Brainscape's Knowledge GenomeTM

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


See full index

Foundations Of Medicine > Carbohydrates > Flashcards

Carbohydrates Flashcards

1
Q

What are is the function of carbohydrates

A

Highly oxidizable - major metabolic process
Store potential energy - glycogen
Structural/protective - ECM of cells
Contribute to cell-to-cell communication - ABO blood groups

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

What are monosaccharides

A

Carb with one sugar subunit
3 hexoses (6C sugars) - Glucose (Glc), Galactose (Gal), Fructose (Fru)

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

What are disaccharides

A

Monosaccharide monomers, linked by glycosidic bond
3 important - Maltose, Lactose, Sucrose

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

What is a glycosidic bond

A

Covalent bond between hydroxyl group and anomeric carbon

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

What is an anomeric carbon

A

Different anommers are mirros images
C 1 on Glc residue
Stabilises Glc structure
Only residue that can be oxidised

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

Describe maltose

A

Anomeric C-1 can be oxidised
Reducung sugar

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

Describe Lactose

A

Glycosidic bond between galactose and glucose
Anomeric C on glucose is oxidised, reducing sugar

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

Describe Sucrose

A

No free anomeric C-1
no oxidiation site
non-reducing sugar

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

Descibre Polysaccharides

A

Long chain carbs, many monosaccharide monomers

Homopolysaccharides - single monomeric species
Heteropolysaccharides - Two or more monomeric species

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

Descibe Starch

A

Two types of Glc polymers:
Amylose (20-25%) - (α1→4) join glucose chains
Amylopectin (75-80%) - (α1→6) create branches

Many non-reducing ends, few reducing

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

Describe Oligosaccharides

A

Polymer with small numbers of monsaccharides
Cell regeneration and cell adhesion
Lack in diet lead to poor health

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

Describe the digestion of Carbs

A

Mouth - Salivary amylase hydrolyses (α1→4) bonds of starch
Stomach - no carb digestion
Small intestines

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

Describe the digestion of carbs in small intestines

A

Isomaltase - hydrolyses (α1→6) bonds
Glucoamylase – removes Glc sequentially from non-reducing ends
Sucrase – hydrolyses sucrose
Lactase – hydrolyses lactose

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

Describe the absorbtion of glucose

A
  1. Absorbed indirectly by ATP into epithelial cells
  2. Glucose and Na+ transported at same time down Na+ conc. gradient
  3. Works continually even when blood glucose is high
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the absorbtion of Galactose

A

Similar to glucose, using conc. gradients to facilitate transport

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

Describe the absorbtion of Fructose

A

Binds to channel protein GLUT5
Moves down conc. gradient, high in gut lumen low in blood

17
Q

Fate of absorbed glucose

A

Absorbed by intesine epithelial cells into blood towards liver
Phosphorolated to glucose-6-phosphate by hepatocytes
G6P cannot diffuse out cell

18
Q

What enzymes catalysts are there for glucose absorbtion

A

Glucokinase (liver)
Hexokinase (other tissues)

19
Q

Describe Glucokinase

A

Blood Glc is high
High glucokinase Vmax can phosphorylate Glc quickly
Most absorbed Glc trapped in liver

20
Q

Describe hexokinase

A

Hexokinase low Km means at low Glc, tissues can absorb effectively
Hexokinase low Vmax, tissues “easily satisfied”, don’t keep absorbing Glc

21
Q

What is the function of glycogen

A

Energy storage
90% in:
Liver - replenishes blood glucose when fasting
Skeletal muscle - catabolism produces ATP for contraction

22
Q

Describe glycogen synthesis

A

Step 1:

  1. Glygogenin (enz) covalently bonds Glc from (UDP)-glucose to chains of 8 Glc
  2. Glycogen synthase extends Glc chains

Step 2:

  1. Glycogen chains broken by glycogen-branching enzyme and re-attached by (α1→6) bonds to give branch points
23
Q

What is the process of glycolysis

A

1 - Phosphorylation of Glc - hexokinase, 1 ATP used
2 - G-6-P to F-6-P
3 - F-6-P to F-1,6-bisP
6 - Oxidation of Glyceraldehyde-3-P to 1,3-bisPGlycerate - 2 NADH produced
7 - Pi transfer from 1,3-bisPG to ADP = 3-PG, 2 ATP produced
10 - Transfer of Pi from PEP to ADP = Pyruvate, 2 ATP produced

24
Q

What happens to pyruvate

A
  1. Ethanol
  2. Lactate
  3. CO2
25
Q

Describe pyruvate to lactate

A

NADH oxidation reduces pyruvate to lactate
Nad+ replinished for glycolysis
Lactate dehydrogenase is catalyst
Redox balanced

26
Q

Describe pyruvate to acetyl coenzyme A (acetyl CoA)

A

Cells with access to O2, pyruvate oxidised to acetyl CoA
Pyruvate dehydrogenase acts as catalyst

27
Q

What is the precursor to gluconeogenesis

A

Lactate (non-carbs), get turned into glucose

28
Q

What is the function and process of gluconeogenesis

A

4 reactions that sidestep 3 irreversible reactions of glycolysis (1,3,10)
Independent control of glycolysis and gluconeogenesis pathways

29
Q

What are the 4 bypass reactions

A

A - Pyruvate to Oxaloacetate
B - Oxaloacetate to PEP
C - Fru 1,6 Bisphos to F-6-P (step 3)
D - G-6-P to glucose (step 1)

30
Q

What are the fates of absorbed fructose and galactose

A

Fructose and galactose can enter glycolysis at various points

31
Q

What is substrate level phosphorylation

A

Phosphate group is transferred from donor compound
Method of ATP production

32
Q

What is Oxidative phosphorylation

A

Metabolic pathway generates ATP from ADP
Oxidation of nutrients gives energy for phosphorylation

33
Q

What is the cori cycle

A

Lactate to Glucose in liver
Glucose to Lactate in Muscle

34
Q

What is function of galactokinase

A

Phosphorylate galactose with ATP to galactose-1-phosphate

35
Q

What is fructokinase

A

Catalyzes conversion of fructose and ATP into fructose-1-phosphate and ADP

36
Q

What is a glycoprotein

A

Proteins with carbs covalently attached

Increases proteins solubility
Influence protein folding and conformation
Protect from degradation
Communicate between cells

37
Q

What is a proteoglycan

A

GAGs covalently attaching to proteins
Macromolecules found on surface of cells or ECM
Form part of many connective tissues in body

Foundations Of Medicine (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions