Glycolysis Flashcards
What is metabolism
Collection of biochemical reactions that converts chemical energy into work.
What is a catabolic pathway
leads to the degradation of macromolecules for energy capture, -G, supplies NADH
what is an anabolic pathway
using energy from ATP hydrolysis to synthesize biomolecules, +G, requires NADH
Before breakfast blood glucose levels are ___ from fasting
low
Before breakfast insulin is ___ and Glucagon is ___
low, high
After breakfast insulin is ____ and Glucagon is ___
high, low
How many carbon atoms do glucose and fructose have
6
What test is used to predict the presence of reducing sugars
Benedict’s test
T or F: Disaccharides can either be reducing or nonreducing sugars
T
For one molecule of glucose how many G3Ps are created?
2
T or F: Glycolytic pathways are highly conserved
T
1 of the 4 questions: What does glycolysis accomplish
-generates as small amount of ATP and generates pyruvate, the precursor of acetyl- coA, lactate and ethanol
What is the overall net reaction of glycolysis?
Glucose + 2NAD+ + 2ADP + 2Pi –> 2 Pyruvate + 2NADH + 2H+ + 2ATP + H2O
What are the key enzymes?
hexokinase, phosphofructokinase-1, pyruvate kinase
What is an example in everyday biochemistry of glycolysis
Maintaining blood glucose levels
Where does glycolysis occur in the cell?
In the cytosol
What is the overall reaction for glycolytic pathway reaction I??
Glucose + ATP –> (hexokinase) Glucose-6-Phosphate + ADP
What is the overall reaction for glycolytic pathway reaction III?
Fructose-6-Phosphate + ATP –> (Phosphofructokinase-1) Fructose-1,6 BP + ADP
What is the overall reaction for glycolytic pathway reaction 10?
Phosphoenol pyruvate + ADP –> (Pyruvate kinase) Pyruvate + ATP
What happens to the two NADH molecules that are created in glycolysis?
Under aerobic conditions reoxidized to NAD+ by transfer of their electrons to the ETC
Metabolic flux is controlled by ?
rate-limiting enzymes
What ensures that liver cells requester glucose
Different glucose binding affinities of hexokinase and glucokinase
What is one thing that affects PFK-1 activity?
Allosteric regulators
What are the two components of sucrose?
Glucose + Fructose
What are the two components of lactose
Galactose+ Glucose
What is the metabolic fate o fpyruvate under aerobic conditions
is metabolized in the mitochondria to produce CO2 and H2O
What is the metabolic fate of pyruvate under anaerobic conditions
pyruvate is converted to lactate or ethanol (fermentation)
What is the net reaction for lactate fermentation
Pyruvate + NADH + H+ –> (Lactate dehydrogenase) Lactate + NAD+
What is the net reaction for ethanol fermentation
Pyruvate –> (CO2) Acetyaldehyde + NADH + H+ –> Ethanol
What is an inhibitor of phosphofructokinase-1
CItrate, ATP
What is an allosteric regulator of PFK-1
Fructose 2,6 BP, ADP
Which enzymes in the glycolysis pathway requires ATP as a substrate
Hexokinase
What is the net formation of molecules by the glycolytic pathway during the conversion of 1 mol of fructose 1,6 BP to 2 mol of pyruvate?
2 mol of NADH and 4 mol ATP
What is the benefit of converting pyruvate to either ethanol or lactate under anaerobic conditions?
NAD+ is regenerated, which allows glycolysis to continue
Two reactions (Rxn 1- 2.3 kJ/mol, Rxn 2- 12.3 kJ/mol). Which is more likely to require ATP coupling?
Rxn 2, since it is nonspontaneous
Rxn 1- A+B –> C
Rxn 2- C–>D
What is the coupled reaction?
A + B –> D
What is the net reaction in stage 1 fo glycolysis with 2 moles of glucose
2 Glucose + 4 ATP –> 4 G3P + 4 ADP
If 2 moles of glucose were conveted into 4 pyruvate, there would be a net yeild of ___ ATP
4 ATP
Phosphorylation of glucose requires 1 ATP. Can the reverse reaction be used for substrate-level phosphorylation?
No, it is not spontaneous enough to couple ATP synthesis
Why cant glucose phosphoylation occur without ATP investment
Without ATP investment, one or both substrates would need to exceed the solvent capacity of the cell for glucose phosphorylation to occur
Which enzymes catalyze rate determining steps in glycolysis?
phosphofructokinase, pyruvate kinase, and hexokinase.
