Biochem Exam 1: Set 4 (Glycolysis, Fat Metabolism) Flashcards
Which cells can not generate ATP from glycolysis?
they all can
What proteins are responsible for glucose transport into cardiocytes (heart)?
GLUT1 (10%) and GLUT4 (90%)
What are the 4 possible fates of G-6-P?
Storage as glycogen, pentose phosphate pathway, stored in liver to regulate blood glucose, glycolysis
Why do red blood cells possess hexokinase instead of glucokinase?
hexokinase has a much lower Km, ensuring RBC’s will utilize glucose for ATP synthesis before the liver
What is the first committed step of glycolysis?
Conversion of F-6-P to F-1,6-BP via phosphrofructokinase 1
How does the cell trap glucose in the cytoplasm?
addition of charged phosphate (glucose–>G-6-P) via hexo/glucokinase prevents diffusion out of the membrane
What are the intermediates of glycolysis?
glucose G-6-P F-6-P F-1,6-BP G-3-P (and DAP) 1,3-BPG 3-PG 2-PG PEP Pyruvate
What are the enzymes of glycolysis?
gluco/hexokinase phosphoglucose isomerase phosphofructokinase fructosebisphosphate aldolase (triose phosphate isomerase) glyceraldehyde-3-phosphate dehydrogenase phosphoglycerate kinase phosphoglycerate mutase enolase pyruvate kinase
Where does glycolysis occur?
in the cytoplasm
How many ATP is obtained per NADH via the glycerol 3-phosphate shuttle?
1.5
How many ATP is obtained per NADH via the malate-asparate shuttle?
2.5
What are the regulators of glycolysis?
\+AMP \+ADP \+fructose-2,6-BP -ATP -acidosis -citrate -NADH -acetyl CoA
How does F-1-P inhibit glucokinase activity?
F-1-P interferes with the interaction between GK and its regulatory protein (RP), allowing GK to diffuse outside of the nucleus
How does the interaction between epinephrine and PFK2 differ between the heart and the liver?
Heart PFK2 isozyme is activated by phosphorylation and induces glycolysis, and liver PFK2 isozyme is inhibited by phosphorylation
What compounds activate glucokinase activity?
glucose and F-6-P
How much acetyl-CoA would be obtained from complete beta oxidation of palmitate?
palmitate= 16:0 so 8 acetyl-CoA
How many carbons make up a short, medium, and long fatty acid chain?
short: 4
medium: 6-12
long: 12-20
What percentage of naturally occurring unsaturated fatty acids contain trans double bonds?
0%
chemical hydrogenation of polyunsaturated vegetable oil produces trans bonds
What drives the reaction of fatty acyl CoA synthetase?
removal of pyrophosphate product (hydrolysis to 2Pi)
Which phosphate of ATP does the fatty acid attach in the first step of fatty acyl CoA synthesis?
the first phosphate
What is the net equation for the reaction catalyzed by fatty acyl CoA synthetase?
fatty acid + ATP + CoA –> 2Pi + AMP + fatty acyl CoA
Where in the cell are the acyl-CoA synthetase isozymes located that are specific for short, medium, long and very long fatty acid chains?
Short- cytosol or on the mitochondrial membrane
Medium- transported into mitochondria and activated in the matrix
Long- ER, outer mitochondrial membrane, or peroxisomal membranes
Very Long- Only in peroxisomes
What molecule is required for fatty acyl CoA transport into the mitochondria
carnitine (via carnitine palmitoyl transferases I and II)
Describe the general steps in B-oxidation of saturated fatty acyl-CoA’s
- trans double bond formed between alpha and beta carbon
- double bond reacts with water to form alcohol on beta carbon
- alcohol is oxidized to a ketone
- CoA-SH attacks beta ketone releasing acetyl-CoA
