Metabolism Flashcards

(42 cards)

1
Q

What is the standard 16 carbon fatty acid found in the diet?

A

Palmitate

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2
Q

What enzymes are activated by insulin in the liver?

A

Glucokinase

Glycogen synthase

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3
Q

What enzymes are inhibited by insulin in the liver?

A

Glycogen Phosphorylase

Glucose -6 - Phosphotase

Phosphophenolpyruvate carboxykinase

Pyruvate carboxylase

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4
Q

What is the incretin effect and what enzymes are released?/

A

release of G.I hormones that stimulate insulin release

Glucagon like peptide -1

Gastric inhibitory peptide

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5
Q

What enzyme stimulates the formation of glycerol?

A

Dihydroxyacteone - 1

DHAP

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6
Q

What hormones are needed for the formation of TAGs via vLDL?

A

Lipoprotein lipase - breaks fatty acids off the vLDL

Diaglycerol Acyl Transferase (DGAT)
- reforming the fatty acids with glycerol in the adipocyte

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7
Q

What is the enzyme that reverses PFK-1?

A

Fructose 1,6 Bisphosphotase

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8
Q

What is the committed step in the pentose pathway?

A

Glucose - 6 - Phosphate being dehydrogenated by:

Glucose - 6 - phosphate dehydrogenase

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9
Q

What does Glycogen synthase use for its production?

A

G-6-P is turned into Glucose - 1 - phosphate

this is then activated into UDP glucose by G-1-P Uridlytrasnferase

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10
Q

Why can’t muscles contribute to blood glucose levels?

A

They lack Glucose-6-phosphates and thus are unable to remove the phosphate keeping the glucose in the cell.

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11
Q

What determines whether a glucose molecule is Alpha or Beta?

A

Where the hydroxy group is located on carbon 1.

If below it is alpha formation

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12
Q

What bond does fructose have?

A

Alpha 1-2 Glycosidic bond

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13
Q

What are the different type of starch structures and how do they affect digestion? with examples.

A

Type A - Latice structure with high surface area - easily digestible: wheat.

Type B - Helical structure - low surface area difficult to digest: Potato starch

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14
Q

Some cooking methods and storage methods cause starch to take on a helical structure which make it completely indigestible. what is this called?

A

Retrograde starch

turning type A into type B

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15
Q

What happens to carbohydrates that are not digested in the small intestine?

A

Within the first half of the colon, bacteria ferment them into short chained fatty acids, which can be exchanged for HCO3-

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16
Q

How do GLUT receptors differ form SGLT receptors?

A

GLUT allow glucose in down its concentration gradient

SGLT - force glucose against its concentration gradient

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17
Q

What GLUT receptors can carry fructose?

A

GLUT 2 and GLUT 5

18
Q

What are the theoretical fates of glucose?

A

To be used by the cell for energy

Glycogen formation

Pentose pathway

Used to make triglycerides

Formation of glycoproteins - this is a small %

19
Q

What is the yield from glycolysis?

A

2 ATP

2 NAHD+

2 Pyruvate

4 H+

20
Q

Between what reactions do you get the ATP production during Glycolysis?

A

1,3 Bisphosphoglycerate - 3 Phosphoglycerate (x2)

Phosphophenolpyruvate - Pyruvate acid (x2)

21
Q

What is the committed step for glycolysis?

22
Q

What is the yield from Krebs cycle? and how does this equate to ATP production from one glucose?

A

3 NADH+ (x2)

1 GTP (x2)

1 FADH+ (x2)

24 ATP - taking into account both split molecules off the glucose molecule

23
Q

How ATP does one glucose molecule yield?

24
Q

What is the pentose pathway important for?

A

NADPH production - reductive abilites

Ribose - 5 - phospahte - DNA and RNA synthesis

25
In order for glycogen to be formed, what must happen to Glucose - 6 - phosphate and what enzyme achieves this?
converted to glucose - 1 - phosphate phospho- glucomutase
26
What enzyme reverses hexokinase/ Glucokinase activity? and where is it found and what up-regulates it?
Glucose - 6 - phosphatase. expressed in R.E.R - Glucagon - adrenaline - cortisol
27
What are the two enzymes needed to reverse pyruvate?
[Pyruvate Carboxylase] creating Oxaloacetate which is then converted to Phosphophenopyruvate via: [Phosphophenopyruvate Carboxykinase]
28
What protein kinase does insulin work through?
Protein kinase B
29
How does Glucagon work intracellularly?
Increases cAMP levels. induces PKA
30
What is fasting glucose level normally? and what are levels post prandial?
4-5mmol 8-12mmol
31
What are the functions of insulin in adipose tissue?
Supress lipolysis Increase GLUT 4 and fatty acid synthesis
32
What does DGAT stand for and when is it used?
Diacylglycerol acyl transferase Used to convert Fatty acids into triglycerides
33
What is the target of orlistat?
Pancreatic lipases and colic lipsases
34
What is the fate of triglycerides and fatty acids?
Storage - adipose tissue Beta - oxidation Ketone production Phospholipid production
35
How much ATP does a 16 carbon fatty acid (Palmitate) produce?
106 ATP
36
What are the two key regulatory hormones in fatty acid synthesis?
Acetly CoA carboxylase Fatty Acid synthesis
37
What does Acetly CoA carboxylase need in order to produce malonyl CoA
Biotin ATP CO2
38
Where does the enzyme fatty acid synthesis work? and what does it require?
Cytosol of the cell NADPH - derived from pentose pathway
39
What are the major ketones produced?
Acetoacetate Acetone Beta - hydroxybutyrate
40
Name two essential fatty acids? | and why are they important?
w- 3 w- 6 precursors for: eicosanoids and prostanoids - pro-inflammatory responders Decrease LDL **high levels may also lower HDL
41
What 3 main areas does insulin regulate triglyceride production?
Up-regulates GLUT 4 Acetyl CoA Carboxylase enzyme Lipoprotein lipase
42
What occurs to the lipoprotein lipase activity during the fed state in muscles and cardiac tissue?
Activity goes down - the tissues don't need fatty acids within the cells for energy