Deck 9: Microbial Genetics

Question 1

Eukaryotic chromosomes differ from bacterial chromosomes because only eukaryotes have

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

Answer 1

E

Question 2

Each nucleotide is composed of

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

Answer 2

A

Question 3

Base pairs in DNA are held together by ______ bonds.

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

Answer 3

D

Question 4

The expression of genetic traits is referred to as the organism's ______.

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

Question 5

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 6

A ______ is a specific segment of DNA that codes for the production of one functional product.

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

Question 7

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

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

Question 8

Which is incorrect about purines?

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

Question 9

A nucleosome is a linear chromosome wound around the _______.

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

Question 10

Structural genes code for

A) ribosomal RNA molecules.
B) transfer RNA molecules.
C) cellular proteins.
D) gene expression elements.

Question 11

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 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

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.

Question 14

The DNA of an organism is made up of subunits called _______.

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

Question 15

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

Question 16

Microorganisms exhibit genomes contained on

A) chromosomes.
B) plasmids.
C) mitochondrial DNA.
D) chloroplast DNA.
E) All of the choices are correct depending on the type of microorganism observed.

Question 17

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

A) It contains structural genes that code for proteins.
B) It has regulatory genes that control gene expression.
C) It contains genes that code for RNA.
D) It is inherited.
E) It has expressed traits governed by the genes.

Question 18

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 that 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 19

The duplication of a cell's DNA is called _______.

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

Question 20

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 21

Helicase ______.

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

Question 22

Which of the following is not a type of microRNA?

A) tRNA
B) miRNA
C) Antisense RNA
D) Riboswitch
E) siRNA

Question 23

RNA polymerase binds to the

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

Question 24

The three-base sequence on DNA that codes for an amino acid is called a/an ________.

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

Question 25

Replication of DNA begins at a/an _______ rich area.

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

Question 26

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 the choices are correct.

Question 27

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 28

DNA Polymerase I

A) removes primers.
B) adds bases to new DNA chain.
C) seals DNA gaps.
D) proofreads DNA chain.

Question 29

DNA Polymerase III

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

Question 30

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 31

The enzyme that can proofread replicating DNA,detect incorrect bases,excise them,and correctly replace them is _______.

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

Question 32

Which molecule is translated into an amino acid sequence?

A) Ribosomal RNA
B) Messenger RNA
C) Transfer RNA
D) Primer RNA
E) Ribozymes

Question 33

A permanent,inheritable change in the genetic information is called ________.

A) translation
B) transcription
C) a mutation
D) an alteration
E) regeneration

Question 34

Which of the following is incorrect about transfer RNA?

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

Question 35

If a codon for alanine is GCA,then the anticodon is ______.

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

Question 36

DNA gyrase

A) copies DNA bases.
B) synthesizes RNA primers.
C) closes gaps between DNA bases.
D) removes supercoiling ahead of origin.

Question 37

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 38

All of the following pertain to transcription except

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

Question 39

A primer comprised of _______ is needed at the origin of nucleotide addition.

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

Question 40

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 41

Which of the following is incorrect about termination codons?

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

Question 42

A sequence of bases within a gene that does not code for protein is called a/n _______.

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

Question 43

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 44

Which of the following is not associated with a bacterial ribosome?

A) It is a 70s holoenzyme.
B) It has a peptide (P) site.
C) It has an exit site.
D) Its small subunit provides the enzymes for making peptide bonds.
E) It has an amino acid (A) site.

Question 45

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 46

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 47

Repressible operons require that ______ binds 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 48

Which is incorrect about inducible operons?

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

Question 49

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

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

Question 50

The most serious type of mutation is a ______ mutation.

A) point
B) silent
C) frameshift
D) back

Question 51

The operon segment composed of the gene that codes for a protein repressor is called the ________.

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

Question 52

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 53

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 54

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) Point
B) Nonsense
C) Insertion
D) Deletion
E) Silent

Question 55

The following pertain to ribosomes during protein synthesis except

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

Question 56

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 57

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 58

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 59

Full induction of the lactose operon requires

A) lactose present.
B) lactose and glucose present.
C) lactose present without glucose.
D) lactose and arabinose present.

Question 60

Split genes

A) are common in bacteria 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) are acted upon by spliceosomes to excise introns and then join exons.

Question 61

Bacterial conjugation involves

A) a bacteriophage carrying donor DNA to the recipient cell.
B) a donor cell with a plasmid that synthesizes a pilus.
C) naked DNA fragments from a lysed donor cell taken up by a recipient cell.
D) new progeny cells with genes from two parent bacterial cells.

Question 62

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

Question 63

Which of the following is not true of transposons?

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

Question 64

Which cell can transfer the most DNA?

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

Question 65

Hfr transfer involves all of the following except

A) gene integration into the bacterial chromosome.
B) independent plasmid 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 66

The jumping of a gene from one location to another is done by ________.

A) conjugation
B) transposons
C) transformation
D) transduction
E) transmission

Question 67

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) Involves the action of bacteriophage
E) The donor retains a copy of the transferred genes

Question 68

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

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

Question 69

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.

Question 70

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 71

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.Which microbial process had Griffith identified?

A) Transduction
B) Conjugation
C) Transformation
D) Cloning

Question 72

The process in which mutations are removed and the correct bases added is called ________.

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

Question 73

Transcription occurs within the nucleus or at the nucleoid.

Question 74

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

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

Question 75

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

A) Transformation
B) Conjugation
C) Mitosis
D) Transduction

Question 76

In bacteria,initiator tRNA carries formyl methionine.

Question 77

The smallest unit of heredity is a chromosome.

Question 78

DNA replication proceeds in one direction around the bacterial chromosome.

Question 79

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 80

The development of virulent,toxin-producing bacterial strains due to the presence of a temperate phage can occur through the process of ________.

A) bacterial conjugation
B) transformation
C) generalized transduction
D) specialized transduction