Brainscape's Knowledge GenomeTM

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


See full index

Isaak: Biochemistry MBS > Lecture 13: Carbohydrate Conjugation > Flashcards

Lecture 13: Carbohydrate Conjugation Flashcards

1
Q

What is a hexose?

Name a common example.

A

A six-carbon sugar. Glucose is an example of a hexose.

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

What is a pentose?

Name a common example.

A

A five-carbon sugar. Ribose is an example of a pentose.

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

Name a carbohydrate that is an aldehyde.

A

Glucose.

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

Name a carbohydrate that is a ketone.

A

Fructose.

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

True or false?

Glucose, galactose, and mannose are all stereoisomers of the same chemical structure.

A

True.

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

What is a glycosidic bond and where are they found?

A

The charecteristic bond through an anomeric carbon of a sugar. It may be an alpha (hydroxyl down) or beta conformation (hydroxyl up).

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

What kind of polysaccharide makes up dental plaque?

A

Dextrans.

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

Why are mammalian enzymes unable to digest polysaccharides such as dextrans or cellulose?

A

Cellulose is linked via beta 1-6, while dextrans is linked via alpha 1-6.

Mammalian enzymes are not capable of cleaving these bonds.

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

How can one differentiate the starches amylose and amylopectin?

A

Although amylose and amylopectin are both homopolymers of glucose linked primarily through alpha 1-4 linkages, only amylopectin branches via alpha 1-6 linkages.

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

What is glycogen?

A

A homopolymer of glucose linked via alpha 1-4 linkages with alpha 1-6 branching approximately every 8-10 residues.

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

What is dextrans?

A

A homopolymer of glucose linked via alpha 1-6. Synthesized by bacteria and is partially responsible for dental plaque.

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

What are the five major glocosaminoglycans?

A
  1. Hyaluronate
  2. Chondroitin sulfate
  3. Keratan sulfate
  4. Dermatan sulfate
  5. Heparin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the general structure of a glycosaminoglycan?

A

Long linear polysaccharides with repeating disaccharide units with considerable negative charge (including sulfate).

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

What are glycolipids (e.g. gangliosides) composed of?

A

They are lipids modified with sugars.

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

What is glycation?

A

The non-enzymatic glycosylation of proteins that occurs by a simple reaction of a protein side chain and a carbohydrate.

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

What is the clinical relevance of glycation?

A

Since we know the rough half life of an erythrocyte, one can calculate the % of hemoglobin that has been glycated to form hemoglobin A1c…a 3 month “average” of blood sugar levels.

17
Q

How is enzymatic conjugation of carbohydrates achieved?

A

Activation of the sugar by formation of sugar-nucleotides, such as UDP-glucose.

18
Q

How is the enzymatic formation of polysaccharides performed?

A

By enzymatic addition of one sugar at a time, using an enzyme of the correct specificity and the appropriate substrate.

19
Q

Where is the only location of glycoproteins (with the exception of O-GlcNac)?

A

“Outside” of the cell, such as in the lumern of the ER, ectoplasmic face of the plasmolemma, or secreted from the cell.

20
Q

How are O-linked structures constructed?

A

O-linked structures are built one sugar at a time on serine or threonine residues.

21
Q

How are N-linked structures constructed?

A

N-linked structures are initially added in a 14-sugar block to asparagine constructed on a dolichol phosphate lipid.

22
Q

True or false?

The initial transfer to N (in N-linked structure construction) is cotranslational (occuring while translation is underway) in the endoplasmic reticulum.

A

True.

23
Q

What happens to both N and O linked carbohydrate structures once they are constructed in the ER?

A

They are processed as they are trafficked through the Golgi apparatus.

24
Q

What is the relationship between lysosomes and glycoprotein/polysaccharide sugars?

A

The lysosome contains many enzymes that can degrade glycoprotein/polysaccharide sugars.

25
Q

What is an LSD that occurs from a single defective enzyme?

A

Pompe disease.

26
Q

What kind of diseases result from the lysosomes inability to degrade its contents?

A

Lysosomal storage diseases, or LSDs.

27
Q

What LSD results from the complete lack of enzymes in the lysosome due to a trafficking/targeting defect?

A

I-Cell disease. It results from a failure of the mannose-6-phosphate trafficking system.

28
Q

How are LSDs characterized?

A

By their cellular inclusions.

29
Q

What are proteoglycans and why are they named as such?

A

The suffix is what the majority is.

Therefore, these molecules are mostly sugar (>90%) and a small amount protein.

30
Q

Where can one find proteoglycans?

A

In the matrix that makes up tissue structure, such as cartilage, dentin, and predentin.

31
Q

How do proteoglycans provide cushioning?

A

They are hydrated.

32
Q

Other than mechanical purposes, what roles do proteoglycans have?

A

Because of their negative charge, they can also bind growth factors as well as chemokines/cytokines.

33
Q

In a general sense, what is one of the main purposes of glycosylation?

A

Biological recognition.

34
Q

How does protein recognition of carbohydrate structures occur?

A

Via lectin domains.

35
Q

What contributes to the difference in ABO blood groups?

A

Carbohydrate structures.

36
Q

How do viruses (such as influenza) or bacteria (such as H. pylori) infect cells?

A

They hijack the carbohydrate recognition system.

37
Q

What is the role of carbohydrates in leukocyte migration/rolling?

A

They mediate the cell-cell contact between them and the endothelial cells. These interactions can initiate the process of invading into the tissue.

38
Q

What is the role of carbohydrate binding inside the cell’s ER?

A

Carbohydrate binding mediates chaperone-mediated protein folding in the ER

39
Q

What is the role of carbohydrate binding in the golgi apparatus?

A

It helps to mediate trafficking of enzymes to the lysosomal compartment, as in the mannose-6-phosphate trafficking system.

Isaak: Biochemistry MBS (11 decks)

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