Past paper questions higher

Question 1

Cytoplasm

Answer 1

where many of the chemical reactions happen.

Question 2

Nucleus

Answer 2

Contains DNA

Question 3

Cell membrane

Answer 3

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

Question 4

Mitochondria

Answer 4

where most energy is released in respiration.

Question 5

Ribosomes

Answer 5

where protein synthesis occurs.

Question 6

Chloroplast

Answer 6

contains chlorophyll, which absorbs light energy for photosynthesis.

Question 7

Cell wall

Answer 7

strengthens the cell and supports the plant.

Question 8

Permanent vacuole

Answer 8

Filled with cell sap

Question 9

calculate the magnification of an image

Answer 9

Magnification= size of image / real size of object

Question 10

what are the risks of investigating with a light microscope.

Answer 10

Care must be taken when looking down the microscope if the illumination is too bright.
Care must be taken when using microscope stains.
Care must be taken when handling coverslips and microscope slides.

Question 11

State the name of the part of the cell that is the site of respiration.

Answer 11

Mitochondria

Question 12

Many exchange surfaces in living things have a large surface area.
What is an example of an exchange surface.

Answer 12

The villi in the digestive system

Question 13

Communicable diseases, like the common cold, can infect organisms in different ways. Select the correct way in which many farmers believe tuberculosis infects their cows.

Answer 13

Vector

Question 14

Explain why the potato pieces in the 0.4 mol/dm3 salt solution decreased in mass.

Answer 14

water moves out of cells / potato
by osmosis
(because) the solution in the
cells / potato is less
concentrated than outside
or
(because) the solution in the
cells / potato is more dilute than
outside

Question 15

Which disease is caused by a fungus?

Answer 15

rose black spot

Question 16

Give a reason for each of the following steps in the method.
1. A thin layer of onion epidermis is used.

Answer 16

help see individual cells

Question 17

Give a reason for each of the following steps in the method.
2. Iodine solution is added to the onion epidermis.

Answer 17

to stain / see the parts of the cell

Question 18

Give a reason for each of the following steps in the method.
3. The cover slip is lowered onto the onion epidermis at an angle.

Answer 18

to prevent / reduce air bubbles

Question 19

two ways the student could improve the drawing of onion cells

Answer 19

any two from:
* include magnification / scale
* use continuous lines
or ensure no gaps in lines
* do not draw overlapping cells
* draw (wider) cell walls
* do not shade
* draw all the cells present
* draw correct cell shapes
* do not have gaps between
cells
* draw nuclei in correct location
* label cell part(s)

Question 20

Give two ways onion cells would look different when seen using an electron
microscope.

Answer 20

(cell would) have more detail

Question 21

Identify whether each defence is a chemical response or a physical response.
1.Thick, waxy layer on leaf surface

Answer 21

Physical

Question 22

Identify whether each defence is a chemical response or a physical response.
2. Berries that are poisonous

Answer 22

chemical

Question 23

Identify whether each defence is a chemical response or a physical response.
3. Bark on trees that falls off

Answer 23

physical

Question 24

Explain why a tree might die if the roots of the tree are damaged.

Answer 24

• less absorption of water
  o less water so lower rate of photosynthesis
• less absorption of (named) ions / minerals
  o fewer nitrates so fewer proteins made for growth
• damage to phloem
  o less transport of sugars to root cells
• damage to xylem
  o less water transported (to cells)
• less anchorage

Question 25

Mitosis,
Cells divide when:

Answer 25

an organism grows
an organism becomes damaged and needs to produce new cells

Question 26

length of phase=

Answer 26

number of cells at that state / total number of cells ^ total length of time in the cell cycle.

Question 27

Water and carbon dioxide are exchanged between leaves and the atmosphere
through pores called stomata.
Name the cells that control the opening and closing of the stomata.

Answer 27

guard cells

Question 28

Water moves through a plant in the transpiration stream.
Describe two differences between the transpiration stream and translocation.

Answer 28

transpiration (stream)
involves xylem and
translocation involves
phloem
* transpiration (stream)
transports water (and
minerals / ions) and
translocation transports
(dissolved) sugars