BIOL 5220 Unit 1 Quizzes

How many origins of replication are present in the E. coli genome? 1 2 100 Uncountable

1

Length of Okazaki fragments in eukaryotes ranges between ____________ nucleotides. 100-200 400-800 1000-2000 1200-1600

100-200

A complete DNA polymerase III holoenzyme contains ____________ subunits. 6 17 22 8 None of the above

22

The proofreading function of some DNA polymerases depends on which of the following? 3' to 5' exonuclease activity accurate selection of nucleotides endonuclease degradation 5' to 3 ' exonuclease activity reverse reaction by polymerase "activity" mismatch repair system

3' to 5' exonuclease activity

DNA polymerase moves along the template strand of DNA in the ____ direction and adds nucleotides to the ____ end of the newly synthesized strand. 3' to 5'; 3' 5' to 3'; 5' 5' to 3'; 3' 3' to 5'; 5' 3' to 5': either 3' or 5' depending on the strand it is synthesizing 5' to 3': either 3' or 5' depending on the strand it is synthesizing

3' to 5'; 3'

Cytosine makes up 20% of the nucleotides in a sample of DNA from a cellular organism. Approximately, what percentage of the nucleotides in this sample will be thymine and adenine?

60

Which property (properties) is (are) shared by E. coli DNA polymerase I and DNA polymerase III? Both enzymes require a template Both enzymes require a primer Both enzymes present 5'to 3'exonuclease activity Both enzymes present 3' to 5' exonuclease activity

Both enzymes present 3' to 5' exonuclease activity Both enzymes require a template Both enzymes require a primer

The R group or side chain of the amino acid methionine is -CH2-CH2-S-CH3. The R group or side chain of the amino acid alanine is -CH3. Where would you expect to find these amino acids in a globular protein in an aqueous solution? Both methionine and alanine would be in the interior of a globular protein. Methionine would be in the interior, and alanine would be on the exterior of a globular protein. Alanine would be in the interior, and methionine would be on the exterior of a globular protein. Both methionine and alanine would be on the exterior of a globular protein. Impossible to predict because both Alanine and Methionine could be found either on the exterior or the interior.

Both methionine and alanine would be in the interior of a globular protein.

How does DNA polymerase discriminate between the insertion of correct and incorrect nucleotides as DNA replication proceeds? Correct base paring of template and the incoming dNTP allows for proper positioning of the substrates within the active site. Incorrect nucleotides repel each other because of their charges. Incorrect dNTPs cannot enter the active site If the new "base pair" exhibits improper geometry within the active site the incorrect nucleotide will not be incorporated and will diffuse away.

Correct base paring of template and the incoming dNTP allows for proper positioning of the substrates within the active site. If the new "base pair" exhibits improper geometry within the active site the incorrect nucleotide will not be incorporated and will diffuse away.

Which protein can catalyze the formation of phosphodiester bonds? DNA ligase DnaA protein DnaB protein Tus protein Helicase

DNA Ligase

Which enzyme (s) is/are used to remove the primer from the Okazaki fragment in prokaryotes? Exonuclease DNA Pol I DNA ligase DNA polymerase III Primase

DNA Pol I

A new DNA strand elongates only in the 5' to 3' direction because DNA polymerase can only add nucleotides to the free 3' end. DNA polymerase begins adding nucleotides at the 5' end of the template. RNA primers prevent elongation in the 3' to 5' direction. the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. replication must progress toward the replication fork.

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

A new DNA strand elongates only in the 5' to 3' direction because: DNA polymerase can only add nucleotides to the free 3' end. DNA polymerase begins adding nucleotides at the 5' end of the template. RNA primers prevent elongation in the 3' to 5' direction. the polarity of the DNA molecule prevents addition of nucleotides at the 3' end. replication must progress toward the replication fork.

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

With respect to eukaryotic replication, which of the following proteins are not correctly paired with their function? Pick all that apply DNA polymerase alpha - primase DNA polymerase δ - elongation of DNA leading strand DNA polymerase ε - elongation of DNA lagging strand τ (Tau) protein - connects DNA Polymerase III cores via clamp loader All proteins are correctly paired with their function

DNA polymerase δ - elongation of DNA leading strand DNA polymerase ε - elongation of DNA lagging strand τ (Tau) protein - connects DNA Polymerase III cores via clamp loader

Which of the following is false about nucleosomes? The core is composed of an octamer of 4 different histone proteins. Each core histone is a small negatively charged protein. The function of chromatin may be modulated by acetylation, phosphorylation or methylation of core histones. Each core histone is composed of the histone fold motif and the unstructured amino (N)- terminal domain.

Each core histone is a small negatively charged protein.

Mismatched DNA does not affect the rate of activity of DNA polymerase. True False

False

In an analysis of the nucleotide composition of any double stranded DNA, which of the following is true? G + T = A + C A = G and C = T A + T = G + C A+T/G+C = 1 A=C and G=T

G + T = A + C

Which function can be carried out by DNA replication proteins? Topoisomerases wind the DNA into a double-helix. DNA ligase can initiate new DNA chains SSBs convert double-stranded DNA into single-stranded DNA. Helicases break hydrogen bonds in the DNA. None of the above

Helicases break hydrogen bonds in the DNA.

Which statement is false? There are at least five different classes of histones In eukaryotes, histones are poorly conserved Histones are rich in lysine and arginine residues The 30nm fiber form of chromatin is more compact than the beads on a string form

In eukaryotes, histones are poorly conserved

Which of the following is/are false about DNA replication? Select ALL that apply: In unidirectional replication there is only one replication eye whereas in bidirectional replication there are two. DNA replication of most bacterial genomes is unidirectional. In bidirectional replication both strands are replicated but in unidirectional replication only one strand is replicated. In unidirectional replication there is only one replication fork whereas in bidirectional replication there are two.

In unidirectional replication there is only one replication eye whereas in bidirectional replication there are two. DNA replication of most bacterial genomes is unidirectional. In bidirectional replication both strands are replicated but in unidirectional replication only one strand is replicated.

What must the mismatch repair system be able to distinguish in order to "know" which nucleotide of a mismatched pair to replace? It must be able to distinguish which chain possesses the right sequence. It must be able to distinguish which chain contains more incorrect bases. It must be able to distinguish the newly-made strand from the parental strand. It must be able to distinguish which chain is of the right polarity. It must be able to distinguish the leading strand from the lagging strand

It must be able to distinguish the newly-made strand from the parental strand.

You have discovered a new exo- mutant of DNA polymerase. The enzyme's 3' to 5' exonuclease function has been destroyed but the ability to join nucleotides together is unchanged. Which of the following properties do you expect the mutant polymerase to have? It will polymerase in both the 5' to 3' direction and the 3' to 5' direction It will polymerase more slowly than than the normal exo+ polymerase It will fail off the template more frequently than the normal exo+ polymerase It will be more likely to generate mismatched base pair None of the above

It will be more likely to generate mismatched base pair None of the above

In prokaryotes, DNA helicase travels along _________ Leading strand template in 3'→5' direction Leading strand template in 5'→3' direction Lagging strand template in 3'→5' direction Lagging strand template in 5'→3' direction

Lagging strand template in 5'→3' direction

In Eukaryotes, the selection of the origin of replication is mediated by the formation of pre-replicative complex. It comprises of _________________ ORC and the initiator protein ORC and helicase A helicase loader and a helicase ORC, two helicase loaders and a helicase

ORC, two helicase loaders and a helicase

Statement A. Genetic information in viruses and other gene "creatures" may be in the form of RNA or DNA. Statement B. Genetic information in cellular organisms may be in the form of DNA or RNA. only A is true only B is true both A and B are true both A and B are false

Only A is true

Which is a characteristic of E. coli DNA polymerases? Pol I functions as a holoenzyme that participates in DNA repair. Pol I functions as a core enzyme that clamps around the DNA Pol III functions as a holoenzyme that polymerizes DNA with high processivity. Pol III functions as a single polypeptide chain that can form phosphodiester bonds

Pol III functions as a holoenzyme that polymerizes DNA with high processivity.

What is the difference in the rate of replication (nucleotides added) between prokaryotes and eukaryotes? Eukaryotes are 50 times slower. Eukaryotes are 20 times faster. Prokaryotes are 100 times slower. Prokaryotes are 10 times faster.

Prokaryotes are 10 times faster.

Which of the following combination is a correct observation for the transformation experiment performed by Griffith? S strain (living) + mouse = dead S strain (heat killed) + mouse = dead R strain (living) + mouse = dead S strain (heat killed) + R strain (living) + mouse = living

S strain (living) + mouse = dead

Which of the following is not a function of Dna A? Select ALL that apply DNA binding Expansion of the replication bubble Initiates DNA melting Replication protein recruitment of primer

Synthesis of primer Expansion of the replication bubble

Why does PCR require a specific type of polymerase? Taq polymerase can withstand the range of temperatures in PCR without denaturing. Taq polymerase is the most common type of polymerase. Taq polymerase is the most inexpensive type of polymerase. A specific type of polymerase is unnecessary.

Taq polymerase can withstand the range of temperatures in PCR without denaturing.

Which of the following is false? The double helix of DNA under physiological conditions is usually in the A-form. In a nucleic acid double helix pyrimidine always pairs with a purine. DNA duplex with higher G-C vs A-T content is more stable because it contains more hydrogen bonds. The double helix of DNA under physiological conditions is usually in the B-form. All nucleic acids with complementary sequences can form duplexes.

The double helix of DNA under physiological conditions is usually in the A-form.

Which mechanism (s) contributes to accuracy during DNA replication in E coli? The mismatch repair system recognizes an incorrect base-pair and corrects the mistake. Using primers increases accuracy because the first nucleotides in a new nucleic acid chain are more likely to be correct. The 3'to 5'exonuclease activity of some DNA polymerases which can remove incorrect nucleotides during replication. Shape recognition of the correct base pairs in the active site of DNA Polymerases All of the above

The mismatch repair system recognizes an incorrect base-pair and corrects the mistake. The 3'to 5'exonuclease activity of some DNA polymerases which can remove incorrect nucleotides during replication. Shape recognition of the correct base pairs in the active site of DNA Polymerases

Select all that is true about DNA polymerases structure... The polymerase active site is located in the palm domain The dNTP-binding site is located in the fingers domain The 3'-5' exonuclease activity is located in the thumb domain All of the statements are true. None of the statements is correct

The polymerase active site is located in the palm domain The dNTP-binding site is located in the fingers domain

With respect to the "tails" of the histone molecules, which of the following is not true? They are located in the N -terminal end of the histones They lack defined structure They are required for the association (link) of nucleosomes They are sites for extensive chemical modifications

They are required for the association (link) of nucleosomes

The binding of polymerase III and helicase ensures helicase efficiency. True False

True

The two divalent metal ions of the active site of DNA polymerase are catalytic elements that bring about changes required for the joining of the nucleotides. True False

True

The condensation reaction (also called dehydration synthesis) involving 2 amino acids results in ______________________. Select ALL that apply. a formation of a dipeptide a formation of water molecule a formation of peptide bond a formation of a hydrogen bond a formation of a polypeptide a formation of phosphodiester linkage a formation of ionic bond

a formation of a dipeptide a formation of water molecule a formation of peptide bond

Beta barrel motif can be described as ______________________ a super secondary structure of a protein a tertiary structure of a protein a quaternary structure of a protein a secondary structure of DNA a super-secondary structure of RNA an A or B form of nucleic acid

a super secondary structure of a protein

Where would you most likely find chromatin in the "beads on a string" conformation? Heterochromatin Actively transcribed chromatin Silenced chromatin 30 nm fiber chromatin

actively transcribed heterochromatin

Histone acetylation can disrupt the interaction between adjacent nucleosomes... because acetylated nucleosomes are targeted for degradation because it causes nucleosomes to release the DNA because it prevents histone H1 from forming a bridge between histone H1 in two adjacent nucleosomes. because it prevents the N-terminal tail of histones interacting with the N-terminal tail of histones in the next nucleosome

because it prevents the N-terminal tail of histones interacting with the N-terminal tail of histones in the next nucleosome

How can the transformed cells (having the recombinant DNA) be screened? By selectable markers By bacterial resistance gene For restriction site By ARS sequence

by selectable markers

Which molecules form the sides (backbone) of the DNA? deoxyribose and adenine deoxyribose and nitrogenous bases deoxyribose and a hydrogen bond deoxyribose and phosphate

deoxyribose and phosphate

Okazaki's Fragments are generated on: the leading strand in a 5' to 3' direction the lagging strand in the 5' to 3' direction the lagging strand in the 3' to 5' direction the leading strand in a 3' to 5' direction

he lagging strand in the 5' to 3' direction

Which of the following is not a part of every amino acid? hydroxyl group hydrogen amino group alpha C carboxyl group

hydroxyl group

A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to ampicillin and tetracycline. The plasmid has one recognition site for EcoRI which is located within the gene for ampicillin resistance. This mixture is incubated for several hours, exposed to DNA ligase, and then used to transform bacteria that are susceptible to both ampicillin and tetracycline. The bacteria are grown on nutrient broth media (without antibiotics) and replica plates are made on 4 types of media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth with no antibiotics. Bacteria that do NOT contain any plasmid would grow... in all four types of broth. in the nutrient broth without antibiotics only. only in the broth containing both antibiotics. in the broth containing tetracycline, but not in the broth containing ampicillin. in the nutrient broth plus ampicillin, but not in the broth containing tetracycline.

in the nutrient broth without antibiotics only.

When histone H1 binds to a nucleosome, _______________________ the nucleosome is about to be moved by a remodeling enzyme it means that replication of the DNA has just occurred it increases the probability that condensation of the chromatin will occur into a higher level of packaging it means that the underlying DNA is probably a core promoter

it increases the probability that condensation of the chromatin will occur into a higher level of packaging

Hershey and Chase experiments (1952) using T2 bacteriophages labeled with radioactive sulfur and radioactive phosphorus demonstrated all of the following, except: most of the radioactive phosphorus entered the cells. DNA is the genetic material of T2 phages DNA was injected into bacteria most of the proteins remained on the outer surface of bacteria most of the radioactive sulfur entered bacterial cells

most of the radioactive sulfur entered the bacterial cells

Deoxiibose differs from ribose by having: an extra oxygen. one less oxygen. one less hydrogen. an extra carbon in the ring. an extra hydrogen. one less carbon

one less oxygen

The primary structure of proteins is maintained (held) by peptide bonds phosphodiester bonds hydrogen bonds ionic bonds hydrophobic interactions

peptide bonds

Nucleic acids are polymers of nucleotide units, covalently joined by _____________ bonds. In a nucleotide, the nitrogenous base is linked to the _________ of ribose or deoxyribose, while the phosphate group is liked to the ______ . phosphodiester/ 1 prime carbon/5 prime carbon hydrogen/ 3 prime carbon/ 5 prime carbon phosphodiester/3 prime carbon/ 5 prime carbon hydrogen/ 1 prime carbon/5 prime carbon phosphodiester/ 5 prime carbon/ 1 prime carbon

phosphodiester/ 1 prime carbon/5 prime carbon hydrogen/ 3 prime carbon/ 5 prime carbon

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

pyrimidines; purines

Which of the following is inconsistent with the Central Dogma? Select all that apply. transfer of information into RNA is irreversible information in nucleic acids can be perpetuated information in proteins cannot be perpetuated transfer of information into protein is irreversible

transfer of information into RNA is irreversible

A nucleosome core is composed of: two copies each of histone H2A, H2B, H3 and H4 and 146 bp of DNA. two copies each of histone H2A, H2B, H3 and H4 and 1460 bp of DNA. four copies each of histone H2A, H2B, H3 and H4 and 146 bp of DNA. four copies each of histone H2A, H2B, H3 and H4 and 1460 bp of DNA. one copy of histones H2A, H2B, H3 and H4 and 146 bp of DNA.

two copies each of histone H2A, H2B, H3 and H4 and 146 bp of DNA.

During the initiation of replication in E.coli: DNA polymerases denature A-T rich sequences at the origin replication begins when Dna A protein binds the origin and synthesizes primers. DnaB protein cleaves the double-helix to produce template strands two replication forks need to be created to establish bidirectional replication. All of the above

two replication forks need to be created to establish bidirectional replication.

Which of the following statements is true: DNA polymerase moves along the template strand in the 3' to 5' direction DNA polymerase requires a primer to initiate replication. Polymerization of DNA for both the lagging and the leading strands is in the 5' to 3' direction. All of the above statements are true. None of the above statements are true.

All of the above statements are true.