Deck 7: Genomes and Chromosomes

Question 1

Enzymes that synthesize DNA or RNA can synthesize in a __________ direction.

A) forward
B) 3'-to-5'
C) 5'-to-3'
D) reverse
E) 5'-to-3' or 3'-to-5'

Answer 1

C

Question 2

__________ are bicyclic bases and __________ are monocyclic.

A) Pyrimidines; purines
B) Adenines; guanines
C) Thymines; cytosines
D) Thymines; uracils
E) Purines; pyrimidines

Answer 2

E

Question 3

Supercoiling in bacteria is typically introduced by an enzyme called:

A) gyrase
B) helicase
C) ligase
D) polymerase
E) endonuclease

Answer 3

A

Question 4

The semiconservative mechanism of replication provides for each daughter duplex to be checked for __________, based on its parent strand.

A) pseudogenes
B) introns
C) plasmids
D) redundancy
E) accuracy

Question 5

The intestinal bacterium __________ was the initial focus of efforts to understand genes and genetics.

A) Salmonella enterica
B) Escherichia coli
C) Staphylococcus aureus
D) Mycoplasma genitalium
E) Streptococcus pneumoniae

Question 6

In a test tube at chromosome-packing density, DNA is almost a:

A) solid
B) gel
C) gas
D) liquid
E) plasma

Question 7

Gene transfer from parent to child is called:

A) expression
B) horizontal transmission
C) vertical transmission
D) transformation
E) recombination

Question 8

The smallest cellular genomes identified thus far are those of:

A) E. coli
B) Staphylococcus
C) Streptococcus
D) Mycoplasma
E) yeast

Question 9

The lagging strand is synthesized __________ , while the leading strand can be synthesized __________.

A) continuously; discontinuously
B) discontinuously; continuously
C) 5'-to-3'; 3'-to-5'
D) 3'-to-5'; 5'-to-3'
E) quickly; slowly

Question 10

A nucleoid gently released from E. coli appears as 30-100 tightly wound loops, each defined by anchoring:

A) histones
B) histone-like proteins
C) supercoils
D) gyrase
E) topoisomerase

Question 11

It takes approximately how many minutes to move the entire E. coli chromosome from one cell to another?

A) 10
B) 20
C) 30
D) 100
E) 500

Question 12

The thermal stability of the helix is predominantly due to the __________ of the hydrophobic base pairs.

A) attraction
B) binding
C) repulsion and hydrogen bonding
D) stacking and hydrogen bonding
E) transformation

Question 13

__________ allowed genes to be mapped relative to each other based on the time of transfer.

A) Transformation
B) Transduction
C) Conjugation
D) Polycistrons
E) Polymerase chain reaction

Question 14

Hyperthermophilic archaea possess an unusual gyrase called __________, which introduces positive supercoils into the chromosome in order to protect the DNA from __________.

A) DNA ligase; thermal denaturation
B) DNA helicase; thermal denaturation
C) reverse DNA gyrase; excessive gene expression
D) reverse DNA gyrase; thermal denaturation
E) reverse transcriptase; excessive gene expression

Question 15

The nucleoids of bacteria and most archaea, as well as the nuclear DNA of eukaryotes, are kept __________ supercoiled.

A) positively
B) neutrally
C) negatively
D) reverse
E) extra

Question 16

Bacteria are capable of __________ transmission-the transfer of genetic information from one cell to another.

A) vertical
B) horizontal
C) recombination
D) transformation
E) pseudogene

Question 17

Intestinal microbes contain __________ times more genes than the human genome?

A) 10
B) 20
C) 50
D) 100
E) 1,000

Question 18

__________ in the DNA helix provide DNA-binding proteins access to base sequences buried in the center of the molecule, so that proteins can interact with the bases without the strands being separated.

A) Cohesive ends
B) Grooves
C) Nicks
D) Attractions
E) Repulsions

Question 19

Which of the following is NOT true about the two strands of DNA in a double helix?

A) The base pairs of one strand interact with the base pairs of the other.
B) They are antiparallel.
C) They are complementary.
D) They have equal amounts of adenine and guanine.
E) They have base-stacking interactions.

Question 20

Bacteria and archaea growing at extreme pH or temperature protect their DNA from denaturation through the use of:

A) pseudogenes
B) Okazaki fragments
C) DNA-binding proteins
D) introns
E) ligase

Question 21

__________ is an enzyme that may have evolved from ancient progenitor cells with an RNA genome. It functions as a __________.

A) Primase; helicase
B) Primase; reverse transcriptase
C) Telomerase; helicase
D) Telomerase; reverse transcriptase
E) Telomerase; methylator and acetylator

Question 22

The primer in DNA replication is:

A) an RNA primer with a free 3' OH group
B) an RNA primer with a free 5' OH group
C) a DNA primer with a free 3' OH group
D) a DNA primer with a free 5' OH group
E) a telomere with a free 5' phosphate

Question 23

Plasmids have a high probability of being present in the new generation of cells by all of the following EXCEPT:

A) being present at a high number so that some copies will end up in each new cell after cell division
B) encoding traits such as antibiotic resistance that are required for growth in some environments
C) having replicative processes that are not tied to replication of the chromosome
D) using actin-like ParM filament to bind to ParR-parC complexes on the plasmid
E) carrying host survival genes and self-preservation genes

Question 24

Which of the following is NOT true of DNA replication in E. coli?

A) DnaA triggers initiation
B) It is bidirectional.
C) One new strand is synthesized discontinuously.
D) It is conservative.
E) Synthesis occurs in the 5'-to-3' direction.

Question 25

Which of the following is NOT involved in the replication termination process?

A) ter sites
B) DNA ligase
C) XerC
D) XerD
E) specific sequences called dif

Question 26

Initiation of DNA replication is controlled by DNA __________ and by the binding of a specific initiator protein to the origin sequence.

A) restriction
B) ligase
C) helicase
D) methylation
E) gyrase

Question 27

When the chromosome replicates, how is the newly made strand related to its template strand?

A) The two strands have identical sequences and are parallel to each other.
B) The two strands have complementary sequences and are parallel to each other.
C) The two strands have identical sequences and are antiparallel to each other.
D) The two strands have complementary sequences and are antiparallel to each other.
E) The two strands have identical sequences and are antiparallel to each other, except that U replaces T.

Question 28

Archaea resemble eukaryotes in all of the following EXCEPT:

A) nuclear membrane
B) DNA-packing proteins
C) RNA polymerase
D) ribosomal components
E) DNA polymerase

Question 29

Accidental errors during replication are corrected by the DNA proofreading activity intrinsic to:

A) DNA polI
B) DNA polII
C) DNA polIII
D) DNA polIV
E) DNA polV

Question 30

Eukaryotic chromosomes are __________, contained within a nucleus, and their separation into the two cells involves the process of __________.

A) linear; meiosis
B) linear; mitosis
C) circular; mitosis
D) circular; meiosis
E) circular; rolling circle

Question 31

Which of the following terms refers to gene duplications that have decayed into nonfunctional entities?

A) introns
B) contigs
C) orthologs
D) pseudogenes
E) Okazaki fragments

Question 32

Which of the following is NOT true of plasmids?

A) They are found in archaea.
B) They are found in bacteria.
C) They are found in eukaryotes.
D) They are not supercoiled.
E) They are usually circular.

Question 33

Which of the following is NOT true about histones?

A) They are rich in arginine and lysine.
B) They bind to negatively charged DNA.
C) They are positively charged.
D) They are used to control expression of bacterial operons.
E) They form units with DNA called nucleosomes.

Question 34

Okazaki fragments in E. coli are approximately how many bases in length?

A) 10
B) 50
C) 100
D) 1,000
E) 2,000

Question 35

__________ is a process that involves cell-to-cell contact to move the plasmid from a donor cell to a recipient cell.

A) Transformation
B) Transduction
C) Pseudogene
D) Conjugation
E) Transposon

Question 36

__________ and __________ are noncoding sequences that make up a large portion of eukaryotic chromosomes.

A) Exons; introns
B) Bacteriophages; plasmids
C) Plasmids; introns
D) Introns; pseudogenes
E) Pseudogenes; bacteriophages

Question 37

Which molecule is responsible for removing torsional stress during DNA replication?

A) DNA primase
B) single-stranded binding protein
C) RNase H
D) DNA gyrase
E) DNA ligase

Question 38

What type of bonds does DNA polymerase form?

A) aminoacyl bonds
B) peptide bonds
C) phosphodiester bonds
D) hydrogen bonds
E) disulfide bonds

Question 39

Two kinds of extragenomic DNA molecules are __________ and the genomes of __________.

A) bacteriophages; pseudogenes
B) introns; bacteriophages
C) plasmids; bacteriophages
D) plasmids; introns
E) introns; exons

Question 40

The sliding clamp is used to __________ and is loaded by ___________.

A) open the helix; clamp loader complex
B) open the helix; DNA polIII
C) tether the polymerase to the chromosome; clamp loader complex
D) tether the polymerase to the chromosome; DNA polI
E) tether the polymerase to the chromosome; DNA primase

Question 41

Explain how understanding topoisomerases has helped healthcare.

Question 42

Agarose gel electrophoresis separates pieces of linear DNA based on:

A) size
B) charge
C) sequence
D) supercoiling
E) methylation

Question 43

Describe how the name of a gene and its gene product are denoted.

Question 44

Which of the following is NOT a palindrome?

A) toot
B) rotor
C) racecar
D) radar
E) toto

Question 45

The Sanger method of DNA sequencing involves __________ that bring about chain termination.

A) 2' deoxyribonucleotides
B) 3' deoxyribonucleotides
C) 2', 3' dideoxyribonucleotides
D) 2' deoxyadenosine
E) 3' dideoxyadenosine

Question 46

Pyrosequencing has aided in the understanding of:

A) uses for polymerase chain reaction
B) the expression of the LacZ genes
C) use of plasmids in both the hospital and in the research arena
D) colony collapse disorder and genomes of possible pathogens present in collapsed hives that may be a cause of the problem
E) development of fluorescent labels for chain termination

Question 47

When E. coli was lysed and its chromosome released, researchers found that it was 1,500 times as long as the cell. List three questions that emerge from this finding.

Question 48

Pieces of DNA that have been cut with restriction enzymes can then be "grafted" together using the enzyme:

A) DNA gyrase
B) DNA ligase
C) DNA primase
D) RNA polymerase
E) reverse transcriptase

Question 49

What is the correct order of the steps in a cycle of PCR?

A) annealing, denaturation, extension
B) denaturation, extension, annealing
C) extension, annealing, denaturation
D) denaturation, annealing, extension
E) annealing, extension, denaturation

Question 50

DNA contains structural genes and control sequences. Describe each.

Question 51

A genome is referred to by its length. If a genome is said to be 5 kb, what does that mean? If it were 5 kb, what would that tell you?

Question 52

What determines when DNA replication begins?

Question 53

What role does lysozyme play when isolating DNA?

A) dissolves the cell membranes
B) degrades the peptidoglycan cell wall
C) precipitates the proteins in a high-salt solution
D) elutes DNA from the DNA-binding column
E) performs alcohol precipitation of DNA

Question 54

Differentiate between topoisomerase type I and topoisomerase type II. What is the role they play in bacterial chromosome structure?

Question 55

In the early days of cloning, DNA was __________ into E. coli and then could be transferred to another organism using a __________.

A) conjugated; contig
B) conjugated; shuttle vector
C) transformed; shuttle vector
D) transformed; contig
E) transformed; polymerase chain reaction

Question 56

Describe the similarities and differences between DNA and RNA.

Question 57

Describe the role of the two RNA polymerases that are involved early on in the DNA replication process.

Question 58

__________ naturally function to cut the DNA of invading plasmids and phages at specific points.

A) Topoisomerases
B) Restriction endonucleases
C) Ligases
D) Polymerases
E) Gyrases

Question 59

The ability of cohesive ends of DNA from different organisms to __________ forms the basis of recombinant DNA technology.

A) be methylated
B) be cut
C) base-pair
D) repel
E) be sequenced

Question 60

It takes 40 minutes for E. coli chromosome replication but only 20 minutes for cell division. How is this possible?

Question 61

Describe two ways that the study of bacteria and their processes has led to the development of molecular biology and revolutionized genetics.

Question 62

How are archaeal genomes similar to both bacterial and eukaryotic genomes?

Question 63

How has the study of metagenomics allowed discovery of so many new species? How is it possible to know about these organisms without being able to grow them in a laboratory?

Question 64

Humans have an immune system that can distinguish self from nonself. How is the bacterial restriction-modification system similar?

Question 65

Describe how pyrosequencing led to an understanding of colony collapse disorder in bees. Why is traditional Sanger sequencing not sufficient for this task?

Question 66

Describe the role that DNA Pol I plays in replication.

Question 67

How can plasmids ensure that they are passed on from one generation to the next?

Question 68

In addition to primases and polymerases, name three other proteins required for initiation of and elongation during replication. Describe their functions.

Question 69

Describe three functions of DNA polymerase III.

Question 70

Why is replication of the lagging DNA strand a problem, and how is this problem overcome?