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