b3.1 gas exchange

Question 1

ventilation system in fish

Answer 1

• extracts oxygen and remove CO2 from water
• has to keep moving or else will reach equilibrium

Question 2

ventilation system of small organisms

Answer 2

exchange gases directly with their surroundings thru diffusion

Question 3

alveoli

Answer 3

surrounded by capillaries to continuously bring in fresh blood

Question 4

why is a ventilation system needed

Answer 4

1. large organisms
2. land borne

Question 5

respiration

Answer 5

controlled release of energy from organic compounds to produce ATP

Question 6

ventilation

Answer 6

movement of air into and out of lungs during inhalation and exhalation

Question 7

how is ventilation controlled

Answer 7

by movement of ribcage and diaphragm

Question 8

gas exchange

Answer 8

diffusion of oxygen and carbon dioxide to and from the blood at the alveoli and respiring tissues

Question 9

where would more stomata be found + why

Answer 9

• lower epidermis
• control loss of water vapour

Question 10

what happens if transpiration is too quick

Answer 10

• plant will dehydrate and die

Question 11

shape of open stomata

Answer 11

kidney bean shape
- gap forms in the middle

Question 12

why doesnt AT2 secrete water

Answer 12

water is polar + cohesive + adhesive
- alveolus will collapse

Question 13

function of AT2

Answer 13

secretes surfactant

Question 14

AT1 function

Answer 14

thin so allows for rapid gas exchange

Question 15

function of surfactant [3]

Answer 15

1. prevents collapse
2. reduce surface tension
3. prevents alveolus from sticking tgt

Question 16

adaptation of alveolus [4]

Answer 16

1. large surface area for gas exchange
2. network of capillaries
   - maintain high concentration gradient
3. very thin membranes
4. moist surface
   - allow for gases to dissolve so gas exchange can occur

Question 17

tidal volume

Answer 17

amount of air that moves in and out of lungs within each respiratory cycle while breathing nomrally

Question 18

vital capacity

Answer 18

volume of air after maximum inspiration

Question 19

respiratory reserve

Answer 19

volume of air inhaled forcefully after normal tidal volume

Question 20

expiratory reserve

Answer 20

volume of air exhaled forcefully after a normal exhalation

Question 21

how to identify spongy mesophyll layer

Answer 21

lighter green

Question 22

function of waxy cuticle

Answer 22

waterproof to reduce water loss

Question 23

function of spongy mesophyll layer

Answer 23

air spaces for water vapour and oxygen to circulate

Question 24

function of guard cells

Answer 24

• control opening and closing of stomata

Question 25

structure of haemoglobin

Answer 25

• 4 chains of polypeptide + 4 haem groups

Question 26

co-operative binding

Answer 26

binding of oxygen to haemoglobin

Question 27

characteristic of haemoglobin binding to oxygen (+ states)

Answer 27

either completely saturated (R state) or no oxygen (T state)

Question 28

where do haemoglobin bind to oxygen

Answer 28

at the lungs

Question 29

where do haemoglobin lose oxygen

Answer 29

at respiring cells

Question 30

what happens when oxygen binds

Answer 30

conformational change
- makes other haem groups increase their affinity to bind

Question 31

when oxygen concentration in atmosphere increase what happens to oxygen saturation level of haemoglobin

Answer 31

positive but non-linear relationship

Question 32

partial pressure

Answer 32

proportion of total pressure exerted by each gas in a mixture

Question 33

eq of partial pressure

Answer 33

(air pressure x percentage of oxygen) / 100

Question 34

at what partial pressure is haemoglobin 100% saturated

Answer 34

30 kPa

Question 35

what happens when partial pressure is below 10 kPa

Answer 35

releases oxygen to repsiring cells

Question 36

action of haemoglobin at low kPa

Answer 36

give oxygen

Question 37

action of haemoglobin at high kPa

Answer 37

take oxygen

Question 38

how is co-operative binding useful

Answer 38

helps to unload oxygen quickly in tissue where aerobic respiration has to decrease oxygen concentration

Question 39

why is the oxygen dissociation curve better than a straight line

Answer 39

• can bind to more oxygen at a much lower kPa
• so able to bind even when oxygen concentration is low
• can release oxygen at higher concentration

Question 40

shape of fetus sigmoid curve

Answer 40

same shape but steeper

Question 41

why do fetus have a different sigmoid curve

Answer 41

• has to pick up oxygen from maternal blood at the placenta (parasitic relationship)
• high affinity to take more oxygen

Question 42

result of fetus haemoglobin having higher affinity

Answer 42

can pick up greater proportion of oxygen from adult haemoglobin at any given partial pressure of oxygen

Question 43

bohr shift

Answer 43

shift in oxygen affinity in haemoglobin due to carbon dioxide concentration

Question 44

oxygen affinity when there is low carbon dioxide concentration at lungs

Answer 44

• oxygen affinity is higher
  haemoglobin binds to oxygen easier at lower partial pressure

Question 45

oxygen affinity when there is high carbon dioxide concentration at muscles

Answer 45

• oxygen affinity of haemoglobin is lower
• haemoglobin releases oxygen easier to help cell respire aerobically

Question 46

where does gas exchange occur in the lungs

Answer 46

in type I pnuemocytes