Cell Bio Final
Which of the following statements is TRUE -Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes. - Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria. - Mitochondrial proteins are synthesized on the rough ER and transported to the mitochondria by vesicle.
Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.
which of the following is not a method of epigenetic inheritance? - histone modification - positive feedback loop - DNA recombination - DNA methylation
DNA recombination
Which of the following choices reflects the appropriate order of locations through which a protein destined for the plasma membrane travels? - ER to lysosome to plasma membrane - lysosome to endosome to plasma membrane - golgi to ER to plasma membrane - ER to Golgi to plasma membrane
ER to Golgi to plasma membrane
What is the role of the nuclear localization sequence in a nuclear protein? - It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore. - It is a hydrophobic sequence that enables the protein to enter the nuclear membranes. - It aids in protein unfolding so that the protein can thread through nuclear pores.
It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore.
Which of the following statements about the genetic code is CORRECT? - All codons specify an amino acid. - Some amino acids are specified by more than one codon. -All codons specify more than one amino acid. - All amino acids are specified by more than one codon.
Some amino acids are specified by more than one codon.
which of the following is true about operons? - operons are more common in eukaryotes than prokaryotes - the operator is a trans-acting regulatory element - all genes in the operon are transcribed into one mRNA molecule - the repressor gene is contained in the operon
all genes in the operon are transcribed into one mRNA molecule
Which of the following channels would not be expected to generate a change in voltage by movement of its substrate across the membrane where it is found? - a calcium channel - a proton channel - an aquaporin - a sodium channel
an aquaporin
secondary structure of a protein is ____ - a particular amino acid sequence -double helices - beta sheets and alpha helices - the joining of two polypeptide chains
beta sheets and alpha helices
Which of the following would NOT occur following the unfolded protein response (UPR) - endoplasmic reticulum increasing in size - activation of chaperone genes - apoptosis - cell division
cell division
which RNA regulates miRNA function? - scRNA -miRNA -circRNA -snRNA
circRNA
which type of chemical bond shares electrons?
covalent
When a signal needs to be sent to most cells throughout a multicellular organism, the signal most suited for this is a ___________. - synaptic - contact dependent - hormonal
hormonal
Which of the following statements about a protein in the lumen of the ER is FALSE - Some of the proteins in the lumen of the ER can end up in the plasma membrane - some of the proteins in the lumen of the ER can end up in the lumen of an organelle in the endomembrane system - a protein in the lumen of the ER is synthesized by ribosomes on the ER membrane
some of the proteins in the lumen of the ER can end up in the plasma membrane
which RNA functions as a carrier of amino acids? - tRNA -mRNA - gRNA - rRNA
tRNA
which enzyme involved in DNA replication is not present in prokaryotes? - primase - helicase - DNA ligase - telomerase
telomerase
which of the following DNA replication enzymes is NOT needed for leading strand synthesis - telomerase - helicase - primase
telomerase
what part of a phospholipid is hydrophobic
the fatty acid tail
what accounts for the polarity of the water molecule - there is hydrogen bonding between water molecules - the oxygen is more electronegative than the hydrogen atoms - the hydrogen atoms are more electronegative than the oxygen atom
the oxygen is more electronegative than the hydrogen atoms
T/F, in prokaryotes, translation can begin before transcription is complete
true
T/F; CO2 and O2 are molecules that diffuse freely by passive transport across cell membranes
true
T/F; in transmembrane proteins, both start-transfer sequences and stop-transfer sequences are hydrophobic
true
T/F; steroid hormones can pass through the plasma membrane to interact with intracellular receptors
true
All of the following promote apoptosis EXCEPT - Bad -Bcl2 - bax - cytochrome c
Bcl2
which of the following functional groups is nonpolar?
-CH3
an exported mRNA containing 900 nucleotides can initially be translated into a protein that is approximately how many amino acid residues in length? - 600 amino acids - 300 amino acids - 2700 amino acids - 900 amino acids
300 amino acids
In prokaryotes, which of the below underlined codons will be selected as the translation initiator codon? Codon number in parentheses after codon. 5'...AUAUGCGCACAUG(1)GCGCCGCCCACCAUG(2)AUGUAGGCAGGAGGUAUG(3)GACCAGGAGGUGCAUAAUG(4)GAGGCGGAC...3'
4
Which of the following double-stranded DNA sequences would have the highest melting temperature? - 5' ATATTTTTCCGTTAAAAG 3' - 5' GCCTATCCCCGGCCCC 3' - 5' GCCCTATC 3" - 5' ATTTCCTTA 3'
5' GCCTATCCCCGGCCCC 3'
The nucleotide consensus sequence found at the 3′ splice site of intron-exon boundaries is _____. - 5'-GUAAGU-3' - 5'-UACUAAC-3' - 5'-AAUAAA-3' - 5'-PyPyPyPyPyPyNCAG-3'
5'-PyPyPyPyPyPyNCAG-3'
During translation elongation, a charged tRNA enters the ribosome at which site - A site - P site - T site - E site
A site
Comparing DNA polymerase and RNA polymerase, which of the following statements is incorrect? - DNA polymerase requires a separate helicase enzyme, RNA polymerase has helicase activity. - Both polymerases require a short RNA primer to be synthesized by primase before they can synthesize DNA or RNA. - For both polymerases, nucleotide polymerization only occurs in the 5' to 3' direction.
Both polymerases require a short RNA primer to be synthesized by primase before they can synthesize DNA or RNA.
For Cyclin-cdk complexes to be active, inhibitory phosphates must be removed by phosphatases such as ___ - p21 -Cdc6 - p27 - Cdc25
Cdc25
To initiate DNA replication, ____ seperates a segments of DNA double helix to expose single stranded DNA
DNA helicase
You examine some cells under the microscope, they initiate DNA replication and complete DNA synthesis, but the DNA backbone has gaps in it that do not get repaired . Which enzyme likely has a defect? - DNA topoisomerase - DNA ligase - primase - DNA helicase
DNA ligase
Which of the following is not an example of epigenetic inheritance? - DNA methylation - DNA recombination - histone modifications
DNA methylation
at replication forks, ____ catalyze addition of nucleotides to the 3' end of a growing DNA strand by using parental DNA strand as a template
DNA polymerase
Which of the following statements is TRUE - A cell-surface receptor capable of binding only one type of signal molecule can mediate only one type of response in all cell types. - Extracellular signal molecules that are small and hydrophobic must bind to a cell-surface receptor so as to signal a target cell to change its behavior. - Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior.
Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior.
T/F, in DNA and RNA, the new nucleotides are always added to the 5' end of the nucleic acid strand
False
T/F, primase is only for the lagging strand DNA synthesis
False
In eukaryotic cells, intronic sequences coded for within the DNA are not translated into proteins. Why? - Intronic sequences are removed from RNA molecules by the spliceosome, which works in the nucleus. - The ribosome will skip over intron sequences when translating RNA into protein. -Introns are not transcribed by RNA polymerase. - Introns are removed by catalytic RNAs in the cytoplasm.
Intronic sequences are removed from RNA molecules by the spliceosome, which works in the nucleus.
which of the following is true about a newly synthesized human chromosome? - it was synthesized by continuous DNA synthesis from a single origin of replication - It was synthesized by continuous and discontinuous DNA synthesis from a single origin of replication - It was synthesized by continuous and discontinuous DNA synthesis from multiple origins of replication.
It was synthesized by continuous and discontinuous DNA synthesis from multiple origins of replication.
A protein has a mutation that prevents it from being ubiquitinated. What what would be the most likely outcome? - Levels of the protein would be lower. - Levels of the protein would be higher - Translation would be inhibited. -The protein would be inactive
Levels of the protein would be higher
Which of the following statements about the function of the centrosome is FALSE - centrosomes are the major microtubule-organizing center in animal cells - Microtubules emanating from the centrosome have alternating polarity such that some have their plus end attached to the centrosome while others have their minus end attached to the centrosome. - during mitosis, the centrosome forms a mitotic spindle
Microtubules emanating from the centrosome have alternating polarity such that some have their plus end attached to the centrosome while others have their minus end attached to the centrosome.
Cells use membranes to help maintain set ranges of ion concentrations inside and outside the cell. Which of the following ions is the most abundant outside a typical mammalian cell? (a) Na+ (b) K+ (c) Ca2+ (d) Cl-
Na+
The bacterial gene PheC has extensive mutations in its terminator sequence. What would be the most likely outcome? - PheC mRNA will be translated into a polypeptide chain which is longer than usual - PheC mRNA transcripts are longer than normal. - The PheC gene is not transcribed. - PheC mRNA is not translated.
PheC mRNA transcripts are longer than normal.
Which of the following protects mRNA in a eukaryotic cell from degradation by RNases? -RNA editing - RNA splicing - Poly (A) tail - RNA interference
Poly (A) tail
Which of the following statements is TRUE -Proteins destined for the ER are translated by a special pool of ribosomes whose subunits are always associated with the outer ER membrane. - Proteins destined for the ER are translated by cytosolic ribosomes and are targeted to the ER when a signal sequence emerges during translation. - Proteins destined for the ER are translated by a pool of cytosolic ribosomes that contain ER-targeting sequences that interact with ER-associated protein translocators.
Proteins destined for the ER are translated by cytosolic ribosomes and are targeted to the ER when a signal sequence emerges during translation.
Unlike DNA, which typically forms a helical structure, different molecules of RNA can fold into a variety of three-dimensional shapes. This is largely because_______. - RNA nucleotides use a different chemical linkage between nucleotides compared to DNA - RNA is single-standed - RNA bases cannot form hydrogen bonds with each other - RNA contains uracil and uses ribose as the sugar
RNA is single-stranded
which of the following statements about RNAi is true? - RNAi is induced when double stranded RNA is present in the cell - siRNAs increase translation of target molecules - the RNAi mechanism is only found in animals
RNAi is induced when double stranded RNA is present in the cell
In a eukaryotic chromosome, where would you expect find regions of euchromatin? - In a skin cell, a region containing genes coding for digestive enzymes. - In the telomeres. - Regions containing housekeeping genes, which are constitutively (constantly) expressed - In the centromere.
Regions containing housekeeping genes, which are constitutively (constantly) expressed
Which of the following statements about prokaryotic mRNA molecules is FALSE? - A single prokaryotic mRNA molecule can be translated into several proteins. - Ribosomes can start translating an mRNA molecule before transcription is complete. - mRNAs are not polyadenylated. - Ribosomes must bind to the 5′ cap before initiating translation.
Ribosomes must bind to the 5′ cap before initiating translation.
T/F, by wobble pairing, a single tRNA is sometimes able to decode more than one codon sequence
True
T/F, not all proteins have quaternary structure
True
T/F, poly A tails can vary in length
True
T/F; endosomes mature into lysosomes, which contain hydrolytic enzymes that are only active in acidic conditions
True
How could you decrease the transcription of just one specific gene in a bacterial cell? - a decrease in the amount of RNA polymerase - a mutation that introduced a stop codon into the DNA that precedes the gene's coding sequence - a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site - a decrease in the amount of sigma factor
a mutation that introduced extensive sequence changes into the DNA that precedes the gene's transcription start site
which statement is true? - a nonpolar molecule is hydrophilic - a nonpolar molecule is negatively charged - a nonpolar molecule is negatively charged - a nonpolar molecule is hydrophobic
a nonpolar molecule is hydrophobic
Binding of adrenaline to a GPCR stimulates cAMP synthesis, which can ultimately activate glycogen phosphorylase to break down glycogen to glucose. Which of the following proteins can diminish signal transduction of this pathway? - activated protein kinase - activated cyclic AMP phosphodiesterase - activated PKA - activated adenylyl cyclase
activated cyclic AMP phosphodiesterase
Pumps are transporters that are able to harness energy provided by other components in the cells to drive the movement of solutes across membranes, against their concentration gradient. This type of transport is called________. - passive transport - active transport - diffusion - facilitated diffusion
active transport
Which of the following protein families are NOT involved in directing transport vesicles to the target membrane? - Rabs - SNAREs - adaptins - tethering proteins
adaptins
Which of the following conditions is likely to increase the likelihood of skeletal muscle contraction? - a decrease in the amount of ATP in the cell - addition of a drug that increases Ca2+ binding to troponin - a mutation in tropomyosin that increases it affinity for the actin filament
addition of a drug that increases Ca2+ binding to troponin
Both excitatory and inhibitory neurons form junctions with muscles. By what mechanism do excitatory neurotransmitters cause the postsynaptic cell to fire an action potential? - by opening Na+ channels - by closing K+ channels - by preventing the secretion of inhibitory neurotrasmitters
by opening Na+ channels
Apoptosis differs from necrosis in that necrosis - causes DNA to fragment - involves caspase cascade - causes cells to swell and burst, whereas apoptotic cells shrink and condense
causes cells to swell and burst, whereas apoptotic cells shrink and condense
Which of the following statements about chromatin is TRUE? - chromatin remodeling only occurs in prokaryotes - chromatin remodeling affects transcription by altering chromatin structure to allow accessibility to the DNA - nucleosomes activate transcription when bound to the promoter - although RNA polymerase can access DNA packing within nucleosomes, the general transcription factors and transcriptional regulators cannot
chromatin remodeling affects transcription by altering chromatin structure to allow accessibility to the DNA .
which of the following statements about eu. chromatin is TRUE - chromatin remodeling complexes change the accessibility of chromatin to other proteins - chromatin structure is static and does not change - euchromatin is highly condensed and usually transcriptionally inactive
chromatin remodeling complexes change the accessibility to the other proteins
Which of the following methods is NOT used by cells to regulate the amount of a protein in the cell? - Proteins can be tagged with ubiquitin, marking them for degradation. - circRNA can bind mRNA and prevent translation. - Genes can be transcribed into mRNA with different efficiencies.
circRNA can bind mRNA and prevent translation.
Your friend has just joined a lab that studies vesicular transport and has been given a cell line. He wants to start designing some experiments but was not listening carefully when he was told about the molecular defect of this cell line. He is too embarrassed to ask and comes to you for help. He does recall that this cell line forms coated vesicles that completely bud off of the parent membrane but cannot dock with the target membrane. Which of the following proteins might be lacking in this cell line? - adaptin - Rab - dynamin - clathrin
clathrin
In eukaryotes, which of the below underlined codons will be selected as the translation initiator codon? Codon number in parentheses after codon 5'...AUAUGCGCACAUG(1)GCGCCGCCCACCAUG(2)AGGGCAGCGGCGCCAUG(3)GACGCCGCCACCAUG(4)GAGGCGGAC...3'
codon 4
You observe cells under a microscope undergoing mitosis. The sister chromatids have condsensed, but they are not paired up. The cell is in Prometaphase. This is likely due to a defect in which protein? - tubulin - condensin - cohesin - Cdc25
cohesin
Razzle, a new drug, is structurally similar to the hormone endorphin and binds to opioid receptors. What kind of regulation is this? - competitive inhibition - allosteric inhibition - noncompetitive activation - allosteric activation
competitive inhibition
cell cycle progression is controlled by Cdk-cyclin activity. all of the following are methods to regulate cdk-cylin activity except - degradation of the cyclin by separase - Ubiquitination of the cyclin by APC -synthesis of the cyclin component - inhibitory phosphates
degradation of the cyclin by separase
Nucleotides are joined together to form DNA or RNA by ____ reactions
dehydration
Which of the following statements is true - disulfide bonds stabilize but do not change a proteins final conformation - a disulfide bond is an ionic bond - disulfide bonds form between serine amino acid chains - disulfide bonds are more common in intracellular proteins
disulfide bonds stabilize but di not change a proteins final conformation
If lactose is absent and glucose is absent, transcription of the lactose operon ____ - occurs because the repressor can no longer bind to the operator - does not occur because the repressor can no longer bind to the operator, but CAP/cAMP is not available - does not occur because the promoter is blocked by the repressor, even though CAP/cAMP is available. - occurs because the repressor can no longer bind to the operator, and CAP/cAMP is available.
does not occur because the promoter is blocked by the repressor, even though CAP/cAMP is available.
which factor makes direct contact with the 5' cap on mRNA at the start of translation - eIF-4B - eIF-4E - eIF-4A - eIF-4G
eIF-4E
Signal sequences that direct proteins to the correct compartment are ____ - added to a protein by a protein translocator - added to proteins through post translational modification - encoded in the amino acid sequence and sufficient for targeting a protein to its correct destination
encoded in the amino acid sequence and sufficient for targeting a protein to its correct destination
in eukaryotic cells, genes that are frequently expressed by a cell are usually located in ___
euchromatin
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. Which of the following processes could be responsible for its secretion? - pinocytosis -exocytosis - endocytosis - phagocytosis
exocytosis
T/F, DNA has an overall positive charge
false
T/F, all functional DNA sequences inside a cell code for protein products
false
T/F, in eukaryotes, DNA polymerase II add the poly A tail
false
T/F, in the aqueous environment of a cell, amino acids with polar side chains are usually located in interior of the protein
false
T/F, replication origins are usually GC rich
false
T/F, the DNA-binding motifs of transcription factors have an overall negative charge
false
S28- phosphorylation and K23-acetylation would cause gene silencing or gene expression
gene expression
Active transport requires the input of energy into a system so as to move solutes against their electrochemical and concentration gradients. Which of the following is not one of the common ways to perform active transport? - ATP driven Ca+ pump - Glucose transporter uniport - Glucose-Na+ coupled symport - Light driven bacteriorhodopsin H+ pump
glucose transporter uniport
why does it take the same amount of time for a human cell and the bacterial cell E. coli to replication their DNA? - they have the same amount of DNA - human replication forks move faster than bacterial replication forks - human cells have multiple origins of replications, E. coli only has one
human cells have multiple origins of replication, E. coli only has one
in the DNA double helix, what type of bond helps keep the two complementary strands together? - ionic -phosphodiester - van der Waals - hydrogen
hydrogen
Which of the following choices best describes GAP regulation of GTP-binding proteins? - Hydrolyzes GTP to GDP to activate the protein -Hydrolyzes GTP to GDP to deactivate the protein - Exchanges GDP for GTP to activate the protein
hydrolyzes GTP to GDP to deactivate the protein
which of the following statements is true - only eu. cells have ribosomes - in a pro. cell, the cell wall provides structural support and protection from the environment - pro. cells do not contain membranes - in a eu. cell, the nucleoid contains the genetic material
in a pro. cell, the cell wall provides structural support and protection from the environment
a eukaryotic cell line has a defect in the enzymes that add the poly A tail to mRNA transcripts. Where would you expect to find the mRNA which does not have a poly A tail - in the nucleus and cytoplasm - in the cytoplasm only - in the nucleus only
in the nucleus only
ligand and ligand binding site interactions depend of many weak non covalent interactions. where is the binding site usually located on a protein? - on the proteins surface - completely inside the protein - inside a deep cavity on the proteins surface - it forms when the ligand first interacts with the protein
inside a deep cavity on the proteins surface
all of the following cytoskeleton components are involved in mitosis and cytokinesis EXCEPT - intermediate filaments - microtubules - actin - microfilaments
intermediate filaments
During RNA splicing, ____ are excised and ____ are ligated - exons, intron - scRNA, snRNA - introns, exons - snRNA, scRNA
introns, exons
Combinatorial gene control of gene expression _____ - involves only the use of gene activators used together to regulate genes appropriately - occurs in prokaryotes only - is seen only when genes are arranged in operons - involves groups of transcription regulators working together to determine the expression of a gene
involves groups of transcription regulators working together to determine the expression of a gene
which noncovalent interactions between nonpolar amino acid side chains contribute to the tertiary structure of a protein - van der Waals - electrostatic - hydrogen bonds - ionic bonds
ionic bonds
which of the following is NOT a eukaryotic transcription factor binding motif? - iron finger - helix-turn-helix - leucine zipper - zinc finger
iron finger
How dies S-Cdk help guarantee that replication occurs only once during each cell cycle? - it phosphorylates the Cdc6 protein, marking it for destruction - it promotes the assembly of prereplicative complex - it blocks the rise of Cdc concentration early in G1
it phosphoylates the Cdc protein, marking it for destruction
In a eukaryotic cell, what would happen if poly (A) polymerase was not functional? - mRNA transcripts would have poly (A) tails shorter than usual - mRNA transcripts would have poly (A) tails longer than usual. - mRNA transcripts would not have poly (A) tails. - There would be no change to processed mRNA transcripts.
mRNA transcripts would not have poly (A) tails.
Some chemotherapy drugs function by preventing mitotic spindle formation and function and as a result preventing cell division. which cytoskeleton component are they targeting? -microtubules -microfilaments -actin -intermediate filaments
microtubules
Which type of DNA repair fixes replication errors? - non homologous end joining - nucleotide excision repair - homologous recombination - mismatch repair
mismatch repair
The DNA that codes for the ribosome-binding sequences in the bacterial TrpA gene is deleted. The removal of these sequences will lead to _______. - a longer half-life for the TrpA mRNA. -no translation of the TrpA mRNA. - more TrpA protein being produced due to faster ribosome movement across the TrpA mRNA. - less translation of the TrpA mRNA
no translation of the TrpA mRNA.
If lactose is present and glucose is absent, transcription of the lactose operon_____ - does not occur because the promoter is blocked by the repressor, even though CAP/cAMP is available. - occurs because the repressor can no longer bind to the operator - occurs because the repressor can no longer bind to the operator, and CAP/cAMP is available. - does not occur because the promoter is blocked by the repressor.
occurs because the repressor can no longer bind to the operator, and CAP/cAMP is available.
if allolactose is present and glucose is absent, transcription of the lactose operon____ - occurs because the repressor can no longer bind to the operator - does not occur because the repressor can no longer bind to the operator, but CAP/cAMP is not available - occurs because the repressor can no longer bind to the operator, and CAP/cAMP is available. - does not occur because the promoter is blocked by the repressor.
occurs because the repressor can no longer bind to the operator, and CAP/cAMP is available.
Irradiated mammalian cells usually stop dividing and arrest at a G1 checkpoint. Which of the following would occur first A. production of p21 B. p53 is ubiquitylated C. inhibition of cyclin-Cdk complexes D. p53 is phosphorylated
p53 is phosphorylated
You examine some cells under the microscope, they form replication bubbles and forks, but DNA synthesis does not begin. Which enzyme likely has a defect? - DNA ligase - DNA topoisomerase - DNA helicase - primase
primase
During which stage of mitosis does mitotic spindle begin to form? -prophase -prometaphase -anaphase -metaphase
prophase
Enzymatic ____ catalyze the transfer of a phosphate group to a specific amino acid side chin on a target protein
protein kinases
what type of macromolecule helps package DNA in eu. chromosomes - carbs - proteins -lipids - RNA
proteins
A protein contains a KDEL endoplasmic reticulum retention signal sequence. Which protein processing mechanism would permit the protein to transport out of the endoplasmic reticulum? - proteolytic cleavage of the KDEL signal sequence from the protein - phosphorylation of the lysine residue of the KDEL signal sequence - ubiquitination of the lysine residue of the KDEL signal sequence - sequestration by an ER-resident chaperone protein
proteolytic cleavage of the KDEL signal sequence from the protein
which subatomic particle determines the electronegativity of an atom? - neutrons - protons - electrons
protons
what is the RNA component of a ribosome -gRNA -snRNA -rRNA -kRNA
rRNA
which of the following structures shorten during muscle contractions? - z-discs - mysoin filaments - sarcomeres
sarcomeres
in a water molecule, what is the charge of the hydrogen atoms compared to the oxygen atom? - slightly negative - slightly positive - no difference
slightly positive
Which RNA is involved in RNA splicing - miRNA - circRNA - kRNA - snRNA
snRNA
the storage form of carbohydrates is ___ in plants and ___ in animals
starch, glycogen
The microtubules in a cell form a structural framework that can have all the following functions except which one? (a) holding internal organelles such as the Golgi apparatus in particular positions in the cell (b) creating long, thin cytoplasmic extensions that protrude from one side of the cell (c) strengthening the plasma membrane (d) moving materials from one place to another inside a cell
strengthening the plasma membrane
involved in translation termination, eRF-1 has a structure similar to which of the following choices? - eIF-1 - tRNA - mRNA - miRNA
tRNA
The cat can run. Which of the following would be analogous to a frameshift mutation of this sentence? - the cat run - the cax tca nru n - nur nac tac eht - the cat run can
the cax tca nru n
DNA damage is present during the G1 stage of interphase. all of the following are possible outcomes EXCEPT - cell cycle progression is stopped - cell cycle is paused while DNA repair takes place -the cell undergoes apoptosis - the cell immediately enters S phase
the cell immediately enters S phase
which of the following descriptions is consistent with the behavior of a cell infected with a virus that inhibits checkpoint mechanisms that normally operates during G2 - the cell would pass through M phase more slowly than normal cell - the cell would be unable to enter M phase - the cell would enter M phase under conditions when normal cells would not - the cell would be unable to enter G2
the cell would enter M phase under conditions when normal cells would not
the eukaryotic gene BAB is only expressed during fetal development. In an adult organism, which of the following statements would FALSE? - the promoter of the BAB gene is methylated - the histones associated with the BAB gene are methylated - BAB is located in an area of heterochromatin - the histones associated with the BAB gene are acetylated
the histones associated with the BAB gene are acetylated
which of the following does NOT occur before a eukaryotic mRNA is exported from the nucleus - RNA polymerase dissociates - the ribosome binds to the mRNA - the mRNA is polyadenylated at its 3' end - 7-methylguanosine is added in a 5' to 3' linkage to the mRNA
the ribosome binds to the mRNA
What would most likely happen if the start codon in a transcript was mutated? - there would be no change in translation - the translated polypeptide chain would be shorter than expected - the transcript would not be translated
the transcript would not be translated
in a DNA double helix, - thymine pairs with cytosine - the two DNA strands run antiparallel - purines pair with purines - the two DNA strands are identical
the two DNA strands run antiparallel
K+ leak channels are found in the plasma membrane. These channels open and close in a random fashion. What do they accomplish in a resting cell? - they keep the resting membrane potential at slightly below zero - they keep the resting membrane potential at zero - they increase the magnitude
they keep the resting membrane potential at slightly below zero
which of the following statements is true about chaperone proteins that act as isolation chambers? - they degrade improperly folded proteins, so they do not interact with correctly folded proteins - they protect the proteins from interacting with other proteins while they fold - they increase the local protein concentration, which speeds up the folding process - they transport unfolded proteins out of the cell
they protect the proteins from interacting with other proteins while they fold
The DNA duplex consists of two long covalent polymers wrapped around each other many times over their entire length. The separation of the DNA strands for replication causes the strands to be "overwound" in front of the replication fork. How does the cell relieve the torsional stress created along the DNA duplex during replication? - nothing needs to be done b/c the two strands will be separated after replication is complete - topoisomerases nick the phosphate backbone, allowing local unwinding of DNA ahead of the replication fork
topoisomerases nick the phosphate backbone, allowing local unwinding of DNA ahead of the replication fork
Which of the following is NOT a process that delivers material to the lysosome - phagocytosis - autophagy - transcytosis - pinocytosis
transcytosis
what would be the effect of changing the codon UAA to UGA in a mRNA transcript - translation would not occur - the translated polypeptide chain would be longer than normal - the translated polypeptide chain would be shorter than usual - translation would proceed normally
translation would proceed normally
Proteins that are fully translated in the cytosol do not end up in____ - transport vesicles - the mitochondria - the cytosol - the interior of the nucleus
transport vesicles
Flipodia are long, thin, actin-containing extensions
true
Posttranslational modification with ____ marks proteins to be located to the proteasome - ubiquitin - phosphorylation - hydroxylation - lipidation
ubiquitin
which of the following is required for the secretion of neurotransmitters in response to an action potential? - neurotransmitter receptors - voltage gated K+ channels - voltage gated Ca2+ channels
voltage gated Ca2+ channels
which of these pathways is NOT a function of an endosomal compartment? - transcytosis - UPR - recycling - degradation
UPR
After translation, what would NOT occur to turn a polypeptide chain into a functional protein? - Ubiquitination - Phosphorylation - Protein folding - Proteolytic cleavage
Ubiquitination
Which of the following statements is TRUE about RNA splicing in a eukaryotic cell? - All introns will be removed. Some or all of the exons will be in the final processed mRNA. - All introns will be removed. All of the exons will be in the final processed mRNA. - Some or all of the introns will be removed. Some or all of the exons will be in the final processed mRNA.
All introns will be removed. Some or all of the exons will be in the final processed mRNA.
A nucleosome consists of DNA wrapped around a core of histone proteins. which histone protein is not part of the octomeric core? - H1 - H3 - H4 - H2A
H1
the formation of heterochromatin maintains genes in a transcriptionally silent state. which histone modification is associated with the formation of the most common type of heterochromatin? - H3 lysine 3 acetylation -H3 lysine 27 acetylation - H3 serine 10 phosphorylation - H3 lysine 9 methylation
H3 9 methylation
which of the following statements about skeletal muscle contraction is FALSE - A change in the conformation of troponin leads to changes in tropomyosin such that it no longer blocks the binding of myosin heads to the actin filament. - The changes in voltage across the plasma membrane that occur when a muscle cell receives a signal from the nervous system cause an influx of Ca2+ into the sarcoplasmic reticulum, triggering a muscle contraction. - an action potential is generated and travels down the T-tubules
The changes in voltage across the plasma membrane that occur when a muscle cell receives a signal from the nervous system cause an influx of Ca2+ into the sarcoplasmic reticulum, triggering a muscle contraction.
