L1 - Glycolysis and PPP and their Role in Metabolism Flashcards
Feb. 5, 2019
Which enzyme(s) convert pyruvate to…
1) acetyl CoA
2) alanine
3) oxaloacetate
4) lactate
1) pyruvate dehydrogenase complex
2) alanine aminotransferase aka alanine transaminase (ALT)
3) pyruvate carboxylase
4) lactate dehydrogenase
Glucose transporters work through which mechanism?
facilitated diffusion
Which molecule does arsenate inhibit the formation of?
1,3-bisphosphoglycerate
Where are glycolytic enzymes present in the cell?
cytosol
What is the enzyme transketolase used as a marker for? What vitamin does it require?
1) thiamine concentration
2) thiamine, vitamin B1
What are the four fates of pyruvate?
1) alanine
2) acetyl CoA
3) lactate
4) oxaloacetate
Which two metabolites increase activity of PFK-1?
1) AMP
2) fructose 2,6-bisphosphate
Glucokinase has a _____ Km and a ______ Vmax. It is found in the ______. as well as the _________.
1) high
2) high
3) liver
4) beta cells in the pancreas
Hexokinase facilitates which reaction? PFK-1 facilitates which reaction?
1) glucose –> glucose 6-phosphate
2) fructose 6-phosphate –> fructose 1,6-bisphosphate
Hexokinase has a _____ Km and a _______ Vmax. Where is it found in the body? What does it function as?
1) low
2) low
3) functions as a high-affinity glucose transporter
Fructose 2,6-bisphosphate is not a proper metabolite of glycolysis, so why is it relevant?
It acts as an allosteric activator of PFK-1. Its levels are correlated with glylcolytic activity because it is byproduct of the formation of fructose 1,6-bisphosphate made by PFK-2
The conversion of PEP into pyruvate is catalyzed by which enzyme?
pyruvate kinase
What four tissues does the PPP occur primarily in? Why?
1) liver
2) adipocytes
3) adrenal cortex
4) gonads
Because they are very active in reductive biosynthesis
GLUT-4 is an insulin-_________ glucose transporter that is found in ________ and __________.
1) sensitive
2) adipose
3) skeletal muscle
Glucokinase acts as what in terms of glucose metabolism?
glucose sensor, it picks up on high levels of glucose in the blood
What molecule inhibits glyceraldehyde 3-phosphate DHG?
arsenate
How do we use the Warburg effect clinically?
In PET scans you can localize a tumor by using fluorodeoxyglucose, a radiocompound of glucose
How does the muscle clear the lactate that is made via exercise?
By the Cori cycle via the liver
The conversion of pyruvate into lactate produces what?
NAD+
What is the name of the glucose transporter in the liver? What is special about it?
GLUT2, it is bidirectional
Fructose 1,6-bisphate activates pyruvate kinase. What is this an example of?
Feed-forward activation
What is the name of the protein that takes up glucose from the GI? What is different about it as compared to GLUTs?
SGLT-1
It is a sodium-glucose cotransporters rather than a glucose-only transporter
Pyruvate is shuttled where in anaerobic conditions? Where does it go if it is in aerobic conditions?
anaerobic - liver
aerobic - mitochondria
What element determines which direction the reactions related to pyruvate will go?
NADH/NAD+ ratio
What disorder is the result of an inherited mutation of glucokinase?
MODY-2, maturity-onset diabetes of the young, type 2
NADPH is needed in the body for synthesis of _______ and ______ as well as ________ metabolism.
1) fatty acid
2) steroid
3) drug
The first and third step of glycolysis use which enzymes? Why are they important?
1) hexokinase and PFK-1, respectively
2) irreversible steps which are regulated
What effect does insulin have on PFK-2 activity?
Increased insulin leads to increased PFK-2 activity.
Where can GLUT1 and GLUT3 be found?
GLUT1 - BBB
GLUT3 - neurons
What is the effect whereby cancer cells increase their uptake and metabolism of glucose?
Warburg effect
