bio unit 5

The leading and the 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 leading strand is synthesized continuously, whereas the lagging strand is synthesized in short fragments that are ultimately stitched together. d. both A and B e. both A and C

both a and c

Which of the following statements about telomeres is correct? a. They contain multiple copies of a short RNA sequence. b. They are present at the ends of eukaryotic chromosomes. c. They can be extended by an enzyme called telomerase. d. both A and B e. both B and C

both b and c

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

by adding methyl groups to adenines and cytosines

Use the figure below to answer the following questions. The DNA profiles below represent four different individuals Which of the following are probably siblings? a. C and D b. B and D c. A and C d. A and D e. A and B

c and d

Which enzyme catalyzes the elongation of a DNA strand in the 5' ----> 3' direction? a. primase b. topoisomerase c. DNA ligase d. helicase e. DNA polymerase

dna polymerase

A frameshift mutation could result from a. a base insertion only. b. a base substitution only. c. either an insertion or a deletion of a base. d. a base deletion only. e. deletion of three consecutive bases.

either an insertion or a deletion of a base.

What are polyribosomes? a. groups of ribosomes reading a single mRNA simultaneously b. ribosomes containing more than two subunits c. multiple copies of ribosomes associated with giant chromosomes d. aggregations of vesicles containing ribosomal RNA e. ribosomes associated with more than one tRNA

groups of ribosomes reading a single mRNA simultaneously

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? a. unwind the parental double helix b. stabilize the unwound parental DNA c. catalyze the lengthening of telomeres d. join Okazaki fragments together e. synthesize RNA nucleotides to make a primer

join Okazaki fragments together

synthesizes short segments of RNA A. helicase B. nuclease C. ligase D. DNA polymerase I E. primase

primase

Which of the following is analogous to telomeres? a. the correct letters used to replace errors in a document after they have been deleted in a word processor b. the mechanism of a zipper that allows the separated parts to be joined c. the pull tab on a soft drink can d. the central spindle that a CD fits around while in the case e. the two ends of a shoelace

the two ends of a shoelace

Replicating the lagging strand of DNA-that is, adding bases in the 3' -----> 5' direction-utilizes which of the following? a. DNA ligase b. RNA primers c. Okazaki fragments d. A and B only e. A, B, and C

a b and c

Which enzyme was used to produce the molecule in the figure below? a. RNA polymerase b. a restriction enzyme c. DNA polymerase d. ligase e. transcriptase

a restriction enzyme

Which of the following modifications is least likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? a. decreasing the length of the DNA fragment b. methylating the cytosine bases within the DNA fragment c. neutralizing the negative charges within the DNA fragment d. increasing the length of the DNA fragment e. altering the nucleotide sequence of the DNA fragment

altering the nucleotide sequence of the DNA fragment

What determines the nucleotide sequence of the newly synthesized strand during DNA replication? a. the particular DNA polymerase catalyzing the reaction b. the relative amounts of the four nucleoside triphosphates in the cell c. the nucleotide sequence of the template strand d. the primase used in the reaction e. both A and D

the nucleotide sequence of the template strand

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately, what percentage of the nucleotides in this sample will be thymine? a. 24 b. 12 c. 31 d. 38 e. It cannot be determined from the information provided.

12

A particular eukaryotic protein is 300 amino acids long. Which of the following could be the maximum number of nucleotides in the DNA that codes for the amino acids in this protein? a. 3 b. 900 c. 100 d. 1,800 e. 300

900

Which of the following best describes the addition of nucleotides to a growing DNA chain? a. A nucleoside triphosphate is added to the 5' end of the DNA, releasing a molecule of pyrophosphate. b. A nucleoside monophosphate is added to the 3' end of the DNA. c. A nucleoside diphosphate is added to the 5' end of the DNA, releasing a molecule of phosphate. d. A nucleoside diphosphate is added to the 3' end of the DNA, releasing a molecule of phosphate. e. A nucleoside triphosphate is added to the 3' end of the DNA, releasing a molecule of pyrophosphate (2 phosphates together).

A nucleoside triphosphate is added to the 3' end of the DNA, releasing a molecule of pyrophosphate (2 phosphates together).

During translation, chain elongation continues until what happens? a. The ribosomes run off the end of mRNA. b. The polypeptide is long enough. c. No further amino acids are needed by the cell. d. A stop codon is encountered. e. All tRNAs are empty.

A stop codon is encountered.

The completion of the Human Genome Project revealed that the human genome contains fewer genes than expected, not so many more than simpler organisms. How can this be reconciled with the greater complexity of humans relative to many other organisms? a. RNA transcripts of human genes are more likely to undergo alternative splicing. b. Post-translational processing adds diversity to the resulting polypeptides. c. Polypeptide domains are combined in a variety of ways. d. Gene expression patterns in humans are often more complex than those in other organisms. e. All of the above are correct.

All of the above are correct.

Use the figure below to answer the following questions. The DNA profiles below represent four different individuals. Which of the following statements is consistent with the results? a. A is the child of B and C. b. D is the child of B and C. c. A is the child of C and D. d. B is the child of A and C. e. C is the child of A and B.

C is the child of A and B.

Use the figure below to answer the following questions. The DNA profiles below represent four different individuals Which of the following statements is most likely true? a. D is the child of A and C. b. A is the child of C and D. c. D is the child of B and C. d. B is the child of A and C. e. D is the child of A and B.

D is the child of A and B.

A new DNA strand elongates only in the 5' to 3' direction because a. DNA polymerase can only add nucleotides to the free 3' end.This is the correct answer. b. replication must progress toward the replication fork. c. DNA polymerase begins adding nucleotides at the 5' end of the template. d. the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. e. Okazaki fragments prevent elongation in the 3' to 5' direction.

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

Which of the following statements is false when comparing prokaryotes with eukaryotes? a. The prokaryotic chromosome is circular, whereas eukaryotic chromosomes are linear. b. The rate of elongation during DNA replication is higher in prokaryotes than in eukaryotes. c. Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. d. Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. e. Eukaryotes have telomeres, and prokaryotes do not.

Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.

RNA polymerase and DNA polymerase differ in that a. RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to double-stranded DNA. b. RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA. c. RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis. d. RNA polymerase is much more accurate than DNA polymerase. e. RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template.

RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

If you discovered a bacterial cell that contained no restriction enzymes, which of the following would you expect to happen? a. The cell would be unable to replicate its DNA. b. The cell would create incomplete plasmids. c. The cell would be easily infected and lysed by bacteriophages. d. The cell would become an obligate parasite. e. Both A and D would occur.

The cell would be easily infected and lysed by bacteriophages.

Which of the following statements does not apply to the Watson and Crick model of DNA? a. The two strands of the DNA form a double helix. b. The two strands of the helix are held together by covalent bonds. c. The framework of the helix consists of sugar-phosphate units of the nucleotides. d. The distance between the strands of the helix is uniform. e. The purines form hydrogen bonds with pyrimidines.

The two strands of the helix are held together by covalent bonds.

Which of the following statements are true about protein synthesis in prokaryotes? a. Translation can begin while transcription is still in progress. b. Extensive RNA processing is required before prokaryotic transcripts can be translated. c. Prokaryotic cells have complicated mechanisms for targeting proteins to the appropriate cellular organelles. d. Only A and B are true. e. A, B, and C are true.

Translation can begin while transcription is still in progress.

The function of the ribosome in polypeptide synthesis is to a. hold mRNA and tRNAs together. b. catalyze the addition of amino acids from tRNAs to the growing polypeptide chain. c. move along the mRNA and eject tRNAs during the translocation process. d. A and B only e. A, B, and C

a b and c

Which of the following is (are) true of snRNPs? a. They are made up of both protein and RNA. b. They bind to splice sites at each end of the intron. c. They join together to form a large structure called the spliceosome. d. Only A and C are true. e. A, B, and C are true

a b and c

A particular triplet of bases in the template strand of DNA is AGT. The corresponding codon for the mRNA transcribed is a. TCA. b. ACU. c. either UCA or TCA, depending on wobble in the first base d. UGA. e. AGT.

acu

The polymerase chain reaction (PCR) has been used to amplify DNA from which of the following? a. fossils b. fetal cells c. viruses d. bacteria e. all of the above

all of the above

Which of these mechanisms ensures that the DNA sequence in the genome remains accurate? a. proofreading during DNA replication b. mismatch repair c. excision repair d. complementary base pairing during DNA replication e. all of the above

all of the above

A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation? a. an accumulation of B and no production of A and C b. an accumulation of A and B and no production of C c. an accumulation of B and C and no production of A d. an accumulation of A and no production of B and C e. an accumulation of C and no production of A and B

an accumulation of A and no production of B and C

The nitrogenous base adenine is found in all members of which group? a. proteins, ATP, and DNA b. alpha glucose, ATP, and DNA c. ATP, RNA, and DNA d. proteins, carbohydrates, and ATP e. proteins, triglycerides, and testosterone

atp rna and dna

Alternative RNA splicing a. is a mechanism for increasing the rate of transcription. b. can allow the production of proteins of dramatically different sizes from a single mRNA. c. can allow the production of proteins of dramatically different amino acid sequences from a single mRNA. d. B and C only e. A, B, and C

b and c only

Using RNA as a template for protein synthesis instead of translating proteins directly from the DNA is advantageous for the cell because a. RNA is much more stable than DNA. b. RNA acts as an expendable copy of the genetic material, allowing the DNA to serve as a permanent, pristine repository of the genetic material. c. many mRNA molecules can be transcribed from a single gene, increasing the potential rate of gene expression. d. B and C only e. A, B, and C

b and c only

In an analysis of the nucleotide composition of DNA, which of the following is true? a. A = C b. A = G and C = T c. A + C = G + T d. G + A = T + C e. both C and D

both c and d

Which of the following helps to stabilize mRNA by inhibiting its degradation? a. TATA box b. spliceosomes c. 5' cap d. poly-A tail e. both C and D

both c and d

removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments A. helicase B. nuclease C. ligase D. DNA polymerase I E. primase

dna polymerase I

what is a ribozyme a. An enzyme that synthesizes RNA primers during DNA replication b. An enzyme that catalyzes the association between the large and small ribosomal subunits c. An enzyme made up of RNA d. An enzyme that uses RNA as a substrate e. An enzyme that synthesizes RNA as part of the transcription process

enzyme made up of rna

Once transcribed, eukaryotic mRNA typically undergoes substantial alteration that includes a. fusion into circular forms known as plasmids. b. union with ribosomes. c. excision of introns d. fusion with other newly transcribed mRNA. e. linkage to histone molecules.

excision of introns.

What are the coding segments of a stretch of eukaryotic DNA called? a. replicons b. transposons c. exons d. introns e. codons

exons

Restriction fragments of DNA are typically separated from one another by which process? a. centrifugation b. PCR c. electron microscopy d. filtering e. gel electrophoresis

gel electrophoresis

____ separates molecules by movement due to size and electrical charge A. restriction enzymes B. gene cloning C. DNA ligase D. gel electrophoresis E. reverse transcriptase

gel electrophoresis

separates the DNA strands during replication A. helicase B. nuclease C. ligase D. DNA polymerase I E. primase

helicase

What kind of chemical bond is found between paired bases of the DNA double helix? a. hydrogen b. covalent c. ionic d. phosphate e. sulfhydryl

hydrogen

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent a. leading strands and RNA primers. b. lagging strands and Okazaki fragments. c. RNA primers and mitochondrial DNA. d. leading strands and Okazaki fragments. e. Okazaki fragments and RNA primers.

leading strands and Okazaki fragments.

covalently connects segments of DNA A. helicase B. nuclease C. ligase D. DNA polymerase I E. primase

ligase

The polymerase chain reaction is important because it allows us to a. incorporate genes into viruses. b. make DNA from RNA transcripts. c. insert eukaryotic genes into prokaryotic plasmids. d. make many copies of a targeted segment of DNA. e. insert regulatory sequences into eukaryotic genes.

make many copies of a targeted segment of DNA.

a codon a. consists of two nucleotides. b. may code for the same amino acid as another codon. c. consists of discrete amino acid regions. d. catalyzes RNA synthesis. e. is found in all eukaryotes, but not in prokaryotes.

may code for the same amino acid as another codon.

What amino acid sequence will be generated, based on the following mRNA codon sequence? 5'AUG-UCU-UCG-UUA-UCC-UUG a. met-ser-ser-leu-ser-leu b. met-arg-glu-arg-glu-arg c. met-ser-leu-ser-leu-ser d. met-glu-arg-arg-gln-leu e. met-leu-phe-arg-glu-glu

met-ser-ser-leu-ser-leu (wtf is this question)

DNA-cutting enzymes used in the repair of DNA damage A. helicase B. nuclease C. ligase D. DNA polymerase I E. primase

nuclease

Which of the following represents a similarity between RNA and DNA? a. the presence of uracil b. Both are double-stranded. c. the presence of an OH group on the 2' carbon of the sugar d. Both are found exclusively in the nucleus. e. nucleotides consisting of a phosphate, sugar, and nitrogenous base

nucleotides consisting of a phosphate, sugar, and nitrogenous base

What is the sequence of a peptide based on the mRNA sequence 5' UUUUCUUAUUGUCUU 3' ? a. leu-cys-tyr-ser-phe b. phe-ser-tyr-cys-leu c. leu-pro-asp-lys-gly d. cyc-phe-tyr-cys-leu e. phe-leu-ile-met-val

phe-ser-tyr-cys-leu

Sickle-cell disease is probably the result of which kind of mutation? a. nonsense b. nondisjunction c. point d. frameshift e. both B and D

point

Of the following types of mutations, which one is likely to be the most common? a. point mutation b. base-pair substitution c. nonsense mutation d. frameshift mutation e. missense mutation

point mutation

If the triplet CCC codes for the amino acid proline in bacteria, then in plants CCC should code for a. cystine. b. proline. c. leucine. d. valine. e. phenylalanine.

proline

The DNA double helix has a uniform diameter because ____, which have two rings, always pair with ____, which have one ring. a. pyrimidines; purines b. deoxyribose sugars; ribose sugars c. nucleotides; nucleoside triphosphates d. ribose sugars; deoxyribose sugars e. purines; pyrimidines

purines; pyrimidines

What is the function of topoisomerase? a. elongation of new DNA at a replication fork by addition of nucleotides to the existing chain b. stabilizing single-stranded DNA at the replication fork c. unwinding of the double helix d. the addition of methyl groups to bases of DNA e. relieving strain in the DNA ahead of the replication fork

relieving strain in the DNA ahead of the replication fork

The Y-shaped structure where the DNA double helix is actively unwound during DNA replication is called the a. Y junction. b. unwinding point. c. replication Y. d. elongation junction. e. replication fork.

replication fork

____ cuts DNA molecules at specific locations A. restriction enzymes B. gene cloning C. DNA ligase D. gel electrophoresis E. reverse transcriptase

restriction enzymes

During splicing, which molecular component of the spliceosome catalyzes the excision reaction? a. protein b. RNA c. sugar d. lipid e. DNA

rna

What kind of molecule or substance is the primer that is used to initiate the synthesis of a new DNA strand? a. phosphate b. protein c. RNA d. DNA e. sulfur

rna

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in its a. sequence of bases. b. different five-carbon sugars. c. side groups of nitrogenous bases. d. complementary pairing of bases. e. phosphate-sugar backbones.

sequence of bases

All of the following can be determined directly from X-ray diffraction photographs of crystallized DNA except the a. number of strands in a helix. b. sequence of nucleotides. c. diameter of the helix. d. spacing of the nitrogenous bases along the helix. e. helical shape of DNA.

sequence of nucleotides

Dideoxyribonucleotide chain-termination is a method of a. synthesizing DNA. b. cloning DNA. c. digesting DNA. d. sequencing DNA. e. separating DNA fragments.

sequencing dna

Which of the following help to hold the DNA strands apart while they are being replicated? a. ligase b. DNA polymerase c. single-strand binding proteins d. primase e. exonuclease

single-strand binding proteins

Which of the following is not a part of the eukaryotic transcription initiation complex? a. promoter b. snRNP c. TATA box d. transcription factors e. RNA polymerase

snRNP

What is an anticodon part of? a. an activating enzyme b. DNA c. a ribosome d. tRNA e. mRNA

tRNA

Which of the following is least related to the others on the list? a. Okazaki fragments b. telomerase c. replication fork d. DNA polymerase e. semiconservative model

telomerase

The strands that make up DNA are antiparallel. This means that a. base pairings create unequal spacing between the two DNA strands. b. one strand contains only purines and the other contains only pyrimidines. c. the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. d. one strand is positively charged and the other is negatively charged. e. the twisting nature of DNA creates nonparallel strands.

the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

the difference between ATP and the nucleoside triphosphates used during DNA synthesis is that a. ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. b. triphosphate monomers are active in the nucleoside triphosphates, but not in ATP. c. the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. d. ATP contains three high-energy bonds; the nucleoside triphosphates have two. e. the nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups.

the nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose.

What is the function of DNA polymerase? a. to add nucleotides to the end of a growing DNA strand b. to unwind the DNA helix during replication c. to degrade damaged DNA molecules d. to seal together the broken ends of DNA strands e. to rejoin the two DNA strands (one new and one old) after replication

to add nucleotides to the end of a growing DNA strand

What is the enzymatic function of restriction enzymes? a. to join nucleotides during replication b. to repair breaks in sugar-phosphate backbones c. to add new nucleotides to the growing strand of DNA d. to cleave nucleic acids at specific sites e. to join nucleotides during transcription

to cleave nucleic acids at specific sites

Which of the following is least related to the other items? a. translation b. RNA polymerase II c. TATA box d. template strand e. transcription

translation

A eukaryotic cell lacking telomerase would a. undergo a reduction in chromosome length. b. be highly sensitive to sunlight. c. produce Okazaki fragments. d. have a high probability of becoming cancerous. e. be unable to repair thymine dimers.

undergo a reduction in chromosome length.