respiratory gas exchange

Question 1

2 types of respiration and what do they entail

Answer 1

external respiration - gas exchange from external environment to cells
cellular respiration - energy production via aerobic metabolism

Question 2

3 functions of external respiration

Answer 2

O2 uptake,
CO2 removal
pH regulation

Question 3

2 types of gas movement

Answer 3

diffusion,
bulk transport

Question 4

what is the name of the equation for measuring diffusion rate

Answer 4

Fick’s law

Question 5

what happens if diffusion constant (D) increases

Answer 5

rate of diffusion increases

Question 6

what happens if area (A) increases

Answer 6

rate of diffusion slows

Question 7

what happens if there is a higher pressure (p) difference between the two sides

Answer 7

rate of diffusion increases

Question 8

what happens if the distance over which diffusion occurs (d) increases

Answer 8

rate of diffusion decreases

Question 9

4 qualities of gas exchange surfaces

Answer 9

permeable to gas,
moist,
thin,
maximise surface area

Question 10

3 types of breathing method

Answer 10

cutaneous breathers (through skin),
water-breathers (gills),
air-breathers (lungs or tracheae)

Question 11

how do flatworms carry out gas exchange

Answer 11

only a few cells thick so easy diffusion across membrane

Question 12

how do earthworms carry out gas exchange

Answer 12

excrete mucus to stay moist, if dry the earthworm suffocates
skin is thin to minimise diffusion distance
gas diffuses across thin membrane to very dense net of capillaries

Question 13

how do salamanders respire

Answer 13

soley skin breathers

Question 14

explain respiration throughout a tadpole and frog lifecycle and the changes that occur

Answer 14

tadpoles get more oxygen via skin breathing as they are exclusively aquatic - use both gills and skin for oxygen uptake - cutaneous
frogs have no gills, instead using the lungs which are responsible for most of the oxygen uptake, however carbon dioxide excretion still happens through ski

Question 15

give 2 examples of a water-breather and how they are adapted

Answer 15

axolotls have a crown of feathery gills to maximise surface area
fish have highly evaginated gills protected by a bony flap

Question 16

what do air-breathers require

Answer 16

structural support

Question 17

what are the benefits of being an air breather

Answer 17

occurs internally so easier to keep surface moist

Question 18

what animals are capable fo both water and cutaneous breathing

Answer 18

amphibious fish e.g. mangrove killy fish

Question 19

what animals use convection of external medium only to achieve gas exchange and how

Answer 19

Cnidarians (jellyfish and corals) use tentacles or flagella to move water and maintain concentration gradient

Question 20

what animals use convection of internal medium only to achieve gas exchange

Answer 20

earthworms

Question 21

3 challenges of water breathing

Answer 21

susceptible to toxic molecules in water,
high viscosity and dense,
low oxygen solubility,
low diffusion rate

Question 22

what is the flow of water in fish gills and what is the benefit of this

Answer 22

unidirectional to maintain concentration gradient across gills allowing constant diffusion

Question 23

what are 2 methods of ventilation in fish and which uses energy

Answer 23

active buccal pump - uses energy
ram ventilation

Question 24

explain how the active buccal pump works

Answer 24

fish opens mouth increasing volume of buccal chamber, drawing water in
closes mouth, contracts buccal cavity, forcing water out over gills

Question 25

explain how ram ventilation occurs

Answer 25

occurs in fast-moving fish - open their mouths and water moves in naturally due to fast speed

Question 26

how many gill arches are there

Answer 26

4

Question 27

what do gill arches have attached to them and what are these made up of

Answer 27

gill filaments with many lamellae

Question 28

what is the role of lamellae

Answer 28

creates dense network of capillaries

Question 29

where does counter-current exchange occur in fish gills

Answer 29

between the blood flow in the lamellae and the flow of water over the gills - opposite directions

Question 30

what is the oxygen extraction efficiency of fish

Answer 30

70%

Question 31

what is the oxygen extraction efficiency of humans

Answer 31

25%

Question 32

is carbon dioxide easier to excrete as an air-breather or water-breather

Answer 32

easier as a water-breather

Question 33

what was the possible driver of the evolution on to land

Answer 33

in the tropics the water is warm and oxygen solubility is low, fish that live there must be able to breathe out of water as water source can dry up

Question 34

what is the colloquial name for a well-known amphibious fish species

Answer 34

lungfish

Question 35

3 challenges of breathing air

Answer 35

water loss,
heat loss,
structural support

Question 36

how do insects air breathe

Answer 36

have spiracles which are open to the air and connect to the tracheae

Question 37

what structure do mammals have to maximise surface area

Answer 37

alveoli

Question 38

what is another benefit of alveloli

Answer 38

minimise diffusion distance with thin alveoli cell walls and are surrounded by capillary network

Question 39

what are the 2 types of capillaries found in birds and what do they do

Answer 39

air capillaries to minimise diffusion distance
blood capillaries to maximise blood flow

Question 40

what other structure do birds have present

Answer 40

air sacs

Question 41

what is the unit of gas exchange in birds

Answer 41

air capillaries

Question 42

what is the direction of air flow in birds and how is it beneficial

Answer 42

unidirectional using a 2 cycle breathing system = no mixing of inhaled and exhaled breathe improving concentration gradient

Question 43

what type of gas exchange to birds use

Answer 43

cross-current

Question 44

how effective is cross-current exchange

Answer 44

more efficient than concurrent but less so than counter-current