Respiration Flashcards
What are some of the problems with glycolysis
- molecules are still not at their lowest energy state
- some of our energy is being held in
- NAD+ is being used up and not replaced
What are the components of the mitochondria
- outer membrane
- inner membrane (with Cristae folding in)
- inter membrane space
- matrix
What is the outer membrane made of in the mitochondria
- 50/50 protein and lipids
- porins
Give one feature of the inter membrane space
- same composition of ions and small molecules as the cytoplasm
What are features of inner membrane
- principle site of ATP membrane
- 70% or more of protein (no porins), has the ETC.
- impenetrable to ions and small molecules except by transporters
What are features of the matrix?
- has Krebs cycle enzymes
- DNA and ribosomes located here.
What happens in Pyruvate oxidation?
- CO2 taken off (exergonic)
- NAD+ reduced to NADH
- coenzyme A reacted to form acetyl CoA.
What happens in the Krebs cycle? (Incomplete)
- Acetyl CoA —> Citrate (CoA goes back into pyruvate oxidation), water used (4C molecule reacted with acetyl CoA (2C molecule)
- converted to isocitrate
- isocitrate is oxidized (producing CO2 and 1NADH)
- 2nd decarboxylation step: produced 1 CO2 and 1NADH
What are the net products of Krebs cycle (per molecule of glucose)
- 6 NADH
- 2 FADH2
- 2 ATP/GTP
- 4 CO2
What are the net products of the link reaction? (Pyruvate oxidation)
- 2 NADH
- 2CO2
What are some problems at the end of Krebs cycle?
- still havent replaced NAD+, only NADH made.
- FADH2 that needs to be reoxidised
- ## still hasn’t transferred energy carried by cofactors to ATP
How many ATPs are theoretically made per molecule of glucose in respiration (Aeobic)
- 36
How is ATP is made on low carb diets?
- fatty acid metabolism
- acetyl groups broken off and adding a coenzyme A, meaning glycolysis not even needed.
What happens to aerobically-respiring cells under
anaerobic conditions?
- can perform glycolysis, but no other steps, so all ATP comes from glycolysis.
- pyruvate undergoes fermentation - serves to generate the NAD+
- additional energy is released per molecule of glucose but the rate of glycolysis is increased to compensate for loss of oxidative phosphorylation. (So rate is faster, but does not squeeze out more energy)
Describe fermentation in brewers yeast
- pyruvate is converted to ethanol through acetaldehyde