Biochemistry/ Carbohydrate And Metabolism I.

Front 1

what is the normal concentration of glucose in peripheral blood

Back 1

5.6 mM (normal range is 4-6mM).

Front 2

what are the glucose transporters?

Back 2

GLUT 1. GLUT 2. GLUT3. GLUT4.

Front 3

GLUT 2 and GLUT 4 are the most significant transporters of glucose. Why is that?

Back 3

because they are located only in specific cells and highly regulated

GLUT 2: in liver and pancreas

GLUT 4: Adipose tissue and Muscle.

Front 4

how does GLUT 2 function and where does it exist?

Back 4

the hepatic portal vein will take blood from intestines (post digestion) to the liver. In the blood, there will be a GLUT 2 low affinity glucose transporter that will take the excess glucose to store in Liver (when glucose is high). Once glucose levels in transporter are low, the glucose stored is released from liver.

Front 5

GLUT 2 also functions in the pancreas, how so?

Back 5

in Beta islet cells of the pancreas, it serves as a sensor for when the insulin should be released.

Front 6

GLUT 4

Back 6

transports in adipose tissue and muscle. The more insulin there is in these tissues and muscle, the more glucose that is transported.

Front 7

Why does Glycolysis occur in RBC, and not other processes like oxidation phosphorlyation or ETC ir citric acid cycle?

Back 7

the reason why is because RBC's do not have mitochondria.

Front 8

Glycolysis. what is it?

Back 8

it is a cytoplasmic pathway that converts a glucose molecule into a 2 pyruvate molecules releasing a modest amount of energy captured in two substrate-level phosphorylation and one oxidation reaction.

Front 9

Glycolysis in anaerobic Vs. Glycolysis in aerobic environments

Back 9

-Glycolysis in aerobic conditions ( presence of mitochondria and oxygen) will have its energy carriers (NADH) feed into pathway of other respirations.

-Glycolysis in an anaerobic conditions will produce less energy.

Front 10

True or False, glycolysis converts excess glucose to fatty acids in LIVER..

Back 10

True.

Front 11

In glycolysis, what does Hexokinase do?

Back 11

Moves 1 phosphate group from ATP to give it to glucose, it will be Glucose 6-P.

Front 12

why does Hexokinase phosphorylate glucose

Back 12

so it gets trapped inside the cell and not carried out by GLUT transporters that carry glucose in/out.

Front 13

How does Hexokinase stop its phosphorylation when no more glucose is needed?

Back 13

its product acts an inhibitor, and inhibits its function.

Front 14

what is Glucokinase

Back 14

an enzyme only found in liver and pancreatic B-islet cells.

Front 15

What causes Glucokinase to be active?

Back 15

it's induced by insulin IN HEPATOCYTES AND PANCREATIC CELLS AS WELL!

Front 16

What is the difference between Glucokinase and Hexokinase

Back 16

glucokinase is in liver and pancreas, whereas hexokinase is in almost every tissue.

Glucokinase is induced by insulin.

Hexokinase is inhibited by glucose 6-phosphate.

Front 17

phosphofructokinase (PFK)

Back 17

enzyme that is rate determining

Front 18

3-phosphateglycerate kinase

Back 18

it takes a phosphate group from the 1,3-phosphoglycerate and gives it to ADP resulting in ATP and 3-phosphateglycerate.

Front 19

substrate level phosphorylation

Back 19

ADP to ATP using a high-energy intermediate

Front 20

What is Pyruvate Kinase? where in glycolysis is it? what does it do?

Back 20

pyruvate kinase is the last enzyme in the aerobic cycle. It carries substrate level phosphorylation on its substarate (PEP).

Front 21

what kind of phosphorylation does Pyruvate Kinase catalyze?

Back 21

its is in glycolysis, substrate-level phosphorylation is what's catalzyed.

Front 22

Feed Forward Activation

Back 22

the product of an earlier reaction of glycolysis (fructose 1,6-biphosphate) stimulates a later reaction that is Pyruvate kinases.

Front 23

Phosphofructokinase 1

Back 23

converts fructose 6-phosphate to fructose 1,6-bi-phosphate.

Front 24

what triggers or turns phosphofructokinase 1 or on or off.

Back 24

-the ATP turns it off= because if there's enough of it then there's no need for this process to occur.

-citrate turns it off= because if there is citrate tje citric cycle will occur.

cAMP turns it on= activates phosphofructokinase 1

Front 25

Phosphofructokinase 2 is turned on and off according to certain molcules, what are they?

Back 25

if insulin is released, then PFK2 is activated,

Front 26

why is PFK2 called that way

Back 26

because it adds a phosphate group to the second carbon of fructose fructose 2-6 bi-phosphate.

Front 27

GlycerALDEHYDE 3-phosphate DEHYDROGENASE. WHAT DOES IT DO?

Back 27

it is a dehydrogenase, so it must dehydrate...through oxidation. The "H" it removes goes to NAD so it becomes NADH for the ETC in mitochondria.

1,3- phospho-glycerATE is its product, as it it adds a phosphate group.

Front 28

fermentation

Back 28

it is done through enzymes of dehydration. The whole purpose of fermentation is to make NAD+ out of NADH.

Front 29

lactate dehydrogenase

Back 29

it oxidizes NADH to NAD+ so it can go back to the Glyceraldehyde 3-phosphate dehydrogenase an get the "H".

Front 30

Glycolysis stops once there is no more NAD+. How is that prevented

Back 30

when NADH is oxidized to NAD+

Front 31

what is the difference between fermentation in yeast cells and humans?

Back 31

in yeasts, the pyruvate is converted to ethanol and carbon dioxide.

Front 32

What are some important intermediates for Glycolysis?

Back 32

*DHAP- Dihydroxyacetone Phosphate= it is converted to Glycerol 3-phosphate ( which is the backbone of triacylglycerol).

-Therefore it is used for the triacylglycerol synthesis in hepatocytes and adipose tissue.