall?

Answer 3

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

Question 4

function of cytoplasm

Answer 4

the site where most chemical reactions occur

Question 5

what are the two functions of the nucleus?

Answer 5

1. controls most cell activities such as cell growth and repair of worn-out parts
2. essential for cell division

Question 6

what is the function of chloroplasts?

Answer 6

to trap light for photosynthesis

Question 7

does chloroplast trap artificial light?

Answer 7

yes

Question 8

does the smooth ER have ribosomes?

Answer 8

no

Question 9

what are the 2 functions of the smooth ER?

Answer 9

1. it is involved in the synthesis of fats and steroids
2. converts harmful substances into harmless substances through detoxification

Question 10

does the rough ER have ribosomes attached to it?

Answer 10

yes

Question 11

what is the function of the rough ER?

Answer 11

it transports protein made by the ribosomes to the Golgi body

Question 12

where do you find ribosomes?

Answer 12

attached to the rough ER or lying freely in cytoplasm

Question 13

what is the function of ribosomes?

Answer 13

it synthesises proteins

*proteins made at rough ER are usually transported out of the cell
*proteins made in the cytoplasm are used within the cytoplasm of that cell

Question 14

what are the two functions of the Golgi body/apparatus?

Answer 14

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

Question 15

1. vesicles containing substances __________ off from the ____________
2. vesicles ________ with the Golgi body, releasing the substances to be __________
3. _________ vesicles containing _______ substances ________ off from the Golgi body and move towards the __________
4. _________ vesicles ______with the cell membrane and their contents ______ the cell

Answer 15

1. pinch, rough ER
2. fuse, modified
3. secretory, modified, pinch, cell membrane
4. secretory, fuse, exit

Question 16

what are the differences between plant and animal cells?

(there are 3)

Answer 16

1. plant cells have a cell wall while animals cells do not have a cell wall
2. plant cells have chloroplast while animal cells do not have chloroplast
3. a plant cell has a large, central vacuole while an animal cell has many small vacuoles

Question 17

describe how the red blood cell is adapted for its function.
(3m)

Answer 17

1. has a circular, biconcave shape —> which increases the surface area-to-volume ratio so that oxygen can diffuse in and out more efficiently
2. has no nucleus —? more space to store more haemoglobin for transport of more oxygen
3. flexible/elastic —> squeeze through capillaries easily

Question 18

describe how the skeletal muscle cell is adapted for its function. (2pts)

Answer 18

1. contains many mitochondria —> to supply more energy for the contraction of the muscle cell
2. has contractile protein fibres —> for the contraction and relaxation of muscle cells to bring about movement

Question 19

describe how the root hair cell is adapted for its function. (2pts)

Answer 19

1. long and narrow extension —? increases surface area-to-volume ratio, thus increased rate of absorption of water and mineral salts
2. cell membrane prevents cell sap from leaking. thus concentrated cell sap maintains a lower water potential in the vacuole —-> thus allowing for water to enter the root hair cell via osmosis