01a: Glycolysis Flashcards
Catabolism of lipids, CHO, and protein converge at (X). Which one(s) go through a pyruvate step?
X = Acetyl-CoA
CHO and protein
In breakdown of AA, (X) product leads to ATP production and (Y) by-product has which fate?
X = keto acids Y = ammonia (NH3)
Urea cycle/excretion
T/F: Once glucose has been phosphorylated to glu-6P, it’s committed to glycolysis.
False
T/F: Glycolysis, glycogenolysis, and glycogen synthesis all take place in cytosol.
True
TCA Cycle takes place in which location? And electron transport chain?
Mito matrix
Inner mito membrane
A key reason for (hyper/hypo)-glycemia in alcoholics is that EtOH (stimulates/inhibits) (X) reaction.
Hypoglycemia;
Inhibits
X = Gluconeogenesis
For 1 glucose going through glycolysis, (X) ATP used, (Y) ATP produced, so NET (Z) ATP (used/produced).
X = 2; Y = 4; Z = 2 produced
Thanks to (X) step and (Y) enzyme requiring E in glycolysis, there’s only a net 2 ATP produced from each molecule glucose.
X = first and third Y = hexokinase/glucokinase and PFK (aka glucose and fructose phosphorylation)
In glycolysis, which compounds are the high-E phosphate donors? Why are they important?
1,3-BPG and Phosphoenolpyruvate
High E drives ADP phosphorylation and ATP production
For each molecule of glucose running through glycolysis, (X) number of NADH produced, thanks to (Y) enzyme.
X = 2 Y = G3P dehydrogenase
Which enzyme(s) responsible for the official ATP production during glycolysis?
- Phosphoglycerate kinase
2. Pyruvate kinase
Pyruvate is (oxidized/reduced) to lactate. Which enzyme catalyzes this?
Reduced;
Lactate dehydrogenase
The Pasteur effect states that (aerobic/anaerobic) conditions (inhibits/stimulates) (Y).
Aerobic
Inhibit;
(and anaerobic stimulate)
Y = glycolysis
Hexokinase has a much (lower/higher) Km for glucose than glucokinase, thus making its rate of rise of activity much (smaller/greater) with increase in glucose concentration.
Lower (more sensitive);
Greater
Normal blood glucose concentration.
5 mM
(Glucokinase/hexokinase) found in liver and (X) cells.
Glucokinase;
X = beta cells (pancreas)
MODY2 stands for (X) and is a(n) (stimulatory/inhibitory) mutation in (Y).
X = mature onset diabetes of the young
Inhibitory;
Y = glucokinase
PHHI is a(n) (stimulatory/inhibitory) mutation in (X). The problem is constant (Y), leading to (hyper/hypo)-glycemia.
Stimulatory;
X = glucokinase (beta cells)
Y = insulin pumped out of pancreas
Hypoglycemia (DANGEROUS)
(Hexokinase/glucokinase) (stimulated/inhibited) by G6P. Why is (hexokinase/glucokinase) not?
Hexokinase;
Inhibited;
Glucokinase half the size of hexokinase (missing allosteric binding site of G6P)
(Hexokinase/glucokinase) is adaptive. This means (X) changes depending on nutritional/hormonal state of body.
Glucokinase;
X = level of enzyme
Glut4 found in (muscle/fat/liver) and Glut 2 in (muscle/fat/liver).
Muscle and fat;
Liver
Glut(2/4) activity (increases/decreases) by anoxia and (increases/decreases) by insulin via which mechanism?
Glut4;
Increases;
Increases (insulin causes intracell vesicles containing transporter to fuse with PM)
Why would (ATP/ADP) be a more sensitive indicator of E change/usage?
ADP; lower concentration, so any change in ATP/ADP levels more prominent
High (ADP/ATP) levels will stimulate PFK. And high (ADP/ATP) levels inhibit it.
ADP (or AMP); ATP
T/F: Between AMP, ADP, and ATP, ADP is the most sensitive indicator of E usage/change.
False - AMP is most sensitive
if ADP rises 3 fold, AMP rises 9 fold
Citrate has (stim/inhib) effect on (X) enzyme in glycolysis. This is because it indicates:
Inhibitory;
X = PFK
availability of alternative fuel (FA oxidation)
PFK is (stimulated/inhibited) by AMP, ADP, and (X).
X = fructose-2,6-BP
T/F: Fructose-2,6-BP is product and feedback inhibitor of PFK.
False - Fructose-1,6-BP is product of PFK
(X) process produces (Y), which must be converted to citrate to (stimulate/inhibit) (Z) glycolytic enzyme. Why?
X = FA Ox
Y = Acetyl-CoA
Inhibit;
Z = PFK
Acetyl-CoA can’t cross mito membrane (to enter cytosol), but citrate has carrier
Fructose-2,6-BP is important for control of (X) processes in (muscle/liver). It’s produced by (Y) enzyme acting on (Z).
X = glycolysis/gluconeogenesis;
Liver
Y = PFK2;
Z = Fructose-6P
Fructose-2,6-BP can be converted back to (X) via (Y) enzyme.
X = Fructose-6P Y = Fructose-2,6-BPase
T/F: The active sites of PFK2 and Fructose-2,6-BPase are on the same polypeptide chain.
True
High PKA activity, such as in high (insulin/glucagon) states, has which effect on Fructose-2,6-BP activity?
Glucagon;
- Inhibits PFK2 (thus lowering Fructose-2,6-BP)
- Stimulates Fructose-2,6-BPase
(Muscle/liver) pyruvate kinase is weakly inhibited by ATP in (competitive/allosteric) manner.
Muscle;
Competitive
(Muscle/liver) pyruvate kinase is strongly inhibited by ATP in (competitive/allosteric) manner.
Liver;
Allosteric
Phosphorylation of (muscle/liver) pyruvate kinase by (X) inhibits it.
Liver;
X = PKA
The activity of (muscle/liver) pyruvate kinase is dependent on high (X) levels.
Liver;
X = Fructose-1,6-BP
“Fructose intolerance” refers to deficiency in (X) enzyme, which ties fructose metabolism at (Y) step/compound. This leads to loss of cell ATP.
X = aldolase B Y = Fructose-1P
Glucokinase inhibitory protein is found in (muscle/liver) and its mechanism is:
Liver;
Binds glucokinase, keeping it in nucleus (can’t go to cytoplasm)
Fructose-1P (stimulates/inhibits) glucokinase activity. What’s the (direct/indirect) mechanism?
Stimulates;
Indirect;
Binds and inhibits glucokinase inhibitory protein from binding glucokinase
Fructose-6P (stimulates/inhibits) glucokinase activity. What’s the (direct/indirect) mechanism?
Inhibits;
Indirect;
Competes with Fructose-1P, which indirectly stimulates glucokinase activity
(Phosphorylated/unphosphorylated) PFK2/F26BP binds glucokinase and has which effect on its activity?
Unphosphorylated;
Maintains its activity by keeping it in cytoplasm
Cataracts can result from accumulation of (X), which is derived from (Y).
X = galactitol; Y = galactose
Why should lactose be avoided in galactosemia?
Lactose = glucose + galactose
(Hexokinase/glucokinase) is sensitive to changes in glucose in the physiological range due to its (high/low) Km.
Glucokinase; High Km (low affinity)
