Cell and movement across membrane

Question 1

What is diffusion?

Answer 1

The movement of particles from a high area of concentration to a low area of concentration across a partially permeable membrane. Doesn’t require energy.

Question 2

What 4 factors affect the rate of diffusion?

Answer 2

Temperature.
Decrease the distance of diffusion.
Increase S.A.
Increase rate of concentration gradient.

Question 3

What is an example of diffusion in plant cells?

Answer 3

CO2 enters the stomata and oxygen moves out of cells by diffusion.

Question 4

Define osmosis.

Answer 4

The movement of water through a partially permeable membrane from a higher water potential to a lower water potential. Doesn’t require energy.

Question 5

Example of osmosis.

Answer 5

Reabsorption of water in the kidneys.

Question 6

What does hypotonic mean?

Answer 6

More dilute solution outside the cell.

Question 7

What does hypertonic mean?

Answer 7

More concentrated solution outside the cell.

Question 8

How do you find the change in mass

Answer 8

(Final mass - Initial mass) / Initial mass x 100

Question 9

Define active transport.

Answer 9

Allows cells to move substances from an area of low concentration to an area of high concentration. Energy is required.

Question 10

Example of active transport.

Answer 10

Nutrients in the soil moves from low to high concentration into the hair cells.

Question 11

Define mitosis.

Answer 11

A type of cell division which produces daughter cells identical to the parent.

Question 12

What are the 3 stages of the cell cycle?

Answer 12

Interphase.
Mitosis.
Cytokinesis.

Question 13

What is interphase?

Answer 13

The replication of the cell, ready for mitosis.

Question 14

What is prophase?

Answer 14

Where the nucleus membrane breaks down.

Question 15

What is metaphase?

Answer 15

When the chromosomes align across the centre of the cell.

Question 16

What is anaphase?

Answer 16

When one copy of each chromosomes move to opposite ends of the cell.

Question 17

What is telophase?

Answer 17

When the nuclear membrane forms.

Question 18

What is cytokinesis?

Answer 18

When the cell membrane and cytoplasm divide into 2 daughter cells.

Question 19

What are stem cells?

Answer 19

They are undifferentiated cells.

Question 20

What are the 2 types of stem cells found in animals?

Answer 20

Embryonic and Adult stem cells.

Question 21

Describe stem cells in plants

Answer 21

They are found in meristems.
They have thin walls, small vacuoles and no chloroplasts.

Question 22

Describe embryonic stem cells.

Answer 22

They are found in embryos.
They are divided by mitosis and can differentiate into all cell types.

Question 23

Describe adult stem cells

Answer 23

They can’t divide into many cell types.
They act as a repair mechanism for the body.

Question 24

Suggest 2 reasons why some people may object to the use of embryonic stem cells.

Answer 24

They are found in embryos which could develop into a person.
There’s no guarantee of how successful the therapies will be.

Question 25

What is a benefit of using stem cells.

Answer 25

They have also been used as a model cells to study how diseases develop or for drug testing.

Question 26

What is the function of a sperm cell?

Answer 26

To transfer genetic material from the male to the ovum.

Question 27

State and explain 2 adaptations of the sperm cell.

Answer 27

Acrosome stores digestive enzymes. Flagellum propels sperm to ovum.

Question 28

What is the function of a fat cell?

Answer 28

For insulation and protection. To store fat.

Question 29

State an adaptation of a fat cell?

Answer 29

They have a smaller layer of cytoplasm surrounding a fat reservoir.

Question 30

What is the function of the red blood cell?

Answer 30

To transport oxygen around the body.

Question 31

State and explain 2 adaptations of the RBC.

Answer 31

No nucleus so there's more space for haemoglobin molecules. Full of haemoglobin so protein binds to oxygen to form oxyhaemoglobin which is red.

Question 32

What is the function of a ciliated cell?

Answer 32

The cilia sweeps mucus to the back of the throat to be swallowed.

Question 33

What is the function of the palisade cell?

Answer 33

To carryout photosynthesis.

Question 34

State and explain 2 adaptations of palisade cell.

Answer 34

Large S.A to absorb as much sunlight as possible. Packed with chloroplast to absorb sunlight.

Question 35

What is the function of the root hair cell?

Answer 35

Takes up water and nutrients for a plant.

Question 36

State and explain 2 adaptations of the root hair cell.

Answer 36

Large S.A to absorb water. Long and thin to penetrate between soil particles.

Question 37

What is an egg cell?

Answer 37

A female sex cell that's fertilised by a sperm cell to form an embryo.

Question 38

State and explain 2 adaptations of an egg cell.

Answer 38

Cytoplasm provides nutrients for the embryo. Large cell to store all the nutrients.

Question 39

As the size of an organism increases, …

Answer 39

it's S.A:V decreases.

Question 40

What is the formula for S.A?

Answer 40

S.A = height x length x number of faces.