Cell Biology - Final Exam Review

Give the sequence of the mRNA based on sequence of a coding strand: 5'-GCATTCGTGGGTAG-3' A. 5'-GCAUUCGUGGGUAG-3' B. 5'-CUACCCACGAAUGC-3' C. 5'-CTACCCACGAATGC-3' D. 5'-CGUAAGCACCCAUC-3'

A. 5'-GCAUUCGUGGGUAG-3'

What is NOT true for euchromatin and heterochromatin? A. All the euchromatin regions are highly opened and host expressing genes. B. Genes that are packaged into heterochromatin are generally silenced. C. Specific histone modifications can trigger formation and spreading of heterochromatin. D. Both euchromatin and heterochromatin are packaged into highly condensed structure during cell division.

A. All the euchromatin regions are highly opened and host expressing genes.

Which of the following is NOT a mechanism that mediate RNAi (RNA interference)? A. DNA cleavage B. RNA cleavage C. translation repression D. heterochromatin formation

A. DNA cleavage

Which of the following statements is TRUE? A. Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell. B. To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol. C. A receptor bound by only one type of signal molecule can mediate only one kind of cell response. D. Each type of receptor must induce an independent signaling pathway and avoid interference with other intracellular signaling pathways.

A. Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell.

Which of the following would you expect to see in a cell that has been exposed to colchicine? A. Failure of the cell to divide B. Inability to regulate cell size C. An increased synthesis of cellular proteins D. Disappearance of the nucleus

A. Failure of the cell to divide

Which of the following is NOT directly required for the function of synapse? A. H+ pump B. SNARE C. Synaptic vesicle D. voltage gated Ca2+ channel

A. H+ pump

A particular strain of yeast produces strains with a mutant cdc2 (M-Cdk) gene, resulting in little to no production of the M-Cdk protein kinase. As a result, what would be expected? A. None of these. B. These cells will enter M phase. C. These cells will have the nuclear envelope disperse. D. These cells will have chromosome condensation.

A. None of these.

Which of the following statements about fluorescence microscopy is FALSE? A. The excitation wavelength of GFP is longer than its emission wavelength. B. Confocal microscopy improves the resolution of fluorescence microscopy by excluding out-of-focus lights. C. The resolution limit of a regular fluorescence microscopy is around 200 nm. D. GFP protein can be used to track the expression of specific genes or proteins in living cells.

A. The excitation wavelength of GFP is longer than its emission wavelength.

To study a protein that controls development, which of the following model organism may NOT be chosen? A. Yeast B. Arabidopsis C. Drosophila D. C elegans

A. Yeast

Prokaryotic cells do NOT contain __________. A. chromatin B. DNA polymerase C. ribosome D. tRNA

A. chromatin

In the backbone of a polypeptide, amino acids are connected by __________. A. covalent bonds B. ionic bonds C. hydrogen bonds D. hydrophobic bonds

A. covalent bonds

A cell with mutated lamins that cannot be phosphorylated in M phase will be unable to A. disassemble its nuclear lamina at prometaphase. B. reassemble its nuclear envelope at telophase. C. begin to grow microtubules for spindle assembly. D. condense its chromosomes at prophase.

A. disassemble its nuclear lamina at prometaphase.

Which of the following mechanisms can induce heterochromatin formation? A. histone methylation B. Pol II phosphorylation C. CRISPR-Cas9 D. all of the above

A. histone methylation

Which of the following statements about genome is FALSE? A. Most of the human genes contain intron. B. All of the human genes code for proteins. C. Many human genes undergo alternative splicing. D. Human genome is distributed on 46 chromosomes.

B. All of the human genes code for proteins

In ___________, each individual cells can be tracked during development. A. zebrafish B. C. elegans C. Drosophila D. Arabidopsis

B. C. elegans

Acetylcholine controls the contraction of skeleton muscle and smooth muscle using different signaling pathways. Which mechanism is shared by these two pathways? A. Acetylcholine binds to ion-channel receptor B. Ca2+ release from sarcoplasmic reticulum C. Ca2+ activates calmodulin D. Phosphorylation of myosin

B. Ca2+ release from sarcoplasmic reticulum

During the action potential propagation on neuron cell, which of the following best describes the voltage changes in one plasma membrane region? A. -60 mV > -40 mV > 0 mV > +40 mV > -60 mV B. -40 mV > 0 mV > +40 mV > -40 mV C. -60 mV > -40 mV > 0 mV > -40 mV > -60 mV D. 0 mV > +40 mV > +60 mV > +40 mV > 0 mV

A. -60 mV > -40 mV > 0 mV > +40 mV > -60 mV

Given the sequence of a coding strand: 5' - GCATTCGTGGGTAG - 3' Give the sequence of the mRNA and label the 5' and 3' ends. A. 5'- GCAUUCGUGGGUAG -3' B. 5'-CUACCCACGAAUGC-3' C. 5'-CTACCCACGAATGC-3' D. 5'-CGUAAGCACCCAUC-3'

A. 5'- GCAUUCGUGGGUAG -3'

Which of the following statements is FALSE? A. A histone core contains two of each of the core histones (H1, H2, H3, H4). B. Chromatins are present in eukaryotic cells, but not in prokaryotic cells. C. The N-terminal tails of core histones can be covalently modified. D. A nucleosome contains a histone core with DNA wrapped around it approximately two times.

A. A histone core contains two of each of the core histones (H1, H2, H3, H4).

Which of the following statements is FALSE? A. Most G-protein-coupled receptors are multipass transmembrane proteins with 7 α-helixes. B. Activated G protein produces 3 separate subunits that function independently. C. Each calmodulin can bind to 4 calcium ions. D. Receptor tyrosine kinases (RTK) always form dimers after binding with signal molecules.

B. Activated G protein produces 3 separate subunits that function independently.

Which of the following can be found in the backbone of DNA? A. Ribose B. Deoxyribose C. Thymine D. Uracil

B. Deoxyribose

Which of the following is FALSE of the sodium-potassium pump? A. It creates an electrochemical gradient across the cell membrane. B. It transports 2 sodium ions out of the cell and 3 potassium ions into the cell each time. C. It has enzyme activity to catalyze hydrolysis of ATP to ADP. D. The sodium gradient created by the pump is used for glucose absorption in the gut.

B. It transports 2 sodium ions out of the cell and 3 potassium ions into the cell each time.

Which statement about synapse is TRUE? A. Neurotransmitters are released by the presynaptic cell and absorbed by the postsynaptic cell. B. One neuronal cell can be attached by many synapses. C. The presynaptic cell and postsynaptic cell are connected by tight junctions. D. Synapse is a specific structure that only mediates signal transduction between neuronal cells.

B. One neuronal cell can be attached by many synapses.

Which of the following statements is TRUE? A. Hydrophobic interactions are most likely to occur on the surface of a water-soluble protein. B. Phospholipids have both hydrophilic and hydrophobic components. C. hydrogen bonds between amino acid side chains allow the formation of α helices and β sheets. D. All hydrophilic molecule form hydrogen bonds with water molecules.

B. Phospholipids have both hydrophilic and hydrophobic components.

Which of the following amino acid can be most like found on the surface of a protein? A. Phe B. Thr C. Val D. Met

B. Thr

Which of the following codons is a stop codon? A. AUG B. UAA C. AAA D. all of them

B. UAA

Transcription factors _______. A. tend to bind to the small groove of DNA B. always function as dimer C. can bind anywhere of the genome D. should have binding sites very close to a gene

B. always function as dimer

Some drugs are allosteric inhibitors for enzymes. These drugs can ___________. A. block substrate binding sites B. block ligand binding sites C. block binding sites for both substrate and ligand D. denature the enzymes

B. block ligand binding sites

The activity of a protein can be posttranscriptionally regulated by any of the methods except . A. covalent modification B. controlling gene expression C. protein interaction D. ligand binding that induces allosteric conformation

B. controlling gene expression

In an eukaryotic transcription, 5'-cap is added to the mRNA during _________. A. initiation B. elongation C. termination D. mRNA splicing

B. elongation

Which of the following is generally NOT be a mechanism of gene silencing? A. heterochromatin B. histone acetylation C. transcription repressor D. RNAi

B. histone acetylation

Which type of RNA in the following controls gene silencing? A. rRNA B. miRNA C. snRNA D. tRNA

B. miRNA

In a muscle cell, which internal organelle would you expect to be particularly abundant? A. chloroplast B. mitochondria C. Golgi D. lysosome

B. mitochondria

Which of the following is a type of noncoding RNA? A. intron B. siRNA C. mRNA D. non-coding genomic sequence

B. siRNA

Which type of RNA in the following controls mRNA splicing? A. rRNA B. snRNA C. mRNA D. tRNA

B. snRNA

Which of the following is a characteristic of electron microscopy? A. is easy and inexpensive B. super high resolution C. has many available dyes for staining cells D. can be used to image live cells

B. super high resolution

Place the following events of M phase into the correct order. 1. Alignment of the chromosomes at the spindle equator 2. Attachment of microtubules to chromosomes 3. Breakdown of nuclear envelope 4. Reformation of the nuclear envelope 5. Condensation of the chromosomes 6. Separation of sister chromatids A. 3,5,2,1,6,4 B. 5,3,1,2,6,4 C. 5,3,2,1,6,4 D. 3,5,1,2,6,4

C. 5,3,2,1,6,4

Which of the following DNA fragments (show only one strand) has a higher Tm (melting temperature)? A. ATCGGCTAATCG B. ATATCGTTTAAA C. CCCGGGTAGGCCGCGG D. CATACGTTTAAATTAAAT

C. CCCGGGTAGGCCGCGG

In DNA replication the lagging strand is synthesized discontinuously at the replication fork because A. DNA polymerase removes the last few nucleotides synthesized whenever it stops. B. DNA polymerase always falls off the template DNA every ten nucleotides or so. C. DNA polymerase can polymerize nucleotides only in the 5'-to-3' direction. D. DNA polymerase needs RNA primer to start DNA synthesis.

C. DNA polymerase can polymerize nucleotides only in the 5'-to-3' direction.

Which of the following statements about enzyme is FALSE? A. Many enzymes speed reactions by creating and stabilizing transition states. B. Enzymes can form enzyme-substrate complexes during the reactions. C. Enzymes speed reactions by decreasing DG (energy difference between reactant and product). D. Enzymes remain unchanged after finishing catalyzing a reaction.

C. Enzymes speed reactions by decreasing DG (energy difference between reactant and product).

About eukaryotic transcription and prokaryotic transcription, which of the following statements is FALSE? A. Eukaryotic transcription occurs in the nucleus, prokaryotic transcription in the cytoplasm B. Eukaryotic mRNAs have a 5' cap and a 3' polyA tail, prokaryotic mRNAs don't. C. Eukaryotic initiation requires specific DNA sequences at promoter, prokaryotic initiation doesn't. D. Prokaryotic transcription can be coupled with translation, eukaryotic transcription cannot.

C. Eukaryotic initiation requires specific DNA sequences at promoter, prokaryotic initiation doesn't.

Which of the following statements about genome is FALSE? A. Human genome is distributed on 46 chromosomes in most normal cells. B. Many human genes are believed to undergo alternative splicing. C. Most of the human genome code for proteins. D. Most of the human genes contain intron.

C. Most of the human genome code for proteins.

Which of the following microscopy can be used to visualize single proteins? A. fluorescence microscopy B. confocal C. PALM/STORM D. phase contrast

C. PALM/STORM

Which of the following statements about fluorescence microscopy is FALSE? A. The resolution limit of a traditional fluorescence microscopy is around 200 nm. B. Confocal microscopy improves the resolution of fluorescence microscopy by excluding out-of-focus lights. C. The excitation wavelength of GFP is longer than its emission wavelength. D. GFP protein can be used to track the expression of specific genes or proteins in living cells.

C. The excitation wavelength of GFP is longer than its emission wavelength.

Which of the following statements about membrane-enclosed organelles is TRUE? A. The endomembrane system contains all of the membrane-enclosed organelles. B. All the membrane-enclosed organelles are surrounded by a double membrane. C. The membrane of nucleus is always continuous with the membrane of ER. D. The nucleus is the only organelle that contains DNA.

C. The membrane of nucleus is always continuous with the membrane of ER.

Which of the following statements about the translation is TRUE? A. The start and stop codons do not code any amino acids. B. Among the three sites (A, P, E) on ribosome, E site is the entrance of charged tRNA. C. The newly synthesized peptide always begins with methionine (Met). D. The assembly of a ribosome on mRNA prevents the binding of other ribosome units to the same mRNA.

C. The newly synthesized peptide always begins with methionine (Met).

What would happen if you add a ER-specific signal sequence to the amino-terminal end of a normally cytosolic protein? A. The ER signal sequence will not be recognized and the protein will remain in the cytosol. B. The ER signal sequence will be cleaved off and the protein will remain in the cytosol. C. The protein will be delivered to the ER and fully synthesized in ER. D. The protein will be fully synthesized in cytosol and then be delivered into the ER.

C. The protein will be delivered to the ER and fully synthesized in ER.

Which of the following statements about protein transport to mitochondria is TRUE? A. Proteins are translocated into the mitochondria as completely folded proteins. B. A protein has to be transported though the outer membrane and the inner membrane separately. C. The signal that directs a protein to mitochondria is always cleaved off from the final folded protein. D. All the proteins in mitochondria need to be imported from cytosol.

C. The signal that directs a protein to mitochondria is always cleaved off from the final folded protein.

Which of the following happens when a G-protein-coupled receptor activates a G protein? A. The β subunit exchanges its bound GDP for GTP. B. The GDP bound to the α subunit is phosphorylated to form bound GTP. C. The α subunit exchanges its bound GDP for GTP. D. It activates the α subunit and inactivates the βγ complex.

C. The α subunit exchanges its bound GDP for GTP.

Which of the following mechanisms can NOT activate a transcription factor? A. To activate its coding gene. B. To remove its inhibitors. C. To relocate it to cytosol. D. To inhibit its proteasomal degradation.

C. To relocate it to cytosol.

Which of the following means of transport would most likely be used for moving an amino acid from a low concentration on the outside to a high concentration on the inside of a cell? A. free diffusion B. passive transport through a transporter C. active transport though a transporter D. active transport through a channel

C. active transport though a transporter

The CRISPR-Cas9 genomic editing system ___________. A. uses non-coding RNA to cleave DNA B. uses Cas9 to target specific DNA sequence C. can be applied for both gene knockout and gene activation D. all of the above

C. can be applied for both gene knockout and gene activation

Which organelle can be found in both animal and plant cells? A. cell wall B. chloroplast C. cytoskeleton D. all of the above

C. cytoskeleton

A malignant tumor is more dangerous than a benign tumor because its cells ________________. A. cause neighboring normal cells to mutate B. proliferate faster C. invade other tissues D. attack and phagocytose neighboring cells

C. invade other tissues

Which gene mutation causes substitution of one amino acid in a protein sequence? A. silent mutation B. nonscence mutation C. missence mutation D. frameshift mutation

C. missence mutation

In a muscle cell, which internal organelle would you expect to be particularly abundant? A. lysosome B. endoplasmic reticulum C. mitochondria D. chloroplast

C. mitochondria

Which of the following proteins can move cargos through an actin filament? A. dynein B. kinesin C. myosin D. filamin

C. myosin

Histone modifications can NOT ________. A. Directly affect nucleosome packaging B. Serve as docking sites for other regulatory proteins C. re-position nucleosomes using the energy of ATP D. retain after cell division

C. re-position nucleosomes using the energy of ATP

Which of the following mechanisms can NOT pass through cell division? A. histone modification B. DNA methylation C. spliceosome D. transcription factor

C. spliceosome

Which of the following molecule has the highest permeability to plasma membrane? A. proton B. water C. steroid hormone D. glucose

C. steroid hormone

hydrogen bonds are A. weak bonds formed between hydrocarbons in water B. weak covalent bonds that are easily disrupted by heat C. weak bonds formed between polar groups D. weak bonds formed only between polar O-H groups

C. weak bonds formed between polar groups

Which of the following statements is FALSE? A. Telomerase carries a RNA template, synthesizes and extends template DNA strand at telomere. B. Cancer cells proliferate indefinitely, presumably related with the stabilization of telomeres. C. Somatic cells only divide a limited number of cycles, likely due to the shorten of telomeres. D. A loss-of-function mutation of telomerase will convert a normal cell to a cancer cell.

D. A loss-of-function mutation of telomerase will convert a normal cell to a cancer cell.

Which of the following statements about cancer is FALSE? A. Cancers are caused by the accumulation of a series mutations on oncogenes and tumor suppressor genes. B. Many cancer cells have abnormal chromosomes representing genetic instability. C. Carcinogens cause cancer by changing the nucleotide sequence of DNA. D. A mutation in a single cancer-critical gene is sufficient to convert a normal cell into a cancer cell.

D. A mutation in a single cancer-critical gene is sufficient to convert a normal cell into a cancer cell.

To study the functions of a novel protein, which of the following approaches can be employed? A. imaging assays to check its subcellular localization B. genetic studies to examine the mutants that lack this protein C. molecular analyses to identify the interacting partners of this protein D. All of above.

D. All of above.

Which of the following statements about apoptosis is TRUE? A. The Fas ligand and Fas receptor work to inhibit apoptosis. B. Bax and Bak promote apoptosis by binding to procaspases in the apoptosome. C. Cells that constitutively express Bcl2 will be more prone to undergo apoptosis. D. Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria.

D. Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria.

Which of the following statements about the cytoskeleton is FALSE? A. The cytoskeleton controls the location of organelles in eukaryotic cells. B. The cytoskeleton is made up of three types of protein filaments. C. The cytoskeleton of a cell can change in response to signals. D. Covalent bonds between protein monomers hold together cytoskeletal filaments.

D. Covalent bonds between protein monomers hold together cytoskeletal filaments.

Which of the following neurotoxins directly blocks the acetylcholine receptor? A. Tetrodotoxin B. VX C. Botulinum Toxin D. Curare

D. Curare

Which of the following statements about antibodies is TRUE? A. Antibodies adapt different overall shapes so that they can bind to different antigens. B. Each antibody is composed of two polypeptide chains. C. α helices establish domains in the polypeptide chains. D. Disulfide bonds are formed between the polypeptide chains.

D. Disulfide bonds are formed between the polypeptide chains.

Which of the following statements is TRUE? A. Nucleosomes are present in both eukaryotic chromosomes and prokaryotic chromosomes. B. In living cells, chromatin only adopts the extended "beads-on-a-string" form. C. Nucleosomes bind DNA so tightly that they cannot move from the position once assembled. D. Genes that are being transcribed are thought to be packaged in a less condensed type of chromatin.

D. Genes that are being transcribed are thought to be packaged in a less condensed type of chromatin.

Which of the following statements is TRUE? A. In anaphase A, chromosome movement is driven by shorten of aster microtubules. B. Anaphase A is driven by motor proteins kinesin and dynein. C. In anaphase A, both kinetochore microtubules and interpolar microtubules shorten. D. In anaphase B, microtubules associated with the cell cortex shorten.

D. In anaphase B, microtubules associated with the cell cortex shorten.

Cell movement involves the coordination of many events in the cell. Which of the following phenomena is NOT required for cell motility? A. Integrin association with the extracellular environment. B. Myosin-mediated contraction at the rear of the moving cell. C. Nucleation of new actin filaments. D. Influx of Ca2+ into cytoplasm.

D. Influx of Ca2+ into cytoplasm.

Which group of enzymes control protein activate by adding phosphate groups to the protein? A. Phosphatase B. Protease C. Ligase D. Kinase

D. Kinase

Which of the following statement is TRUE? A. An α-helix containing 20 amino acids must be a transmembrane structure. B. Sugars are added to glycolipids at the cytosolic side of Golgi. C. Incorporation of cholesterol increases the fluidity of membrane. D. New phospholipids are synthesized at the cytosolic side of ER.

D. New phospholipids are synthesized at the cytosolic side of ER.

Which of the following statements is TRUE? A. Covalent bonds can be established by condensation reaction, which needs water molecules B. Heat can unfold a protein molecule and broke it into small peptides. C. The folding of a protein can be mediated only by noncovalent bonds. D. Noncovalent bonds help assemble large protein complexes from protein subunits.

D. Noncovalent bonds help assemble large protein complexes from protein subunits.

Which of the following statements is TRUE? A. Hydrophobic interactions are most likely to occur on the surface of a water-soluble protein. B. Ionic bonds are strong bonds that make molecules un-soluble in water. C. All hydrophilic molecule form hydrogen bonds with water molecules. D. Phospholipids have both hydrophilic and hydrophobic components.

D. Phospholipids have both hydrophilic and hydrophobic components.

Which of the following will be most likely induced by an insertion of one base pair into an exon? A. No change in the protein sequence as the insertion may be removed during mRNA splicing. B. No change in the protein sequence as it could be a nonsense mutation. C. Producing a protein with one amino acid changed. D. Producing a protein with many amino acids changed.

D. Producing a protein with many amino acids changed.

A mutation on securin prevents its ubiquitynation and degradation. In a cell containing this mutation, which of the following phenotypes can be predicted? A. The condensing complex will not be assembled. B. The cohensin complex will not be assembled. C. Mitotic chromosomes will not be aligned correctly in metaphase. D. Sister chromatids will not be segregated after metaphase.

D. Sister chromatids will not be segregated after metaphase.

What will NOT happen if too many misfolded proteins are accumulated in the ER? A.More chaperon proteins will be produced to correct misfolded proteins. B. Protein synthesis will be reduced to avoid adding more misfolded proteins. C. Cell will attempt suicide if the problem can't be solved in time. D. The misfolded proteins will be packaged and secreted outside to keep the cell healthy.

D. The misfolded proteins will be packaged and secreted outside to keep the cell healthy.

Which of the following statements about the differences between DNA and RNA is TRUE? A. DNA and RNA have the same backbone, only one of the four bases is different. B. DNA can form double helix while RNA cannot. C. Genetic code can be transferred from DNA to RNA, but cannot be transferred from RNA to DNA. D. Unlike the unique function of DNA, RNAs can serve as messenger, structural, or regulatory molecules.

D. Unlike the unique function of DNA, RNAs can serve as messenger, structural, or regulatory molecules.

Interaction with another protein may ___________ a transcription factor. A. activate B. inhibit C. relocate D. all of above

D. all of above

Mutation of a gene leads to a protein that does not function normally, which leads to human diseases. What level(s) of protein structure could be affected by this mutation? A. secondary B. tertiary C. quaternary D. all of above

D. all of above

Which of the following structures need hydrogen bonds for assembly? A. α-helix B. β-sheet C. coiled-coil D. all of above

D. all of above

Which of the following may affect or control the function of a protein? A. point mutation B. phosphorylation C. protein interaction D. all of the above

D. all of the above

Hydrophilic molecules can form ___________ with water molecules? A. Ionic bonds B. hydrogen bonds C. noncovalent bonds D. all of them

D. all of them

Which of the following histone modifications may be found at activated gene regions? A. acetylation B. phosphorylation C. methylation D. all off above

D. all off above

cDNA _________. A. is produced through mRNA splicing B. is synthesized by RNA polymerase B. always contains noncoding sequences D. can be used to directly predict protein sequences

D. can be used to directly predict protein sequences

In a benign tumor we may found the following defected programs except ________. A. excessive cell growth B. misregulated cell cycle C. suppressed apoptosis D. enhanced cell migration

D. enhanced cell migration

Which microscope can NOT be used to look at the subcellular localization of single ribosomes (30nm). A. TEM B. PALM C. SEM D. phase contrast

D. phase contrast

Which of the following statements is FALSE? A. Chromatins are present in eukaryotic cells, but not in prokaryotic cells. B. A histone core contains two of each of the core histones including H1, H2, H3, and H4. C. A nucleosome contains a core of histone with DNA wrapped around it approximately two circles. D. The N-terminal tails of core histones can be covalently modified.

B. A histone core contains two of each of the core histones including H1, H2, H3, and H4.

Give the sequence of the template strand for a coding sequence: 5'-GCATTCGTGGGTAG-3'. A. 5'-CGTAAGCACCCATC-3' B. 5'-CUACCCACGAAUGC-3' C. 5'-CTACCCACGAATGC-3' D. 5'-GCATTCGTGGGTAG-3'

C. 5'-CTACCCACGAATGC-3'

Which of the following statements is TRUE? A. Covalent bonds can be established by condensation reaction, which release water molecules. B. Heat can unfold a protein molecule and broke it into small peptides. C. The folding of a protein can be mediated only by noncovalent bonds. D. Covalent bonds help assemble large protein complexes from protein subunits.

A. Covalent bonds can be established by condensation reaction, which release water molecules.

To study a protein that controls the phosphorylation of RNA polymerase II, which of the following model organism can NOT be chosen? A. E. Coli B. Yeast C. Drosophila D. Arabidopsis

A. E. Coli

You use GFP tag to track a protein that will ultimately be secreted from the cell. If all is functioning well, in which order (from first to last) do you expect to find the protein in the cell until it is secreted? A. ER → Golgi → secretory vesicle → outside of the cell B. nucleus → ER → Golgi → secretory vesicle → outside of the cell C. ER → Golgi → endosome → outside of the cell D. Golgi → ER → secretory vesicle → outside of the cell

A. ER → Golgi → secretory vesicle → outside of the cell

Irradiated mammalian cells usually stop dividing and arrest at a G1 checkpoint. Place the following events in the order in which they occur. I. production of p21 II. DNA damage III. inhibition of cyclin-Cdk complexes IV. activation of p53 A. II-IV-I-III B. II-I-IV-III C. II-IV-III-I D. I-II-III-IV

A. II-IV-I-III

Apoptosis can occur _______________. A. in some normal cells B. only during embryonic development C. only in unhealthy or abnormal cells D. only when extrinsic death signals are present

A. in some normal cells

Which of the following is NOT an epigenetic mechanism? A. mRNA splicing B. DNA methylation C. histone modification D. non-coding RNA

A. mRNA splicing

You want to design a drug to inhibit neuron transduction in brain. Which of the following protein complexes can NOT be a target? A. mechanical-gated cation channel B. K+ leak channel C. Ca2+ pump D. voltage-gated Na+ channel

A. mechanical-gated cation channel

Proteins that are tagged with poly-Ub will be delivered to ______. A. proteasome B. ribosome C. lysosome D. spliceosome

A. proteasome

Which gene mutation give rise to unchanged amino acid sequence in a protein? A. silent mutation B. frameshift mutation C. nonscence mutation D. missence mutation

A. silent mutation

Progression through the cell cycle requires a cyclin to bind to a Cdk because _________. A. the binding of a cyclin to Cdk is required for Cdk enzymatic activity B. cyclin binding inhibits Cdk activity until the appropriate time in the cell cycle C. without cyclin binding, a cell-cycle checkpoint will be activated D. the cyclins are the molecules with the enzymatic activity in the complex

A. the binding of a cyclin to Cdk is required for Cdk enzymatic activity

Which of the following compounds can be a potential anti-cancer drug? A. A compound that activates Ras-GEF B. A compound that activates Ras-GAP C. A compound that activates MAPKK D. A compound that activates mTOR

B. A compound that activates Ras-GAP

Which of the following statements is CORRECT? A. Loss-of-function mutations in a tumor suppressor gene make the coding protein hyperactive. B. A gain-of-function mutation in only one allele of oncogene can stimulate cell survival or division. C. A loss-of-function mutation in an oncogene makes the coding protein hyperactive.. D. Loss-of-function mutation in one allele of tumor suppressor gene may be sufficient to stimulate cell division.

B. A gain-of-function mutation in only one allele of oncogene can stimulate cell survival or division.

Researchers studying vesicular transport assembled several transport components in vitro (in a test tube). They set up the stabilized microtubules, then added vesicles and kinesin. When they put everything together, there was no movement of transport vesicles along microtubule. What were they missing? A. Ca2+ B. ATP C. SNARE D. GTP

B. ATP

Which of the following hydrocarbon tail would yield the most highly mobile phospholipid (listed as number of carbons and number of double bonds, respectively)? A. 16 carbons with no double bonds B. 20 carbons with 2 double bonds C. 15 carbons with 2 double bonds D. 24 carbons with 1 double bond

C. 15 carbons with 2 double bonds

DNA isolated from mouse liver cells contains 26% A. What percent will be G? A. 74% B. 26% C. 24% D. 13%

C. 24%