Module 2: The Nucleus and Endomembrane System

Question 1

The nuclear envelope

Question 1 options:
a. Contains nuclear pore complexes to allow large macromolecules to exit.
b. Consists of a single membrane that is attached to the endoplasmic reticulum.
c. Prevents RNA from being damaged by keeping it in the nucleus.
d. Retains oxygen in the nucleus for DNA synthesis.

Answer 1

a. Contains nuclear pore complexes to allow large macromolecules to exit.

Question 2

The low acidic pH of the lysosome is the result of:

Question 2 options:
a. Phosphates released from DNA
c. MP6
d. Glycocalyx
b. Proton pumps

Answer 2

b. Proton pumps

Question 3

The amino acid Cysteine

Question 3 options:
b. Has an aromatic ring structure
d. Has a rigid ring.
c. Is hydrophobic
a. Can form disulfide bonds

Answer 3

a. Can form disulfide bonds

Question 4

Vesicle mediated transport steps follow this order:

Question 4 options:
b. Budding tethering, transport, fusion, uncoating
a. Budding, Uncoating, Scisson, Docking, Tethering
d. Budding, fusion, scission, tethering, uncoating
c. Budding, scission, uncoating, transport, docking

Answer 4

c. Budding, scission, uncoating, transport, docking

Question 5

Sugars (oligosaccharides!) are added to proteins and lipids in:

Question 5 options:
a. Smooth ER.
c. Rough ER
d. Trans-Golgi network
b. Medial-Golgi Network

Answer 5

b. Medial-Golgi Network

Question 6

The “beads on a string” structure is

Question 6 options:
a. The fifth level of DNA packaging.
b. Wraps DNA around a helicase core.
c. Shortens the DNA 12-fold.
d. Consists of histones and DNA to make nucleosomes.

Answer 6

d. Consists of histones and DNA to make nucleosomes.

Question 7

The coat protein used to shuttle cargo from the golgi apparatus to the ER is:

Question 7 options:
a. Clathrin
b. COPI
c. COPII
d. Coatin

Answer 7

b. COPI

Question 8

The smooth endoplasmic reticulum
Question 8 options:

c. Makes lipids and steroids.
b. Is the site for post-transcriptional processing of RNA.
d. Is connected to the inner nuclear membrane.
a. Has ribosomes to make proteins.

Answer 8

c. Makes lipids and steroids.

Question 9

Which of the following is not a covalent post-translational modification to protein?

Question 9 options:
a. Addition of methyl groups
b. 5’ guanisine cap
c. Disulfide bonds
d. Addition of acetyl groups

Answer 9

b. 5’ guanisine cap

Question 10

Alpha helices are likely to not contain proline because:

Question 10 options:
a. Proline is basic, so it can’t interact with other amino acids.
d. Proline is very large, so it will block other amino acids.
b. Proline is rigid and prevents the protein from folding.
c. Proline is hydrophobic and interferes with folding.

Answer 10

b. Proline is rigid and prevents the protein from folding.

Question 11

Cargo is targeted to the lysosome by:

Question 11 options:
a. M6P
b. COPI
c. COPII
d. LLS

Answer 11

a. M6P

Question 12

What liquid like substance contains nuclear nutrients?

Answer 12

Nucleoplasm

Question 13

What network of filaments provides organization to the DNA?

Answer 13

Nuclear matrix

Question 14

What is an organized form of DNA?

Answer 14

Chromatin

Question 15

Prevents unwanted material from entering the nucleus; connects to the ER

Answer 15

Nuclear envelope

Question 16

Organizes chromatin for genes that encode rRNA, production site of ribosomes

Answer 16

Nucleolus

Question 17

What structure is responsible for anchoring the ribosome to the surface of the RER and reinitiating translocation?

A) PDI (protein disulphide isomerase)
B) BiP (binding protein)
C) Signal recognition particle (SRP)
D) Translocon

Answer 17

D) Translocon

Question 18

The COPII is involved in shuttling proteins to the Glolgi:

A) True
B) False

Answer 18

A) True

Question 19

Vesicles transport between organelles in the cell using free diffusion:

A) True
B) False

Answer 19

B) False

Question 20

Which step of the endocytic pathway involves the action of the protein Clathrin?

A) The early endosome
B) The late endosome
C) Formation of the endosome
D) The lysosome

Answer 20

C) Formation of the endosome

Question 21

Why is it important that the early endosome be a slightly acidic environment?

A) To facilitate the fusion of vesicles with the early endosome
B) To transport cargo across the cell
C) To store cargo in storage granules
D) To cause vesicles to release their cargo into the early endosome

Answer 21

D) To cause vesicles to release their cargo into the early endosome

Question 22

Which factor is NOT involved in the maturation of the early endosome to the late endosome?

A) Degradation of cargo providing essential building blocks
B) Cytosolic proteins disassemble the Clathrin coat
C) Recycling of receptors and cargo continues
D) Proton pumps further lowering the pH

Answer 22

B) Cytosolic proteins disassemble the Clathrin coat