Respiration And Gas Exchange

Question 1

Hypoxia

Answer 1

Reduced O2 levels

Question 2

Anoxia

Answer 2

Very low O2 levels

Question 3

Hypercapnia

Answer 3

Increased CO2 levels

Question 4

Respiratory components

Answer 4

Breathing mechanism
Diffusion of O2 and CO2 across respiratory epithelium/skin
Bulk transport of gases by blood
Diffusion of O2 and CO2 across the capillary walls between blood and mitochondria in cells

Question 5

Breathing control centers

Answer 5

In the Pons and medulla oblongata

Question 6

Oxygen transport in cells

Answer 6

NO ACTIVE TRANSPORT MECHANISM

Distribution relies on partial pressure gradients

Question 7

Haemoglobin

Answer 7

Produced by red blood cells
4 molecules of O2 bind
20% blood CO2 carried by Hb
When bound to oxygen: oxyhaemoglobin
When not bound: deoxyhaemoglobin
Much higher affinity for carbon monoxide than O2 (carboxyhaemoglobin)

Question 8

Haemoglobin subunits

Answer 8

2 alpha chains and 2 beta chains

Each consist of helical protein chain with a non-protein heme group

Question 9

Heme

Answer 9

Porphyrin ring holds protein chain in place

Provides binding site for O2 (4 molecules per Hb molecule)

Question 10

Antarctic ice fish

Answer 10

No haemoglobin
Low metabolic rate
High O2 solubility
Bloods intrinsic affinity to O2 is adequate to meet metabolic requirements

Question 11

Haemoglobin O2 affinity reduced by

Answer 11

Elevated temperature
Binding of organic phosphates DPG, ATP to haemoglobin
Decrease in pH, increase in H+ ions
Increase in CO2 concentration

Question 12

Bar-headed goose respiratory adaptations

Answer 12

Single amino acid substitution increases O2 affinity
Left ventricle in heart has significantly more capillaries
Mitochondria significantly closer to sarcolemma in muscle cells, which reduces diffusion distance from capillaries

Question 13

CO2 transport

Answer 13

CO2 + H2O
H2CO3 (carbonic acid)
H+ & HCO3- (bicarbonate)
Slow transition or 
fast (by enzyme: carbonic anhydrase in RBC) = CO2 + -OH