Cellular Respiration Flashcards
What are common high energy electron carriers in cellular respiration?
NADH ad FADH2
What are the four steps of cellular respiration?
- glycolysis
- pyruvate dehydrogenase complex
- Krebs Cycle
- Electron transport/oxidative phosphorylation
What occurs during glycolysis?
glucose is partially oxidized and split in half to form two pyruvic acid molecules
Where in the cell does glycolysis occur?
cytoplasm
Does glycolysis require the presence of oxygen?
no
What occurs during PDC?
pyruvate is decarboxylated to form an acetyl group
What is the Krebs cycle also known as?
tricarboxylic acid cycle (TCA cycle)
citric acid cycle
What occurs during the Krebs cycle?
acetyl group from PDC is added to oxaloacetate to form citric acid
Which steps of cellular respiration can only occur when oxygen is present but doesnt actually use the oxygen?
Krebs Cycle
PDC
Where does the Krebs cycle take place in the cell?
in the matrix of the mitochondria
Where does the PDC take place in the cell?
in the matrix of the mitochondria
What occurs during electron transport/oxidative phosphorylation?
high energy electron carriers are oxidized by the ETC creating a proton gradient that will drive the formation of ATP
What is the net surplus of ATP and NADH formed during glycolysis?
2 ATP
2 NADH
What is the overall simplified reaction for glycolysis?
glucose + 2 ADP + 2 P + 2 NAD+ –> 2 pyruvate + 2 ATP + 2 NADH + 2 H2O + 2H
What enzyme catalyzes the first step of glycolysis?
hexokinase
What feedback inhibits hexokinase?
the product, G6P
What enzyme catalyzes the third step of glycolysis?
phosphofructokinase (PFK)
What is the thermodynamically favorable and irreversible reaction of glycolysis?
the third step catalyzed by PFK
What is a committed step?
irreversible step in a reaction that commits the reaction to proceed
What is a generalization about what steps get regulated in a reaction?
they usually undergo allosteric regulation
early steps in a pathway tend to get regulated
What are aerobic conditions? What are anaerobic conditions?
aerobic = in the presence of oxygen
anaerobic = in the absence of oxygen
What is fermentation?
a process that has developed to allow glycolysis to continue under anaerobic conditions
What are two examples of fermentation?
- the reduction of pyruvate to lactate in human muscle cells
- the reduction of pyruvate to ethanol in yeast cells
What does it mean to be an activated acetyl unit?
activated means the acetyl unit is not floating around freely but is instead attached to a carrier, mainly coenzyme A forming acetyl-CoA
What is a prosthetic group?
when a cofactor is tightly or covalently bonded to an enzyme
What is a prosthetic group?
when a cofactor is tightly or covalently bonded to an enzyme
What prosthetic group does PDC contain?
TPP = thiamine pyrophosphate
