Semester II exam questions

Which of the following events is the fourth to occur for the initiation of translation of mRNA to synthesize a polypeptide? a) the initiator methionine-tRNA binds to the start codon on mRNA b) the small ribosomal subunit binds to the start codon of the mRNA c) the large ribosomal subunit binds to the initiation complex d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur e) translocation of ribosome to the next codon and release of tRNA

d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur

An inducible operon is usually controlled by: a) a specific inducer molecule that keeps it in the "off" state b) an inactive repressor protein that keeps it in the "off" state c)being active at all times d) an inducer such as allolactose that removes the active repressor to allow transcription of the operon e) being turned off, usually by the end product synthesized by the enzymes reuslting from the xpression of the operon

d) an inducer such as allolactose that removes the active repressor to allow transcription of the operon

Which of the following relationships about nucleotide composition in DNA is true? a) G+A = C+T b) C+G=A+T c) C+A=G+T d) both answer choices choices a and c are correct e) C=A and G=T

d) both answer choices choices a and c are correct

How might identical and obviously duplicated gene sequences have gotten from one chromosome to another? a) by normal meitotic recombination b) normal mitotic recombination between sister chromatids c) by transcription followed by recombination d) by chromosomal translocation e) by deletion followed by insertion

d) by chromosomal translocation

What is the role of maternal effect genes in Drosophila? a) code for the production of yolk proteins b) control the shape and size of the eggs produced c) prepare the female fly for reproduction d) control the anterior to posterior polarity in the early Drosophila embryo development e) control the development of the pupa

d) control the anterior to posterior polarity in the early Drosophila embryo development

Recombination between linked genes comes about for what reason? a) Non-recombinant chromosomes break and then rejoin with one another b) independent assortment sometimes fails c) linked genes travel together at anaphase d) crossovers because these genes result in chromosomal exchange

d) crossovers because these genes result in chromosomal exchange

In eukaryotes, some DNA sequences act as introns in some tissue cells and as exons in other types of tissue cells. This is an example of: a) differential gene repression in the different types of cells b) splicing and recombination of DNA in the different types of cells c) gene amplification in some tissue cells and none occurs in other tissue cells d) different splicing of pre-mRNA into mRNA in the different types of cells

d) different splicing of pre-mRNA into mRNA in the different types of cells

Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this? a) exon shuffling b)pseudogene activation c)differential translation of mRNAs d)differential gene regulation over time

d) differential gene regulation over time

What provides the energy for the polmyerization reactions in DNA synthesis? a) ATP is required by the enzyme reaction b) DNA polymerase is the source of energy c) the breaking the judrogen bonds between conplementary DNA strands provides the energy to drive the reaction d) each of the deoxyribonucleida triphosphate substrates

d) each of the deoxyribonucleida triphosphate substrates

If a human gene for a mRNA were plced into the DNA of a yeast cell. which of the following is allowed: a) it is degraded immediately because human genes can only be expressed in humans b) it can be transcribed into functional mRNA which can be translated into a repeated amino acid chain c) it can be transcribed into functional mRNA which can be translated into a chain of random amino acids not resembling the protein to humans d) it can be transcribed into functional mRNA which can be translated into the protein that is found in humans e) it can be transcribed into functional mRNA which can be translated into yeast specific protein

d) it can be transcribed into functional mRNA which can be translated into the protein that is found in humans

What are prions? a) mobile segments of DNA b) tiny molecules of RNA that infect plants c) viral DNA that has had to attach itself to the host genome d) mis-folded versions of normal brain protein e) viruses that invade bacteria

d) mis-folded versions of normal brain protein

The genetic code is redundant. What is meant by this statement? a) a single codon can specify the addition of more time than one amino acid b) the genetic code is different for different domains of organisms c) the genetic code is universal and therefore the same for all organisms d) more than one codon can specify the addition of the same amino acid

d) more than one codon can specify the addition of the same amino acid

In E. coli, to repair a thymine dimer by nucleotide excision repair, in which order do the neccesary enzymes act? a) nuclease, DNA polymerase III, RNA primase b) helicase, DNA polymerase I, DNA ligase c) DNA ligase, nuclease, helicase, d) nuclease, DNA polymerase I, DNA ligase

d) nuclease, DNA polymerase I, DNA ligase

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight that damage DNA. This occurs because their cells cannot _________. a) replicate DNA b) undergo mitosis c) exchange DNA with other cells d) repair thymine dimers

d) repair thymine dimers

When a prokaryotic regulatory gene is expressed, it mRNA codes for which of the following proteins that help control the expression of a specific operon? a) sigma factor b) inducer c) operator d) repressor e) co-repressor

d) repressor

Which of the following molecules is a protein coded for by a prokaryotic regulatory gene? a) operon b) inducer c) promoter d) repressor e) RNA polymerase

d) repressor

Transcription in eukaryotes requires which of the following in addition to RNA polymerase? a) the protein product of the promoter b) sigma factor c) cAMP-SRP complex d) several transcription factors e) all of the above choices are correct

d) several transcription factors

Once a replication bubble is formed, which of the following hold the two DNA template strands apart while they are being replicated? a) primase b) ligase c) DNA polymerase d) single-strand DNA binding proteins

d) single-strand DNA binding proteins

RNA molecules that can catalyze specific biochemical reactions are known as which of the following? a) donors b) splice receptors c) ribozymes d) tRNAS e) restriction enzymes

d) tRNAS

The lactose operon is likely to be transcribed when: a) the cAMP level is high and the lactose level is low b) the cyclic AMP levels are low c) there is glucose but no lactose in the cell d) the cyclic AMP and the lactose levels are both high within the cell

d) the cyclic AMP and the lactose levels are both high within the cell

What is a telomere? a) the mechanism that holds two sister chromatids together b) DNA replication during telophase c) the site of origin of DNA replication d) the ends of linear chromosomes

d) the ends of linear chromosomes

Which of the following are usually inactive proteins in the cytoplasm of eukaryotes that are activated by membrane signal transduction to influence transcription? a) DNA polymerases b) tumor suppressors c) enhancers d) transcription factors e) promoter elements

d) transcription factors

Hemophilla is caused by an X-linked mutation in humans. If a woman whose paternal uncle (father's brother) was a hemophillac marries a man whose brother is also a hemophilliac, what is the probability of their first child having hemophilia (Note: assumed no other hemophilia in the pedigree and no hidden carriers). a) 0 b) 1/4 c) 1/2 d) 1/8 e) 1

a) 0

DNA sunthesis cocurs in which of the following directions? a) 5'->3' b)3'-5' c) 5'->2' d) 2'->5' e) none of the choices are correct

a) 5'->3'

RNA synthesis occurs in which of the following directions? a) 5-3 b) 3-5 c) 5-2 d) 2-5 e) none of the choices are correct

a) 5-3

The recombindation frequency between genes loci D and E in a test cross i s 50%. This means which of the following? a) D and E are on different pairs of chromosomes b) D and E are linked and exactly 50 map units apart c) D and E are at least 50 map units apart d) either D and E are on different pairs of chromosomes or D and E are linked and exactly 50 map units apart e) either D and E are on different pairs of chromosomes or D and E are linked and at least 50 map units apart

a) D and E are on different pairs of chromosomes

Which of the following techniques would be most appropriate to test the hypothesis that humans and chimps differ in the expression of a large set of shared genes? a) DNA microarray analysis b) polymerase chain reaction c) DNA sequencing d) protein-protein interaction assays

a) DNA microarray analysis

Which of the following enzymes catalyzes phosphodiester bonding of deoxyibonucleotide to the 3 prime hydroxyl end of each newly formed nucleic acid chain that can complementary hydrogen bond the DNA template single chains to synthesize replicas of the DNA template? a) DNA polymerase B) RNA polymerase c) primase d) all of the above answers are correct e) peptidyl transferase

a) DNA polymerase

Which of the following procceses destorys mRNA molecules in a eukaryotic cell if they have a sequence complemtnary to an introduced double-stranded RNA? a) SiRNA interference b) tRNA obstruction c) rRNA blocking d) RNA ribozyme degradation e) proteosomes degradation of RNA

a) SiRNA interference

The fully assembled prokaryotic ribosome consist of which of the following? a) a 70S structure consisting of a 50S subunit and a 30S subunit b) an 80S structure consisting of a 60S subunit and a 40S subunit c) they have 18S rRNA, and proteins in their small subunit d) they have 28S rRNA, 5S rRNA, 5.8S rRNA and proteins in the large subunit e) answers b,c, and d are correct

a) a 70S structure consisting of a 50S subunit and a 30S subunit

Which of the following is the most accurate definition of a gene? a) a DNA sequence that carries information to produce a specific RNA b) a DNA nucleotide sequence that carries information to produce a specific polypeptide c) a DNA or RNA sequence that carries information to produce a single polypeptide d) a DNA nucleotide sequences that carries information to produce an enzyme e) a DNA or RNA sequence that carries information to produce a specific protein

a) a DNA sequence that carries information to produce a specific RNA

The specific white blood cells that HIV attaches to and infect are the a) CD-8 T cells b) regulatory- T cells c) CCR5-T cells d) CXCR4-T cells e) CD-4T cells

e) CD-4T cells

The fully assembled eukaryotic ribosome consist of which of the following? a) a 70S structure consisting of a 50S subunit and a 30S subunit b) an 80S structure consisting of a 60S subunit and a 40S subunit c) they have 18S rRNA, and proteins in their small subunit d) they have 28S rRNA, 5S rRNA, 5.8S rRNA and proteins in the large subunit e) answers b,c, and d are correct

e) answers b, c, and d are correct

Which of the following statements best describes the characteristics of siRNA? a) a double stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA b) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns c) a double-stranded RNA that is formed by cleavage of hairpin loops in a large precursor d) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits

a) a double stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following statements to be true? a) a gene from an organism can theoretically be expressed by any other organism b) DNA was the first genetic material c) the same codons in different organisms translate into different aminoa cids d) Different organisms have different types of amino acids

a) a gene from an organism can theoretically be expressed by any other organism

Which of the following is known as a philadelphia chromosome? a) a human chromosome 22 that has had a specific translocation b) a human chromosome 9 that is found only in one type of cancer c) an animal chromosome found primarily in the mid-Atlantic area of the US d) a chromosome found only in mitochondria

a) a human chromosome 22 that has had a specific translocation

Initiation of transcription requires which of the following? a) a promoter sequence b) DNA polymerase c) an RNA primer d) A DNA primer e) Okazaki fragments

a) a promoter sequence

All female mammals ahve one active X chromosome per cell instead of two. What causes this? a) activation of the XIST gene on the X chromosome that will become the Barr body b) activation of the BARR gene on one X chromosome, which then becomes inactive c) inactivation of the XIST gene on the X chromosome derived from the male parent d) attachment of methyl (CH3) groups to the X chromosome that will remian active

a) activation of the XIST gene on the X chromosome that will become the Barr body

Which axis in the embryo does the protein product of the bicoid genes in Drosphila determine? a) anterior-posterior axis b) anterior-lateral axis c) posterior-dorsal axis d) poterior-ventral axis

a) anterior-posterior axis

Repressible genes like those of the tryptophan operon are stopped from being transcribed when: a) the co-repressor binds to the inactive repressor to activate it to bind to the operator b) the supply of the end product formed by the enzymes encoded by these genes is low c) b) the supply of the end product formed by the enzymes encoded by these genes is high d) quantities of precursor materials are high e) both answer choices a and c are correct

e) both answer choices a and c are correct

If you are a male, your X chromosome contains gene dervied from? a) your paternal grandfather only b) your maternal grandfather only c) both your paternal and maternal grandfathers d) both your paternal grandfather and grandmother e) both your maternal grandfather and grandmother

e) both your maternal grandfather and grandmother

How does the lactose repressor block transcription of the lactose operon? a) by turning off the appropriate genes in the intron b) by regulating the activity of the enzymes that the operon codes for c) by binding allosterically to the appropraite genes d) by slowing the uptake of lactose into the cell e) by binding to the lac operator to block the binding of RNA polymerase to the adjacent promoter

e) by binding to the lac operator to block the binding of RNA polymerase to the adjacent promoter

A prokaryotic mRNA primary transcript has which of the following characteristics? a) it is polycistronic and it has 5' end sequence that is recognized by a small ribosomal subunit b) it begins to be translated before the mRNA has been completely formed c) it must be sliced, capped, and add a 3' poly A tail d) all of the above are correct e) only answers a and b are correct

e) only answers a and b are correct

Which if a prokaryotic single DNA unit that enables bacteria to simultaenously regulate expression of more than one gene in response to signal molecules due to environmental changes? a) promoter b) operator c) regulator d) inducer e) operon

e) operon

In chickens, it is the female that have two different sex chromosomes (Z and W) while the males have two Z chromosomes. A Z-linked gene controls the pattern of the feathers with the dominant B allele causing the barred pattern and the b allele causing non-barred feathers. From which of the following crosses would all of the daughters be of one type (barred or non-barred) and all of the sons the other type? a) barred females x non barred males b) non-barerd females x barred males c) non-barred females x non-barred males d) barred females x barred males e) more than one of the choices are correct

a) barred females x non-barred males

DNA sequences that are methylated by a cell are usually genes that are a) not replicated b) actively expressed c) inactive d) constitutive e) repressed

e) repressed

Allolactose induces the transcription of the lactose operon by: a) binding to the allosteric site of the repressor to remove it from the operator b) stimulating lactose metabolism in the cell c) binding to the glucose operon, making it inoperable d) binding to the allosteric site of RNA polymerase e) inhibiting the activity of CAP

a) binding to the allosteric site of the repressor to remove it from the oeprator

How does a bacterial cell protect its own DNA from being attacked by its own restriction enzymes? a) by adding methyl groups to adenines and cytosines of its DNA b) by using DNA ligase to seal the bacterial DNA into a closed circle c) by adding histones to protect the double-stranded DNA d) by forming sticky ends of bacterial DNA to prevent the enzyme from attaching e) by reinforciing the bacterial DNA structure with covalent phosphodiester bonds

a) by adding methyl groups to adenines and cytosines of its DNA

Which of the following consist of two single poly-deoxyribonucleotide chains hydrogen bonded complementary and antiparallel to each other? a) deoxyribonucleic Acid b) polypeptide c) ribonucleic acid d) phospholipids e) polysaccharides

a) deoxyribonucleic Acid

Homeotic genes: a) encode transcription factors that control the expression of genes responsible for specific anatomical structures b) are found only in Drosophila and other arthoropods c) are the only genes that contain the homeobox domain d) encode proteins that form anatomical structures in the fly e) are responsible for patterning during plant development

a) encode transcription factors that control the expression of genes responsible for specific anatomical structures

Cyclic AMP receptor protein-cyclic AMP complex performs which function in bacteria? a) facilitate the binding of the core bacterial RNA polymerase to a promoter sequence b) decreases bacterial RNA polymerase activity by binding to promoter sequences c) induce RNA polymerase to becomes unfunctional when it binds to the enzyme d) binds and activates RNA polymerase

a) facilitate the binding of the core bacterial RNA polymerase to a promoter sequence

What is the difference between a linkage map and a physical map? a) for a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs b) for a physical map, the ATCG order and sequence must be achieved; however, it does not for the linkage map c) for a linkage map, it is shown how each gene is linked to each other gene d) for a physical map, the distances must be calculble in units such as nanometers e) there is no different between the two except in the type of pictorial representation

a) for a linkage map, markers are spaced by recombination frequency, whereas for a physical map they are spaced by numbers of base pairs

Which of the following is used to describe a situation in which a gene's expression pattern is dependent upon the parent from whom it was inherited? a) genomic imprinting b) spermatogenesis c) hetero-dimerization d) gender-specific RNA stability e) maternal effect gene expression

a) genomic imprinting

Which of the following enzymes attaches to an origin of DNA replication and breaks hydrogen bonds to unwind DNA ahead of each replication fork? a) helicase b) ligase c) topoisomerase d) DNA polymerase III e) primase

a) helicase

Why do histones bind tightly to DNA? a) histones are positively charged, and DAN is negatively charged b) histones are negatively charged, and DNA is positively charged c) both histones and DNA are strongly hydrophobic d) histones are covalently linked to the DNA

a) histones are positively charged, and DAN is negatively charged

What is the function of the release factor during translation in eukaryotes? a) it binds to the stop codon in the A site in place of a tRNA b) it releases the aminoa cid from its tRNA to allow the amino acid to forma peptide bond c) it supplies a source of energy for temerination of translation d) it releases the ribosome from the ER to allow polypeptides into the cytosol

a) it binds to the stop codon in the A site in place of a tRNA

Which of the following functions does the product of the p53 gene carry out? a) it inhibits the cell cycle b) it slows down the rate of DNA replication by interfering with the binding of DNA polymerase c) it causes cells to reduce expression of genes involved in DNA repair d) it allows cells to pass on mutations due to DNA damage

a) it inhibits the cell cycle

Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes? a) it is the recogition site for the binding of a specific transcription factor b) it sets the reading frame of the mRNA during translation c) it is the recognition site for ribosomal binding during translation d) it is the recognition site for ribosomal binding during transcription e) it sit he recognition site for

a) it is the recognition site for the binding of a specific transcription factor

After fertilization forms a zygote it grows and develops into an adult by which of the following nuclear division processes? a) mitosis b) meiosis c) plasmogamy followed by karyogamy d) synapsis e) reduction division

a) mitosis

Which of the following cells have reduced or very little active telomerase activity? a) most normal somatic cells b) most normal germ cells c) most cancer cells

a) most normal somatic cells

In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. THis is due to _________. a) nonidentical genes that produce different versions of globins during development b) pseudogenes, which interfere with gene expression in adults c) the attachment of methyl groups to cytosine following birth, which changes the type of hemoglobin produced d) histone proteins changing shape during embryonic development

a) nonidentical genes that produce different versions of globins during development

Which of the following enzymes attaches to one of the single DNA template chains at a replication fork and synthesize a short primer molecule that is antiparallel, complementary, and hydrogen bonded to the DNA template? a) primase b) helicase c) topoisomerase d) DNA polymerase III e) RNA polymerase

a) primase

Which is the function of topoisomerase? a) relieving strain in the DNA ahead of the replication fork b) elongating new DNA at a replication fork by adding nucleotides to the existing chain c) unwinding of the double helix d) stabilizing single-stranded DNA at the replication fork

a) relieving strain in the DNA ahead of the replication fork

DNA is synthesized through a process known as a) semiconservative replication b) conservative replication c) translation d) transcription

a) semiconservative replication

The DNA molecule carries a vast amount of hereditary information in which of the following? a) sequence of the pyrimidines and purines of the deoxyribo-nucleotides in DNA b) phosphate-sugar backbones of the two chains of DNA c) complementary pairing of bases of the nucletoides of the two chains of DNA d) side groups of nitrogenous bases int he DNA e) the different five-carbon sugars int he DNA

a) sequence of the pyrimidines and purines of the deoxyribo-nucleotides in DNA

Viroids cause a variety of plant diseases and are composed only of: a) single strands of RNA b) double strands of DNA c) protein coats d) peptidoglycan e) capsids

a) single strands of RNA

The tRNA structure shwon in your textbook has its 3' end projecitng beyond its 5' end. Which of the following processes will occur at this 3' end? a) the amino acyl tRNA synthetase catalyzes a reaction that covalently bnds the specific amino acid's carboxyl group to the 3' hydroxyl group b) the excess nucleotdies will be cleaved off at the ribosome c) the small and large subunits of the ribosome will attach to it d) the 5' cap of the mRNA will become covalently bound e) the 3' OH group of the tRNA serves as the recognition site for the small ribosomal subunit to initiate translation

a) the amino acyl tRNA synthetase catalyzes a reaction that covalently bonds the specific amino acid's carboxyl group to the 3' hydroxyl group

What is the main structural difference between enveloped viruses and non-enveloped viruses? a) enveloped viruses have their genetic material enclosed by a layer made only of protein b) Non-enveloped viruses have only a phospholipid membrane, while enveloped viruses have two membranes, the other one being a protein capsid c) Enveloped viruses have a phospholipid membrane outside their capsid, whereas non-enveloped viruses do not have a phospholipid membrane d) both types of viruses have a capsid and phospholipid membrane; but in the non-enveloped virus the genetic material is between these two membranes, while in the envelope virus the genetic material is inside both membranes e) answer choices a and c are correct

c) Enveloped viruses have a phospholipid membrane outside their capsid, whereas non-enveloped viruses do not have a phospholipid membrane

In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome 2 among our 46 chromosomes, whereas the other primates of this group have 48 chromosomes and any pair like the human chromosomes 2 pair is not present; instead, the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation? a) the ancestral organism had 48 chromosomes and at some point a centric fusion event occurred and provided a change when genes are expressed which evolved descendants with new traits b) the ancestral organism had 46 chromosomes, but primates evolved when one of the pairs broke in half c ) at some point in evolution, human ancestors and primate ancestors were able to mate and produce fertile offspring, making a new species d) chromosome breakage results in additional centromeres being made in order for meiosis to proceed successfully e) transposable elements transferred signifcantly large segments of the chromosomes to new locations

a) the ancestral organism had 48 chromosomes and at some point a centric fusion event occured and provided a change when genes are expressed which evolved descendants with new traits

Which of the following statements is true of gene linkage? a) the closer two genes are on a chromosome, the lower the probability that a crossover will occur between them b)the observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100% c) all of the traits that Mendel studied are due to genes linked on the same chromosome d) linked genes are found on different chromosomes

a) the closer two genes are on a chromosome, the lower the probability that a crossover will occur between them

Which of the following statements is true of linkage? a) the closer two genes are on a chromosome, the lower the probability that a crossover will occur between them b)the observed frequency of recombination of two genes that are far apart from each other has a maximum value of 100% c) all of the traits that Mendel studied are due to genes linked on the same chromosome d) linked genes are found on different chromosomes

a) the closer two genes are on a chromosome, the lower the probability that a crossover will occur between them

Humans have twenty-three pairs of chromosomes and chimps twenty-four pairs of chromosomes. What is the most likely explanation for these differences in human and chimp genomes? a) the common ancestor of humans and chimps have twenty-four pairs of chromosomes. After the two groups evolved, two human chromosomes fused end to end b) in the evoltion of chimps, new adaption resulted from additional chromosal material c) at some point in evolution, human and chimp ancestors reproduced with each other d) errors in mitosis resulted in an additional pair of chromosomes in chimps

a) the common ancestor of humans and chimps have twenty-four pairs of chromosomes. After the two groups evolved, two human chromosomes fused end to end

Bacterial inducible operon such as the Lactose operon genes are usually actively transcribed when: a) the inducer substrate removes the repressor from the operator sequence of the operon b) repressor molecules bind to the operator sequence to block binding of RNA polymerase c) inducer molecules such as allolactose is absent from the cell d) quantities of precuros molecules ofr translation are low in the bacterial cell

a) the inducer substrate removes the repressor from the operator sequence of the operon

In order for a bacterial inducible operon to be transcribed into RNA which of the following must occur? a) the inducer substrate removes the repressor from the operator sequence of the operon b) repressor molecules bind to the operator sequence to block binding of RNA polymerase to the operon's promoter c) inducer molecules such as allolactose are absent from the cell d) quantities of precursor molecules for translation are low in the bacterial cell e) there is a specific nutrient introduced into the environment to add to other nutrients which the bacteria is currently metabolizing

a) the inducer substrate removes the repressor from the operator sequence of the operon

Which of the following events is the second to occur for the initiation of translation of mRNA to synthesize a polypeptide? a) the initiator methionine-tRNA binds to the start codon on mRNA b) the small ribosomal subunit binds to the start codon of the mRNA c) the large ribosomal subunit binds to the initiation complex d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur e) translocation of ribosome to the next codon and release of tRNA

a) the initiator methionine-tRNA binds to the start codon on mRNA

During DNA replication, the leading and lagging strand differ in that: a) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction b) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end c) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together d) the leading strand is synthesized at twice the rate of the lagging strand e) both answer choices b and c are correct

a) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction

The leading and lagging strands differ in that ___________. a) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction b) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end c) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together d) the leading strand is synthesized at twice the rate of the lagging strand

a) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction

Why are BRCA1 and BRCA2 considered to be tumor-suppressor genes? a) the normal products participate in repair of DNA damage b) the mutant forms of either one of those prevent breast cancer c) the normal genes make estrogen receptors d) they block penetration of breast cells by chemical carcinogens

a) the normal products participate in repair of DNA damage

The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that _________. a) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose b) the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups c) ATP contains three high-energy bonds; the nucleoside triphosphates have two d) ATP is found only in human cells; the nuceltoside triphosphates are found in all animal and plants cells

a) the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose

How would one explain a testcross involving F1 dihybrid flies in which more parental-type offspring than recombinant-type offspring are produced? a) the two genes are closely linked on the same chromosome b) the two genes are linked but on different chromosomes c) recombination did not occur in the cell during meiosis d) both of the characters are controlled by more than one gene

a) the two genes are closely linked on the same chromosome

One of the characteristics of retrotransposons is that a) they code for an enzymes that synthesizes DNA using an RNA template b) they are found in animal cells c) they generally move by a cut-and-paste mechanism d) they contribute a significant portion of the genetic variability seen within a population o gamaetes

a) they code for an enzymes that synthesizes DNA using an RNA template

What is the function of nucleosomes? a) to store the unexpressed parts of chromatin DNA as determined by the developmental pattern b) to help DNA replicate c) make RNA synthesis possible d) to prevent RNA from tangling with DNA during transcription e) none of these

a) to store the unexpressed parts of chromatin DNA as determined by the developmental pattern

Nurse cells in the ovary of Drosophila females perform which of the following? a) transcribe bicoid mRNA and then transport it and bicoid protein to the cytoplasm of cells undergoing meiosis before they are fertilized b) transport food to the developing embryo c) induce the embryo to transcribe and translate bicoid mRNA d) transduce signals to the developing embryo to differentiate at stages of development

a) transcribe bicoid mRNA and then transport it and bicoid protein to the cytoplasm of cells undergoing meiosis before they are fertilized

Which of the following occurs when allolactose levels increase in E. coli? a) transcription of genes within the lac operon increases b) transcription of genes within the lac operon decreases c) Transcription of genes within the lac operon does not change d) E. coli cells replicated rapidly e) the tryptophan operon becomes more active

a) transcription of genes within the lac operon increases

During the initiation of transcription in eukaryotice cells, which proteins bind to the specific promoter in order to facilitate the binding of RNA polymerase II to the promoter sequence so that it can initiate transcription of the gene? a) transcriptional factors b) primase c) RNA polymerase d) DNA polmerase e) sigma factor

a) transcriptional factors

In the tryptophan operon, the represor actively binds to the operator when: a) tryptophan binds to an allosteric site on the repressor b) trypotphan levels are low c) lactose levels are low d) there is a great need for proteins e) allotryptophan levels are low

a) tryptophan binds to an allosteric site on the repressor

Which of the following is an example of monosomy? a) turner's syndome b) Klinefelter's syndrome c) Down syndrome d) trisomy X

a) turner's syndrome

Bacteriopahges are which of the following? a) viruses that infect bacteria b) plasmids that infect bacteria c) bacteria that infect other bacteria d) enzymes that destory bacteria e) none of the above

a) viruses that infect bacteria

Red-green color-blindness is controlled by an X chromosomal gene in humans. A normal man and woman whose fathers are both color blind marry. What is the probability that their first child will be color-blind? a) 1/2 b) 1/4 c) 1/8 d) 1/3 e) 0

b) 1/4

A DNA specimen that contains 30% guanine contains what percent of thymine? a) 15% b) 20% c) 30% d) 60% e) the amount of thymine cannot be determined

b) 20%

The genetic code of a mRNA chain cocurs in which of the following directions? a) 5-3 b) 3-5 c) 5-2 d) 2-5 e) none of the choices are correct

b) 3-5

The pairwise map distances for four linked genes are as follows: A-B=22 m.u., B-C =7 mu.u, C-D = 9 m.u., B-D = 2 MU.U, a-d 20 m.u. What is the order of thes four genes? a) ABCD b) ADBC c) ABdc d) BADC e) CADB

b) ADBC

In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of radioactive isotopes 35S and 32P because they knew which of ?the following a) DNA contains sulfur, whereas protein does not b) DNA contains phosphorous, whereas protein does not c) DNA contains nitrogen, whereas protein does not d) DNA contains purines, whereas protein includes pyrimidines e) RNA includes

b) DNA contains phosphorous, whereas protein does not

What catalyzes the formation of phosphiodiester bonds between adjacent nucleotides in the DNA polymer chain being synthesized? a) DNA kinase b) DNA polymerase c) Helicase d) primase e) deoxyribonucleotide triphosphates

b) DNA polymerase

Which of the following statements is true of histones? a) each nucleosome consists of two molecules of histone H1 b) Histone H1 is not present in the nuclesome bead; instead, it draws the nucleosomes together c) the carboxyl end of each histone extends outward from the nucleosome and si called a "histone tail" d) histones are found in mammals, but not in other animals or in plants or fungi

b) Histone H1 is not present in the nuclesome bead; instead, it draws the nucleosomes together

Which of the following is the meaning of the chromosome theory of inheritance as expressed in the early 20th century? a) individuals inherit particular chromosomes attached to genes b) Mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis c) no more than single pair of chromosomes can be found in a healthy normal cell d) natural selection acts on certain chromosome arrays rather than on genes

b) Mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis

When the amino acid lysine of a charged transfer RNA (#1) that entered the A-site of a ribosome is peptide bonded to the amino acid carried by tRNA (#2) in the ribsomal P site, where does the charged tRNA #1 move to next in the above question? a) A site b) P site c) E site d) exit tunnel e) directly to the cytosol

b) P site

Replication in prokaryotes differ from the replication in eukaryotes for which of the following reasons? a) Prokaryotice chromosomes have histones, whereas eukaryotic chromosomes do not b) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many c) the rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes d) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not

b) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many

Genomic imprinting is generally due to the addition of methyl groups to C nucleotides and chemical histone changes to silence a given gene. If this depends on the sex of the parent who transmits the gene, which of the following must be true? a) genes required for early development stages must not be imprinted b) Methylation of this kind occur more in males than in females c) Methylation must be reversible in ovarian and testicular cells d) the imprints are transmitted only to gamete-producing cells

c) Methylation must be reversible in ovarian and testicular cells

Which of type of eukaryotic RNA polymerase is involved in transcription of mRNA from a gene that codes for a specific protein? a) ligase b) rna polymerase I c) RNA polymerase II d) RNA polymerase III e) primase

c) RNA polymerase II

The nucleotide substrates for RNA synthesis are composed of which of the following components? a) a ribose sugar b) either a purine or a pyrimidine c) a ribose sugar, three phosphate groups, and either a purine or pyrimidine d) three phosphate groups ester bonded to a ribose while bonded to either a purine of pyrimidine e) a ribose molecule and either a purine or a pyrimidine

c) a ribose sugar, three phosphate groups, and either a purine or pyrimidine

Which of the following statements best describes the termination of transcription in prokaryotes? a) RNA polymerase transcribes through the polyadenylation signal, causing proteins to associate with the transcript and cut it free from the polymerase b) RNA polymerase transcribes until it reaches the terminator sequence, which because the polymerase to separate from the DNA and release the transcript c) once transcription has been initiated, RNA polymerase transcribes until it reaches the end of the chromosome d) RNA polymerase transcribes through a stop codon, causing the polmyerase to stop advancing through the gene and release the mRNA

b) RNA polymerase transcribes until it reaches the terminator sequence, which because the polymerase to separate from the DNA and release the transcript

What is the definition of one map unit? a) the physical distance between two linked genes b) a 1% frenquency of recombination between two genes c) one nanometer of distance between two genes d) the recombination frequency between two genes assorting independtly

b) a 1% frenquency of recombination between two genes

A bacterial repressible operon such as the tryptophan operon is actively transcribed when which of the following occurs? a) repressor molecules bind to the promoter b) a low supply of the end product formed by the enzyme pathway encoded by the operon's genes c) the accumulation of the end product of formed by the pathway in the cell d) quantities of precursor materials are high e) there is no other substrate that can be used by the cell

b) a low supply of the end product formed by the enzyme pathway encoded by the operon's genes

What is bioinformatics? a) a technique using 3D images of genes in order to predict how and when they will be expressed b) a method that uses very large national and international databases to access and work with sequence information c) a software program available from NIH to design genes d) a series of search programs that allow a student to identify who in the world is trying to sequence a given species

b) a method that uses very large national and international databases to access and work with sequence information

Which of the following will occur at the 3 prime hydroxyl end of a tRNA? a) the codon and anticodon complement one another b) a specific amino acid is covalently bonded to the 3' end by a specific amino acyl tRNA synthase c) the excess nucleotides will be cleaved off at the ribosome d) the small and large subunits of the ribosome will attach to it e) the 5' cap of the mRNA will become covalently bound to the 3' end of the tRNA

b) a specific amino acid is covalently bonded to the 3' end by a specific amino acyl tRNA synthase

The onset of AIDs is often accompanied by: a) a steep drop in B cell numbers b) a steep drop in CD4 T cell numbers c) a steep increase in an immune response by antibody against the HIV d) lung infections and other opportunistic infections e) Kaposi's sacroma

b) a steep drop in CD4 T cell numbers

The protein coat of a virus is called the a) capsule b) capsid c) exospores d) phage e) pilus

b) capsid

Correns found that the inherientance of variegated color on the leaves of certain plants was determined only by the maternal parent. What phenomenon explains this pattern? a) ribosome structure b) chloroplast inheritance c) genome imprinting d) sex-linkage

b) chloroplast inheritance

Abnormal chromosomes are frequently found in malignant tumors. Errors such as translocation may place a gene in close proximity to different control regions. Which of the following might then occur to make the cancer worse? a) an increase in nondisjunction b) expression of inappropriate gene products c) a decrease in mitotic frequency d) failure of the cancer cells to multiply

b) expression of inappropriate gene products

A multigene family is composed of _____. a) multiple genes whose products must be coordinately expressed b) genes who sequence are very similar and that probably arose by duplication c) a gene whose exons can be spliced in a number of different ways d) a highly conserved gene found in a number of different species

b) genes who sequence are very similar and that probably arose by duplication

Which are chromosomes that contain the same loci even if some of their alleles are different? a) chromatids b) homologous chromsomes c) sister chromosomes d) daughter cahromosomes e) genes

b) homologous chromsomes

Antiviral drugs that have become useful are usually associated with which of the following properties? a) ability to remove all viruses from the infected host b) interference with viral replication in host cells c) prevention of the host cells form becoming infected d) removal of viral proteins from host cells e) blocking the translation of viral and host mRNAs in infected host

b) interference with viral replication in host cells

Which of the following statements correctly describes a ribozyme? a) it is a catalyst that uses RNA as a substrate b) it is an RNA with specific catalytic activity c) it is an enzyme that catalyzes the association between the large and small ribosomal subunits d) it is an enzyme that synthesizes RNA as part of the transcription process

b) it is an RNA with specific catalytic activity

What is the role of DNA ligase in the elongation of the laggin strand during DNA replciation? a) it synthesizes RNA nucleotides to make a primer b) it joins Okazaki fragments together c) it unwinds the parental double helix d) it stablizies the unwound parental DNA

b) it joins Okzaki fragments together

What is the function of the 5 prime cap of mRNA? a) it decreases the half-life of the mRNA b) it protects newly synthesized mRNA from degradation c) it prevents translation d) it facilitates binding of tRNA e) it marks the mRNA for degradation

b) it protects newly synthesized mRNA from degradation

Which of the following is a common DNA structural change that activates transcription of a specific eukaryotic genes by RNA polymerase II? a) super coiling of DNA near open promoters b) looping of the DNA by transcriptional factors and mediator proteins c) unwinding of the double helix by transcriptional factors d) inducers and co-repressors removing repressing histones from promoters

b) looping of the DNA by transcriptional factors and mediator proteins

Which of the following statements describes the mechanism of transferring heritable traits information from the DNA in the nucleus to the site of protein synthesis in eukaryotic cells? a) DNA from a single gene is replicated and transferred to the cytoplasm, where it serves as a template for protein synthesis b) messenger RNA is transcribed from a single gene on DNA in the nucleus and transported to the cytoplasm, where ribosomes translate the genetic information into a polypeptide c) transfer RNA takes information from DNA directly to a ribosome, where protein synthesis takes place

b) messenger RNA is transcribed from a single gene on DNA in the nucleus and transported to the cytoplasm, where ribosomes translate the genetic information into a polypeptide

Eukaryotic transcription of pre-rRNA takes place in which of the following regions? a) cytoplasm b) nucleolus c) nucleoplasm d) smooth ER e) rough ER

b) nucleolus

Eukaryotic transcription of pre-mRNA takes place in which of the following? a) cytoplasm b) nucleoplasm c) rough ER d) nucleolus e) smooth ER

b) nucleoplasm

Telomere shortening is a problem in which types of cells? a) only prokaryotic cells b) only eukaryotic cells c) cells in prokaryotes and eukaryotes

b) only eukaryotic cells

Viral infections in plants spread from cell to cell via: a) endocytosis b) plasmodesmata c) infected seeds d) pili e) transformation

b) plasmodesmata

What is a major difference between eukaryotic DNA replication and prokaryotic DNA replication? a) prokaryotic replication does not require a primer b) prokaryotic chromosomes have a single origin of replication, while eukaryotic chromosomes have multiple origins of replication c) DNA replication in prokaryotic cells is conservative, DNA replication in eukaryotic cells is semi-conservative d) DNA polymerases of prokaryotes can add nucleotides to both 3' and 5' ends of DNA strands, whiel those of eukaryotes function only in the 5-3 direction

b) prokaryotic chromosomes have a single origin of replication, while eukaryotic chromosomes have multiple origins of replication

In eukaryotic cells, transcription cannot begin until which of the following occurs? a) the two DNA strands have completely separated and exposed the promoter b) several transcription factors have bound to the promoter and the enhancer to loop the DNA c) the 5' caps are removed from the mRNA d) the DNA introns are removed from the template

b) several transcription factors have bound to the promoter and the enhancer to loop the DNA

Prokaryotic ribosomes differ from those present in eukaryotic cytosol therefore which of the following is correct? a) prokaryotes are able to use a much greater variety of molecules as food sources than can eukaryotes b) some antibiotics can block protein synthesis in bacteria without blocking polypeptide synthesis in the eukaryotic cytoplasm of the host c) eukaryotes did not evolve from prokaryotes d) translation can occur at the same time as transcription in eukaryotes but not in prokaryotes e) both answer choices c and d are correct

b) some antibiotics can block protein synthesis in bacteria without blocking polypeptide synthesis in the eukaryotic cytoplasm of the host

Telomere shortening puts a limit on the number of times a cell can divide. Research has shown that telomerase can extend the life span of cultured human cells. How might adding telomerase affect cellular aging? a) telomerase will speed up the rate of cell proliferation b) telomerase eliminates telomere shortening and retards aging c) Telomerase shortens telomeres, which delays cellular aging d) telomerase would have no effect on cellular again

b) telomerase eliminates telomere shortening and retards aging

What is meant by the description "antiparallel" regrading the strands that make up DNA? a) thw twisting nature of DNA creates nonparallel strands b) the 5' to 3' direction of one strands runs counter to the 5' to 3' direction of the other strand c) base pairings create unequal spacing between the two DNA strands d) one strand contains only purine and the other contains only pyrimidines

b) the 5' to 3' direction of one strands runs counter to the 5' to 3' direction of the other strand

What is the difference between the leading strand and the lagging strand in DNA replication? a) the leading strand is synthesized in the 3-5 direction in a discontinuous fashion, while the lagging strand is synthesized in the 5-3 direction in a continuous fashion b) the leading strand is synthesized continuously in the 5-3 direction, while the lagging strand is synthesized discontinuously in the 5-3 direction c) the leading strand requires an RNA primer, whereas the lagging strand does not d) there are different DNA polymerases involved in elongation of the leading strand and the lagging strand

b) the leading strand is synthesized continuously in the 5-3 direction, while the lagging strand is synthesized discontinuously in the 5-3 direction

The comparison between the number of human genes and those of other animal species has led to many conclusions, including: a) the density of the human genome is far higher than in most other animals b) the number of proteins expressed by the human genome is far more than the number of its genes c) most human DNA consists of genes for protein, tRNA, rRNA, and miRNA d) the genomes of other organisms are most significantly smaller than the human genome

b) the number of proteins expressed by the human genome is far more than the number of its genes

How does the pre-mRNA transcript in the nucleus of a eukaryotic cell compare tot he functional mRNA that is translated in the cytoplasm? a) the pre-mRNA transcript is the same size as the mRNA b) the pre-mRNA transcript is longer than the mRNA c) the pre-mRNA transcript is smaller than the mRNA d) both the pre-mRNA functional transcript and mRNA contains introns e) the functional mRNA is degraded as soon as it reaches the cytoplasm

b) the pre-mRNA transcript is longer than the mRNA

When Thomas Hunt Morgan cross his red-eyed F1 generation flies to each other, the F2 generation included both red and white-eyed flied. Remarkably, all the white eyed flies were male. Which was Morgan's explanation for these results? a_ the white eye gene is located on the Y chromosome rather than the X chromosome b) the single recessive white eye allele on the X chromosome is expressed in males because of the absence of a dominate allele but it is not expressed in females homozygous for X c) the white eye gene involved is on an autosome, but is only expressed only in males due to other male-specific factors that influence eye color in flies d) all of the above e) none of the answer choices are correct

b) the single recessive white eye allele on the X chromosome is expressed in males because of the absence of a dominate allele but it is not expressed in females homozygous for X

Which of the following events is the first to occur for the initiation of translation of mRNA to synthesize a polypeptide? a) the initiator methionine-tRNA binds to the start codon on mRNA b) the small ribosomal subunit binds to the start codon of the mRNA c) the large ribosomal subunit binds to the initiation complex d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur e) translocation of ribosome to the next codon and release of tRNA

b) the small ribosomal subunit binds to the start codon of the mRNA

What is proteomics? a) the linkage of each gene to a particular protein b) the study of the full protein set encoded by a genome c) the totality of the functional possibilities of a single protein d) the study of how amino acids are ordered in a protein e) the study of how a single gene activates many proteins

b) the study of the full protein set encoded by a genome

Which of the following statements is true about protein synthesis in prokaryotes? a) extensive RNA processing is required before prokaryotic transcripts can be translated b) translation can begin while transcription is still in progress c) prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles d) translation requires antibiotic activity e) unlike eukaryotes, prokaryotes require no initiation or elongation factors

b) translation can begin while transcription is still in progress

Which of the following are characteristics of viruses? a) manufacture their own ATP, proteins, and nucleic acid b) use he host cell to copy themselves and make viral proteins c) use host cell to copy themselves and then viruses synthesize their own proteins d) metabolize food and produce their own ATP e) All of the above answer choices are correct

b) use the host cell to copy themselves and make viral proteins

Sequencing an entire genome, such as that of C. elegans, a nematode is most important because ________. a) it allows researchers to use the sequence to build a "better" nematode, which is resistant to disease b) it allows research to a group of organisms we don't usually care much about c) a sequence that is found to have a particular function in the nematode is likely to have a closely related function invertebrates d) a sequence that is found to no introns in the nematode genome is likely to have acquired the introns from higher organism s

c) a sequence that is found to have a particular function in the nematode is likely to have a closely related function invertebrates

Eukaryotic genes in euchromatin regions of chromosomes are available for being: a) inhibited b) duplicated c) actively transcribed d) repressed e) unregulated

c) actively transcribed

When does exon shuffling occur? a) during splicing of DNA b) during mitotic recombination c) as an alternative splicing pattern in post-transcriptional processing d) as an alternative clevage of modification post-translationally e) as the result of faulty DNA repair

c) as an alternative splicing pattern in post-transcriptional processing

How do we describe the process of transformation in bacteria? a) the infection of cells by a phage DNA molecule b) the type of semi-conservative replication shown by DNA c) bacteria take up DNA from the environment and incorporates it into their own DNA d) the creation of a strand of DNA from an RNA molecule e) the creation of a strand of RNA from a DNA molecule

c) bacteria take up DNA from the environment and incorporates it into their own DNA

Transformation is a process whereby: a) bacteria are transferred into plasmid cells b) viruses are transferred into bacterial cells c) bacterial cells take up DNA from the environment d) bacteria are transferred into viral cells e) plasmids are transferred into viral cells

c) bacterial cells take up DNA from the environment

The role of a prokaryotic inducer molecule is to do which of the following? a) bind to the promoter region and decrease the affinity of RNA polymerase b) bind to the repressor protein to activate it block transcription of the gene c) bind to the active repressor protein to change its shape which removes the repressor from the DNA to allow transcription of the gene d) all of the above choices are correct e) only choices b and c are correct

c) bind to the active repressor protein to change its shape which removes the repressor from the DNA to allow transcription of the gene

Which are the microtubule-organizing centers in eukaryotic cells? a) centrioles b) ribosomes c) centrosomes d) centromere e) nucleolus

c) centrosomes

Which of the following chemical reactions is catalyzed by an amino acyl-tRNA synthetase? a) folds tRNA molecules into their proper configuration b) adds the appropriate amino acid the carboxyl end of a growing polypeptide chain c) covalently bonds the caroxyl group of a specific amino acid to the 3' hydroxyl end of a tRNA that contains the correct anticodon d) produces tRNA by reading DNA molecules e) synthesizes amino acids

c) covalently bonds the caroxyl group of a specific amino acid to the 3' hydroxyl end of a tRNA that contains the correct anticodon

A symptom of human transmissible spongiform encephalopathy is: a) degeneration of the digestive tract b) progressive immune deficiency c) degeneration of the brain and central nervous system d) inflammation of the reproductive organs e) infleunza-like symptoms

c) degeneration of the brain and central nervous system

Nerve cells, bone cells, and skin cells all contain the same genome; however, their respective protein make-up varies drastically. This observation is best explained by what phenomenon? a) alternative gene splicing b) cytokineses or cell division during the cell cycle c) differential expression of genes in the various tissue types d) crossing over between non-sister chromatids of a tetrad during prophase I of meiosis e) the process of evolution

c) differential expression of genes in the various tissue types

Which of the following is responsible for the synthesis of different unique eukaryotic mRNA molecules from one DNA gene allele locus? a) self-splicing of pre-mRNA b) capping of pre-mRNA c) differential splicing of pre-mRNA d) regulatory splicing of pre-mRNA e) reverse transcription

c) differential splicing of pre-mRNA

Cells becoming progressively more specailized in their structure and gene activity is known as: a) morphogenesis b) determination c) differentiation d) maturation e) growth

c) differentiation

DNA methylation and histone acetylation are examples of which of the following processes? a) genetic mutation b) chromosomal rearrangements c) epigentic phenomena d) translaction

c) epigentic phenomena

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to contributed to this similarity? a) gene duplication b) RNA spliciing c) exon shuffling d) histone modification e) random point mutations

c) exon shuffling

Eukaryotic telomeres replicate differently than the rest of the chromosome. This is a consequence of which of the following? a) the evolution of telomerase enzyme b) DNA polermase that cannot replicate the leading strand template to its 5' end c) gaps left at the 5' end of the lagging strand prevent the formation of an Okazaki fragment would shorten the chromosomes d) gaps left at the 3' end of the lagging strand because of the need for a primer would shorten the chromosomes

c) gaps left at the 5' end of the lagging strand prevent the formation of an Okazaki fragment would shorten the chromosomes

Mitochondrial DNA is primarily involved in coding for proteins needed for protein complexes of the electron transport chain and ATP synthase. Therefore, mutations in mitochondrial genes would most affect a) DNA synthesis in cells of the immune system b) the movement of oxygen into erythrocytes c) generation of ATP in muscle cells d) the storage of urine in the urinary bladder

c) generation of ATP in muscle cells

Which of the following genes code for regulatory proteins that induce development and identity of entire body parts? a) segmentation genes b) egg-polarity genes c) homeotic genes d) inducers

c) homeotic genes

In response to signaling molecules, prokaryotes can do which of the following? a) turn off translation of their mRNA b) alter the production of various proteins required by the cell to function in its changing environment c) increase the number of ribosomes to speed up synthesis of various enzymes d) inactivate their mRNA molecules e) alter the sequence of amino acids in certain proteins

c) increase the number of ribosomes to speed up synthesis of various enzymes

What evolutionary advantage is provided by sexual reproduction? a) making diploid offspring possible b) making clones c) increased genetic diversity within a population d) making polyploidy possible e) being able to work with chromosomes

c) increased genetic diversity within a population

Which of the following is negative regulation of the lac operon? a) forming a loop in the operator that restricts the passage of the polymerase b) the repressor physically blocks the DNA binding site of RNA polymerase c) inducer molecules remove repressor protein from the lac operator d) sigma factor binds to the core RNA polymerase to prevent transcription of the operon's gene e) the repressor blocking passage of the RNA polymerase through the operator

c) inducer molecules remove repressor protein from the lac operator

What did Griffith's observe in his bacterial transformation experiments to learn what cause pneumonia in mice? a) mutant mice were resistant to bacterial infections b)Mixing a heat killed pathogen strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form c) Mixing a heat killed nonpathogen strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic d) infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains e) mice infected with a pathogenic strain of bacteria can spread the infection to other mice

b)Mixing a heat killed pathogen strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form

Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their twenties. How likely is it for a woman to have this condition? a) woman can never have this condition b) 1/4 of the daughters of an affected man would have this condition c) 1/2 of the daughters of an affected father and a carrier mother could have this condition d) only if a woman is XXX could she have this condition

c) 1/2 of the daughters of an affected father and a carrier mother could have this condition

Cells must have at least how many distinct aminoacyl-tRNA synthetases are required to translate the mRNA sequence a) 3 b) 12 c) 20 d) 26 e) 64

c) 20

An Okazaki fragment has which of the following arrangements? a) primase, polymerase, ligase b) 3' primer (RNA chain), DNA chain of nucleotides 5' c) 5' RNA nucleotides (primer), DNA nucleotides 3' d) DNA polyermase I, DNA polyermase III e) 5' DNA to 3'

c) 5' RNA nucleotides (primer), DNA nucleotides 3'

Which of the following are the substrates for transcription catalyzed by RNA polymerases a) dATP, dGTP, dCTP, dUTP, and a DNA template b) the 20 different types of amino acids, tRNA, and a DNA template c) ATP, GTP, CTP, UTP, and a DNA template d) a single DNA template chain and deoxyribonucleotide triphosphates e) rRNA, tRNA, and amino acids

c) ATP, GTP, CTP, UTP, and a DNA template

If a mutation occured in the primase gene, which of the following would you expect? a) DNA replication would only occur on the leading strand b) DNA replication would only occur on the lagging strand c) DNA replication would not occur on either the leading or lagging strand d) DNA replication would not be affected as the enzyme primase in involved with RNA synthesis

c) DNA replication would not occur on either the leading or lagging strand

When the amino acid lysine of a charged transfer RNA (#1) that entered the A-site of a ribosome is peptide bonded to the amino acid carried by tRNA (#2) in the ribsomal P site, where does the uncharged tRNA #2 move to next? a) A site b) P site c) E site d) exit tunnel e) directly to the cytosol

c) E site

Semiconservative replication involves a template. What is the template? a) single-stranded binding proteins b) DNA polymerase c) Each of the separated single strands of the DNA molecule d) an RNA molecule e) a primer

c) Each of the separated single strands of the DNA molecule

How does the enzyme telomerase meet the challenge of repicating the ends of linear chromosomes? a) it adds a single 5' cap structure that resists degradation by nucleases b) it causes specific double-strand DNA breaks that result in blunt ends on both strands c) it catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replicaiton without telomerase activity d) it adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity

c) it catalyzes the lengthening of telomeres, compensating for the shortening that could occur during replicaiton without telomerase activity

Which of the following enzymes can bind to a specific promoter sequence of DNA, catalyze the separation of the DNA chains to use one of the single DNA strands as a template to transcribe the synthesis of compleentary RNA that is antiparallel to the DNA template? a) DNA polymerase I b) DNA polymerase III C) RNA polmyerase d) Primase e) DNA ligase

C) RNA polmyerase

What is metagenomics? a) genomics as applied to a species that most typifies the average phenotype of its genus b) the sequence of one or two representative genes from several species c) the sequencing of only the most highly cosnerved genes in a linage D) sequencing DNA from a group of species from the same ecosystem e) genomics as applied to an entire phylum

D) sequencing DNA from a group of species from the same ecosystem

In E. Coli, which enzyme catalyzes the elongation of a new DNA strand in 5' -> 3' directon? a) primase b) DNA ligase c) DNA polymerase III d) Helicase e) DNA kinase

DNA polymerase III

Which is a common form of reproduction in some animals such as honey bees where unfertilized eggs develop into males? a) syngamy b) binary fission c) mitosis d) meiosis e) parthenogensis

E) partenogensis

In order to determine the probably function of a particular sequence of DNA in humans, what might be the most reasonable approach? a) prepare a knockout mouse without a copy of this sequence and examine the mouse phenotype b) genetically engineer a mouse with a copy of this sequence and examine its phenotype c) look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences d) prepare a genetically engineered bacterial culture with the sequence inserted and assess which new protein is synthesized

c) look for a reasonably identical sequence in another species, prepare a knockout of this sequence in that species and look for the consequences

Which of the following catalyze peptide bonding between an amino acid in the ribosomal P site and an amino acid in the A site during polypeptide synthesis? a) RNA polymerase b) ligase c) peptidyl transferase d) ribonuclease e) amino acyl tRNA synthetase

c) peptidyl transferase

Mad cow disease is an example of an infection caused by a: a) bacterium b) bacteriophage c) retrovirus d) viroid c) prion

c) prion

The pairing zipper-like connection between homologous chromosomes in prophase I in meiosis is known as which of the following? a) spindle fiber b) synaptic junction c) synapsis d) chiasma e) none of the choices are correct

c) synapsis

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and _________ of the last nucleotide in the polymer. a) the 5' phosphate b) C6 c) the 3' OH d) a nitrogen from the nitrogen-containing base

c) the 3' OH

During the replication of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which functional group on the last nucleotide on the DNA chain? a) the 5' phosphate of dexoyribose b) carbon number 2 of deoxyribose c) the 3' OH of deoxyribose d) nitrogen number 3 of the pyrimidine or nitrogen number 9 of the purine e) carbon number 5 of deoxyribose

c) the 3' OH of deoxyribose

How does the first nucleotide at the 5' end of a new mRNA chain differ from the other nucleotides in the chain? a) the first nucleotide is always a uracil b) the first nucleotide is always a guanine c) the first nucleotide retains its triphosphate group, while others do not d) the first nucleotide retains its 3 prime hydroxyl group, while the others in the chain do not e) the first nucleotide is always a modified cytosine

c) the first nucleotide retains its triphosphate group, while others do not

Which of the following events is the third to occur for the initiation of translation of mRNA to synthesize a polypeptide? a) the initiator methionine-tRNA binds to the start codon on mRNA b) the small ribosomal subunit binds to the start codon of the mRNA c) the large ribosomal subunit binds to the initiation complex d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur e) translocation of ribosome to the next codon and release of tRNA

c) the large ribosomal subunit binds to the initiation complex

What is the function of the poly A tail on eukaryotic mRNA? a) the poly A tail is coded for on the DNA gene required for the binding of mRNA to a signal recognition particle b) the poly A tail allows mRNA to bind to the ribosome c) the poly A tail increases stability of mRNA by preventing nuclesae degradation of the mRNA d) the poly A tail increases the rate of mRNA degradation in prokaryotes e) the poly A tail serves as termination sequence for RNA polymerase II

c) the poly A tail increases stability of mRNA by preventing nuclesae degradation of the mRNA

Although transposable elements and short tandem repeats are repetitve DNAs, they differ in that _______________. a) STRs occur within exons; transposable elements occur with introns b) STRs occur within introns; transposable elements occur within exons c) the repeated unit in STRs is clustered one after another; transposable element repeats are scattered throughout the genome d) the repeated unit in STRs is much larger than the repeated unit of transposable elements

c) the repeated unit in STRs is clustered one after another; transposable element repeats are scattered throughout the genome

What can proteomics reveal that genomics cannot? a) the number of genes characteristic of a species b) the patterns of alternative splicing c) the set of proteins present within a cell or tissue type d) the movement of transposable elements within the genome

c) the set of proteins present within a cell or tissue type

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following? a) the sequence of the intron that immediately precedes each exon b) the number of polypeptides making up the functional protein c) the various domains of the polypeptide product d) the number of start sites for transcription

c) the various domains of the polypeptide product

Which of the following statements correctly describes a characteristic of tumor-suppressor gene? a) they are frequently over expressed b) they are cancer-causing genes introduced into cells by viruses c) they encode proteins that help prevent uncontrolled cell growth d) they often encode proteins that stimulate the cell cycle

c) they encode proteins that help prevent uncontrolled cell growth

In E.coli, what is the function of DNA polymerase III? a) to unwind the dna helix during replication b) to seal together the broken ends of DNA strands c) to add nucleotides to the 3' end of a growing DNA strand d) to degrade damaged DNA molecules

c) to add nucleotides to the 3' end of a growing DNA strand

Which of the following is a function of a signal peptide on newly formed polypeptides in eukaryotic cytoplasm? a) to direct specific mRNA molecules into the lumen space of the ER b) to signal that the polypeptide is to be transported from the nucleus into the ER c) to bind to a signal recognition particle which then binds a SRP receptor on the ER to facilitate transport into the ER d) all of the above choices are correct

c) to bind to a signal recognition particle which then binds a SRP receptor on the ER to facilitate transport into the ER

In cats, black fur color is caused by an X-linked allele at this locus causes orange color. The heterozygote in tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male? a) tortoiseshell females; tortosieshell males b) blacks females; orange amles c) tortoise shell females; black males d) orange females; black males

c) tortoise shell females; black males

Maternal effect genes form gradients in the developing egg of which molecules? a) maternal Hox proteins b) maternal DNA genes c) transcription factors d) maternal growth factors

c) transcription factors

One possibel result of chromosomal breakage is for a fragment to join a non-homologous chromosome. Wha tis this alteration called? a) deletion b) inversion c) translocation d) duplication

c) translocation

Which of the following molecules is a co-repressor for the bacterial tryptophan operon? a) glucose b)cAMP c) tryptophan d) CAP e) lactose

c) tryptophan

If the sequence of bases ina section of DNA is 3' ATCGCTCC5', what ist he corresponding sequence of bases in a complementary DNA bonded to it in a double helix? a) 5' ATCCGATT3' b) 5'TAGGCTGG3' c) 5'TATCGGCC3' d) 5'TAGCGAGG3' e) 5' ATCCGATT3'

d) 5'TAGCGAGG3'

Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiemnts in which E. coli was infected by a T2 virus. Which molecule component of the T2 virus actually ended up inside the cell? a) protein b) RNA c) ribosome d) DNA e) steroid hormones

d) DNA

A new DNA strand elongates only in the 5' to 3' direction because _________. a) DNA polymerase begins adding nucleotides at the 5' end of the template b) the polarity of the DNA molecule prevents addition of nucleotides atg the 3' end c) replication must progress toward the replication fork d) DNA polymerase can add nucleotides only to the free 3' end

d) DNA polymerase can add nucleotides only to the free 3' end

For mechanisms of sex determination, which of the following is incorrectly paired? a) X-Y cow b) X-O, grasshopper c) ZZ-ZW, bluebird d) N and 2n, pea plant

d) N and 2n, pea plant

The DNA of telomeres has been highly conserved thoughouyt the evolution of eukaryotes. This most likely reflects a) the low frequency of mutations occuring in the DNA b) continued evolution of telomeres c) that new mutations in telomeres have bene advantageous d) a critical function of telomeres

d) a critical function of telomeres

Which of the following would you expect of a eukaryote lacking telomerase? a) a high probability of somatic cells becoming cancerous b) an inability to produce Okazaki fragments c) an inability to repair thymine dimers d) a reduction in chromosome length in gametes

d) a reduction in chromosome length in gametes

Which of the following statements describes a eukaryotic chromosome? a) a single strand of DNA b) a series of nucleosomes wrapped around two DNA molecules c) a chromosome with different numbers of genes in different cells types of an organism d) a single linear molecule of double-stranded DNA plus protein

d) a single linear molecule of double-stranded DNA plus protein

Which of the following is a chractersitic of tRNA? a) must be recognized by ribosomal subunits in order to bind to them b) must have an anticodon and also an attachment site for the specific amino acid c) must be recognized by a specific aminoacyl-tRNA synthetase that adds the correct amino acid d) all of the above e) only answer choices b and c are correct

d) all of the above

A sequence database such as GenBank could be used to do which of the following? a) compare cow and human insulin protein sequences b) construct a tree to determine the evolutionary relationships between various bird species c) search for genes in a fruit fly that are similar to a human gene d) all of the above answer choices are correct e) compare patterns of gene expression in cancerous and non-cancerous cells

d) all of the above answer choices are correct

After the embryonic segments have developed, the protein products of Hox gene expression regulate which of the following? a) They determine the type structures that will be formed on each segment b) they do not form the actual segments themselves c) their protein products are transcription factors d) all of the above answer choices are correct e) only answer choices a and c are correct

d) all of the above answer choices are correct

Eukaryotic enhancers are capable of which of the following? a) regulating a gene from very long distances b) interacting with proteins that regulate transcription c) increasing the rate of RNA synthesis d) all of the above answer choices are correct e) both answer choices b and c are correct

d) all of the above answer choices are correct

Which of the following is the function of eukaryotic nuelcosomes? a) regulation of gene expression by inactivating genes wrapped around them b) regulation of gene expression by selectively binding active transcriptive factors c) regulate gene expression by using its snRNA for alternative splicing of the mRNA d) all of the above answers are correct e) all of the above answers are correct except answer c

d) all of the above answers are correct

Which of the following are characteristics of eukaryotic pre-mRNA transcripts: a) they have introns that spliceosomes can remove b) they become stablized after a 7 methyl Guanosine triphosphate is added to its 5' end c) they becomes stable when poly A ribonucleotides are added to its 3' end d) all of the above are correct e) only answers a and c are correct

d) all of the above are correct

The ability of glucose to repress the bacterial lac opeon depends on the decrease in which of the following molecules? a) Alllactose b) cAMP c) tryptophan d) all of the above choices are correct e) only answer choices a and b are correct

d) all of the above choices are correct

If two or more forms of the same gene exist, the different forms are called which of the following? a) incomplete dominance b) penetrance and expressivity c) pleiotropic d) alleles e) dihyrbid

d) alleles

What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own? a) they are genes that had a function at one time, but that have lost their function because they have been translocated to a new location b) they are genes that have accumulated mutations to such a degree that they would code for different functional products if activated c) they are duplicates or near duplicates of functional genes but cannot function because they would provide inappropraite dosage of protein products d) they are genes with significant inverted sequences e) they are genes that are not expressed, even though they have nearly identical sequences to expressed genes

e) they are genes that are not expressed, even though they have nearly identical sequences to expressed genes

What is the mode of action of antiviral drugs that have become useful in treating the symptoms of viral infections? a) prevention of the host from becoming infected b) degrading and removing of viral proteins c) degrading and removal of viral mRNAs d) they promote the killing and removal all viruses from the infected host e) they block the replication of virus after the virus has infected the host

e) they block the replication of virus after the virus has infected the host

Which of the following is a function of a signal peptide? a) to direct an mRNA molecule into the cisternal space of the ER b) to bind RNA polymerase to DNA and initiate transcription c) to terminate translation of the messenger RNA d) to translocate polypeptides across the ER membrane e) to signal the initiation of transcription

e) to signal the initiation of transcription

Which of the following events is the fifth to occur for the initiation of translation of mRNA to synthesize a polypeptide? a) the initiator methionine-tRNA binds to the start codon on mRNA b) the small ribosomal subunit binds to the start codon of the mRNA c) the large ribosomal subunit binds to the initiation complex d) an amino acyl-tRNA entry into the A site in order for the peptidyl transferase reaction to occur e) translocation of ribosome to the next codon and release of tRNA

e) translocation of ribosome to the next codon and release of tRNA

A prokaryotic repressible operon like the tryptophan operon is: a) permanently turned on b) turned on only when trtyptophan is present in the growth medium c) turned off only when glucose is present in the growth medium d) turned on only when glucose is present in the growth medium e) turned on until it is turned off whenever tryptophan accumulates in excess inside the cell

e) turned on until it is turned off whenever tryptophan accumulates in excess inside the cell