Question 1

Which of the following best describes a glycoprotein?

Accepted Answer

A hybrid molecule made of mostly proteins covalently linked to relatively small oligosaccharides.

Question 2

In glycosylation, the carbohydrate portion of glycoproteins is usually very _________.

Accepted Answer

heterogeneous

Question 3

Which amino acid is most commonly involved in O-linked glycosylation in eukaryotes?

Accepted Answer

Serine

Question 4

Glycolipids are best described as:

Accepted Answer

Hybrid molecules made of a lipid covalently linked to relatively small sugars.

Question 5

Which of the following is TRUE about the glycosidic bond in N-linked glycoproteins?

Accepted Answer

It forms between the anomeric carbon of a sugar and the amide nitrogen of an asparagine residue.

Question 6

Which equation best represents the formation of an O-linked glycosidic bond?

Accepted Answer

$$\mathrm{Sugar{-}OH} + \mathrm{Ser{-}OH} \rightarrow \mathrm{Sugar{-}O{-}Ser} + \mathrm{H_2O}$$

Question 7

Where are glycoproteins most commonly found in animal cells?

Accepted Answer

On the surface of plasma membranes

Question 8

Which of the following statements about glycosylation is correct?

Accepted Answer

Glycosylation can occur on both proteins and lipids.

Question 9

Which amino acid is most commonly involved in N-linked glycosylation?

Accepted Answer

Asparagine

Question 10

In glycoproteins, the carbohydrate is MOSTLY attached through the amino acid residues of:

Accepted Answer

Asparagine, Serine, or Threonine

Question 11

Which of the following is a major function of glycoproteins on the surface of animal cells?

Accepted Answer

Cell-cell recognition and signaling

Question 12

Which of the following statements about glycolipids is FALSE?

Accepted Answer

Glycolipids are primarily found in the nucleus.

Question 13

Which of the following best describes the difference between O-linked and N-linked glycosylation?

Accepted Answer

O-linked glycosylation attaches the carbohydrate to the hydroxyl group of serine or threonine, while N-linked glycosylation attaches it to the amide nitrogen of asparagine.

Question 14

Which of the following is the correct structure for an N-linked glycosidic bond?

Accepted Answer

$$\mathrm{Sugar{-}NH{-}Asn}$$

Question 15

Which of the following is NOT a typical role of glycoproteins?

Accepted Answer

Structural support in cell walls

Question 16

Which of the following statements about the carbohydrate portion of glycoproteins is correct?

Accepted Answer

It is usually heterogeneous and can be branched.

Question 17

Which of the following is a plausible consequence of a mutation that prevents O-linked glycosylation in a cell?

Accepted Answer

Impaired cell-cell recognition and signaling

Question 18

Which of the following is the correct chemical group involved in O-linked glycosylation?

Accepted Answer

Hydroxyl group ($$\mathrm{-OH})$$

Question 19

Which of the following is the correct chemical group involved in N-linked glycosylation?

Accepted Answer

Amide nitrogen ($$\mathrm{-NH})$$

Glycoconjugates: Structure, Types, and Biological Roles

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