QUESTION 1 Which of the following is a source of energy for transport of protein

Question

QUESTION 1

Which of the following is a source of energy for transport of proteins across the mitochondrial membrane?

The mitochondrial signal sequence

TOM/TIM complexes

The movement of a hydrophilic protein through a hydrophobic membrane

Binding and release of mitochondrial chaperones.

1 points   

QUESTION 2

The expected location of a soluble protein that has an ER signal peptide, but not other signal sequence or retention sequence is:

the cytoplasm

the proteasome

the ER

secretion outside of the cell

1 points   

QUESTION 3

Indicate whether each of the following descriptions better applies to COPI, COPII or clathrin-coated vesicles.

They mediate transport from the ER to the cis Golgi network.

They are involved in retrograde transport in the Golgi.

They are involved in transporting mannose-6-phospate containing molecules to the correct loaction.

These form at the plasma membrane as part of the endocytic process.

COPII coated vesicles

COPI coated vesicles

clathrin-coated vesicles

2 points   

QUESTION 4

Which of the following proteins must be present in the cell for a lysosomal enzyme to traffic correctly to the lysosome (keeping in mind all the steps that need to take place enroute to the lysosome)?

M6P receptor

Sec61p

COPII coat proteins

Rabs specific for delivery of vesicles to the Golgi body

All of the above

1 points (Extra Credit)   

QUESTION 5

You would expect a secreted protein to contain a KDEL sequence.

True

False

0.5 points   

QUESTION 6

Peroxisomal proteins have to be unfolded for import.

True

False

0.5 points   

QUESTION 7

All peroxisomal proteins reach the organelle after their synthesis is complete.

True

False

0.5 points   

QUESTION 8

Which of the following proteins are required for transport of a lysosomal enzyme in the specific step from the Golgi to the lysosome?

M6P receptor

Sec61p

COPII coat proteins

Rabs specific for delivery of vesicles to the Golgi body

All of the above

1 points   

QUESTION 9

All peroxisomal proteins are encoded in the nucleus.

True

False

0.5 points   

QUESTION 10

Peroxisomes and their functions are not required by most eukaryotic cells.

True

False

0.5 points   

QUESTION 11

Unlike mitochondria and chloroplasts, peroxisomes can arise _____________ from precursor membranes, as well as by division from pre-existing organelles.

as dispersions

de novo

en bloc

as condensate

1 points   

QUESTION 12

You would expect a secreted protein to contain an ER signal sequence.

True

False

0.5 points   

QUESTION 13

Many peroxisomal proteins are imported as

unfolded proteins

nascent chains in the process of finishing their elongation

protein fragments that are spliced together inside the peroxisome

folded proteins

a.

The mitochondrial signal sequence

b.

TOM/TIM complexes

c.

The movement of a hydrophilic protein through a hydrophobic membrane

d.

Binding and release of mitochondrial chaperones.

Explanation / Answer

1.

Incorrect: The mitochondrial sequence only direct the mitochondrial protein translocation. The movement of a hydrophilic protein through a hydrophobic membrane and binding or release of mitochondrial chaperones are also not the source of energy but help in the translocation.

Hence, options (a), (c), and (d) are incorrect.

Correct: TOM/TIM complexes are not the source of energy but help in the translocation of protein as their some components act as the receptor and is also a source of energy. This system transport the ATP, ADP and phosphate.

Hence, the correct option is (b).

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