12.10 Gas exchange

Question 1

IN OR OUT
1. Respiratory gases (oxygen and carbon dioxide)
2. Nutrients (glucose, amino acids and lipids)
3. Excretory products (carbon dioxide and urea)
4. Heat

Answer 1

1. IN OR OUT
2. IN
3. IN OR OUT
4. OUT

Question 2

If the surface area decreases does it increase or decrease SA:VOL ????

Answer 2

increase

Question 3

Oxygen is required to produce…during…

Answer 3

ATP
AEROBIC RESPIRATION

Question 4

In diffusion the net moves…

Answer 4

from an area of higher concentration to lower concentration

Question 5

what is Fick’s law? (equation)

Answer 5

Rate of diffusion = SA x Conc gradient / diffusion distance or pathway

Question 6

what makes a good exchange surface?

Answer 6

Large surface area
Large concentration gradient
Thin exchange surface

Question 7

what is the downside to the insect’s surface for gas exchange?

Answer 7

It’s favorable for evaporation leading to fatal dehydration

Question 8

How insects limit water loss

Answer 8

1. waterproof covering over their body surface. This is usually rigid outer skeleton (exoskeleton) covered with waterproof cuticle
2. Relatively small surface area to volume ratio to minimise water loss

Question 9

How oxygen moves through insect

Answer 9

1. Oxygen enters the insect spiracles and into the trachae
   2.Spriracles close
2. Oxygen diffuses through the tracheae into the tracheoles down a conc grad
3. Oxygen is delivered directly to respiratory tissues

Question 10

How the structure of the insect is adapted to gas exchange

Answer 10

Spiracles - tiny pores for gas to enter and exit through as they open and close. (open when CO2 levels increase)

Tracheoles - small tubes with thin walls so diffusion distance is reduced
Highly branched so large surface area

Trachae - tubes full of air for diffusion is fast

Question 11

Oxygen diffusion

Answer 11

1. tissue respire using oxygen - reduces conc of oxygen at tissue
2. Oxygen moves for high to low conc so moves from trachae to tissue
3. lowers oxygen conc in tracheae so oxygen moves into the tracheae from outside via spiricles

Question 12

Carbon dioxide

Answer 12

1. respiration produces CO2 inc conc at tissue
2. Co2 moves from high to low conc at tissue to tracheae
3. Co2 move from high conc in tracheae to low conc outside insect via spiracle

Question 13

explain abdominal pumping

Answer 13

movement of insect’s muscles create mass movement of air in or out trachea thus inc rate of gas exchange.
small air sacs in trachea and muscles around trachea contract and pump air in sacs deeper into tracheoles.

Question 14

Oxygen during flight

Answer 14

at rest water builds up in insect’s tracheoles

During flight insect respire anaerobically and produce lactate (lactic acid)

lowers water potential of muscle cells. As lactate builds up water passes via osmosis from the tracheoles into muscle cells

Question 15

two ways where structure of fish gills is adapted for gas exchange

Answer 15

1. many fillaments/lamellae so there’s a large surface area
2. Lamellae are thin for a short diffusion distance/pathway

Question 16

structure of fish

Answer 16

1. 5 fills each side of its head
2. water moves in through mouth and out through the gills.
3. they have gill fillaments that have lamellae
4. water carrying oxygen enters through fish’s mouth, passes through lamellae on gill fillaments where most oxygen is removed.
5. finally water containing little oxygen leaves through gill opening

Question 17

a fish uses its gills to absorb oxygen from water. Explain how the gills of a fish are adapted for efficient gas exchange (6)

Answer 17

1. LArge SA provided by many lamellae so diffusion is more effiecient
2. Thin epithellium of lamellae distance between water and blood so short diffusion distance
3. water and blood flow in. oppsite directions (counter currantflow) so conc gradient is maintaned
4. as water always next to blood w/ lower concentration of oxygen
5. circulation replaces blood saturated with oxygen
6. ventillation replaces water

Question 18

Explain how counter current mechanism in fish gills ensures the maximum amount of oxygen passes into the blood flowing through gills (3)

Answer 18

1. water and blood flow in opposite directions
2. Blood always passing water with higher oxygen conc
3. Oxygen diffusion / conc gradient maintained across full length of gill lamellae/fillament

Question 19

structure of the leaf

Answer 19

-cuticle
- upper epidermis cells
-palisade mesophyll cells
-spongy mesophyll cells
-sub-stomatal air space
-lower epidermis cells

Question 20

Adaptions of leaf for gas exchange

Answer 20

1. flat - larger surface area to volume ratio
2. many stomata - pores allow air to move in and out of leaf
3. air spaces in leaf so short distance between mesophyll cells and air

Question 21

Diffusion of co2 for photosynthesis

Answer 21

1. mesophyll cells photosynthesis and this reduces the conc of co2 in cells
2. co2 diffuses into air spaces from cells
3. this in turn reduces the co2 conc into airspaces causing co2 to. move into air spaces from outside the leaf through stomata

Question 22

Diffusion of O2 (leaf)

Answer 22

1. mesophyll cells prod o2 from photosynthesis
2. o2 diffuses into airspaces from cells
3. this inc conc of o2 in air spaces causing o2 to move from air spaces to outside leaf via stomata

Question 23

how they’re adapted to reduce water loss

Answer 23

Air spaces saturated with water vapour from xylem and water diffuses out of stomata as it evapourates

at night guard cells close stomata
waxy cuticle

Question 24

Describe how co2 in air outside a leaf reaches mesophyll cells inside a leaf

Answer 24

1. CO2 enters via stomata
2. stomata opened by guard cells
3. diffuses through air spaces
   4.down diffusion gradient

Question 25

xerophytic plants and their adaptions

Answer 25

These are plants that live ina dry/arid environments so have leaf adaptions to avoid water loss 1. Reduced number of stomata = less surface area for water loss 2.Stomata in pits = reduced conc gradient 3. Hair to trap water = reduced conc gradient 4. Rolled leaves = Reduced conc gradient 5. Leaves reduced to spines = Less surface area for water loss 6. Thick waxy cuticles = inc diffusion distance

Question 26

Lung structure

Answer 26

Trachea Bronchi Bronchioles Alveoli Diaphragm

Question 27

Trachea

Answer 27

It’s a wind tube like structure that carries air from mouth to lungs

Question 28

Bronchi

Answer 28

Trachea splits into 2 bronchi as it enters the lungs which allows air to travel to left and right lung

Question 29

Bronchioles

Answer 29

Bronchi further divide into smaller branches called bronchioles. This then supply the alveoli with air

Question 30

Describe the alveoli structure

Answer 30

-small sacks at the end that act as an interference between air in lungs and blood - large surface area and dense capillary network to maintain efficient diffusion rates - total alveolar surface area in human adults is 70m^2 - rich blood supply with circulates the blood to maintain a large concentration gradient between gases in blood and alveoli - deoxygenated blood is brought to lungs by pulmonary artery from heart and return oxygenated via pulmonary vein

Question 31

What is a Thin squashed cell also known as?

Answer 31

Squamous

Question 32

Breathing is not…

Answer 32

Respiring

Question 33

Breathing is…

Answer 33

A result of the difference in pressure between lungs and air outside the body Pressure inside lungs is changed by changes in lung volume

Question 34

Describe Inhalation

Answer 34

- external intercostal muscles contract pulling up rib cage UP and OUT - Diaphragm contracts and pulls down - Theoretic cavity volume increases - Pressure in lungs lower than atmospheric pressure - Air moves into lungs down a pressure gradient

Question 35

Describe Exhalation

Answer 35

- External intercostal muscles relax - Diaphragm relaxes and moves up - Thoracic cavity volume decreases - Pressure in lungs greater than atmospheric pressure - Air moves out of lungs down a pressure gradient

Question 36

Diffusion of gases in lungs

Answer 36

-deoxygenated blood form pulmonary artery has low conc of oxygen a d high conc of CO2 compared to air inside alveoli - as blood reaches capillaries surrounding the alveoli

Question 37

Pulmonary ventilation equation

Answer 37

Pulmonary ventilation rate (dm^3 min^-1) = tidal volume (dm^3) x breathing rate (min^-1)

Question 38

Tidal volume

Answer 38

Natural breathing volume

Question 39

Inspiratory/expiratory rate

Answer 39

Extra volume for a deep breath

Question 40

Residual volume

Answer 40

Air that remains in lungs to prevent collapse of alveoli

Question 41

Vital capacity

Answer 41

Max volume of air a person can expel from the lungs

Question 42

Corrolent coefficient is…

Answer 42

Used when examining an association between two sets of continuous data

Question 43

Null hypothesis..

Answer 43

No significant correlation between x and y

Question 44

Conclusion:

Answer 44

-Accept null hypothesis if P value > 0.05 - - probability of any association between A and B being due to chance is greater than 5% so association isn’t significant - reject null hypothesis (chance less than 5%)