Charlotte Jakes
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Cell Biology and Signalling Quiz on Protein Targeting, created by Charlotte Jakes on 04/01/2020.

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Charlotte Jakes
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Protein Targeting

Question 1 of 39

1

What sequence on a protein helps us target to the endoplasmic reticulum?

Select one of the following:

  • Signal sequence

  • Nuclear localisation sequence

  • SNARE sequence

  • Glucokinase

Explanation

Question 2 of 39

1

The signal sequence is the first part of a ER-targeted protein to be synthesised.

Select one of the following:

  • True
  • False

Explanation

Question 3 of 39

1

At which peptide terminal is the signal sequence found?

Select one of the following:

  • N-terminal

  • C-terminal

Explanation

Question 4 of 39

1

The signal sequence codes for a series of hydrophilic amino acids.

Select one of the following:

  • True
  • False

Explanation

Question 5 of 39

1

What molecule binds to a protein-ribosome complex and facilitates binding to a receptor on the endoplasmic reticulum?

Select one of the following:

  • Signal Recognition Particle (SRP)

  • Nuclear Localisation Sequence (NLS)

  • SNARE protein

  • HSP70

Explanation

Question 6 of 39

1

Through what protein is the new protein guided through after it has been targeted to the endoplasmic reticulum?

Select one of the following:

  • Translocon channel

  • Signal Recognition Particle

  • SNARE

  • Na+/K+ ATPase

Explanation

Question 7 of 39

1

Fill the blank spaces to complete the text.

Fill in the blanks below to describe protein targeting to the endoplasmic reticulum.
1. The first part of the protein synthesised is the . This is a series of amino acids at the -terminus of the peptide.
2. The is recognised by (SRP).
3. is recognised by a receptor on the ER membrane.
4. The is cleaved off, leaving the bound to the ER membrane.
5. The protein is guided through a t protein on the ER membrane as its synthesis continues.
6. The enzyme cleaves the signal sequence off the protein once synthesis is complete.

Explanation

Question 8 of 39

1

From which face of the golgi are vesicles budded off for transport?

Select one of the following:

  • Cis

  • Trans

Explanation

Question 9 of 39

1

At which face of the golgi are vesicles received from transport?

Select one of the following:

  • Cis

  • Trans

Explanation

Question 10 of 39

1

SNARE proteins facilitate the targeting of what?

Select one of the following:

  • Vesicles

  • ER proteins

  • Golgi apparatus proteins

  • Nuclear proteins

Explanation

Question 11 of 39

1

When are v-SNARES incorporated into the membranes of vesicles?

Select one of the following:

  • During budding

  • During phospholipid synthesis

  • During targeting

  • In the cytosol

Explanation

Question 12 of 39

1

What type of SNARE proteins are present at the target membranes where they will be complementary to a specific v-SNARE?

Select one of the following:

  • t-SNARE

  • m-SNARE

  • f-SNARE

  • p-SNARE

Explanation

Question 13 of 39

1

When does mitochondrial targeting occur?

Select one of the following:

  • After translation before folding

  • After folding

Explanation

Question 14 of 39

1

At which terminus of a mitochondrial-targeted protein will you find the matrix-targeting sequence?

Select one of the following:

  • N-terminus

  • C-terminus

Explanation

Question 15 of 39

1

What protein binds to mitochondrial-targeted proteins in the cytosol and matrix to prevent them from folding?

Select one of the following:

  • HSP70 chaperone

  • TIM44

  • TOM40

  • TIM23/17

Explanation

Question 16 of 39

1

The matrix targeting sequence binds to what?

Select one of the following:

  • Import receptor on outer membrane

  • TOM40

  • TIM44

  • HSP70 chaperone

Explanation

Question 17 of 39

1

What import pore is the mitochondrial protein targeted into first?

Select one of the following:

  • TOM40

  • TIM23/17

  • TIM44

Explanation

Question 18 of 39

1

Cytosolic HSP70 is cleaved from the mitochondrial protein as it enters the first import pore.

Select one of the following:

  • True
  • False

Explanation

Question 19 of 39

1

What is required to cleave HSP70 chaperone from mitochondrial proteins?

Select one of the following:

  • ATP hydrolysis

  • GTP hydrolysis

  • ATP synthesis

  • Coenzyme A

Explanation

Question 20 of 39

1

What is the function of matrix processing protease?

Select one of the following:

  • Cleaves matrix-targeting sequence from protein

  • Cleaves HSP70 chaperone from protein

  • Activates TOM40

  • Inactives TIM44

Explanation

Question 21 of 39

1

Fill the blank spaces to complete the text.

Fill in the blanks below to describe how proteins are targeted to the mitochondria.
1. The is found at the terminal of the protein.
2. Cytosolic binds to the protein using energy from to prevent the protein from .
3. The binds to an on the outer membrane.
4. The targets the protein through . Meanwhile, is cleaved from the protein using hydrolysis.
5. The protein enters the matrix via import pores and TIM23/.
6. The protein binds to matrix to prevent it from .
7. enzyme cleaves the from the protein.
8. The protein can now begin .

Explanation

Question 22 of 39

1

When does the targeting of proteins to the nucleus occur?

Select one of the following:

  • After folding

  • After translation before folding

Explanation

Question 23 of 39

1

What property does the Nuclear Localisation Signal have that allows it to target?

Select one of the following:

  • Basic

  • Acidic

  • Polar

  • Hydrophobic

Explanation

Question 24 of 39

1

What protein does the nuclear localisation sequence bind to?

Select one of the following:

  • Importin

  • Ran

  • RanGEF

  • SNARE

Explanation

Question 25 of 39

1

Ran binds to GTP in the cytosol.

Select one of the following:

  • True
  • False

Explanation

Question 26 of 39

1

What converts RanGDP to RanGTP in the cytosol?

Select one of the following:

  • Ran guanine nucleotide exchange factor (RanGEF)

  • MAPK

  • MAPKK

  • ATP

Explanation

Question 27 of 39

1

What happens to RanGTP in the nucleus?

Select one of the following:

  • Binds to importin

  • Binds to Nuclear Localisation Sequence

  • Activated by MAPK

  • Destroyed by RanGEF

Explanation

Question 28 of 39

1

Importin and RanGTP are recycled by their exit from the nucleus after targeting takes place.

Select one of the following:

  • True
  • False

Explanation

Question 29 of 39

1

What does cytosolic Ran GTPase activated protein do?

Select one of the following:

  • Stimulates hydrolysis of RanGTP to RanGDP

  • Stimulates formation of RanGTP from RanGDP

  • Activates binding of importin to RanGTP

  • Activates cleavage of importin from Nuclear Localisation Sequence

Explanation

Question 30 of 39

1

What triggers the release of importin from Ran?

Select one of the following:

  • Hydrolysis of RanGTP to RanGDP

  • Change in pH of the cytosol

  • Formation of RanGTP from RanGDP

  • Action of RanGEF

Explanation

Question 31 of 39

1

Fill the blank spaces to complete the text.

Fill in the blanks below to describe the targeting of proteins to the nucleus.
1. The on the protein binds to in the cytosol.
2. Ran binds to in the cytosol.
3. Both of these complexes enter the nucleus via .
4. In the nucleus, Ran (RanGEF) converts RanGDP to .
5. binds to . This disrupts 's ability to bind to the . The protein is released.
6. Importin and Ran exit the nucleus via a nuclear pore.
7. Cytosolic Ran (Ran GAP) stimulates Ran to hydrolyse to .
8. allows the release of .

Explanation

Question 32 of 39

1

What are lysosomal proteins tagged with in the Golgi apparatus?

Select one of the following:

  • Mannose-6-phosphate

  • Glucokinase

  • Phosphate

  • Importin

Explanation

Question 33 of 39

1

Mannose-6-phosphate and lysosomal proteins are targeted to transport vesicles in the Golgi via what?

Select one of the following:

  • M6P receptors

  • Importin

  • TOM40

  • SNAREs

Explanation

Question 34 of 39

1

What do transport vesicles from the Golgi containing lysosomal proteins fuse with?

Select one of the following:

  • Early endosome

  • Cell membrane

  • Cis face of Golgi apparatus

  • Endoplasmic reticulum

Explanation

Question 35 of 39

1

ATP synthase continuously pumps H+ into the endosome containing lysosomal proteins. What does this cause?

Select one of the following:

  • Dissociation from M6P receptor and a phosphate to form mature hydrolase

  • Dissociation from M6P receptor only

  • Dissociation from a phosphate to form mature hydrolase

  • Cleavage of the lysosomal protein into two products

Explanation

Question 36 of 39

1

M6P receptors used in lysosomal proteins are targeted back to the Golgi.

Select one of the following:

  • True
  • False

Explanation

Question 37 of 39

1

Fill the blank spaces to complete the text.

Fill in the blanks below to describe how proteins are targeted to the lysosomes.
1. Lysosomal proteins are tagged with in the .
2. This complex binds to receptors and is packaged into .
3. bud off the face of the Golgi apparatus and travel to the early with which they fuse.
4. continuously pumps ions into the enzyme, reducing the .
5. The low causes the to be dissociated from the complex as well as to form a mature hydrolase protein.
6. The receptors are recycled back to the via transport .

Explanation

Question 38 of 39

1

What disease is caused by a mutation in the enzyme that phosphorylates mannose?

Select one of the following:

  • Inclusion-cell disease

  • Hartnup disease

  • Wernicke-Korsakoff syndrome

  • Cystic fibrosis

Explanation

Question 39 of 39

1

Fill the blank spaces to complete the text.

In disease, the enzyme that phosphorylates is mutated. This means that lysosomal proteins aren't tagged with so are not targeted to the . The therefore lose their function and accumulates within the cells. This causes developmental defects and often death before the age of 10 due to heart failure/pneumonia.

Explanation

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