7-10: Respiration Flashcards
What was original O2 level compared to today?
0.01%
What does readily available O2 allow
Synthesis of biological macromolecules
Evolution of metazoan life (as gas exchange)
Formation of ozone layer
What are free radicals?
Superoxide (OO-) Hydrogen peroxide (H2O2)
Why can small amounts of oxygen cause problems?
Free radicals form
They are toxic
How do modern organisms prevent free radicals?
Enzymes- eg. catalase
Anti-oxidants- eg. vitamins E and C
What are the respiratory gases?
O2 and CO2
What is a fluid?
Molecules are relatively free to change positions
What is a gas?
Molecules practically unrestricted by cohesive forces
What is a liquid?
Fluid, but weak cohesive forces between molecules
Fixed volume
What is density?
Mass per unit volume or a substance
What is pressure?
Force exerted over an area (for a gas would be container walls)
What is Boyle’s Law?
P V = k
Pressure x volume = constant
Describes relationship between temperature and pressure
p1v1 = p2v2
What is Dalton’s law of pressure?
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
Oxygen facts
Most abundant element in Earth’s crust (49.2%)
20.95% of the Earth’s atmosphere
Only moves by diffusion (no active transport)
What is respiration?
Exchanging CO2 for O2
Via diffusion
Why are convection methods needed?
As size increases, diffusion is not enough
What are convection methods?
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
How can the rate of connective gas transport be increased?
By increasing the concentration of the flow
What do larger and more active animals need for gas transport?
Ventilatory system- to move more volumes of air
Circulatory system- to transfer dissolved O2 to tissues
What are the 4 basic components of gas transport?
Breathing movements
Diffusion of O2 and CO2
Bulk transport of gases by blood
Diffusion of O2 and CO2 across capillary walls
What are diffusion barriers for?
Maximising efficiency of diffusion
One cell thick
How is CO2 transported?
Bicarbonate ions
Blood proteins
In solution with plasma
What is the Haldane effect?
Haemoglobin that has released O2 binds more readily to CO2 than Hb that has oxygen bound to it
What is the Fick equation?
VO2 = Q x A-VO2 diff
What does the Fick equation actually mean?
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
Features of Haemoglobin
Red
Binds oxygen
With Hb, blood has 0.3mL, with is 20mL
Some fish lack Hb, eg antarctic toothfish
Features of Myoglobin
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
What respiratory pigment do molluscs and arthropods have?
Hemocyanin
Copper colour
Similar properties to Hb
What reduces Hb-O2 affinity?
Elevated temperature
Binding organic phosphate ligands
Decrease in pH
Increase in CO2
What is the Bohr effect?
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
What is an open co-current flow?
Animals use general body surfaces to exchange gas
Eg. small animals, amphibians
Blood vessels absorb O2 across skin
What is a uniform pool system?
Like ours Co-current flow Tidal air-flow Lungs are completely internalised, formed by invagination Mainly terrestrial species
What is a counter-current system?
Flow of water is opposite to blood flow
Partial pressure of O2 (pO2) of blood increases along length of gill
Eg. gills
What is a cross-current system?
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
