SB8 Exchange and Transport in Animals

Question 1

List some substances that need to be transported in and out of the body

Answer 1

0xygen, Carbon Dioxide, Water, Food, Mineral ions

Question 2

Define urea

Answer 2

a waste product produced from proteins - diffuses from cells to blood plasma for removal by the kidneys

Question 3

How do you calculate SA:V ratios

Answer 3

1) Find the SA = length x width (for all sides)
2) Find V = length x width x height
3) Divide both sides of the ratio by the volume to get it in the form n:1

Question 4

Why is a larger SA:V ratio good?

Answer 4

The SA is larger than its volume = large area to diffuse substances into cells

Question 5

Define SA in affect to the rate of diffusion

Answer 5

The more SA there is available for molecules to move across, the faster they can get from one side to the other

Question 6

Define conc. gradient in affect to the rate of diffusion

Answer 6

Substances diffuse faster if there’s a big difference in conc. between the area they are diffusing from and to. If there are lots of particles on one side, there are more to move across

Question 7

Define distance in affect to the rate of diffusion

Answer 7

Substances diffuse more quickly when they haven’t got as far to move

Question 8

Formula for rate of diffusion

Answer 8

rate of diffusion ~ surface area x conc. difference / thickness of membrane

Question 9

Define red blood cells (erythrocytes)

Answer 9

• biconcave disc shape = large SA
• no nucleus = more room to carry O2
• haemoglobin binds to O2 to make oxyhaemoglobin

Question 10

Define phagocytes

Answer 10

Change shape to engulf unwelcome microorganisms - this is called phagocytosis

Question 11

Define lymphocytes

Answer 11

Produce antibodies against microorganisms and antitoxins to neutralise toxins

Question 12

Define platelets

Answer 12

Fragments of cells that help blood clot at wounds

Question 13

List substances in plasma

Answer 13

Red & White blood cells, C02, Urea, Hormones, Proteins, Antibodies, Glucose, Amino acids

Question 14

Define arteries

Answer 14

• thick walls to help with high pressure
• thick layers of muscle to strengthen them
• elastic fibres allow the to stretch and spring back

Question 15

Define capillaries

Answer 15

• one cell thick
• permeable walls so substances can diffuse to cell
• narrow so can reach every cell

Question 16

Define veins

Answer 16

• lower pressure blood
• bigger lumen to help flow
• valves to keep blood flowing in the right direction

Question 17

Formula for cardiac output

Answer 17

heart rate x stroke volume

Question 18

Adaptations to the heart

Answer 18

• valves prevent backflow of blood in heart

- left ventricle = thicker wall because it needs more muscle to pump blood to whole body

Question 19

List 4 heart chambers in order

Answer 19

right atrium, right ventricles, left atrium, left ventricle

Question 20

List 4 major blood vessels in order

Answer 20

vena cava, pulmonary artery, pulmonary vein, aorta

Question 21

Describe the flow of blood through the heart

Answer 21

1) Right atrium receives deoxygenated blood from body via the vena cava
2) Deoxygenated blood moves to right ventricle, which pumps it to lungs via the pulmonary artery
3) Left atrium receives oxygenated blood from lungs via the pulmonary vein
4) Oxygenated blood moves to left ventricle, which pumps it to body via aorta

Question 22

Define respiration

Answer 22

The process of transferring (releasing) energy from the breakdown of organic compounds (glucose)

Question 23

Aerobic respiration equation

Answer 23

glucose + oxygen –> carbon dioxide + water

Question 24

Anaerobic respiration equation

Answer 24

glucose –> lactic acid (which builds up in the muscles and causes cramp)

Question 25

Why is respiration exothermic?

Answer 25

Because energy is transferred to the environment. Some of this energy is transferred by heat

Question 26

Anaerobic respiration in plants

Answer 26

glucose –> ethanol + carbon dioxide