7-10: Respiration

Question 1

What was original O2 level compared to today?

Answer 1

0.01%

Question 2

What does readily available O2 allow

Answer 2

Synthesis of biological macromolecules
Evolution of metazoan life (as gas exchange)
Formation of ozone layer

Question 3

What are free radicals?

Answer 3

Superoxide (OO-)
Hydrogen peroxide (H2O2)

Question 4

Why can small amounts of oxygen cause problems?

Answer 4

Free radicals form

They are toxic

Question 5

How do modern organisms prevent free radicals?

Answer 5

Enzymes- eg. catalase

Anti-oxidants- eg. vitamins E and C

Question 6

What are the respiratory gases?

Answer 6

O2 and CO2

Question 7

What is a fluid?

Answer 7

Molecules are relatively free to change positions

Question 8

What is a gas?

Answer 8

Molecules practically unrestricted by cohesive forces

Question 9

What is a liquid?

Answer 9

Fluid, but weak cohesive forces between molecules

Fixed volume

Question 10

What is density?

Answer 10

Mass per unit volume or a substance

Question 11

What is pressure?

Answer 11

Force exerted over an area (for a gas would be container walls)

Question 12

What is Boyle’s Law?

Answer 12

P V = k
Pressure x volume = constant
Describes relationship between temperature and pressure
p1v1 = p2v2

Question 13

What is Dalton’s law of pressure?

Answer 13

Total pressure in a container of mixed gases is equal to the sum of the pressures of each component gas
Gases can be considered separately

Question 14

Oxygen facts

Answer 14

Most abundant element in Earth’s crust (49.2%)
20.95% of the Earth’s atmosphere
Only moves by diffusion (no active transport)

Question 15

What is respiration?

Answer 15

Exchanging CO2 for O2

Via diffusion

Question 16

Why are convection methods needed?

Answer 16

As size increases, diffusion is not enough

Question 17

What are convection methods?

Answer 17

Also called transport by bulk flow
When gas mixture/aqueous solution flows and gas molecules in the gas/liquid are carried from place to place by the fluid flow

Question 18

How can the rate of connective gas transport be increased?

Answer 18

By increasing the concentration of the flow

Question 19

What do larger and more active animals need for gas transport?

Answer 19

Ventilatory system- to move more volumes of air

Circulatory system- to transfer dissolved O2 to tissues

Question 20

What are the 4 basic components of gas transport?

Answer 20

Breathing movements
Diffusion of O2 and CO2
Bulk transport of gases by blood
Diffusion of O2 and CO2 across capillary walls

Question 21

What are diffusion barriers for?

Answer 21

Maximising efficiency of diffusion

One cell thick

Question 22

How is CO2 transported?

Answer 22

Bicarbonate ions
Blood proteins
In solution with plasma

Question 23

What is the Haldane effect?

Answer 23

Haemoglobin that has released O2 binds more readily to CO2 than Hb that has oxygen bound to it

Question 24

What is the Fick equation?

Answer 24

VO2 = Q x A-VO2 diff

Question 25

What does the Fick equation actually mean?

Answer 25

Determines the rate at which a person uses oxygen in their body Maximum VO2 is the greatest amount of oxygen you can take in and utilize, and is a value that can be influenced by genetics and training

Question 26

Features of Haemoglobin

Answer 26

Red Binds oxygen With Hb, blood has 0.3mL, with is 20mL Some fish lack Hb, eg antarctic toothfish

Question 27

Features of Myoglobin

Answer 27

``` Stores O2 in vertebrate muscle Equivalent to one Hb molecule Only found in blood after muscle injury Makes meat red O2 store in diving species ```

Question 28

What respiratory pigment do molluscs and arthropods have?

Answer 28

Hemocyanin Copper colour Similar properties to Hb

Question 29

What reduces Hb-O2 affinity?

Answer 29

Elevated temperature Binding organic phosphate ligands Decrease in pH Increase in CO2

Question 30

What is the Bohr effect?

Answer 30

Increasing conc. of protons and/or CO2 reduces the affinity of Hb for O2 Facilitates O2 transport Allows the body to supply O2 to tissues that need it most

Question 31

What is an open co-current flow?

Answer 31

Animals use general body surfaces to exchange gas Eg. small animals, amphibians Blood vessels absorb O2 across skin

Question 32

What is a uniform pool system?

Answer 32

``` Like ours Co-current flow Tidal air-flow Lungs are completely internalised, formed by invagination Mainly terrestrial species ```

Question 33

What is a counter-current system?

Answer 33

Flow of water is opposite to blood flow Partial pressure of O2 (pO2) of blood increases along length of gill Eg. gills

Question 34

What is a cross-current system?

Answer 34

Uni-directional flow of air through lungs Blood flow is perpendicular to air flow Different pO2 values along different parts of air tubes Very complex Eg. bird lungs