Lecture 15: Glycolysis and Cellular Respiration Flashcards
Define catabolism
Degradation of complex molecules into simpler ones (Exergonic)
Define anabolism
Synthesis of complex molecules (Endergonic)
What is the relationship between catabolism and anabolism?
Energy from catabolism is used to perform anabolism
What are the products of the breakdown of proteins?
Amino acids
What are the products of the breakdown of polysaccharides?
Monosaccharides
What are the products of the breakdown of lipids?
Glycerol + fatty acids
Into which metabolic pathways are organic molecules converted?
Glycolysis or the Tricarboxylic Acid (TCA) cycle
What happens to molecules that enter the TCA cycle?
They are oxidized completely to CO2, reducing NAD+ to NADH & FAD+ to FADH2
What do NADH and FADH2 do during cellular respiration?
They feed into the electron transport chain (oxidative phosphorylation), releasing energy to create ATP
List the three main stages of both aerobic and anaerobic respiration
- Glycolysis (Embden-Meyerhof)
- TCA cycle
- Electron transport
What characterizes aerobic respiration?
O2 accepts electrons taken from organic materials
What characterizes anaerobic respiration?
Some other inorganic electron acceptor accepts electrons taken from organic materials
Define ATP Synthase
Multisubunit enzyme that acts as a proton channel and catalyzes ADP + Pi to ATP
What do NADH and FADH2 do in aerobic respiration?
Donate electrons to cytochrome acceptors with more positive Eo
What are cytochromes?
Proteins that contain iron ions and can undergo redox reactions
What is the final electron acceptor in aerobic respiration?
O2, which is reduced to H2O
How many ATPs are formed when NADH donates its electrons in aerobic respiration?
3 ATPs
How many ATPs are formed when FADH2 donates its electrons in aerobic respiration?
2 ATPs
What happens in anaerobic respiration regarding the final electron acceptor?
It is something other than O2 (e.g., NO3-, SO42-, CO2, S0, Fe3+)
What determines the number of ATP produced in anaerobic respiration?
The Eo of the final electron acceptor
What are facultative anaerobes?
Organisms that can use both aerobic and anaerobic respiration depending on oxygen availability
What are obligate anaerobes?
Organisms that must use anaerobic respiration
What is the total ATP yield from aerobic respiration?
38 ATPs
What is the ATP yield from glycolysis during aerobic respiration?
2 ATPs from substrate-level phosphorylation and 6 ATPs from oxidative phosphorylation
What happens to triglycerides in lipid catabolism?
They are broken down into glycerol and fatty acids by microbial lipases
What is the role of glycerol in lipid metabolism?
It is modified (phosphorylated) and enters glycolysis
What is beta-oxidation?
The process where fatty acids are broken down into 2C acetyl-CoA subunits
What do proteases do in protein catabolism?
They digest proteins into amino acids
What is deamination?
The removal of the amino group from amino acid
What happens to deaminated amino acids?
They are converted into pyruvate, acetyl-CoA, or TCA cycle intermediates
