Deck 12: The Endomembrane System and Peroxisomes

Question 1

Ribosomes that do not anchor to the surface of the rough endoplasmic reticulum during translation most probably

A)have a signal/trafficking error.
B)do not make the appropriate anchor protein.
C)are synthesizing cytoplasmic proteins.
D)have a defect in ribosomal proteins that allow attachment to the ER.
E)all of the above

Answer 1

C

Question 2

You are isolating cell fractions using a variety of centrifuge techniques. You have two very similar fractions, but at this point are unable to discern which fraction is peroxisomes and which is lysosomes. As a result, you need to test the fractions for unique enzyme activities. If you are looking for peroxisomes, one enzyme activity you can test for is

A)ATPase.
B)hexokinase.
C)cytochrome c oxidase.
D)glucose- 6- phosphatase.
E)catalase.

Answer 2

E

Question 3

Which of the following statements is false regarding phagocytosis?

A)It involves ingestion of large particles by the cell.
B)It involves the projection of pseudopodia.
C)It is a method used predominantly by ameba in obtaining food.
D)In vertebrates, macrophages and neutrophils possess this ability.
E)It is mediated by clathrin at the plasma membrane.

Answer 3

E

Question 4

The proteins of bacteria were radioactively labeled and fed to phagocytic cells. The proteins within the phagocytic cell became increasingly more radioactive over time. This observation is the result of the activity of

A)lysosomes.
B)the Golgi apparatus.
C)mitochondria.
D)peroxisomes.
E)chloroplasts.

Question 5

You have genetically engineered a yeast cell to make a protein that will ultimately be secreted from the cell. If all is functioning well, in which order (first to last)do you expect find the protein in the cell until it is secreted?

A)sER -Golgi -secretory vesicle -environment
B)nucleus -rER -Golgi -secretory vesicle -environment
C)rER -Golgi -sER -nucleus -environment
D)rER -secretory vesicle -Golgi -environment
E)rER -Golgi -secretory vesicle -environment

Question 6

Using the techniques of genetic engineering, you design a cytoplasmic protein you want to accumulate within the ER of yeast cells. To accomplish this goal, you need to

A)incorporate the appropriate DNA sequence with the proper signal.
B)incorporate the appropriate mannose- 6- phosphate groups.
C)do nothing; all proteins go through the ER.
D)incorporate the appropriate lipid groups into the lipoprotein.
E)incorporate radioactive amino acids into the protein.

Question 7

All of the following are unique to plant cells EXCEPT

A)peroxisomes.
B)glyoxysomes.
C)chloroplasts.
D)leaf peroxisomes.
E)nodule peroxisomes.

Question 8

Regulatory secretion of hormones would be associated with at the trans- face of the Golgi.

A)non- clathrin vesicles
B)lysosomes
C)clathrin- coated vesicles
D)microsomes
E)endosomes

Question 9

The organelle of plant cells analogous to lysosomes in animal cells is the

A)lysosome.
B)microsome.
C)triskelion.
D)vacuole.
E)endosome.

Question 10

Compared with the proteins of the trans- Golgi, the cis- Golgi proteins would

A)be identical.
B)be glycosylated only.
C)be shorter in length.
D)be glycosylated and contain amino acid modifications.
E)contain sialic acid.

Question 11

Which of the following is associated with extracellular digestion via release of the contents of lysosomes directly to the environment?

A)rheumatoid arthritis
B)fertilization of animal eggs
C)autophagy
D)only A and B
E)choices A, B, and C

Question 12

You are working with cells and observe transport of your target protein within a cell. You suspect that sorting conforms to the SNARE hypothesis. You, therefore, expect

A)to eventually identify transport- SNAP receptors.
B)the protein molecules were internalized by phagocytosis.
C)an association with clatherin- coated pits.
D)to eventually identify vesicle- SNAP receptors.
E)all of the above

Question 13

Which of the following organelles are NOT part of the endomembrane system?

A)smooth endoplasmic reticulum
B)rough endoplasmic reticulum
C)endosomes
D)peroxisomes
E)Golgi complexes

Question 14

Uptake of low- density lipoproteins (LDLs)occurs by

A)simple diffusion.
B)pinocytosis.
C)bulk- phase endocytosis.
D)facilitated transport.
E)receptor- mediated endocytosis.

Question 15

Lysosomal storage diseases are the result of deficiencies in lysosomal proteins. An example of one such disorder is

A)chronic fatigue syndrome.
B)Tay- Sachs disease.
C)adult- onset diabetes.
D)tuberculosis.
E)Huntington's disease.

Question 16

You want to engineer a yeast cell manufacture and secrete a bacterial protein product. To do this properly, you need to make certain that

A)the yeast cell is capable of phagocytosis.
B)the appropriate signal sequence is present.
C)plenty of clathrin- coated pits may be formed.
D)mannose- 6- phosphate is added to the protein.
E)all of the above

Question 17

Of the following cell types, the greatest concentration of high- density lipoprotein (HDLs)would be associated with cells.

A)connective tissue
B)muscle
C)liver
D)blood
E)skin

Question 18

If you were looking within a cell for organized clathrin structures, you would find them associated with which of the following structures?

A)inner membrane of mitochondria
B)endoplasmic reticulum
C)trans Golgi complex
D)extracellular matrix
E)lysosomes

Question 19

All of the following statements about cellular trafficking are true EXCEPT

A)Tethering proteins mediate docking between target and vesicle.
B)COPI- coated vesicles move materials from Golgi to the secretory vesicle.
C)Movement may be mediated by microtubules.
D)v- SNAREs occur in vesicles; t- SNAREs occur on target sites.
E)COPII- coated vesicles move materials from ER to Golgi.

Question 20

A radioactively labeled protein is made by cells and followed through the various organelles in the secretory pathway. After six hours, all of the radioactivity is still primarily in the Golgi apparatus. This suggests that the

A)protein does not possess a signal peptide for localization within the lumen of the rough endoplasmic reticulum.
B)protein possesses a signal for localization within the Golgi apparatus.
C)secretory vesicles are not fusing with the plasma membrane.
D)protein was not translated by the ribosomes.
E)all of the above

Question 21

Which of the following cellular processes has/have been linked to cancer/tumor formation?

A)autophagy
B)EGF desensitization
C)NMDA receptors
D)caveolae uptake
E)both A and B

Question 22

In a longitudinal section of a nerve cell, at the presynaptic site you note a variety of vesicles that are anchored to the plasma membrane. The vesicles must be specialized for

A)polarized secretion.
B)constitutive secretion.
C)zymogen secretion.
D)regulated secretion.
E)none of the above

Question 23

Exocytosis is stimulated by regional increases in concentration.

Question 24

In a lysosomal storage disease, the hydrolases of lysosomes are released from the cells, rather than being isolated into vesicles. What is one possible mechanism for this result?

A)A proton gradient within vesicles was not generated.
B)There is a mutation in all hydrolase genes that results in loss of the signal peptide.
C)Lysosomal enzymes were not phosphorylated in the rER.
D)There is a lack of mannose- 6- phosphatase activity.
E)ER was unable to produce lysosomal vesicles.

Question 25

Distinguish among the following: endocytosis, pinocytosis, and phagocytosis.

Question 26

During receptor- mediated endocytosis, the ultimate fate of the vesicle and/or its contents include(s)

A)recycling of receptors.
B)transcytosis.
C)transport to late endosome for digestion.
D)only B and C
E)choices A, B, and C

Question 27

Pharmacogenetics is a new field of study that arose from the study of

A)mixed- function oxidases.
B)residual bodies.
C)phagocytosis by specifically vertebrate white blood cells.
D)cholesterol uptake.
E)ATP- dependent calcium ATPases.

Question 28

act as proton pumps and keep the internal proton concentration of lysosomes high.

Question 29

Coated vesicles known as are thought to potentially be associated with cholesterol uptake and/or have a role in signal transduction.

Question 30

Peroxisomes

A)possess amylase activity.
B)possess acid phosphatase activity.
C)are not derived from the endoplasmic reticulum.
D)are bounded by double membranes.
E)all of the above

Question 31

The continuous release of mucus by the epithelial cells lining the respiratory tract is an example of

A)the formation of clathrin- coated pits.
B)phagocytosis.
C)regulated secretion.
D)the mucus response.
E)constitutive secretion.

Question 32

A protein is destined to be secreted from a cell. In which of the following organelles would you expect to find the protein first?

A)lysosome
B)endosome
C)Golgi apparatus
D)secretory vesicle

Question 33

are proteins associated with clathrin- coated vesicles that are involved in the binding of vesicles to specific receptors.

Question 34

is the molecule associated with receptor- mediated endocytosis that "coats" the vesicle until it is released.

Question 35

The investigation of the movement of proteins and lipids to their appropriate location within a cell is known as .

Question 36

Microsomes are

A)organelles of eukaryotic cells.
B)organelles through which electrons cannot pass.
C)artifacts generated during homogenization of cells.
D)structures observed in cyanobacteria.
E)too small to be seen with an electron microscope.

Question 37

In plants, peroxisomes associated with nitrogen fixation in legumes can be found in great abundance in

A)root nodules.
B)cotyledons.
C)leaves.
D)stems.
E)phloem and xylem.

Question 38

Cells of the pancreas produce and directly release enzymes to the digestive system. The type of secretory mechanism associated with the pancreatic cells is

A)regulated secretion.
B)transport secretion.
C)consistent secretion.
D)constitutive secretion.
E)intracellular secretion.

Question 39

The chronic use of the class of drugs can result in decreased effectiveness of antibiotics, anticoagulants, and steroids.

Question 40

Which of the following organelles is associated with the ability to catabolize alkanes found in oil and petroleum products?

A)smooth endoplasmic reticulum
B)mitochondria
C)lysosomes
D)peroxisomes
E)all of the above