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Structural Basis for Biological Function (Protein Modifications) Quiz on Physical Modifications, created by gina_evans0312 on 21/12/2013.

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Physical Modifications

Physical Modifications

Question 1 of 33

1

Physical modifications are reversible

Select one of the following:

  • True
  • False

Explanation

Question 2 of 33

1

Give an example of protein oxidation

Select one of the following:

  • Disulphide bond formation

  • Hydrogen bond formation

  • Glycosylation

Explanation

Question 3 of 33

1

Where are proteins with oxidated modifications are nearly universally found where?

Select one or more of the following:

  • Outside the cell

  • The cytoplasm

  • Nucleus

  • I.e. Oxidative environments

Explanation

Question 4 of 33

1

What is so useful about disulphide bonds?

Select one or more of the following:

  • They're heat stable

  • They're protease resitant

  • They're structurally resilient

Explanation

Question 5 of 33

1

Where do oxidation reactions occur?

Select one of the following:

  • The golgi

  • The ER

  • The ribosome

Explanation

Question 6 of 33

1

Disulphide bonds assist in recovery from denaturation

Select one of the following:

  • True
  • False

Explanation

Question 7 of 33

1

In Maristoylation, what is added?

Select one of the following:

  • Maristic acid

  • Maristoylate

  • Maristoyl-3-phosphate

Explanation

Question 8 of 33

1

Describe the substrate added in Myristoylation

Select one or more of the following:

  • 4C

  • 5C

  • 6C

  • Saturated & hydrophobic

  • Unsaturated & hydrophilic

Explanation

Question 9 of 33

1

What is the point of Myristoylation?

Select one of the following:

  • It polarises a protein

  • It binds a protein to a membrane

  • It binds two ends of a protein together

Explanation

Question 10 of 33

1

What sequence is the Myristoylation substrated added to?

Select one or more of the following:

  • The N-terminus

  • The C-terminus

  • MGXXX(T/S)

  • MPXXX(G/F)

  • SDXXX(S/R)

Explanation

Question 11 of 33

1

The protein that performs Myristoylation is N-Myristoyl transferase

Select one of the following:

  • True
  • False

Explanation

Question 12 of 33

1

How is the Myristoylation substrate added?

Select one or more of the following:

  • First the phenylalinine is removed

  • First the methionine is removed

  • First the tyrosine is removed

  • Then the substrate is added to the glycine

  • Then the substrate is added to the leucine

  • Then the substrate is added to the isoleucine

Explanation

Question 13 of 33

1

Prenylation is the addition of ketones

Select one of the following:

  • True
  • False

Explanation

Question 14 of 33

1

Name the two substrates most often added in prenylation

Select one or more of the following:

  • Farnesyl

  • Geranylgeranyl

  • Derisyl

  • Nitrosyl

Explanation

Question 15 of 33

1

Where does prenylation occur?

Select one of the following:

  • In a CAAX box (where A should be Alanine, but anything small and hydrophobic will do)

  • In a FAAX box (where A should be Isoleucine, but anything small and hydrophobic will do)

  • In a CAAT box (where A should be Alanine, but anything small and hydrophobic will do)

Explanation

Question 16 of 33

1

In prenylation, the X of the sequence must be the terminal aa of the chain

Select one of the following:

  • True
  • False

Explanation

Question 17 of 33

1

Put the following in order
A- The COOH group is modified to a methyl group to make it uncharged
B- The substrate is added to the cystine
C- The last three aa are removed

Select one of the following:

  • A-C-B

  • B-C-A

  • A-B-C

Explanation

Question 18 of 33

1

Prenylation is done to proteins destined for the cytoplasm

Select one of the following:

  • True
  • False

Explanation

Question 19 of 33

1

Name the types of glycosylation

Select one or more of the following:

  • N-linked

  • O-linked

  • C-Mannosylation

  • Phosphoserine Linked

Explanation

Question 20 of 33

1

Glycosylation is the addition of carbohydrate chains

Select one of the following:

  • True
  • False

Explanation

Question 21 of 33

1

What is the site of N-linked glycosylation?

Select one of the following:

  • The Asn in an NX(S/T)

  • The Phe in an FX(S/T)

  • The Gly in a GX(S/T)

Explanation

Question 22 of 33

1

What is the residue that is attached to the amino acid?

Select one of the following:

  • Mannose

  • Glucose

  • N-acetyl-galactosamine

  • N-acetyl glucosamine

Explanation

Question 23 of 33

1

What residues are on the tips of the branches?

Select one of the following:

  • Mannose

  • Glucose

  • Fructose

Explanation

Question 24 of 33

1

If the branches end with mannose, what is the process called?

Select one of the following:

  • High-mannose Biantennary N-glycosylation

  • High-mannose N-glycosylation

  • Mannosylation

Explanation

Question 25 of 33

1

Why are 3 glucose added to the sugar complex in the golgi?

Select one of the following:

  • So they can be removed as markers for protein folding and transport

  • So the Golgi knows they're bound for the membrane

  • So the Golgi can degrade the protein as faulty

Explanation

Question 26 of 33

1

Why is it called High-Mannose Biantennary N-Glycosylation?

Select one of the following:

  • Because one of the three branches is removed, giving two 'antenna'

  • Because another branch is formed off the first one, giving two 'antenna'

  • Because proteins with this type of glycosylation act as receptor proteins with two antenna

Explanation

Question 27 of 33

1

Once the Biantennary complex has been formed, what happens next?

Select one or more of the following:

  • Mannose is removed

  • Addition of N-acetyl neuraminic acids

  • Addition of glucose

  • Removal of N-acetyl glucosamine

  • Addition of a fucose to the GlcNac bound to the amino acid

Explanation

Question 28 of 33

1

Why the complicated process of adding and removing sugars?

Select one of the following:

  • It adds a date stamp to the cell- over time the NeuAc's fall off, which signals the protein for degredation

  • It adds a transport signal- depending on what is added or removed, proteins are directed to different areas by carrier proteins

  • It's quality control- the contortions required to add and remove all the sugars mean that the protein has folded properly

Explanation

Question 29 of 33

1

The HIV virus can use glycosylation to hide from the immune system

Select one of the following:

  • True
  • False

Explanation

Question 30 of 33

1

Why is N-linked glycosylation potentially dangerous?

Select one of the following:

  • Because the immune system is programmed to ignore it, viral coat proteins can use it to hide the virus

  • Because NeuAc's can be toxic in high concentrations

  • Because the removal of mannose can cause the protein to misfold

Explanation

Question 31 of 33

1

HIV1-gp120 has many N-X-(T/S) sequences to be glycosylated

Select one of the following:

  • True
  • False

Explanation

Question 32 of 33

1

Where does HIV1-gp120 bind?

Select one of the following:

  • CD4 receptor

  • CD8 receptor

  • B-lymphocyte receptors

Explanation

Question 33 of 33

1

How does the HIV virus invade the lyphocyte?

Select one or more of the following:

  • It's only glycosylated on a very small binding site

  • It's only not glycosylated on a very small binding site

  • Which allows it to bind and invade

Explanation

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