Deck 9: Microbial Genetics

Question 1

Base pairs in DNA are held together by _____ bonds.

A) peptide
B) nonpolar covalent
C) polar covalent
D) hydrogen
E) sulfhydryl

Answer 1

D

Question 2

Each _____ is a specific segment of the DNA with the code for production of one functional product.

A) intron
B) exon
C) gene
D) operator
E) triplet

Answer 2

C

Question 3

During replication, each parent DNA strand serves as a _____ for synthesis of new DNA strands.

A) copy point
B) template
C) comparison molecule
D) scaffold
E) reservoir

Answer 3

B

Question 4

The antiparallel arrangement within DNA molecules refers to

A) each base bonding at the 1'position of the sugar.
B) a purine always bonding to a pyrimidine.
C) one helix strand that runs from the 5'to 3'direction and the other strand runs from the 3'to 5'direction.
D) an original parent DNA strand and one newly synthesized DNA strand comprising a new DNA molecule.

Question 5

The expression of genetic traits is the

A) genome.
B) genotype.
C) proteome.
D) phenotype.
E) proteotype.

Question 6

The duplication of a cell's DNA is called

A) mitosis.
B) replication.
C) transcription.
D) translation.
E) mutation.

Question 7

Structural genes code for

A) ribosomal RNA molecules.
B) transfer RNA molecules.
C) cellular proteins.
D) gene expression elements.
E) All of these choices are correct.

Question 8

All of the following pertain to nitrogenous bases except

A) they form pairs by hydrogen bonding.
B) guanine pairs with uracil.
C) adenine pairs with thymine.
D) cytosine and thymine are pyrimidines.
E) they allow variation from one nucleotide to another which creates the encoded information.

Question 9

The _____ is all of the genetic material of a cell.

A) chromosome
B) plid
C) prophage
D) genome
E) proteome

Question 10

Each nucleotide is composed of

A) one phosphate, one nitrogenous base, one sugar.
B) one phosphate, one nitrogenous base, two sugars.
C) two phosphates, one nitrogenous base, one sugar.
D) two phosphates, one nitrogenous base, two sugars.
E) one phosphate, two nitrogenous bases, one sugar.

Question 11

A nucleosome is a linear chromosome wound around the

A) nuclear membrane.
B) rRNA.
C) mRNA.
D) histone.
E) nucleolus.

Question 12

The enzyme that helps pack DNA into the cell by coiling the DNA into a tight bundle is

A) DNA ligase.
B) DNA polymerase.
C) DNA helicase.
D) DNA gyrase.
E) primase.

Question 13

Which of the following is not true of an organism's genotype?

A) The genotype is inherited.
B) The genotype is made up of structural genes coding for proteins.
C) The genotype includes genes coding for RNA.
D) The genotype includes regulatory genes controlling gene expression.
E) The genotype includes the expressed traits governed by the genes.

Question 14

Among the microorganisms, various genomes can include

A) chromosomes.
B) plids.
C) mitochondrial DNA.
D) chloroplast DNA.
E) All of these choices are correct.

Question 15

The DNA of microorganisms is made up of subunits called

A) histones.
B) amino acids.
C) nucleotides.
D) mRNA.
E) polymerases.

Question 16

Okazaki fragments are attached to the growing end of the lagging strand by

A) DNA ligase.
B) DNA polymerase.
C) DNA helicase.
D) DNA gyrase.
E) primase.

Question 17

Semiconservative replication refers to

A) each base bonding at the 1'position of the sugar.
B) a purine always bonding to a pyrimidine.
C) one helix strand that runs from the 5'to 3'direction and the other strand runs from the 3'to 5'direction.
D) an original parent DNA strand and one newly synthesized DNA strand comprising a new DNA molecule.

Question 18

Which is incorrect about purines?

A) Purines are only found in DNA, not in RNA.
B) Purines are nitrogenous bases.
C) Purines are always paired with a specific pyrimidine.
D) Purines include adenine and guanine.
E) Purines are found within nucleotides.

Question 19

Eukaryotic chromosomes differ from prokaryotic chromosomes because only eukaryotes have

A) histone proteins.
B) chromosomes in a nucleus.
C) several to many chromosomes.
D) elongated linear, not circular, chromosomes.
E) All of these choices are correct.

Question 20

DNA polymerase III

A) is needed for adding nucleotides during mRNA synthesis.
B) synthesizes new DNA only in the 5'to 3'direction.
C) cannot add nucleotides to the lagging strand.
D) synthesizes an RNA primer.
E) All of these choices are correct.

Question 21

The site where the old DNA strands separate and new DNA strands will be synthesized is called the

A) primer.
B) Okazaki fragment.
C) template.
D) rolling circle.
E) replication fork.

Question 22

DNA gyrase

A) unwinds DNA.
B) supercoils DNA.
C) cleaves DNA.
D) joins free DNA ends.

Question 23

A permanent, inheritable change in the genetic information is called an)

A) translation.
B) transcription.
C) mutation.
D) alteration.
E) regeneration.

Question 24

Replication of DNA begins at an)

A) guanine-cytosine rich area.
B) uracil-adenine rich area.
C) adenine-thymine rich area.
D) adenine-cytosine rich area.
E) guanine-adenine rich area.

Question 25

RNA molecules differ from DNA molecules because only RNA

A) has ribose.
B) has uracil.
C) is typically one strand of nucleotides.
D) does not have thymine.
E) All of these choices are correct.

Question 26

The three-base sequence on DNA that codes for an amino acid is called an)

A) codon.
B) exon.
C) anticodon.
D) intron.
E) triplet.

Question 27

DNA polymerase I

A) removes primers.
B) adds bases to new DNA chain.
C) seals DNA gaps.
D) proofreads DNA chain.
E) All of these choices are correct,

Question 28

What molecule is synthesized as a copy of a gene from the DNA template strand?

A) ribosomal RNA
B) messenger RNA
C) transfer RNA
D) primer RNA
E) ribozymes

Question 29

The following pertain to ribosomes during protein synthesis except

A) they contain codons within their rRNA molecules.
B) ribosomes participate only in translation.
C) ribosomes bind to the 5'end of mRNA by their small subunit.
D) ribosomes use their large subunit to supply enzymes for peptide bonding.
E) ribosomes shift toward the 3'end of the mRNA strand from one codon to the next.

Question 30

If a codon for alanine is GCA. What is the anticodon?

A) GCA
B) CGT
C) ACG
D) CGU
E) UGC

Question 31

Helicase

A) unwinds DNA.
B) supercoils DNA.
C) unwinds RNA.
D) winds RNA.

Question 32

RNA polymerase binds to the

A) start codon.
B) termination sequence.
C) regulation sequence.
D) promoter sequence.

Question 33

A primer of ____ is needed at the origin of nucleotide addition.

A) polymerase III
B) polymerase I
C) helicase
D) RNA
E) DNA

Question 34

Groups of three consecutive bases along the DNA of a gene have the code for one

A) protein.
B) nucleotide.
C) amino acid.
D) purine.

Question 35

All of the following pertain to transcription except

A) occurs on a ribosome in the cytopl.
B) occurs before translation.
C) requires RNA polymerase.
D) requires a template DNA strand.
E) is a process of protein synthesis.

Question 36

DNA polymerase III

A) synthesizes primer.
B) removes primer.
C) joins Okazaki fragments.
D) unzips the DNA helix.
E) proofreads new DNA.

Question 37

Which of the following is incorrect about transfer RNA?

A) has a bottom hairpin loop with an anticodon
B) An anticodon is complementary to a codon.
C) contains a binding site for an amino acid
D) The initiator tRNA that binds to the P site has the anticodon UAC.
E) Initiator tRNA in bacteria carries tryptophan.

Question 38

The nontranscribed region of DNA to which RNA polymerase binds to initiate transcription is called the

A) promoter.
B) operator.
C) operon.
D) exon.
E) intron.

Question 39

The RNA molecules that carry amino acids to the ribosomes during protein synthesis are called

A) ribosomal RNA.
B) messenger RNA.
C) transfer RNA.
D) primer RNA.
E) ribozymes.

Question 40

The enzyme that can proofreads replicating DNA, detects incorrect bases, excises them, and correctly replaces them is

A) DNA ligase.
B) DNA polymerase.
C) DNA helicase.
D) DNA gyrase.
E) primase.

Question 41

Gene regulation can involve a protein repressor that blocks _____ from initiating transcription.

A) DNA polymerase I
B) DNA polymerase III
C) RNA polymerase
D) mRNA
E) rRNA

Question 42

Which of the following is incorrect about termination codons?

A) They are also called nonsense codons.
B) They occur where the bond between the final tRNA and the growing polypeptide is broken.
C) Termination codons include AUG.
D) Termination codons include UAA, UAG, UGA.
E) Termination codons do not have corresponding tRNA.

Question 43

What type of mutation alters the base, but not the amino acid being coded for?

A) silent
B) back
C) point
D) nonsense
E) missense

Question 44

A screening system called the _____ test is used for detecting chemicals with carcinogenic potential.

A) Koch
B) Ames
C) mutation
D) cancer
E) Iowa

Question 45

Synthesis of a repressible enzyme is inhibited by

A) repressor alone bound to operator.
B) substrate bound to repressor.
C) substrate bound to promoter.
D) corepressor and repressor binding to operator.

Question 46

Synthesis of an inducible enzyme requires

A) repressor alone bound to operator.
B) substrate bound to repressor.
C) substrate bound to promoter.
D) corepressor and repressor binding to operator.

Question 47

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT, what type of mutation would change the sequence to THE CAT ATE THE BAG RAT?

A) missense
B) nonsense
C) insertion
D) deletion
E) silent

Question 48

A frameshift is caused by ______ mutations?

A) missense and insertion
B) missense and nonsense
C) nonsense and deletion
D) deletion and insertion
E) insertion and nonsense

Question 49

Which of the following is not true of the prokaryotic ribosome?

A) Prokaryotic ribosomes are 70S.
B) A prokaryotic ribosome has a peptide P) site.
C) A prokaryotic ribosome has an exit E) site.
D) The small subunit provides the enzymes for making peptide bonds.
E) The prokaryotic ribosome has an amino acyl A) site.

Question 50

The most damaging type of mutation is a

A) point mutation.
B) silent mutation.
C) frameshift mutation.
D) back mutation.
E) All the choices are equally damaging.

Question 51

Split genes

A) are common in prokaryotes and eukaryotes.
B) only have exons initially transcribed to mRNA.
C) have introns located only at the beginning and end of a coding region.
D) require spliceosomes to excise introns and then join exons.
E) All of these choices are correct.

Question 52

Repressible operons require that _____ bind to the repressor protein before it can bind to the operator.

A) the product
B) a cofactor
C) a coenzyme
D) the substrate
E) the reactant

Question 53

A mutation that changes a normal codon to a stop codon is called a

A) point mutation.
B) silent mutation.
C) back mutation.
D) missense mutation.
E) nonsense mutation.

Question 54

The gene of an operon that codes for a protein repressor is called the

A) operator.
B) structural locus.
C) regulator.
D) promoter.

Question 55

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT, what type of mutation would change the sequence to THE CAT ATA ETH EBI GRA T?

A) missense
B) nonsense
C) insertion
D) deletion
E) silent

Question 56

A sequence of bases within a gene that will be transcribed, but removed from the transcript prior to translation is a/an

A) promoter.
B) operator.
C) operon.
D) exon.
E) intron.

Question 57

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT, what type of mutation would change the sequence to THE CAT ATE stop)?

A) Missense
B) Nonsense
C) Insertion
D) Deletion
E) Silent

Question 58

Full induction of the lactose operon requires

A) that lactose be present.
B) that lactose and glucose both be present.
C) that lactose be present without glucose.
D) that lactose and arabinose both be present.
E) All of these choices induce the lactose operon.

Question 59

The lactose repressor

A) is transcribed with the structural lac genes.
B) is activated by binding lactose.
C) is inactivated by binding lactose.
D) requires lactose for its transcription.

Question 60

Which is incorrect about inducible operons?

A) have genes turned off by a buildup of end product
B) often encode enzymes for catabolic pathways
C) are normally turned off
D) are turned on by the substrate of the enzyme
E) include the lac operon

Question 61

In bacteria, initiator tRNA carries formyl methionine.

Question 62

Genes that jump from one location to another in the genome are

A) repressors.
B) transposons.
C) transformers.
D) plids.
E) operons.

Question 63

The development of virulent, toxin-producing bacterial strains due to the presence of a temperate phage can occur in

A) bacterial conjugation.
B) transformation.
C) generalized transduction.
D) specialized transduction.
E) All of these choices are correct.

Question 64

Which of the following is not true of transposons?

A) can change pigmentation
B) can replace damaged DNA
C) can transfer drug resistance
D) can change the genome
E) are always part of plids

Question 65

Introns have no detectable functions.

Question 66

DNA replication proceeds in one direction around the bacterial chromosome.

Question 67

The transfer of DNA fragments from a dead cell to a live, competent recipient cell that results in a changed recipient cell is

A) transduction.
B) conjugation.
C) transformation.
D) transmission.
E) mitosis.

Question 68

Which cell can transfer the most DNA?

A) F⁺ cell
B) F^-cell
C) Hfr cell
D) R cell
E) B cell

Question 69

The smallest unit of heredity is a chromosome.

Question 70

Bacterial conjugation involves

A) bacteriophage carrying donor DNA to the recipient cell.
B) a donor cell that transfers a copy of a plid to a recipient cell through a pilus.
C) the take-up of naked DNA fragments from a lysed donor cell by a recipient cell.
D) new progeny cells with genes from two parent bacterial cells.

Question 71

A bacteriophage transfers DNA of the previous host to the current host. This is an example of

A) conjugation.
B) generalized transduction.
C) specialized transduction.
D) creation of an Hfr cell.

Question 72

Of the following list, which antibiotics affect protein synthesis?

A) penicillin
B) tetracycline
C) chloramphenicol
D) ciprofloxacin
E) Both tetracycline and chloramphenicol are correct.

Question 73

In Griffith's experiments with Streptococcus pneumoniae, rough nonencapsulated Streptococci were converted into smooth encapsulated Streptococci in the presence of the heat-killed smooth encapsulated Streptococci. What is the term that describes this process?

A) transduction
B) conjugation
C) transformation
D) cloning

Question 74

Which of the following is not a type of bacterial DNA recombination?

A) transformation
B) conjugation
C) mitosis
D) transduction

Question 75

The process in which mutations are removed and replaced with the correct bases is called

A) transduction.
B) excision repair.
C) frameshift.
D) back mutation.
E) transformation.

Question 76

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

Question 77

Hfr transfer involves all of the following except

A) gene integration into the bacterial chromosome.
B) plid gene transfer.
C) F factor is part of the F⁺ donor chromosome.
D) high frequency transfer.
E) a pilus connection between F⁺ and F^- cells.

Question 78

Transcription occurs in the nucleus or at the nucleoid.

Question 79

Which of the following additions have been made to principles of the central dogma of biology?

A) DNA information cannot be converted into RNA information.
B) Protein information can be converted into DNA information.
C) RNA can be used to regulate gene function.
D) DNA codes for proteins.
E) All of these choices are correct.

Question 80

Which of the following is not true of conjugation?

A) involves direct contact between cells
B) transfers genes for drug resistance
C) transfers genes for enzymes and adherence molecules
D) transfers genes for a polysaccharide capsule
E) The donor retains a copy of the transferred genes.