Brainscape's Knowledge GenomeTM

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


See full index

Biochemistry > Glucose Metabolism > Flashcards

Glucose Metabolism Flashcards

1
Q

Define Metabolism

A

Metabolism includes all reactions which occur to food stuffs inside the body.
The reactions are arranged to pathways where the product for one reaction is the reactant for the next reaction.

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

Name the three metabolic pathways

A
  1. Anabolic pathways
  2. Catabolic pathways
  3. Amphibolic pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe Anabolic pathways

A
  • Synthetic pathways
  • Reactions that require energy that is provided by breaking down ATP to ADP + P
  • Synthesis of protein, glycogen and fat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are catabolic pathways

A
  • Degradative pathways
  • involve oxidative processes that release free energy
  • Complex molecules are broken down into simple building blocks while releasing free energy.
  • Proteins to amino acids
  • Polysaccharideds to monosaccharides
  • Triglyceride to free fatty acids and glycerol
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the major dietary carbohydrates sources

A
  • Starch
  • Sucrose
  • Lactose
  • Small amounts of free glucose and fructose
  • Glycogen
  • Indigestible polysaccharides such as cellulose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Carbohydrate Digestion and Absorption

A

Salivary alpha-amylase cleaves starch and glycogen by breaking in random alpha 1,4 linkages between glucose residues within the chains leading to alpha-dextrins.
Pancreatic alpha- amylase also clease 1,4 linkages giving ride to maltose, maltotriose and small olignosaccharides containing alpha-1,4 and 1,6 linkages.
Brush border intestinal enzymes are olio 1,6 glucosidase releases glucose residues from branched oligosachharides.

Sucrase converts sucrose to glucose and fructose
Lactase converts lactose to glucose and galactos
Maltase converts maltose to two glucose molecules.

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

Fate of Absorbed Monosaccharides

A
  • Glucose is absorbed through portal blood to the liver
  • Fructose and galactose are converted to glucose in the liver.
  • The only sugar utilized by the body is glucose
  • Majority is taken up to the liver and stored as glycogen or oxidised by glycolysis for acetyl CoA and lipid synthesis.
  • During fasting conditions, minimal amount passes through sstemic circlation to maintain blood sugar levels.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the fate of glucose

A

Three major pathways:
1. Oxidation to pyruvate, may undergo further oxidation to citric acid cycle

  1. Storage as the polysaccharide glycogen for rpaid utilization at a later time
  2. Conversion to other sugars and intermediates essential for other important biosynthetic/ metabolic pathways.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The major pathways in which glucose is used for energy production

A

Glycolysis

Citric Acid cyle

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

The minor pathways for oxidation which are not for energy production

A 
Hexosemonophosphate shunt (HMS) pathway
Uronic acid pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

In what forms is glucose stored:

  1. In liver and muscles tissues
  2. Adipose tissues
A
  1. Glycogen

2. Triglycerides

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

Glucose converted substances as

A
  • Galactose
  • Fructose
  • Amino sugars
  • Non-essential amino acids
  • Fatty acids
  • Ribose-5-P
  • Glucuronic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is another name for Glycolysis pathway

A

Embden meyerhof pathway

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

Site of glycolysis

A

Cell cytosol of all tissues

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

Define glycolysis pathway

A

Series of enzymatic pathway in which glucose is oxidized to pyruvate while generating ATP and NADH and to provide intermediates for other synthetic and metabolic pathways.

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

What is the importance of the glycolysis pathway

A
  • Only pathway that is taking place in all cell of the body
  • Glycolysis is the only source of energy in erythrocytes.
  • Glycolysis forms the major source of energy for muscles
  • Glycolytic pathway considered as preliminary step before complete oxidation
  • Glycolytic pathway provide carbon skeletons for synthesis of nonessential amino acids as well as glycerol part of fat.
  • Most of the reactions are reversible.
17
Q

Irreversible steps of Glycolysis

A
  1. Hexokinase catalyzing the first priming reaction from glucose to glucose 6-phosphate.
  2. Phosphofructokinase catalyzing the second priming reaction from fructose 6-phosphate to fructose 1,6-bisphosphate
  3. Pyruvate Kinase catalysing second ATP forming from Phosphoenolpyruvate to pyruvate.
18
Q

How does the hormonal regulation of glycolysis take place

A

Glucagon is secreted in hypoglycemia or in carbohydrate deficiency. It affect liver as it act as inhibitors for glycolytic key enzymes (glucokinase, PFK-1, pyruvate kinase).

Insulin: Secreted in hyperglycemia and after carbohydrates feeding, it causes stimulation of glycolytic key enzymes.

19
Q

What are the inhibitors of glycolysis

A

Hexokinase: 2-deoxyglucose
Glyceraldehyde-3-P dehydrogenase: Mercury and iodoacetate
Fluoride inhibits Enolase by removal of magnesium as magnesium fluoride.

20
Q

Fate of pyruvate in anaerobic condition

A

Pyruvate can enter in lactic acid fermentation and alcoholic fermentation in anaerobic condition. Pyruvate convert to lactate by lactate dehydrogenase

21
Q

Fate of pyruvate in aerobic condition

A

Aerobic condition pyruvate loss hydrogen and carbon dioxide and convert into acetyl CoA and enter into the TCA cycle, and also enter into the biosynthetic pathway

22
Q

What happens in Cori Cycle.

A

Lactate is formed during anaerobic oxidation of glucose in muscles and in RBCs , then diffuses to the blood then to the liver. In the liver, lactate is converted to glucose by gluconeogenesis. Glucose goes back to the red cells , muscles or any tissue and is reutilized for production of energy.

23
Q

What are inhibitors of cyclic acid cycle

A
  • Fluorocitrate inhibits aconitase.
  • Mercury and arsenite inhibit pyruvate and α–ketoglutarate dehydrogenase complex.
  • Malonic acid inhibits succinic acid dehydrogenase
24
Q

What are proteins

A
  • Proteins are one of the most abundant organic molecules in
    living systems
  • Each cell in a living system may contain thousands of
    different proteins, each with a unique function.
    • Made up of chains of amino acids
    • Are found in every cell in the body
    • Are involved in most of the body’s functions and life
    processes
    • The sequence of amino acids is determined by DNA
25
Q

Functions of Proteins

A
  • Act as enzymes (pepsin, DNA polymerase)
  • Are structural proteins (keratin, collagen)
  • Act as carrier and transport (haemoglobin, aquaporin)
  • Some proteins need for cell signalling (insulin & other hormones)
  • Some proteins involving in defence mechanism (antibodies)
  • Some proteins are storage proteins (bean seed proteins)
26
Q

Formation of peptide bond

A
  • covalent bond between NH2 (amine) of one amino acid & COOH (carboxyl) of another amino acid.
  • During the peptide bond formation a water molecule is removed, this is called condensation.
  • Then form C–N bond
  • Broken through hydrolysis

Biochemistry (4 decks)

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