Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Gastrointestinal Biochem > Flashcards

Gastrointestinal Biochem Flashcards

1
Q

Major storage of glucose

A

Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define: Glycogenesis

A

Synthesis of glycogen from glucose (freely available)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define: Glycogenolysis

A

Breakdown of glycogen to form glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Muscle glycogen broken down can be consumed everywhere? True/false

A

False. It can only be consumed in the muscle cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When does liver glycogen provides glucose

A

Between meal times. Maintains glucose levels in blood for brain and RBCs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the primary source of glucose overnight?

A

Gluconeogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Glycogen is a polymer consisting of…?

A

Glucose molecules joined by 1,4 - glycosidic links.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What aids the conversion of glucose to glucose -6- phosphate?

A

ATP and Hexokinase (enzyme)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the function of phosphoglucomutase?

A

Converts glucose 6 phosphate to glucose 1 phosphate to then form UDP - glucose, which becomes glucose…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glycogen Synthase causes UDP-glucose to form glucose molecules and UDP. True/false

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is UDP glucose?

A

An activated form of glucose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the rate limiting enzyme in glycogenesis?

A

Glycogen Synthase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What catalyses glycogenolysis?

A

Glycogen phosphorylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to glucose -6 - phosphate in the liver?

A

Dephosphorylated and released into the blood stream as glucose.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glucose -6- phosphate is dephosphorylated in skeletal muscle to release glucose. True/false

A

False.

Cannot be dephosphorylated. Provides energy via glycolysis and TCA cycle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Summarise Glycogen breakdown in liver

A

Glycogen (glycogen phosphorylase) FORMS glucose-1-phosphate (phosphoglucomutase) FORMS glucose-6-phosphate (glucose-6-phosphotase) FORMS glucose in liver.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is glucose passed into the blood stream?

A

GLUT2 transporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define: Gluconeogenesis

A

Synthesis of glucose from non carbohydrate precursors (lactate, amino acids, glycerol) during starvation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Summarise the Cori Cycle

A

Lactate is precursor of gluconeogenesis; it’s formed in fast twitch muscles. Blood transports lactate to liver - liver converts it to glucose. Glucose released into bloodstream; this process relieves metabolic burden during heavy exercise.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are lipids?

A

Hydrocarbons containing long chain fatty acids and insoluble in water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Triglycerides are the main storage form in adipose tissue. True/false?

A

True.

They are hydrophobic, compact molecules which give a high energy yield.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Double Bonds in fatty acids usually are in the trans-configuration? True/False?

A

False. They ae usually in the cis-configuration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What fatty acids are liquids at room temperature?

A

Any with up to 8 carbons.

Longer chains are solids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The main natural fatty acids

A

Palmitic Acid
Stearic Acid
Oleic Acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Main products of fat digestion are?

A

Glycerol
Fatty acids
Monoglycerides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a chylomicron composed of?

A

Protein, phospholipid and cholesterol coat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What do chylomicrons act?

A

They enter the bloodstream and cleave to lipoprotein lipases in the muscle and adipose tissues. They are then resynthesized and oxidised.

28
Q

Lipolysis

A

the breakdown of lipids.

29
Q

Hormone sensitive lipases

A

E.g. Adrenaline sensitive. These are involved in the initial cleavage release of free fatty acids and glycerol; but this only occurs when energy is needed.

30
Q

Fatty acid + CoA

A

Acetyl-CoA

31
Q

Fatty Acid Oxidation Activation

A

Before fatty acids can be oxidised they are transformed into CoA derivatives in the cytoplasm

32
Q

Where does further oxidation occur

A

The mitochondrial Matrix

33
Q

Carnitine Shuttle

A

The transportation of long-chain acyl groups from fatty acids into the mitochondrial matrix, so they can be broken down through β-oxidation to acetyl CoA to obtain usable energy via the citric acid cycle.

34
Q

Acyl group on CoA can now be transferred to carnitine and the resulting acylcarnitine transported into the mitochondrial matrix; what are the steps for this mechanism?

A
  1. ) Acyl CoA is transferred to the hydroxyl group of carnitine by carnitine acyltransferase I (palmitoyltransferase) located on the outer mitochondrial membrane
  2. ) Acylcarnitine is shuttled inside by a carnitine-acylcarnitine translocase
  3. Acylcarnitine is converted to acyl CoA by carnitine acyltransferase II (palmitoyltransferase) located on the inner mitochondrial membrane. The liberated carnitine returns to the cytosol.
35
Q

What is the function of the enzyme carnitine acyltransferase II (palmitoyltransferase)

A

This is involved in the conversion of acyl CoA from acylcarnitine.

36
Q

What cycle does Beta oxidation occur in

A

Citrate Cycle

37
Q

What are the products of the citrate cycle?

A

1 acetyl-CoA
1 FADH2
1 NADH+ and H+
1 fatty acyl-coA (shortened by 2 carbons)

38
Q

What does glycerol kinase do?

A

Activates the glycerol to form glycerol-3-phosphate.

39
Q

Glycerol-3-phosphate is present in adipose tissue, skeletal and cardiac muscle? True/false

A

False, it is absent.

It is only present in the liver and kidneys

40
Q

What are ketone bodies

A

Important molecules of metabolism for heart muscle and renal cortex; they are converted back to acetyl-CoA during the TCA cycle.

41
Q

Where are ketone bodies formed?

A

The mitochondria of the liver. They then diffuse into the blood stream and peripheral tissues

42
Q

What is oxaloacetate?

A

A side product of glycolysis which is necessary for the formation of citrate.
It is consumed for gluconeogenesis

43
Q

What happens to Acetyl-CoA when there are high levels of it in the blood?

A

It is converted into ketone bodies due to high levels in blood.

44
Q

Accumulation of ketone bodies leads to…?

A

Metabolic Acidosis (severe)

45
Q

Define Lipogenesis

A

This is the formation of fatty acids. It mainly occurs in the kidney, liver, mammary glands, adipose tissues and brain. Takes place when energy in excess and is a reductive process.

46
Q

How are fatty acids transported?

A

In plasma bound to albumin.

47
Q

Where is acetyl-CoA generated ?

A

Mitochondria

48
Q

What is the function of pyruvate dehydrogenase complex?

A

Generates acetyl-CoA in the mitochondria

49
Q

At high concentrations, what is transported back into the cytoplasm>

A

Citrate

50
Q

What is malonyl-CoA

A

A direct precursor of acetyl-synthesis. It donates carbon atoms to new lipids

51
Q

What is the purpose of fatty acid synthase?

A

Catalyses the synthesis f saturated long chain fatty acids from malonyl CoA, acetyl-CoA and NADPH. It consists of a dimer of identical polypeptides.

52
Q

Amino acids cannot be stored in the body. True/false?

A

True

53
Q

Where is the major site of amino acid degradation?

A

Liver

54
Q

What do proteolytic enxymes produce and where are they found?

A

Single, di and tri peptides. Found in stomach and intestines.

55
Q

What product of amino acid breakdown is toxic at high concentrations?

A

NH4+

56
Q

What is the major excretory nitrogen-containing excretory product?

A

Urea

57
Q

What ae the three steps in the synthesis of urea?

A

Transamination
Deamination
Urea cycle/synthesis

58
Q

Transamination

A

Amino acid –> keto acid

59
Q

Deamination (liver)

A

Ketoglutarate –> glutamic acid

60
Q

What are major carriers of nitrogen in the blood

A

Alanine and Glutamine

61
Q

(ferrous) Fumarate

A

An intermediate in the citrate cycle

62
Q

Maple Syrup Urine Disease

A

This is when degradation of valine, isoleucine and leucine is blocked and the urine smells like maple syrup.
Can lead to mental and physical retardation

63
Q

Alcaptonuria

A

degradation of phenylalanine and tyrosine

64
Q

Phenylketonuria

A

When phenylalanine accumulates in the body fluids, leading to slow and severe mental retardation. Diet therapy mainly.

65
Q

Where are primary bile acids converted into secondary bile acids?

A

Ileum

Biochemistry (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions