3.3.2 Gas Exchange

Question 1

Why aren’t insects bigger?

Answer 1

More cell more demand of oxygen
Tracheal system could not meet respiratory demand
Especially there’s low oxygen concentration in the air
Mass of exoskeleton increase , decrease the speed of movement

Question 2

How do you reduce water loss of an insect?

Answer 2

Lipid layer
Hard exoskeleton, polysaccharide chitin
Spiracle close
Small surface area to volume ratio
Hair and waxy cuticle around the body

Question 3

Describe and explain the tracheal system of insect

Answer 3

tracheae held by rings of chitin
Prevent collapsing, keep them open

Tracheoles is extant throughout all the insects body tissue (thin and permeable)
Carrying oxygen directly to respiring cells and removing carbon dioxide
Short diffusion pathway from tracheoles to body cell only with 1 layer of cell

Spiracle equipped it with valves , atrium, and dust filter to trap humid air
Fluid filled end of tracheoles

Question 4

What is the movement of gas cause by？

Answer 4

Concentration and diffusion gradient
Contraction of muscles around the tracheal system (rhythmic, abdominal movement)
End of tracheoles are filled with water

Question 5

Adaptation to gas exchange of insect

Answer 5

Large surface area allowed, a large number of fine tracheoles

Question 6

Three ways of gas exchange

Answer 6

Diffusion

Mass transport
Contract and relax abdominal muscle which squeeze the air sac to move the air from sacs to tracheoles and use the air when spiracle is closed
Change volume of thorax / Abdomen pressure change in tracheae to push the air in and out

Anaerobic respiration
Produce lactate
decrease water potential of the cell
Allow water to move from tracheoles to the cell by osmosis
Decrease the volume in tracheae, decrease the pressure
So the air is drawn in

Question 7

The end of trachea this connects directly with the inside tomato tissue and filled with water when flying water is absorbed into the master tissue removal of water from the tracheoles increase the rate of diffusion of oxygen between the tracheoles and muscle tissue. Suggest one reason why.

Answer 7

Guess Move and feels faster in air than water
Increase volume of water

Question 8

Leaf structure, description

Answer 8

Waxy cuticle: prevent water loss
Upper and lower epidermis : allow light to penetrate so photosynthesis happen in the chloroplast
Palisade mesophyll : a vertical, compact, maximise chloroplasts exposed to light
Spongy mesophyll: with air, space, increase surface area exposed to the air, faster diffusion
Stomata : open in a day allowed water to get in and become turgid, dehydrated loose, water flaccid closed
Guard cell : expand/ strink , open and close the stomata

Question 9

How old is guard cell Open the stomata?

Answer 9

When I get enough water, it doesn’t matter to lose some when open it
Inner wall can’t expand as much

Question 10

adaptation of leaf structure

Answer 10

Thin and flat, large surface area to volume ratio
Stomata on the lower surface , reduce evaporation rate as it is shady, and damp
No cell far from the source of air because there is interconnecting air space, so the diffusion distance are short

Question 11

Adaptation of Xerophytes

Answer 11

Thick waxy cuticle : prevent water loss, waterproof, impermeable
Needle leaves : decrease surface area to volume ratio
Spikes : defends from insect , drinking the water, decrease surface area to volume ratio
Stomata sunken in the folded area : shady prevent sunlight and wind, so to reduce concentration gradient, and conserve, water, high humidity, saturatedlayer of still there inside
Hair and curled leaves : trap moisture, increase local humidity, maintain shallow concentration gradient
Longer route network : to reach water underneath

Question 12

Some herbicides cause the stomata of plans to close. Such as how do use herbicide might lead to the death of the plant.

Answer 12

When there’s herbicide the stomata close, there is the need to get exchange happen, and some interexchange of O2 and CO2 for photosynthesis. Near the process can continue indefinitely by relying exclusively on gas produced by the other. Some gas must be obtained from the environment. no supply both photosynthesis and respiration will ultimately stopped and the plants will die

Question 13

Why does bird need more gas than jellyfish?

Answer 13

More energetic
Maintain body temperature
Nutrients for maintain metabolic rate

Question 14

Why fish can’t leave water?

Answer 14

Gills, will clumps together, due to water, cohesion and adhesion, reduced surface area for gas exchange
A lot of nutrients in water
One-way respiration, water is denser

Question 15

Two types of flow in the fish

Answer 15

Counter current flow
Parallel flow

Question 16

Describe and explain counter current flow

Answer 16

Water and blood flow in opposite direction
Blood is always meeting water with a higher oxygen concentration
Concentration gradient is maintained across the whole length of gills lamellae
Diffusion of oxygen into the blood can occur across the whole length of gills
This ensure maximum possible gas exchange

Question 17

Describe and explain, parallel proof

Answer 17

Water and blood flow in the same direction
Equilibrium is reached halfway across the gills
No gas diffusion across the whole length

Question 18

Two. Type of fish

Answer 18

Cartilaginous fish
Bony fish

Question 19

How is cartilaginous fish ventilate? (What fish)

Answer 19

Parallel flow
Have to keep swimming in order for oxygenated water to flow over the gills (ramming ventilation)
Buccal pumping / gulping
Spiracle breathing

Ray/ sharks

Question 20

Which type of flow does bony fish use

Answer 20

Counter current flow in the gills

Question 21

Please draw out a diagram of human respiratory system

Answer 21

Answer on page 81 half note
Epiglottis
Larynx
Trachea
Bronchus / bronchi
Bronchioles
Alveoli
Rib cage
Intercostal muscle
Pleural membrane
Pleural cavity
Lungs
Diaphragm
Thoracic cavity

Question 22

Ventilation process

Answer 22

Breathe in (inhalation/inspiration)
Respiration (metabolic process) chemical reaction
Breathing out (exhalation/expiration)

Question 23

How will the intercostal muscle move when breathing in and out

Answer 23

Breathe out
External relax internal contract
Breathe in
External contract internal relax

Question 24

What does the composition of inspired alveoli exspired air show?

Answer 24

The nitrogen concentration similar, we don’t breathe in nitrogen
We don’t intake all of the oxygen
We breathe out CO2 as waste
Water vapour is a waste product of respiration

Question 25

Property of lung tissue

Answer 25

Elastic
Recoil , regain, original shape, push air out of the lungs
Stretch and expand

Question 26

Full inspiration process

Answer 26

Ribs: external intercostal, muscle, contracts, and rib rise
Diaphragm contracts to become flatten and pushes digestive organ down
Volume of chest cavity increased
Pressure in chest cavity drops below atmospheric pressure
Air contain oxygen is stuck in through the mouth
Air Move into lungs

Question 27

Full expiration process

Answer 27

External intercostal, muscle, relax and ribs fall
Diaphragm relax, and is pushed up by displace organ underneath
Volume of chest cavity decrease
Pressure in lungs increase and rise above atmospheric pressure
Air moves out of lung
Air is forced out through the mouth, removing waste carbon dioxide

Question 28

Feature of Air sac

Answer 28

Cartilage , maintain airway, open prevent collapse
Pulmonary surfactant : keep alveoli open, so cohesive water don’t attract

Question 29

Adaptation of air sac as a good gas exchange surface

Answer 29

Steep concentration gradient
Capillary wall and alveoli walls are thin , short, diffusion distance
Large number of alveoli , large surface area
Moist surface of gas to dissolve before they diffuse
Surrounded by many blood vessel called capillaries

Question 30

How do you calculate pulmonary ventilation rate?

Answer 30

Tidal volume x breathing rate
Dm3 min -1

Question 31

Why diffusion of gases between alveoli and blood is very efficient

Answer 31

Red blood cell are slow as they pass through pulmonary capillaries
This increase the time for diffusion

Rbc are flattened against a capillary wall
Distance between Alviola, air and red blood cell decrease

Wall of both alveoli and capillaries are thin
Diffusion distance shot

Alveoli and pulmonary capillary have a very large total surface area

Breathing movement, ventilate the lungs and heart circulate blood around alveoli constantly
Maintain steep Concentration gradient

Blood flow through the pulmonary capillaries
Maintain a concentration gradient

Question 32

Two type of COPD

Answer 32

Emphysema: air sac breakdown
Persistent bronchitis : information and execss sputum

Question 33

Feature of COPD lungs is

Answer 33

Damage tissue
Inflamed Airways
Floppy elastic lining

Question 34

Risk factor of lung disease

Answer 34

Smoking
Air pollution
Genetic
Infection
Occupation (worker exposed to harmful chemical dust)

Question 35

Definition of cause and relationship

Answer 35

Correlation
Change in one covariable is reflected by a change in another variable

Causation
What the variable costs are there for another variable to change

Question 36

How to minimise the risk factor of lung disease

Answer 36

Banning, smoking in public places in workplaces
Ban on tobacco advertising
Increase cigarette tax
Minimum wage increase to 18 for buying tobacco
Plain, packaging or graphic image
Health warning on packages
NHS. Free support to give up vaping as alternative.
Education
Various air pollution control
Promotion of electric vehicles, reducing diesel cars

Question 37

How old is loss of elasticity, makes expiration difficult

Answer 37

Is hard to maintain concentration gradient

Question 38

Suggest a reason why there is a time like between the number of cigarette smoke in the corresponding change in the number of death from lung cancer

Answer 38

Lung cancer develop overtime, so death occur some years later

Question 39

Possible reason for lung cancer death increase

Answer 39

Greater percentage of people smoking
Increase in air pollution
Increase in population size

Question 40

One measure of lung function is force expiratory volume. This is the volume of a dark and possibly be blown out in one second after full inspiration. Suggest how pulmonary fibrosis might affect FEV and explain why

Answer 40

FEV lower due to difficulty expiring due to loss of elasticity

Question 41

Why we use umol g-1 h-1 for the rate of oxygen uptake

Answer 41

Small uptake, volume
Avoid use of power /standard form

Question 42

Explain what cause the oxygen concentration in the tracheae to fall when the spiracles are closed in the insect

Answer 42

Metabolic respiration
Therefore, diffusion tissue
Oxygen, unable to enter organism

Question 43

Exam Q: describe the feature of fish gills that give them a large surface area

Answer 43

Lamellae on filament
/a lot /Both layers of gills

Question 44

Explain why the figures in the table given per gram of tissue (table, shows the flow of blood to the lungs into the diaphragm in a seal when did this on land and when is underwater?)

Answer 44

Allowed comparison
AS organ differ in size
Larger organ need more blood

Question 45

Exam question：there is a greater percentage reduction in blood flow to the diaphragm down to the lungs during a dice, explain the advantages of a diving seal, in terms of blood continuing to throw to the lungs, and a large reduction in blood flow to the diaphragm

Answer 45

Blood continue flowing to lungs, because some oxygen still in lungs, remove of CO2 who
A large reduction in blood flow to the diaphragm so more blood available to order organ, supply, oxygen and remove carbon dioxide
Diaphragm do not contract because no breathing will not required as much oxygen