CH 4: METABOLISM Flashcards
(31 cards)
Activation energy
Energy required to break chemical bonds in reactants to start rxn
Properties of enzymes
highly specific, very efficient, subject to controls
Models of enzyme-substrate interaction
lock-and-key, induced-fit
Factors that influence enzymatic reaction
Temperature, pH, substrate concentration
Metabolic pathway
Initial substrate converted to end product via series of intermediates
Two mechanisms of phosphorylation
Substrate-level phosphorylation, oxidative phosphorylation
Substrate-level phosphorylation
adds phosphate group from an intermediate directly to ADP
Location of substrate-level phosphorylation
cytosol and mitochondrial matrix
(glycolysis and krebs cycle)
Oxidative phosphorylation
adds phosphate group to ADP by using series of electron carriers (i.e. electron transport chain)
Location of oxidative phosphorylation
Inner mitochondrial membrane
Purpose of cellular respiration
Break down nutrient (glucose) to produce ATP
Reactions involved in cellular respiration
Glycolysis, formation of acetyl CoA, Krebs cycle, electron transport chain
Aerobic respiration
Term for both Krebs cycle and electron transport chain (they require oxygen)
What happens to cellular respiration, if oxygen is not available?
Only anaerobic glycolysis, and the resulting pyruvic acid gets converted to lactic acid
What is role of ATP in anabolism and catabolism?
Catabolism releases ATP (exergonic), which allows anabolic reaction to use ATP (endergonic)
Location and Overview of Glycolysis
converts glucose into pyruvic acid (substrate-level phosphorylation)
in cytoplasm
Location and Overview of Formation of Acetyl CoA
adds acetyl group onto pyruvic acid to form acetyl CoA
in mitochondrial matrix
Location and Overview of Krebs Cycle
series of reactions that convert one acid to another
happens in mitochondrial matrix
Location and Overview of Electron Transport Chain
produces ATP via oxidative phosphorylation (adds phosphate group to ADP via intermediates)
happens in inner mitochondrial membrane
What happens if glucose is not needed for immediate ATP production?
glycogenesis (converted to glycogen by liver)
However, IF glycogen stores are full –> converted to triglycerides and stored as adipose tissue
how many ATP can be generated during cellular respiration and during which stages?
30 or 32 ATP total
4 via substrate-level phosphorylation (2 glycolysis and 2 krebs)
26 or 28 via oxidative phosphorylation (electron transport chain)
Why is there a range in amount of ATP that can be produced during cellular respiration?
Sometimes, 2 molecules of NADH + H from glycolysis do not enter mitochondria, which impacts amount of ATP that can be made in electron transport chain
What is role of NAD+ and FAD in ATP generation?
They act as coenzymes. Pick up hydrogen during early parts of cellular respiration and carry them for use in electron transport chain (NADH + H, and FADH2)
What are the potential fates of pyruvic acid?
in aerobic conditions: converted to acetyl CoA
in anaerobic conditions: converted to lactic acid
