Deck 2: Cellular Homeostasis

Question 1

The sections of a gene that contain the coding sequences for the final protein product are:

A)Exons
B)Introns
C)UTRs
D)Nucleosomes

Answer 1

Exons

Question 2

The point in the cell cycle after which cell division is complete but before the next round of DNA synthesis is:

A)The G₂ phase
B)The G0 phase
C)The G₁ phase
D)The R phase

Answer 2

The G₁ phase

Question 3

Which phospholipids are found predominantly in the outer layer of the lipid bilayer?

A)Phosphatidylethanolamine and phosphatidylserine
B)Phosphatidylethanolamine and phosphatidylcholine
C)Phosphatidylserine and sphingomyelin
D)Phosphatidylcholine and sphingomyelin

Answer 3

Phosphatidylcholine and sphingomyelin

Question 4

All of the following are initiators of apoptosis except:

A)BCL-2
B)Caspases
C)TNF-alpha
D)Fas Ligand

Question 5

If an organism fails to regulate apoptosis,resulting in excessive apoptosis,which of the following processes might result?

A)Neurodegenerative disorder
B)Autoimmune disorder
C)Lymphoma
D)Carcinoma

Question 6

Apoptosis plays a role in human development in all of the following except:

A)Removal of interdigital webs of the hands and feet
B)Formation of the blood vessels and the gastrointestinal tract
C)Differentiation (divergence)of mast cells and basophils
D)Selection of appropriate T and B lymphocyte clones

Question 7

Which cyclin component is predominant in the G₁ phase of the cell cycle?

A)Cyclin A
B)Cyclin B1
C)Cyclin E
D)Cyclin D

Question 8

Which of the following is a mechanism of apoptosis in hematopoiesis?

A)Expansion of B cell clonal populations in response to infection
B)Elimination of PMNs and eosinophils after an inflammatory response
C)Production of RBCs in response to anemia
D)Progression of acute leukemias

Question 9

Structurally abnormal proteins can be eliminated from the body by tagging them with _________ and sending them to the __________.

A)Caspase;apoptosis pathway
B)Ubiquitin;proteosome
C)Cyclins;necrosis pathway
D)CDKs;apoptosis pathway

Question 10

Which cytoplasmic organelle's function is lipid synthesis?

A)Smooth endoplasmic reticulum
B)Golgi apparatus
C)Mitochondria
D)Ribosomes

Question 11

In order to maintain ________,terminally differentiated blood cells must undergo _________.

A)Cell cycle division;necrosis
B)Tumor suppression;apoptosis
C)Homeostasis;apoptosis
D)Cell regeneration;necrosis

Question 12

To be considered a true polymorphism,a SNP must occur with a frequency of:

A)>1%
B)>5%
C)>10%
D)>25%

Question 13

In which phase of the cell cycle is a cell quiescent?

A)The G₁ phase
B)The G0 phase
C)The R phase
D)The S phase

Question 14

In which phase of mitosis do the chromosomes align on opposite poles of the cell?

A)Prophase
B)Metaphase
C)Anaphase and telophase
D)Interphase

Question 15

The plasma membrane of blood cells is characterized by which of the following?

A)Carbohydrate components (glycolipids,glycoproteins)embedded in the lipid bilayer
B)The asymmetric distribution of the phospholipids
C)The hydrophilic ends of the phospholipids directed toward the inside of the lipid bilayer
D)The absence of peripheral proteins

Question 16

What protein is responsible for activating phosphorylation of all kinases involved in the cell cycle?

A)Cdk
B)CAK
C)Cyclin
D)Cdk inhibitor

Question 17

Which phospholipids are predominantly found in the inner layer of the lipid bilayer?

A)Phosphatidylethanolamine and phosphatidylcholine
B)Phosphatidylethanolamine and phosphatidylserine
C)Phosphatidylserine and sphingomyelin
D)Phosphatidylcholine and sphingomyelin

Question 18

Which of the following influence the stability of the mRNA and the efficiency of translation?

A)Introns
B)Untranslated regions
C)Single-nucleotide polymorphisms
D)Exons

Question 19

Protein synthesis occurs predominantly in the:

A)Cell membrane
B)Nucleus
C)Lysosome
D)Cytosol

Question 20

The (R)restriction point occurs during what phase in the cell cycle?

A)S
B)G₂
C)G₁
D)M

Question 21

At which checkpoint would detection of unreplicated DNA strands occur?

A)G₁ checkpoint
B)G₂/M checkpoint
C)S phase checkpoint
D)Metaphase checkpoint

Question 22

Explain in detail how p53 and Rb can contribute to the onset of malignancy.

Question 23

Which regulatory protein is present in all stages of the cell cycle but has varying degrees of phosphorylation (activation)from phase to phase?

A)p53
B)Rb protein
C)p21
D)Cyclin D

Question 24

Which of the following are apoptosis activators?

A)BCL-2
B)Mcl-1
C)Bcl-XL
D)Bak

Question 25

Exposure to radiation would lead to activation of which caspase pathway?

A)Extrinsic pathway
B)Intrinsic pathway
C)Common pathway
D)None of the above

Question 26

All of the following are potential proto-oncogenes except:

A)Proteins that function as growth factor receptors
B)Proteins that bind DNA
C)Growth factors
D)Proteins that neutralize growth factor receptors

Question 27

Describe the apoptotic pathway.

Question 28

Initiation of apoptosis occurs primarily with:

A)Activation of p53
B)Cleavage of appropriate caspases at timely intervals
C)Stimulus from an inflammatory response
D)Activation of BCL-2

Question 29

List three ways in which the caspase pathway can be activated.Explain the role of each,and indicate which arm of the caspase pathway will be activated.

Question 30

What feature distinguishes necrosis from apoptosis?

A)Necrosis requires ATP.
B)Necrosis is characterized by cellular shrinkage and chromatin condensation.
C)Necrosis induces inflammation.
D)Necrosis results in nuclear fragments of 185 base pairs.

Question 31

Which two proteins are critical for the effective function of the G₁ checkpoint?

A)Cdk4 and Cdk6
B)Cyclin E
C)P21 and p57
D)P53 and Rb

Question 32

Cdks must be complexed with what molecule to drive one cell to the next cell-cycle stage?

A)DNA
B)Phosphorylating enzymes
C)mRNA
D)Cyclin

Question 33

Predict the effect that the Bax:Bcl-2 complex will have on the apoptotic pathway.

A)The pathway is activated by Bax: Bcl-2.
B)The pathway is inhibited by Bax: Bcl-2.
C)The pathway is not affected by Bax: Bcl-2.
D)The pathway is activated and then is inhibited by Bax:Bcl-2.

Question 34

Predict the effect of p16 on the cell cycle of dividing cells.

A)Increases cell cycle progression
B)Decreases cell cycle progression
C)Causes no change in the cell cycle progression
D)Initiates apoptosis

Question 35

UTRs constitute which segments of mRNA?

A)Exons
B)Introns
C)3' and 5' ends
D)Heteronuclear RNA

Question 36

Explain the role of epigenetic alterations in cancer development.

Question 37

List the four major phospholipids found in the plasma membrane of hematopoietic cells,and explain their unique distribution.

Question 38

Disposal of damaged or misfolded proteins is carried out by which cell component?

A)Lysosome
B)Ubiquitin/proteosome system
C)Caspase/apoptosis system
D)Molecular chaperones

Question 39

Malignancies can result from which of the following?

A)Accelerated apoptosis
B)Inhibited apoptosis
C)Normal occurrence of apoptosis
D)None of the above

Question 40

Clearance of cytotoxic T cells after an immune response results from:

A)Accelerated apoptosis
B)Inhibited apoptosis
C)Normal occurrence of apoptosis
D)None of the above