B1

Question 1

What is the function of the chloroplast

Answer 1

Where photosynthesis takes place, providing food for the plant

Question 2

What is the function of the vacuole

Answer 2

Contains cell sap and is where the cell stores water

Question 3

size of image =

Answer 3

magnification * size of object

Question 4

What is made out of cellulose

Answer 4

Cell wall

Question 5

what is the maximum magnification and resolution a light microscope can have?

Answer 5

magnification - x2000

resolving power - 200nm

Question 6

if the image is blurry do we turn the coarse or fine focus wheel

Answer 6

coarse

Question 7

what does the coarse focus wheel do

Answer 7

allows for quick focusing by moving the objective lens or stage up and down - initial focusing

Question 8

what does the fine focus wheel do

Answer 8

sharpen the focus quality of the image

Question 9

1 micrometre is 1 x 10^-6 m. what is 0.0008cm in micrometres

Answer 9

8 micrometres

Question 10

suggest why there are many more mitochondria in muscle cells than in skin cells

Answer 10

muscles are used most of the time. this means that muscles, and therefore muscle cells will require more energy than skin cells. since skin cells are not always using energy. mitochondria provides the energy using aerobic respiration so more wil be needed in a muscle cell

Question 11

what is diffusion

Answer 11

the movement of a substance from an area of high concentration to an area of lower concentration

Question 12

what is osmosis

Answer 12

the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a partially permeable membrane

Question 13

what is active transport

Answer 13

the movement of particles from an area of low concentration to an area of high concentration against the concentration gradient

Question 14

give an example of where active transport takes place

Answer 14

root hairs or in the gut

Question 15

give an example where osmosis takes place

Answer 15

Movement of salt-water in animal cell across our cell membrane

Question 16

give me an example of where diffusion takes place

Answer 16

oxygen/carbon dioxide exchange, urea

Question 17

what is a hypertonic solution

Answer 17

one that contains more solute

Question 18

what is a hypotonic solution

Answer 18

one where there is more solvent

Question 19

what is an isotonic solution

Answer 19

contain equal concentrations of impermeable solutes on either side of the membrane

Question 20

what is turgor

Answer 20

Pressure exerted by fluid in a cell that presses the cell membrane against the cell wall. it’s what makes the leaves and stems of a plant rigid

Question 21

what is plasmolysis

Answer 21

where the cell membrane moves away from the wall due to too much water moving out of the cell and the external solution is less dilute

Question 22

give one use of sugar in the body

Answer 22

it can be broken down into glucose for aerobic respiration and anaerobic respiration for energy

Question 23

explain how villi are adapted for efficient absorption of sugar molecules

Answer 23

• cell membrane is one cell thick which allows the rate of diffusion to be increase as the sugar molecules do not need to travel very far
• there are many microvilli which increases the surface area

Question 24

what is a prokaryotic cell

Answer 24

a single celled organism that lacks a nucleus

Question 25

what is an eukaryotic cell

Answer 25

any cell or organism that possesses a clearly defined nucleus

Question 26

explain how a student could modify their investigation to determine the concentration of the solution inside each [egg]

Answer 26

use five or more different concentrations of salt/sugar solutions in the beakers. plot the percentage change (mass/volume) on a graph. plot a line of best fit and find the concentration of the egg by looking at 0% change.

Question 27

mass before - 73.5 70.3, 72.4, 71.6, 70.5
mass after - 77.0, 73.9, 75.7, 73.1, 73.8

a student said the result for egg 4 was anomalous. do you agree?

Answer 27

yes because the mass change is much lower than the other results

WORK IT OUT AMY

Question 28

what is the role of the mitochondria

Answer 28

Mitochondria are the site of aerobic respiration, so they release energy for the cell

Question 29

Which of the following are included in the ‘5 kingdoms of life’

Answer 29

Plants

Bacteria

Fungi

Animals

Protoctists

Question 30

what does heterotrophs mean

Answer 30

animals need to get their energy from other organisms

Question 31

what is differentiation

Answer 31

the process by which a cell changes to become specialised

Question 32

what does autrotrophs mean

Answer 32

they get their energy from the sun

Question 33

State and explain features that most exchange surfaces have in common.

Answer 33

Feature 1 - Large surface area

Explanation 1 - Lots of molecules can diffuse across at the same time

Feature 2 - Surfaces are very thin

Explanation 2 - Substances only have to diffuse a short distance

Feature 3 - Surfaces are permeable

Explanation 3 - Substances are able to pass through the surface

Feature 4 - Good blood supply (good supply of ‘internal medium’)

Explanation 4 - Maintains a strong concentration gradient as blood is constantly replaced

Feature 5 - Good supply of ‘external medium’

Explanation 5 - Maintains a strong concentration gradient as the air or food etc is constantly replaced

Question 34

Which adaptation in plants contributes to the efficient exchange of gases?

Answer 34

The flattened shape of their leaves

Question 35

name the two types of stem cells found in animals

Answer 35

adult stem cells and embryonic stem cells