B8

Question 1

What does it mean if an organism is
unicellular or multicellular?

Answer 1

Unicellular - if it is only made of one cell.
Multicellular - made of multiple cells.

Question 2

Small organisms will have a
__________ SA:V ratio.

Answer 2

Small organisms will have a large SA:V
ratio.

Question 3

Large organisms have a __________
SA:V ratio.

Answer 3

Large organisms have a small SA:V ratio.

Question 4

How do you work out the surface
area of a cube?

Answer 4

Surface area of one face of a cube = length
x height of cube.
Then x6 as there are 6 sides on a cube.

Question 5

How do you work out the volume of
a cube?

Answer 5

Volume = length x height x width

Question 6

Give 3 ways in which alveoli are
adapted.

Answer 6

• Lots of alveoli so they have a large
  surface area.
• Ventilation maintains a concentration
  gradient.
• Alveoli walls are very thin so the
  diffusion distance is short.
• They are moist which allows gases to
  diffusion quicker.

Question 7

What is the structure of an artery?

Answer 7

Arteries have:

• thick, elastic walls to withstand
  high pressures
• a narrow tube (lumen)

Question 8

Describe the structure of a vein.

Answer 8

Veins have:

• Thin, flexible walls
• a wide tube (lumen)
• valves

Question 9

Describe the structure of a capillary.

Answer 9

Capillaries have:

• thin walls to allow for faster
  exchange of substances.

Question 10

What is the function of valves?

Answer 10

Valves prevent the backflow of blood.

Question 11

What is the scientific term for a red
blood cell?

Answer 11

Erythrocyte

Question 12

What is the function of an erythrocyte
(red blood cell)?

Answer 12

To carry oxygen around the body.

Question 13

What substance in red blood cells
binds to the oxygen?

Answer 13

Haemoglobin

Question 14

In the blood, what is the function of
platelets?

Answer 14

For blood clotting

Question 15

In the blood, what is the function of
lymphocytes (white blood cells)?

Answer 15

These are part of the immune system
and destroy pathogens.

Question 16

Arteries carry blood _______ the
heart.

Answer 16

Arteries carry blood away from the
heart.

Question 17

Veins carry blood _______ the heart.

Answer 17

Veins carry blood towards the heart.

Question 18

Which part of the heart is thicker and
why?

Answer 18

The left ventricle is thickest because it
must pump blood around the body at
high pressures.

Question 19

What is the equation for cardiac
output?

Answer 19

Cardiac output = stroke volume x heart
rate.

Question 20

What do you call the top and bottom
chambers in the heart?

Answer 20

Top - Atria (singular - atrium)
Bottom - Ventricles

Question 21

What is the equation for aerobic
respiration?

Answer 21

glucose + oxygen → carbon dioxide +
water

Question 22

What is the equation for anaerobic
respiration?

Answer 22

glucose → lactic acid

Question 23

Where does aerobic and anaerobic
respiration occur?

Answer 23

Aerobic in the mitochondria.
Anaerobic in the cytoplasm.

Question 24

In the core practical, why did you add
soda lime?

Answer 24

To absorb the carbon dioxide.

Question 25

In the core practical, what would a
control experiment be?

Answer 25

Set up the same experiment with
dead/no organisms

Question 26

In the core practical, what way would
you expect the bubble to move?

Answer 26

It would move towards the organisms
because the pressure in the tube
decreased.

Question 27

In the core practical, what would be
some control variables?

Answer 27

• mass/number of organisms
• volume of soda lime