Cell & Cancer Bio - Exam 1

The Central Dogma of biology refers to:

• how DNA is replicated

• how DNA is transcribed to RNA

• how RNA is translated to proteins

• A and B

• the flow of genetic information

the flow of genetic information

The site of mRNA production is:

• the nucleosome

• the nucleus

• the nucleolus

• the nuclear pore

• A and B

the nucleus

hnRNA (or pre-mRNA) maturation includes:

• splicing

• 5’ capping and 3’ polyadenylation

• exporting to the cytoplasm

• A and B

• A, B, and C

A and B

The start codon is:

• ATG

• AUG

• UAA

• TAA

• B and C

AUG

Which of the following statements are true:

• A. Grade describes the appearance of cancer cells and tissues

• B. Stage describes how large the tumor is and how far it has spread

• C. Grade describes how large the tumor is and how far it has spread

• D. Stage describes the appearance of cancer cells and tissues

A and B

“Hallmarks of cancer” is a set of capabilities that enables cancer cells to:

• avoid immune destruction

• grow, invade, and spread

• evade apoptosis

• A and C

• B and C

grow, invade, and spread

Which of the following is NOT a primary hallmark of cancer (2000 criteria):

• evading apoptosis

• insensitivity to anti-growth signals

• self-sufficiency in growth signals

• epithelial-to-mesenchymal transition

• sustaining angiogenesis

epithelial-to-mesenchymal transition

Phospholipids have:

• cholesterol

• either saturated or unsaturated fatty acids

• saturated or unsaturated fatty acids, or both

• A and B

• none of the above

saturated or unsaturated fatty acids, or both

Which of the following lipid is negatively charged:

• phosphatidylethanolamine (PE)

• phosphatidylinositol (PI)

• phosphatidylcholine (PC)

• phosphatidylserine (PS)

• sphingomyelin (SM)

phosphatidylserine (PS)

Sphingolipids are different from other phospholipids because:

• they don’t have phosphate group

• they don’t have glycerol

• they have cholesterol instead of fatty acids

• A and C

• A and B

they don’t have glycerol

Proton pumps are used in the following organelles:

• ribosomes

• lysosomes

• mitochondria

• A and C

• B and C

B and C

Lysosomes are the acceptor vesicles for:

• late endosomes, phagosomes, and autophagosomes

• autophagosomes

• exosomes

• A and C

• B and C

late endosomes, phagosomes, and autophagosomes

Organelles that are topologically distinct from the cytoplasm are:

• mitochondria

• autophagosomes

• nucleus

• A and B

• A, B and C

A and B

What is the function of the E-, P-, and A- sites on ribosomes?

• they regulate how the mRNA is threaded into the ribosome

• they regulate translation initiation

• they regulate the binding and movement of tRNAs inside the ribosome

• A and B

• A and C

they regulate the binding and movement of tRNAs inside the ribosome

The bond between the 3’OH of tRNA and the COOH of an amino acid is:

• a peptide bond

• a phosphodiester bond

• an ester bond

• a phosphoester bond

• and amid bond

an ester bond

The wobble hypothesis results in:

• a fewer tRNAs compared to the number of amino acids

• more tRNAs compared to the number of amino acids

• fewer tRNAs compared to the number of codons

• more tRNAs compared to the number of amino acids and less compared to the number of codons

• fewer tRNAs compared to the number of amino acids, and more tRNAs compared to the number of codons

more tRNAs compared to the number of amino acids and less compared to the number of codons

Where does an incoming loaded tRNA binds to the ribosome?

• E-site

• P-site

• A-site

• large (60S) ribosomal subunit

• small (40S) ribosomal subunit

A-site

Which of the following is correct:

• A. the hydrolysis of the peptidyl-tRNA ester bond cause release of energy and conformational changes in the 60S ribosomal subunit

• B. the hydrolysis of the peptidyl-tRNA ester bond is caused by peptidyl transferase

• C. the hydrolysis of the peptidyl-tRNA ester bond cause release of energy and conformational changes in the 40S ribosomal subunit

• D. The hydrolysis of the aminoacyl-tRNA ester bond cause release of energy and conformational changes in the 40S ribosomal subunit

• E. none of the above

none of the above

After protein synthesis at the ribosomes, a secretory protein ends up in the ER lumen. Which of the following are needed for the protein to go through the ER membrane?

• translocator protein and signal peptidase

• start-transfer signal

• stop-transfer signal

• A and B

• A, B, and C

A and B

EGFR is a single-pass transmembrane protein, with its NH2-terminus being extracellular and the COOH-terminal being cytoplasmic. Which of the following signals should be on the EGFR protein?

• NH2-terminus start-transfer signal

• internal start-transfer signal with positively charged amino acids close to the NH2 end

• stop-transfer signal

• A and B

• A and C

A and C

Which of the following contribute to correct protein folding?

• glycosylation

• chaperon proteins

• ubiquitination

• A and B

• B and C

A and B

Moving from the ER to the plasma membrane, what is the correct order of vesicles?

• vesicular-tubular cluster (VTC) > cis-Golgi > medial cisternae > trans-Golgi > secretory vesicles

• vesicular-tubular cluster (VTC) > trans-Golgi > medial cisternae > cis-Golgi > secretory vesicles

• cis-Golgi > medial cisternae > trans-Golgi > vesicular tubular cluster (VTC) > secretory vesicles

• cis-Golgi > vesicular-tubular cluster (VTC) > medial cisternae > trans-Golgi > secretory vesicles

• cis-Golgi > medial cisternae > vesicular-tubular cluster (VTC) > trans-Golgi > secretory vesicles

vesicular-tubular cluster (VTC) > cis-Golgi > medial cisternae > trans-Golgi > secretory vesicles

ER resident proteins are sorted by:

• COPI-coated vesicles

• COPII-coated vesicles

• KDEL-sequences and KDEL-receptors

• A and C

• B and C

A and C

COPI is to KDEL receptors, what clathrin is to:

• dynamin

• adaptin

• cargo receptors

• A and B

• B and C

adaptin

Proteins in the mitochondria are synthesized by:

• mitochondrial ribosomes in the matrix

• mitochondrial ribosomes in the intermembrane space

• cytoplasmic ribosomes

• A and C

• B and C

• A, B, and C

A and C

What is/are the most critical metabolic reaction(s) happening on the inner mitochondrial membrane?

• oxidative phosphorylation

• production of ATP

• beta oxidation (fatty acid oxidation)

• A and B

• A and C

• B and C

A and B

The mitochondrial gene mt-ND1 encodes the protein NADH dehydrogenase 1, a component of the mitochondrial respiratory chain complex I. Which protein translocator complex is/are needed for the transport of mt-ND1 through mitochondrial membranes?

• TOM

• OXA

• TIM22

• TIM23

• TOM and TIM22

OXA

Considering nuclear import through nuclear pores:

• Ran-GTP concentration is higher in the cytosol

• only proteins smaller than 5,000 kDa can be transported

• proteins must have a nuclear localization signal (NLS) and bind to a nuclear import receptor

• A and C

• B and C

proteins must have a nuclear localization signal (NLS) and bind to a nuclear import receptor

Which of the following are NOT correct?

• A. nuclear receptors have a DNA-binding domain

• B. all transmembrane receptors form dimers

• C. GPCRs activate small G proteins

• D. protein kinases can activate or inactivate their substrates

• E. SH2 and SH3 domains recognize phospho-tyrosine (pY) residues

B, C, and E

Which of the following amino acids can NOT be phosphorylated?

• methionine

• histidine

• serine

• threonine

• tyrosine

methionine

Considering G-proteins, which of the following statements are correct?

• they are active when bound to GTP

• they have intrinsic GTPase activity

• they are inactivated by GAPs

• A and B

• A and C

• A, B, and C

A, B, and C

Which enzyme is responsible for the formation of diacylglycerol (DAG) and inositol-1,4,5-triphosphoate (IP3)?

• adenylyl cyclase

• phospholipase C-beta

• phosphodiesterase

• P13 kinase

• PIP kinase

phospholipase C-beta

Which of the following are NOT phospholipids?

• PI

• DAG

• IP3

• A and B

• A and C

• B and C

Which of the following activate Protein Kinase A (PKA)

• Ca2+

• cAMP

• DAG

• IP3

• DAG and IP3

cAMP

Activation of Receptor Tyrosine Kinases (RKTs) involves which of the following?

• receptor auto- and trans-phosphorylation

• receptor phosphorylation on serine/threonine residues

• receptor homo- or hetero-dimerization upon binding to a ligand

• A and B

• A and C

• A, B, and C

A and C

Why is HER2-positive breast cancer more aggressive?

• HER2 has higher affinity to epidermal growth factor (EGF)

• in addition to EGF, HER2 binds to multiple other ligands

• HER2 is constitutively active

• A and B

• A and C

HER2 is constitutively active

Which is the correct order of the Ras-specific MAPK cascade?

• Raf > Ras > Mek > Erk

• Erk > Mek > Ras > Raf

• Ras > Raf > Mek > Erk

• Erk > Mek > Raf > Ras

• Ras > Mek > Raf > Erk

Ras > Raf > Mek > Erk

Which of the following is/are true?

• A. Ras was the first member of the Ras superfamily

• B. the Ras sub-family has the most members of the Ras superfamily

• C. the Rab sub-family has the most members of the Ras superfamily

• D. Rho sub-family members participate in regulation of the cytoskeleton and cell movement

• E. the Ran sub-family has only one member

A, C, D, and E

Which of the following is NOT correct: endocytosis promotes cancer cell growth by:

• nutrient scavenging

• increasing autophagy

• internalization of adherens junction proteins and integrins

• activating the immune response

• decreasing therapeutics efficacy

activating the immune response

Which of the following are relevant to the Warburg effect?

• A. increased glucose update

• B. aerobic glycolysis

• C. lactate production

• D. fatty acid oxidation

• E. AMPK activation

A, B, and C

Which of the following are the three major cytoskeleton filaments?

• A. nuclear lamins

• B. microfilaments

• C. protofilaments

• D. microtubules

• E. intermediate filaments

B, D, and E

The basic subunit of microtubules is:

• alpha-tubulin

• beta-tubulin

• gamma-tubulin

• alpha- and beta-tubulin dimer

• gamma-TuRC

alpha- and beta-tubulin dimer

With regard the formation of actin filaments or microtubules nucleation means:

• the ability of monomers to polymerize

• the ability of oligomers to act as seeds for polymerization of monomers

• the ability of polymers to attach to the nuclear envelope

• A and B

• A, B, and C

the ability of oligomers to act as seeds for polymerization of monomers

Treadmilling on an actin filament or microtubule occurs when:

• more subunits are added to the PLUS end

• more subunits are removed from the MINUS end

• there’s equal rate of addition of subunits at the PLUS end and removal of subunits at the MINUS end

• A and B

• none of the above

there’s equal rate of addition of subunits at the PLUS end and removal of subunits at the MINUS end

Which of the following statements is NOT true:

• ATP is for actin what GTP is for tubulin

• profilin attaches to actin dimers and prevents from polymerizing

• Arp2/Arp3 cause nucleation of actin filaments

• lamellipodia are fan-like projections of the cytoplasm

• cytochalasin binds to the filament plus ends

profilin attaches to actin dimers and prevents from polymerizing

Which of the following are found in the gel-like actin network in the cell cortex:

• stress fibers

• tight bundles

• fimbrin

• filamin

• B and C

filamin

During platelet activation, which of the following is correct:

• Ca2+ increase precedes PIP2 increase

• gelsolin is inhibited by Ca2+

• short filaments cause rapid polymerization and immediate formation of stress fibers

• A and B

• A and C

Ca2+ increase precedes PIP2 increase

The basic structural unit of an intermediate filament is:

• a filamentous protein with a central alpha-helix

• a coiled-coil dimer

• a tetramer or two staggered dimers

• an octamer

• none of the above

a tetramer or two staggered dimers

Which of the following statements is correct:

• microtubules are hollow

• microfilaments exhibit polarity

• intermediate filament flexibility is between that of microtubules and microfilaments

• A and B

• A, B, and C

A and B

The cylindrical structure of microtubules is made by:

• 9 protofilaments

• 13 triplets

• 0+0 triplets

• 9+2 triplets

• none of the above

none of the above

GTP-capping of a microtubule occurs:

• at the PLUS end

• at the MINUS end

• on beta-actin molecules

• A and C

• B and C

at the PLUS end

Lysosomes are the acceptor vesicles for:

• late endosomes, phagosomes, and autophagosomes

• autophagosomes

• exosomes

• A and C

• B and C

late endosomes, phagosomes, and autophagosomes

Microtubule Organizing Centers (MTOCs) are also called

• centromeres

• centrioles

• centrosomes

• kinetochores

• telomeres

centrosomes

Which of the following is/are responsible for astral microtubule nucleation and organization:

• A. centrioles

• B. MTOCs

• C. gamma-TuRC

• D. basal bodies

• E. mother centrioles

B and C

Which of the following statement are NOT correct:

• A. the axoneme is a bundle of microtubules

• B. the microtubule arrangement of the axoneme and the basal body is the same

• C. the microtubule arrangement of the centriole and the basal body is the same

• D. the motor protein responsible for the movement of the axoneme is dynein

• E. cilia are found in all human cells

B and E

Which of the following statements are correct?

• A. all myosins move on microfilaments

• B. all kinesins move toward the PLUS end of microtubules

• C. all myosins utilize ATP

• D. all kinesins utilize GTP

• E. all dyneins utilize ATP

A, C, and E

What is the role of tropomyosin in muscle contraction?

• it releases Ca2+ from the sarcoplasmic reticulum

• it binds to myosin-binding sites on actin

• it prevents ATP hydrolysis from myosin

• A and B

• A, B, and C

it binds to myosin-binding sites on actin

Looking at a micrograph of a longitudinal section of a striated muscle fiber what is the primary component of the dark band?

• myosin filaments

• actin filaments

• tropomyosin filaments

• A and B

• A and C

myosin filaments

What is the cause of rigor mortis?

• decrease in ATP production by the mitochondria

• inability of myosin’s motor head to detach from the actin filament

• strenuous exercise

• A and B

• A, B, and C

A and B

Which of the following is NOT correct?

• ATP-bound myosin binds on actin filaments

• ATP-bound kinesin binds on microtubules

• ADP release from a myosin causes the motor head to move forward (power stroke)

• ATP hydrolysis from a kinesin causes it to release from the microtubule

• ATP hydrolysis from a kinesin causes it to move forward

ATP-bound myosin binds on actin filaments

Which of the following are correct?

• most myosins and kinesins consist of two heavy and two light chains

• dyneins are always heterodimers

• dyneins are large multimeric complexes

• A and B

• A and C

A and C

In which of the following functions do myosins participate?

• A. muscle contraction

• B. cilia and flagella movement

• C. intracellular transport

• D. spindle movement during anaphase

• E. contractile ring function during cytokinesis

A, C, and E

In which of the following cellular functions do kinesis participate?

• A. muscle contraction

• B. cilia and flagella movement

• C. intracellular transport

• D. spindle movement during anaphase

• E. contractile ring function during cytokinesis

C and D

In which of the following cellular functions do dyneins participate?

• A. muscle contraction

• B. cilia and flagella movement

• C. intracellular transport

• D. spindle movement during anaphase

• E. contractile ring function during cytokinesis

B, C, and D

How is the kinetochore distinct from the centromere:

• the kinetochore holds the sister chromatids together during mitosis, whereas the centromere holds the sister chromatids together after DNA replication

• the kinetochore is the protein component that attaches to the microtubules, whereas the centromere mostly refers to the part of the chromosome where the kinetochore attaches

• the kinetochore is primarily involved in sister chromatid attachment through cohesins, whereas the centromere is the part of the actual sister chromatids

• the kinetochore is necessary for formation of the synaptonemal complex during pachytene phase of prophase I, whereas the centromere is involved in mitosis and meiosis II

• they are indistinguishable

the kinetochore is the protein component that attaches to the microtubules, whereas the centromere mostly refers to the part of the chromosome where the kinetochore attaches

Centriole duplication occurs duplicated during:

• G1 phase

• S phase

• G2 phase

• M phase

• interphase

G2 phase

Which phase of mitosis does the nuclear envelope breaks down?

• prophase

• prometaphase

• metaphase

• anaphase

• telophase

prometaphase

During anaphase the movement of sister chromatids to the two opposing poles of the mitotic spindle is due to:

• depolymerization of MTs attached to the kinetochore

• depolymerization of astral microtubules (MTs)

• attached of astral MTs on cell cortex

• movement of motor proteins on kinetochore MTs

• movement of kinesins toward the PLUS ends of overlap MTs

depolymerization of MTs attached to the kinetochore

Which of the following directly regulate the cell cycle?

• A. cyclins and cyclin-dependent kinases (CDKs)

• B. temporal and spatial phosphorylation and dephosphorylation of CDKs and their substrates

• C. proteasomal degradation of transcription factors

• D. proteasomal degradation of cyclins

• E. spindle microtubules

A, B, and D

What is the role of Rb?

• phosphorylation of Rb by an M cyclin-CDK allows the separation of sister chromatids during anaphase

• phosphorylation of E2F by Rb during late G1 leads to G1/S transition

• phosphorylation of Rb by a G1 cyclin-CDK removes Rb’s inhibition of E2F which is responsible for transcription of S-phase genes, which leads to G1/S transition

• Rb signaling leads to asymmetry in concentration of cortical Numb which results in asymmetric cell division

• phosphorylation of Rb by an M cyclin-CDK during late G2 allows the cell to enter M phase

phosphorylation of Rb by a G1 cyclin-CDK removes Rb’s inhibition of E2F which is responsible for transcription of S-phase genes, which leads to G1/S transition

Which of the following is the critical phosphatase that allows the G2/M transition?

• Cdc20

• Cdc6

• Wee1

• Cdc25

• none of the above

Cdc25

Which protein/protein complex is responsible for the direct degradation of cohesin molecules between sister chromatids?

• anaphase promoting complex (APC)

• securin

• separase

• A and B

• A, B, and C

separase

Which of the following DO NOT result from asymmetric cell division?

• platelet production

• 1st mitotic division of the human zygote

• production of human ovum (egg)

• epithelial tissue regeneration

• stem cell renewal

1st mitotic division of the human zygote

What is the name of the protein structure that holds together two chromatids from the two homologous chromosomes during zygotene and pachytene of prophase I?

• cohesin complex

• synaptonemal complex

• centromere

• recombination nodule

• A, C, and D

synaptonemal complex

After binding to delta, Notch undergoes a series of proteolytic cleavages? What is the result of the final proteolytic cleavage?

• the extracellular domain of Notch is released from the cell surface and inhibits cells having delta

• the cytosolic fragment of Notch is degraded in the proteasome and Notch signaling ceases

• the cytosolic fragment of Notch moves to the nucleus and, after binding with other proteins, leads to the transcription of Notch responsive genes

• A and B

• A and C

What is the purpose of mitochondrial (mt) fission?

• production of more mitochondria to cover the energy needs of a growing cell

• separation of dysfunctional parts of a mitochondrion

• destruction of mitochondrial through mitophagy

• A and B

• B and C

A and B

How can metformin lead to mitochondrial damage?

• releases cytochrome C from the mitochondria

• inhibits Complex I of the electron transport chain leading to a backlog of reduced electron carriers (NADH) and increased levels of high-energy electrons and ROS

• inhibits the citric acid cycle (TCA cycle)

• A and B

• A and C

inhibits Complex I of the electron transport chain leading to a backlog of reduced electron carriers (NADH) and increased levels of high-energy electrons and ROS

Which of the following randomizes mitochondrial inheritance?

• actin waves

• actin-based tethering

• myosin-based tethering

• actin-based motility (comet tail)

• myosin-based motility

actin-based motility (comet tail)