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Gycolysis Reactions
WVSOM Class of 2012 Glycolysis Reactions
Question | Answer |
---|---|
at the end of the first, preparative phase of glycolysis, what two events occur? | 1. 2 ATP have been expended to activate molecules 2. two triose-phosphate molecules are formed from each glucose molecule. |
at the end of the second phase of glycolysis, for each glucose oxidized, what has happened? | (1) two NAD+ have been reduced to 2 NADH (2)4 ATP have been produced (a net of 2 ATP are produced overall) |
hexokinase and glucokinase are what kind of molecules? | isoenzyme forms of the same enzyme |
where does glucokinase occur? | liver |
function of glucokinase? | processes excess glucose for storage as glycogen or conversion to triglyceride |
what is the only site that can reverse or dephosphorylate glucose-6-phosphate and export glucose? | liver |
what enzyme regulates glycolysis? | Phosphofructokinase (PFK1) |
NAD+ is reduced to NADH by what molecule? | glyceraldehyde-3-phosphate dehydrogenase. |
is glycolysis aerobic or anaerobic? | anaerobic |
what are the starting materials for glycolysis? | glucose, NAD+, ADP (ATP) |
Products of aerobic glycolysis? | Pyruvate, NADH, ATP, (ADP) |
Products of anaerobic glycolysis? | Lactate, ATP, NAD+ |
The two ATP producing reactions are catalyzed by? | phosphoglycerate kinase and pyruvate kinase |
Is glycolysis Reversible? | Overall, glycolysis has a large negative ΔG and cannot be reversed |
site of glycolysis? | cytosol |
can acetyl coa be converted to pyruvate? | no |
under anaerobic conditions, what happens to pyruvate after glycolysis? | reduced to lactate and exported from the cell |
3 uses for pyruvate? | (1)Pyruvate may be converted to oxaloacetate for TCA Cycle (or other) use (2)Pyruvate may be transaminated to alanine (3) Pyruvate may be used in fatty acid synthesis |
what is the function of a dehydrogenase? | Dehydrogenases catalyze different oxidation / reduction reactions |
what happens if a dehydrogenase also oxidizes carbon to CO2? | it is a decarboxylase as well as a dehydrogenase |
for glycolysis to continue, what needs to happen to NADH? | NADH needs to be reoxidized |
Most pyruvate carbons enter the TCA cycle as what? | acetyl coa |
Pyruvate dehydrogenase does what? is pdh reversible? | converts pyruvate to acetyl CoA; no |
what is the first, activating reaction of glycolysis? | production of Glucose-6-P |
Production of Glucose-6-P is catalyzed by what? | hexokinase or glucokinase |
what tissues have low aerobic cell ATP production? | eye, skin cells |
in the fasted state, what can lactate be used for? | gluconeogenesis |
what cycle can be used in the anaerobic fasted state? | cori cycle |
NADH produced by glycolysis needs to be reoxidized for what two reasons? | to maintain NAD+ availability and to utilize NADH electrons to produce ATP (e.g., linking the glycolytic process with aerobic metabolism.) |
what happens In the glycerol-phosphate shuttle? | electrons from cytosolic NADH are moved to mitochondrial FADH2 |
what happens in the malate-aspartate shuttle? | transamination is used to achieve electron membrane crossing, NADH is produced |
what occurs as LDH reduces pyruvate to lactate? | Anaerobic reoxidation of NADH to NAD+ |
Aerobic NADH reoxidation to NAD+ occurs via what process? | oxidative phosphorylation |
what happens to the electrons in the malate-aspartate shuttle | The electrons are placed on to a mitochondrial NAD+, forming NADH. |
in hypoxia, what happens to 2,3-BPG in RBC's? | increases |
in what state can lactate be used for gluconeogenesis? | fasted |
what kind of molecule is PDH? | decarboxylase |
wnat enzyme adds phosphate from ATP to a molecule’s hydroxyl group? | kinase |
what enzyme relocates functional groups within a molecule to produce different isomers? | isomerase |
what enzyme catalyzes different oxidation / reduction reactions? | dehydrogenase |
in production of glucose-6-phosphate, what is required for energy and what is the catalyst? | atp is required, hexokinase is the catalyst |