Deck 7: Microbial Genetics

Question 1

In DNA,the base adenine always pairs with what other base?

A) guanine
B) adenine
C) uracil
D) thymine

Answer 1

D

Question 2

Which statement is true?

A) proofreading that occurs during transcription changes the RNA into DNA
B) translation is a less accurate process than transcription
C) reverse transcription is a less accurate process than regular transcription
D) errors in replication can be proofread during transcription

Answer 2

C

Question 3

After DNA replication of a bacterial chromosome,the new DNA contains

A) 2 newly synthesized strands of DNA copied from the original parent strands
B) one strand of parent DNA along with one newly synthesized strand
C) small segments of parent DNA interspersed with newly synthesized segments of DNA
D) two of the above

Answer 3

B

Question 4

Which of the following statements is true?

A) during DNA replication the leading strand serves as a template for replication of the lagging strand
B) fragments on the lagging strand are joined together by ligase
C) a bacterial chromosome is made up of individual units called Okazaki fragments
D) two strands of a double helix combine by base pairing in a parallel fashion

Question 5

A plasmid is a/an:

A) extrachromosomal piece of DNA
B) chromosomal site to which genetic activity can be traced
C) body found in the cytoplasm that directs protein synthesis
D) molecule that carries the genetic message of the chromosomal DNA

Question 6

Transcription results in the formation of what type of new molecule?

A) DNA
B) RNA
C) Protein
D) lipid

Question 7

During replication,DNA is synthesized by

A) DNA polymerase
B) RNA polymerase
C) ribosomes
D) ribozymes

Question 8

Bacterial genomes

A) have rarely been sequenced as it takes a very long time
B) only contain adenine, uracil, cytosine and guanine
C) contain all the information for the structure and functioning of a cell
D) when sequenced 100% of the genes are with known cellular function

Question 9

During DNA replication

A) the leading strand is synthesized in the 3' to 5' direction
B) the leading strand is synthesized discontinuously
C) the lagging strand is synthesized in the 5' to 3' direction
D) both strands are synthesized discontinuously

Question 10

Genes with different information at the same locus are called

A) chromosomes
B) homologs
C) plasmids
D) alleles

Question 11

A linear sequence of DNA nucleotides which provides the genetic information for a single characteristic is a

A) chromosome
B) plasmid
C) gene
D) base pair

Question 12

A permanent alteration in the DNA of an organism is called a/n

A) mutation
B) hereditary marker
C) replicon
D) allele

Question 13

Bacterial chromosomes

A) must be present for bacteria to stay alive and reproduce
B) are small segments of DNA that have the ability to move from one position to another
C) contain genetic information that is helpful but not necessary for survival
D) are always circular and only one is present in each bacteria

Question 14

Reverse transcription takes place

A) only in fungi
B) in some viruses
C) in all bacteria
D) in some bacteria

Question 15

Mutations

A) when occurring on a particular Okazaki fragment can lead to different loci
B) often change a person's blood from type A to type AB
C) are responsible for heritable variations seen in progeny
D) occur only when the DNA is transmitted to a daughter cell

Question 16

The process of ________ results in the synthesis of a new protein.

A) replication
B) transcription
C) translation
D) transversion

Question 17

Okazaki fragments make up

A) part of the small ribosomal subunit
B) part of the tRNA
C) part of the lagging strand of newly synthesized DNA
D) part of the mRNA

Question 18

Replication results in the formation of what type of new molecule?

A) DNA
B) RNA
C) Protein
D) lipid

Question 19

Which nitrogenous base is not normally found in DNA?

A) guanine
B) thymine
C) uracil
D) adenine

Question 20

Reverse transcription occurs when

A) RNA is used as a template to produce DNA
B) DNA is used as a template to produce RNA
C) Protein is used as a template to produce RNA
D) RNA is used as a template to produce protein

Question 21

The information carried by DNA is used to create a ________ which then moves to the ribosome for protein synthesis.

A) tRNA
B) rRNA
C) siRNA
D) mRNA

Question 22

In eukaryotes,transcription takes place in the ________ while translation takes place in the ________.

A) nucleus, nucleus
B) nucleus, cytoplasm
C) cytoplasm, nucleus
D) cytoplasm, cytoplasm

Question 23

Which of the following properties are exclusive to mRNA?

A) combines with specific proteins to form ribosomes
B) carries information from DNA for synthesis of a protein
C) molecules contain an anticodon
D) contains the nucleotide thymine

Question 24

Which of the following properties are exclusive to tRNA?

A) combines with specific proteins to form ribosomes
B) carries information from DNA for synthesis of a protein
C) molecules contain an anticodon
D) contains the nucleotide thymine

Question 25

In the lactose operon,which of the following is a protein?

A) repressor
B) operator
C) regulator
D) promoter

Question 26

Segments of DNA that do not code for proteins

A) are called introns
B) are found in all bacterial genes
C) can be considered by your immune system as enemy DNA
D) bind to proteins to form ribosomes

Question 27

Protein synthesis

A) in bacteria can occur with several ribosomes attached to the same mRNA molecule
B) uses very little of a bacterial cell's energy
C) can occur at the same time as an mRNA is being transcribed
D) two of the above

Question 28

Inducible enzymes

A) are synthesized continuously by the cell
B) are produced by genes that are always active
C) are synthesized by genes that are sometimes active and sometimes inactive
D) only exist in prokaryotic organisms

Question 29

With regard to the lactose operon,which of the following is false under conditions of low (or no)lactose?

A) the RNA polymerase cannot transcribe structural genes
B) the repressor is bound to the operator
C) lactose is not bound to the repressor
D) RNA polymerase can bind to the promoter

Question 30

RNA polymerase uses ________ as a template to synthesize ________.

A) RNA, proteins
B) RNA, DNA
C) DNA, RNA
D) DNA, proteins

Question 31

Amino acids move from the cytoplasm to the ribosome with the help of

A) mRNA's
B) tRNA's
C) siRNA's
D) rRNA's

Question 32

A mRNA molecule can be broken down into three nucleotide units called

A) amino acids
B) bases
C) codons
D) anticodons

Question 33

In the lac operon,RNA polymerase first binds to the

A) promoter
B) operator
C) repressor
D) regulator

Question 34

Which of the following statements about the genetic code is true?

A) the first position of a codon determines the amino acid
B) an amino acid can be specified for by more than one codon
C) nonsense codons contain no information
D) because DNA only contains three letters there are very few possible genes that can exist

Question 35

Which of the following properties are exclusive to rRNA?

A) combines with specific proteins to form ribosomes
B) carries information from DNA for synthesis of a protein
C) molecules contain an anticodon
D) contains the nucleotide thymine

Question 36

When a cell contains high levels of lactose,the lactose will bind with the

A) repressor
B) operator
C) promoter
D) RNA polymerase

Question 37

In an enzyme catalyzed reaction that displays feedback inhibition

A) excess substrate will inhibit the reaction
B) excess product will inhibit the reaction
C) the reaction continues at the same pace regardless of conditions in the cell
D) excess product is broken down to create new substrate

Question 38

tRNA molecules serve as a link between

A) DNA and mRNA
B) codons and anticodons
C) codons and amino acids
D) mRNA and rRNA

Question 39

An anticodon would be found in/on a ________ molecule.

A) mRNA
B) tRNA
C) the lagging strand
D) rRNA

Question 40

Messenger RNA

A) is formed in the 3' to 5' direction
B) is found only in prokaryotes
C) contains uracil instead of thymine
D) is synthesized using the enzyme ligase

Question 41

Microbial evolutionary biologists have provided evidence against Lamarckian evolution,by demonstrating that genetic mutations arise in the absence of selection,rather than being a response to selection. Describe one method for distinguishing between spontaneous and induced mutations (be sure to include the expected results)

Question 42

Photoreactivation

A) repairs dimers in DNA using an endonuclease
B) uses light to activate repair enzymes
C) removes alkylating agents from bases
D) occurs when UV light causes mutations in DNA

Question 43

The fluctuation tests done by Luria and Delbruck showed that

A) antibiotics induce the development of resistance in bacteria
B) the growth of bacteria fluctuates based on the concentration of antibiotics in the media
C) the concentration of antibiotics fluctuates in response to the number of bacteria in a sample
D) resistance to antibiotics occurs spontaneously in bacteria

Question 44

A frameshift mutation occurs when

A) an adenine is inserted into the DNA sequence of an organism
B) a thymine replaces a guanine in the DNA sequence of an organism
C) three new bases are inserted into the DNA strand
D) three bases are deleted from the DNA strand

Question 45

Mutagens such as 5-bromouracil cause mutations by

A) substituting for one of the bases normally found in DNA
B) adding an alkyl group to a nucleotide
C) removing an amino group from a nucleotide
D) causing breaks in chromosomes

Question 46

Polymerase chain reaction

A) allows for the rapid amplification of a billion copies of DNA without needing a living cell
B) can be applied to historic samples and to criminal investigations
C) requires oligonucleotides to cut DNA into smaller pieces
D) two of the above are true

Question 47

________ refers to the specific characteristics displayed by an organism.

A) Genotype
B) Mutation
C) Phenotype
D) Genes

Question 48

Using the lac and trp operons as examples,describe the two control mechanisms for protein synthesis: one based on enzyme induction and the other based on enzyme repression.

Question 49

Pyrimidine dimers are a type of mutation most commonly caused by

A) alkylating agents
B) deaminating agents
C) ultraviolet light
D) acridine

Question 50

A DNA mutation that results in no change in protein product produced is termed a

A) missense mutation
B) nonsense mutation
C) silent mutation
D) frameshift mutation

Question 51

Which statement about mutations is false?

A) a mutation can alter the genotype of an organism without altering the phenotype
B) frameshift mutations are typically more serious than point mutations
C) spontaneous mutations are the result of exposure to mutagens
D) photoreactivation can take place in non-photosynthetic bacteria

Question 52

Organisms that have lost the ability to synthesize a particular enzyme and which require certain nutrients to be added to their medium to maintain growth are termed

A) phototrophs
B) auxotrophs
C) prototrophs
D) autotrophs

Question 53

RNA plays several important roles in the processes that translate genetic information from DNA into protein products. Illustrate the events of transcription in a bacterial cell and indicate where RNA plays a role. Also indicate what role RNA plays in translation in bacterial cells.

Question 54

Spontaneous mutations are

A) caused by chemicals such as acridine and caffeine
B) caused by physical agents such as ultraviolet light or x-rays
C) the result of errors in the base pairing of nucleotides during replication
D) occur at a rate higher than the rate of induced mutations

Question 55

Catabolite repression

A) allows cells to save energy by not making enzymes they don't need
B) doesn't allow for cells to prioritize consumption of multiple substrates
C) allows cell growth to continue even after the preferred nutrient is used up
D) two of the above

Question 56

The Ames test is used to determine if a chemical

A) increases the rate at which a bacterial cell divides
B) decreases the number of cells in a culture
C) induces mutations in a cell's DNA
D) decreases the ability of a cell to photosynthesize

Question 57

The tryptophan (trp)operon is turned on (i.e. gene expression occurs)when

A) there is a great deal of tryptophan in the cell
B) there is a lack of tryptophan in the cell
C) the trp operon is always turned on
D) the trp operon is always turned off