Exam 3

Question 1

Exosomes are generated from this organelle

Answer 1

Multivesicular body

Question 2

Lipofuscin pigment granule is the cytoplasmic remnant of this organelle

Answer 2

Autophagosome

Question 3

Pyruvate is imported into this organelle

Answer 3

Mitochondria

Question 4

Protein import into this organelle is signaled by a 60 amino acid extension on the N-terminus

Answer 4

Mitochondria

Question 5

Site of O-linked glycosylation

Answer 5

Golgi apparatus

Question 6

Organelle in this list that does not
have a membrane

Answer 6

Proteasome

Question 7

ESCRT complexes are involved in the maturation of this organelle

Answer 7

Multivesicular body

Question 8

Site of separation of housekeeping receptors from their ligands

Answer 8

Early endosome

Question 9

Having the amino acids SKL at the C-terminus of a protein will induce its import into this organelle

Answer 9

Peroxisome

Question 10

Secretory granules bud from this organelle

Answer 10

Golgi apparatus

Question 11

Which of the following pieces of data support the mitochondrial endosymbiont hypothesis?
-Complex 1-4 of the electron transport chain in the inner mitochondrial membrane
-The buildup of protons in the intermembrane space
-Similar codon usage in mitochondrial and bacterial DNA
-The presence of circular DNA in the mitochondrial matrix
-All of the above would support the mitochondrial endosymbiont hypothesis

Answer 11

All of the above would support the mitochondrial endosymbiont hypothesis

Question 12

In this model of Golgi maturation, the membrane cisterna maintain a constant enzymatic content while proteins sequentially move from one cisterna to the next.

Answer 12

Vesicle transport model

Question 13

Which of the following most accurately describes the reason that there are 600 different human E3 ubiquitin ligases?

Answer 13

A wide variety of proteins need to be recognized for ubiquitin conjugation

Question 14

Which phosphoinositide is most closely related to the plasma membrane uptake step in all forms of endocytosis?

Answer 14

PI(4,5)P2

Question 15

Phosphates need to be ____ mitochondria. CO2 diffuses ____ mitochondria down its partial pressure gradient

Answer 15

Imported into; into

Question 16

One of the cellular organelles has a high amount of the enzyme catalase. What is the function of catalase?

Answer 16

It breaks down hydrogen peroxide

Question 17

To which amino acid is the C-terminus of glycine covalently bonded in the final step of ubiquitination?

Answer 17

Lysine

Question 18

The formation of vesicles on the ER membrane destined for transit to the Golgi use _____ proteins to form. Vesicles that form on the Golgi destined for transit back to the ER use ______ proteins to form.

Answer 18

COPII; COPI

Question 19

Polyubituitylation of cellular proteins targets them for which of the following organelles?

Answer 19

Proteasome

Question 20

Proteins are marked with mannnose-6-phosphate to target them for what cellular destination?

Answer 20

Lysosome

Question 21

Forming a polymer of actin from monomers necessitates the initial formation of a ___ nucleus. Once this has formed, there is an equal probability that a either a polymer will form or the nucleus will disassemble.

Answer 21

Trimer

Question 22

alpha/beta tubulin heterodimers are held together via ___ bonds. When they assemble into microtubules, there will be a ring of ___ tubulin at the minus end of the microtubule

Answer 22

Noncovalent; alpha

Question 23

Which form of endocytosis requires the actin-dependent outward protrusion of the membrane?

Answer 23

Phagocytosis

Question 24

The ___ of NAD+ to NADH happens in multiple steps of aerobic respiration. It happens the most in ___

Answer 24

Reduction; the Krebs (citric acid) cycle

Question 25

Which of the following TOM complex members functions similarly to the Sec61 translocon in the ER?

Answer 25

Tom40

Question 26

Cytoskeletal polymers have different properties and organization. ________ are solid structures often organized into branched networks, while _____ are ropelike fibers composed of a variety of related proteins

Answer 26

Actin filaments; Intermediate filaments

Question 27

Which vesicle coat protein can be recruited by either tetrameric or monomeric adaptor proteins?

Answer 27

Clathrin

Question 28

You are performing a biochemical assay called subcellular fractionation, in which you can separate different organellar populations. You identify a fraction that has a high concentration of nucleases, proteases, and lipases. You correctly assume that this is likely to be the ____ fraction.

Answer 28

Lysosomal

Question 29

Which of the following are cellular roles of the actin cytoskeleton? -Providing structural support that can determine the shape of the cell and resist forces that tend to deform it -A network of tracks that direct the movement of materials and organelles within cells -An essential component of the cell's division machinery -All of the above

Answer 29

All of the above