Physical Modifications

Descripción

(Protein Modifications) Structural Basis for Biological Function Test sobre Physical Modifications, creado por gina_evans0312 el 21/12/2013.
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Resumen del Recurso

Pregunta 1

Pregunta
Physical modifications are reversible
Respuesta
  • True
  • False

Pregunta 2

Pregunta
Give an example of protein oxidation
Respuesta
  • Disulphide bond formation
  • Hydrogen bond formation
  • Glycosylation

Pregunta 3

Pregunta
Where are proteins with oxidated modifications are nearly universally found where?
Respuesta
  • Outside the cell
  • The cytoplasm
  • Nucleus
  • I.e. Oxidative environments

Pregunta 4

Pregunta
What is so useful about disulphide bonds?
Respuesta
  • They're heat stable
  • They're protease resitant
  • They're structurally resilient

Pregunta 5

Pregunta
Where do oxidation reactions occur?
Respuesta
  • The golgi
  • The ER
  • The ribosome

Pregunta 6

Pregunta
Disulphide bonds assist in recovery from denaturation
Respuesta
  • True
  • False

Pregunta 7

Pregunta
In Maristoylation, what is added?
Respuesta
  • Maristic acid
  • Maristoylate
  • Maristoyl-3-phosphate

Pregunta 8

Pregunta
Describe the substrate added in Myristoylation
Respuesta
  • 4C
  • 5C
  • 6C
  • Saturated & hydrophobic
  • Unsaturated & hydrophilic

Pregunta 9

Pregunta
What is the point of Myristoylation?
Respuesta
  • It polarises a protein
  • It binds a protein to a membrane
  • It binds two ends of a protein together

Pregunta 10

Pregunta
What sequence is the Myristoylation substrated added to?
Respuesta
  • The N-terminus
  • The C-terminus
  • MGXXX(T/S)
  • MPXXX(G/F)
  • SDXXX(S/R)

Pregunta 11

Pregunta
The protein that performs Myristoylation is N-Myristoyl transferase
Respuesta
  • True
  • False

Pregunta 12

Pregunta
How is the Myristoylation substrate added?
Respuesta
  • 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

Pregunta 13

Pregunta
Prenylation is the addition of ketones
Respuesta
  • True
  • False

Pregunta 14

Pregunta
Name the two substrates most often added in prenylation
Respuesta
  • Farnesyl
  • Geranylgeranyl
  • Derisyl
  • Nitrosyl

Pregunta 15

Pregunta
Where does prenylation occur?
Respuesta
  • 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)

Pregunta 16

Pregunta
In prenylation, the X of the sequence must be the terminal aa of the chain
Respuesta
  • True
  • False

Pregunta 17

Pregunta
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
Respuesta
  • A-C-B
  • B-C-A
  • A-B-C

Pregunta 18

Pregunta
Prenylation is done to proteins destined for the cytoplasm
Respuesta
  • True
  • False

Pregunta 19

Pregunta
Name the types of glycosylation
Respuesta
  • N-linked
  • O-linked
  • C-Mannosylation
  • Phosphoserine Linked

Pregunta 20

Pregunta
Glycosylation is the addition of carbohydrate chains
Respuesta
  • True
  • False

Pregunta 21

Pregunta
What is the site of N-linked glycosylation?
Respuesta
  • The Asn in an NX(S/T)
  • The Phe in an FX(S/T)
  • The Gly in a GX(S/T)

Pregunta 22

Pregunta
What is the residue that is attached to the amino acid?
Respuesta
  • Mannose
  • Glucose
  • N-acetyl-galactosamine
  • N-acetyl glucosamine

Pregunta 23

Pregunta
What residues are on the tips of the branches?
Respuesta
  • Mannose
  • Glucose
  • Fructose

Pregunta 24

Pregunta
If the branches end with mannose, what is the process called?
Respuesta
  • High-mannose Biantennary N-glycosylation
  • High-mannose N-glycosylation
  • Mannosylation

Pregunta 25

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

Pregunta 26

Pregunta
Why is it called High-Mannose Biantennary N-Glycosylation?
Respuesta
  • 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

Pregunta 27

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

Pregunta 28

Pregunta
Why the complicated process of adding and removing sugars?
Respuesta
  • 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

Pregunta 29

Pregunta
The HIV virus can use glycosylation to hide from the immune system
Respuesta
  • True
  • False

Pregunta 30

Pregunta
Why is N-linked glycosylation potentially dangerous?
Respuesta
  • 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

Pregunta 31

Pregunta
HIV1-gp120 has many N-X-(T/S) sequences to be glycosylated
Respuesta
  • True
  • False

Pregunta 32

Pregunta
Where does HIV1-gp120 bind?
Respuesta
  • CD4 receptor
  • CD8 receptor
  • B-lymphocyte receptors

Pregunta 33

Pregunta
How does the HIV virus invade the lyphocyte?
Respuesta
  • 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
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