3.4 Mass transport

Question 1

what transports blood around the body

Answer 1

haemoglobin

Question 2

what is haemoglobin

Answer 2

quaternary protein made up of four chains each with a harm group
> each haem group has an iron ion so there are four binding sites

Question 3

what is harmoglobij called after it binds with oxygen

Answer 3

oxygaemoglobin

Question 4

what is the partial pressure of oxygen

Answer 4

concertation of oxygen

Question 5

what happens when there is a high pO2

Answer 5

haemoglobin has a high affinity for oxygen so combines with it to form oxyhaemoglobin

Question 6

what happens when there’s a low pO2

Answer 6

haemoglobin has a low affinity for oxygen so dissociates from it

Question 7

what is the bohr affect

Answer 7

partial pressure of CO2 has an effect on the haemoglobin dissociation curve
— respiration produces CO2 so pCO2 increases
— causes affinity of oxygen to decrease so haemoglobin dissociates with oxygen
— the curve shifts to the right so more o2 is released

Question 8

what affinity do organisms that live at high altitudes have for o2 (low pO2)

Answer 8

higher affinity for oxygen
curve shifts left

Question 9

what affinity do organisms that have high pO2 have

Answer 9

lower affinity
curve shifts right

Question 10

what is a double circulatory system

Answer 10

blood passes through the heart twice in a complete corcuit

Question 11

where do arteries carry blood

Answer 11

away from the heart

Question 12

where do veins carry blood

Answer 12

to the heart

Question 13

what way does the blood travel through the circulatory system

Answer 13

• to lungs to be oxygenated then travels to the heart, then through the arteries to body cells where oxygen moves into the cells
• deoxygenated blood returns to heart via veins

Question 14

what does the pulmonary artery do

Answer 14

supplies deoxygenated blood to the lungs

Question 15

what does the pulmonary vein do

Answer 15

returns oxygenated blood from lungs to the heart

Question 16

what does the vena cava do

Answer 16

returns deoxygenated blood to the heart

Question 17

what does the aorta do

Answer 17

takes blood away from the heart

Question 18

what does the renal artery do

Answer 18

supplies kidneys with blood

Question 19

what does the renal vein do

Answer 19

removes deoxygenated blood from kidneys

Question 20

what are the four chambers of the heart

Answer 20

left and right atria
left and right ventricles

Question 21

what are the left and right sides of the heart divided by

Answer 21

septum

Question 22

why does the left ventricle have a thicker wall

Answer 22

has to push blood a further distances so requires more force

Question 23

what valves are between the atria and ventricles

Answer 23

atrioventricular valves

Question 24

what valances are between the blood vessels and heart chambers

Answer 24

semilunar valves

Question 25

what are the three stages of the cardiac cycle

Answer 25

atrial systole ventricular systole diastole

Question 26

what happens during atrial systole

Answer 26

atria contract, pushing blood into ventricles ventricles relax atrioventricular valves open

Question 27

what happens during ventricular systole

Answer 27

atria relax ventricles contracting, pushing blood out of the heart semilunar valves open

Question 28

what happens during diasotle

Answer 28

atria and ventricles relax atrioventricular valves are open blood flows into the heart

Question 29

structure of an artery

Answer 29

walls are thick and muscular with elastic tissue to stretch and recoil to maintain pressure as heart beat inner lining is folded to allow stretch can be divided into arterioiles

Question 30

structure of veins

Answer 30

walls are thinner and lumen is larger to decrease resistance as blood is at a low pressure - contains valves to keep flow in the right direction

Question 31

what are capillaries

Answer 31

site of exchange of substances between the blood and the body cells

Question 32

structure of capillaries

Answer 32

walls are one cell thick to give shirt diffusion distance width of one red blood cell to bring them close to minimise diffusion distance form capillary beds to macimase surface for exchange

Question 33

what is tissue fluid

Answer 33

fluid surrounding cells in tissues

Question 34

what forms tissue fluid

Answer 34

blood plasma

Question 35

how is tissue fluid formed

Answer 35

- at artériole end in capillaries > hydrostatic blood pressure in blood vessels is higher than the tissue fluid - water and small molecules are pushed out of gaps in capillary bed and leave the blood plasma - venue end > hydrostatic pressure in tissue fluid is higher than in the blood vessels - water and small molecules re enter blood plasma - causes a constant renewal of tissue fluid

Question 36

what excess tissue fluid drained by

Answer 36

lymphatic system returns to circulatory system

Question 37

how does cardiovascular disease start

Answer 37

formation of atheroma

Question 38

what happens if many atheromas form in coronary arteries

Answer 38

coronary heart disease

Question 39

how is an atheroma formed

Answer 39

endothelium of artery is broken and white blood cells and lipids gather under it forming an atheroma

Question 40

how does an anyeurysm form

Answer 40

inner layers of artery are forced through outer layers - happens because of an atheroma

Question 41

what is thrombosis

Answer 41

blood clot that can dislodge and block a blood vessel elsewhere in the body

Question 42

how does thrombosis occur

Answer 42

atheroma rupturing the inner lining or an artery

Question 43

what happens if atheromas cause a blockage in the coronary arteries

Answer 43

myocardial infarction - bloods nkt getting to the heart

Question 44

risk factors for CHD

Answer 44

- high cholesterol - genetic disposition - high blood pressure

Question 45

what does the xylem transport

Answer 45

water and small mineral ions from the roots up the plant

Question 46

what does the phloem transport

Answer 46

sugars up and down the plant

Question 47

explain cohesion and tension

Answer 47

1. water evaporates from the leaves - transpiration 2. this creates tension which pulls more water into the leaf 3. water molecules are cohesive so they stick together - pulled into the leaf together 4. whole column of water in the xylem moves upwards 5. water enters stem through roots

Question 48

what is translocation

Answer 48

movement of solutes to where they’re needed in a plant - moves solutes from source to sinks

Question 49

what happens in the source end in the ands flow hypothesis

Answer 49

- active transport actively loads solutes from companion cells into sieve tubes of phloem - this lower water potential in sieve tubes so water enters via osmosis from xylem - this creates high pressure inside sieve tubes

Question 50

what happens in the sink in the mass flow hypothesis

Answer 50

- solutes are removed from phloem to be used up - increases water potentioal inside sieve tubes so water leaves by osmosis - this lowers pressure inside sieve tubes

Question 51

what happens in the flow in mass flow hypothesis

Answer 51

- result is a pressure gradient from source end to sink end - gradient pushes solutes along sieve tubes towards the sink - will be used in respiration or stored

Question 52

how can ringing experiments be used to investigate mass flow

Answer 52

- ring of bark that involves phloem is removed - plant is left until bulge forms above ring - fluid will contain a higher concentration of sugars than the fluid below the ring - This shows that there is a downwards flow of sugars

Question 53

how can radioactive tracers be used to investigate mass flow

Answer 53

- one leaf of a plant is exposed to radioactive CO2 - The 14-C will then be combined into the sugars produced by the plant - Photographic film can then be used to track how the radioactive carbon has moved through the plant