Microbiology Chapter 9 study questions

Transcription is characterized by... a. a messenger RNA molecule synthesized from the DNA molecule in the nucleus. b. a transfer RNA molecule synthesized from the DNA molecule in the nucleus. c. a ribosomal RNA molecule synthesized from the DNA molecule in the nucleus. d. the blueprint of the RNA molecule used to bind amino acids together to form proteins. e. the binding of enzymes to their substrates to produce products.

...

A structural gene encodes the information for a specific protein. a. true b. false

A

A transposon can move from the host DNA to a plasmid. a. true b. false

A

A(n) _______ is a section of prokaryotic DNA that contains one or more genes along with a corresponding operator to control transcription. a. operon b. promoter c. transposon d. repressor

A

After DNA replication two identical DNA molecules are formed. a. true b. false

A

All viruses require the use of host cell ribosomes and host cell tRNA to translate viral mRNA into viral proteins. a. true b. false

A

An operon is a group of genes that is under the control of a singe operator site. a. true b. false

A

An uncharged tRNA is one that is not carrying an amino acid. a. true b. false

A

Asymmetrical spacing of the backbones of the DNA double helix generates major and minor grooves. a. true b. false

A

DNA is the blueprint that indicates which kinds of proteins to make and how to make them. a. true b. false

A

DNA mutations are passed on to a cells progeny a. true b. false

A

DNA photolyase is a light-sensitive enzyme able to repair DNA damaged by ultraviolet radiation. a. true b. false

A

Doubled-stranded DNA consists of two antiparallel strands, meaning that one strand is oriented in the 5' to 3' direction, while the other is oriented in the 3' to 5' direction. a. true b. false

A

Plasmids are small pieces of DNA that may carry genetic information for antibiotic resistance. a. true b. false

A

Random change in the DNA arising from errors in replication that occur without a known cause a. spontaneous mutation b. induced mutation c. substitution mutation d. frameshift mutation

A

Random fragments of disintegrating host DNA are taken up by the phage during assembly a. generalized transduction b. specialized transduction

A

Sometimes a piece of bacterial DNA near the specific site of insertion stays attached to the phage DNA, and a piece of phage DNA remains behind. a. true b. false

A

The DNA replication machinery is assembled at the replication fork. a. true b. false

A

The RNA transcript being produced by the RNA polymerase is complementary to the template strand of the DNA. a. true b. false

A

The amino acid sequence of a protein determines its shape and specific function. a. true b. false

A

The enzyme that travels along the leading strand assembling new nucleotides on a growing new strand of DNA is... a. DNA polymerase b. DNA ligase c. RNA primase d. DNA polymerase III e. helicase

A

The genetic material in bacteria is a. double-stranded DNA b. double-stranded RNA c. single-stranded DNA d. single-stranded RNA e. either A or B

A

The host cell DNA enters into the genome of the recipient cell by the process of recombination. a. true b. false

A

The lac operon is normally in an off mode and does not initiate enzyme synthesis when the appropriate substrate is absent. a. true b. false

A

The lac repressor protein is active in the absence of lactose within the cell. a. true b. false

A

The lambda phage DNA always integrates into the host DNA in the same specific site. a. true b. false

A

The large ribosomal subunit joins the translation initiation complex after the small subunit has already joined. a. true b. false

A

The polycistronic mRNA is transcribed from the lac operon when lactose is present in the cell. a. true b. false

A

Transcribed version of a structural gene or genes in DNA a. messenger RNA b. transfer RNA c. ribosomal RNA

A

Translation is terminated when a stop codon is presented at the a. A site b. P site c. E site d. either the A or P site e. either the A or E site

A

Translation termination concludes with the dissociation of the two ribosomal subunits and mRNA from each other. a. true b. false

A

Translocation is promoted by the elongation factor EF-G. a. true b. false

A

When one bacterium donates DNA to another bacterium, a type of genetic recombination known as _________ has occurred. a. horizontal gene transfer b. transportation c. sexual reproduction d. vertical gene transfer

A

Which of the following combinations are correctly matched? a. 70s- ribosome b. anticodon-mRNA c. codon-tRNA d. A and B e. A, B, and C

A

Which of the following statements about tRNA is TRUE? a. No tRNA can recognize a stop codon. b. Only one tRNA can recognize a stop codon. c. Some but not all tRNAs can recognize a stop codon. d. All tRNAs can recognize a stop codon, but they do so rarely. e. All tRNAs can recognize a stop codon, and they do so all the time.

A

a mutation that changes a single nucleotide can result in a different amino acid being added into a protein a. true b. false

A

dsDNA virus a. herpesvirus b. HIV c. poliovirus

A

A mutation that causes a change in a single nucleotide in DNA a. will have no effect on the resulting protein b. changes the corresponding nucleotide in mRNA, resulting in a different codon c. causes the codon to be correct, but the anticodon to be incorrect d. causes protein synthesis to stop

B

A transposon enters a bacterial cell by a bacteriophage. a. true b. false

B

Before DNA replication can occur, the OH bonds between the strands must be broken. a. true b. false

B

Codons are found on tRNA, and anticodons are found on mRNA. a. true b. false

B

Contains the anticodon and an amino acid binding site a. messenger RNA b. transfer RNA c. ribosomal RNA

B

DNA pol III can initiate DNA synthesis. a. true b. false

B

DNA replication does not require a template. a. true b. false

B

DNA replication in bacteria begins at a. a single origin and proceeds in one direction b. a single origin and proceeds in both directions c. two origins and proceeds in both directions d. many origins and proceeds in one direction e. many origins and proceeds in one direction

B

DNA replication is said to be a. dispersive b. semi-conservative c. conservative d. liberal e. inconclusive

B

DNA replication is said to be a. dispersive b. semi-conservative c. conservative d. liberal e. none of the above

B

During DNA replication, the lagging strand is synthesized continuously, while the leading strand is synthesized discontinuously. a. ture b. false

B

During translation elongation, amino acids are brought to the ribosome with the help of a. EF-T b. EF-Tu c. EF-Ts d. EF-Tm e. EF-Tz

B

Elongation of the polypeptide chain is terminated when a stop codon enters the P site of the ribosome. a. true b. false

B

Genetic ______ and the variations they produce result in population changes and thus, evolution. a. regulation b. mutation c. operons d. translations

B

Highly specific part of the host genome is regularly incorporated into the virus a. generalized transduction b. specialized transduction

B

If IF1 is not present, elongation would not occur. a. true b. false

B

In DNA replication a. both strands replicate in the same direction b. each strand replicates in a different direction c. only one strand of DNA is used as a template d. a single strand of DNA is copied to make two single strands of DNA

B

In a repressible operon, excess product acts as a corepressor to increase transcription of the operon. a. true b. false

B

In the presence of tryptophan, transcription of the trp operon is on. a. true b. false

B

In the process of specialized transduction a. all the genes of the first bacterial host are transferred to the second bacterial host by a phage b. only a few specific genes from one bacterial cell are transferred to the second bacterial host by a phage c. only a few specific genes from the bacteriophage are transferred to the second bacterial host by a phage d. the phage lyses the recipient bacterium

B

In transduction, the DNA is being moved between the two cells by ______. a. a third bacterial cell b. a phage c. transposons d. all of the above

B

In transduction, the recombinant cell will always have the same genotype as the original recipient cell. a. true b. false

B

Initial attachment of the transcription enzyme to the gene, results in a structure termed the closed complex. a. true b. false

B

One DNA strand is used as the template to make two new strands of DNA. a. true b. false

B

RNA primers are removed by the action of the enzyme a. DNA polymerase III b. DNA polymerase I c. primase d. helicase e. phophodiesterase

B

Result from exposure to known mutagens, which are primarily physical or chemical agents that damage DNA a. spontaneous mutation b. induced mutation c. substitution mutation d. frameshift mutation

B

Short lengths of RNA called ________ have the ability to control the expression of certain genes. a. messenger RNA (mRNA) b. small interfering RNA (siRNA) c. ribosomal RNA (rRNA) d. transfer RNA (tRNA)

B

The acceptance by a bacterial cell of small DNA fragments from the surrounding environment is termed ________. a. transposition b. transformation c. conjugation d. transduction

B

The bacterial chromosome is linear. a. true b. false

B

The completed polypeptide is released from the tRNA that is in the E site. a. true b. false

B

The correct structure of DNA components can be presented as a. phosphate-base-sugar. b. phosphate-sugar-base. c. base-phosphate-sugar. d. phosphate-sugar-phosphate-base. e. base-sugar-phosphate-base.

B

The donor chromosome is transferred as... a. a plasmid b. single stranded DNA c. double stranded DNA d. single stranded RNA e. double stranded RNA

B

The entire genome of the donor cell is usually transferred to the recipient cell. a. true b. false

B

The enzyme that accomplishes transcription is termed a. DNA polymerase b. RNA polymerase c. DNA ligase d. RNA ligase e. RNA replicase

B

The initiation factors IF2 and IF3 use the energy of ATP to link the ribosomal subunits. a. true b. false

B

The lac repressor binds to what site within the lac operon? a. lacZ b. lacO c. lacA d. lacl e. lacP

B

The newly-synthesized strand of DNA has exactly the same base sequence as that of its template strand. a. true b. false

B

The pilus is found on both the donor and recipient cells. a. true b. false

B

The products of protein synthesis are exclusively enzymes and enzyme products. a. true b. false

B

The sequence for protein synthesis is translation, then transcription. a. true b. false

B

The sex pilus is found on the F- cell. a. true b. false

B

The terminator of a gene is located upstream of the coding region. a. true b. false

B

The transcription enzyme first attaches to the ________ of the gene. a. coding region b. promoter c. operator d. regulator e. initiator

B

To allow simultaneous replication of the leading and lagging strands by dimeric DNA pol III, the DNA of the leading strand has to be folded. a. true b. false

B

Transformation is a mode of genetic recombination in which a plasmid is transferred from a donor cell to a recipient cell via a direct connection. a. true b. false

B

Unwinding of the DNA during transcription is the result of the activity of a helicase enzyme downstream of the RNA polymerase. a. true b. false

B

Which of the following best describes transcription? a. DNA--DNA b. DNA--RNA c. DNA--Protein d. RNA--DNA e. RNA--Protein

B

Which of the following binds to the initiation complex first? a. IF2 b. IF3 c. initiator tRNA d. large ribosomal subunit

B

Which of the following is a true statement concerning protein synthesis? a. translation occurs in the nucleus and transcription occurs in the cytoplasm. b. transcription occurs in the nucleus and translation occurs in the cytoplasm. c. translation occurs in the nucleus and transcription occurs in the mitochondria. d. transcription occurs in the nucleus and translation occurs in the mitochondria. e. for every RNA produced, there is an enzyme or enzyme product produced.

B

Which of the following is correct regarding sigma factor? a. it is involved in the termination of replication b. it recognizes the promoter region c. it forms an open complex d. it forms mRNA e. none of the above are correct

B

Which of the following occurs first in transcription? a. action of the Rho protein b. formation of a holoenzyme c. formation of an open complex d. formation of a closed complex e. elongation of the mRNA

B

Which of the following terms best describes a bacteria that has had its genotype changed by transduction? a. recipient cell b. recombinant cell c. host cell d. transducing phage

B

retrovirus a. herpesvirus b. HIV c. poliovirus

B

the ______ is the sum total of genetic material in a cell a. heredity b. genome c. genetics d. phenotype

B

According to Chargaff's rule, which of the following statements about double-stranded DNA is NOT true? a. A=T and C=G b. A+G=T+C c. A+T=C+G

C

After a tautomeric shift in adenine a. adenine bonds with thymine b. adenine bonds with urasil c. adenine bonds with cytosine d. adenine is unable to bond with any molecule

C

Arrange the following proteins in the proper order in which they participate in DNA replication. 1 = Primase 2 = Helicase 3 = Single-strand binding proteins 4 = DNA polymerase I a. 1,2,3,4 b. 1,3,2,4 c. 2,3,1,4 d. 2,3,4,1 e. 2,4,3,1

C

Changing of single base in the DNA code that may result in the placement of a different amino acid a. spontaneous mutation b. induced mutation c. substitution mutation d. frameshift mutation

C

DNA replication begins at a specific site called the a. initiator b. start codon c. origin d. promoter e. replicator

C

During bacterial conjugation, plasmid replication occurs in a. the donor only b. the recipient only c. both the donor and recipient d. either the donor or the recipient, but not both e. neither the donor nor the recipient

C

F+ refers to a cell containing... a. a single strand of DNA b. a double strand of DNA c. the F plasmid d. any plasmid e. a functional strand of DNA

C

Forms a complex cellular structure that contributes to the process of translation a. messenger RNA b. transfer RNA c. ribosomal RNA

C

Nucleotides are the building blocks of a, DNA only b. RNA only c. both DNA and RNA d. neither DNA nor RNA e. cells

C

The Rho protein is involved in the _____ stage of transcription. a. initiation b. elongation c. termination d. none of the above

C

The protein that promotes translation termination is called a. terminator b. polypeptidase c. release factor d. doomsday factor e. X facto

C

Which of the following DNA sequences is complementary to 5' TAGAC 3'? a. 5' TAGAC 3' b. 5' ATCTG 3' c. 5' GTCTA 3' d. 5' CAGAT 3' e. none of the above

C

Which of the following occurs as the ribosome shifts down the mRNA by a distance of one codon? a. the tRNA that was in the A site picks up another amino acid b. the tRNA that was in the A site releases the growing polypeptide chain c. the tRNA that was in the A site moves into the P site d. the tRNA that was in the P site moves into the A site e. the tRNA that was in the P site picks up another amino acid

C

ssRNA virus a. herpesvirus b. HIV c. poliovirus

C

A certain polypeptide is 100 amino acids in length. During translation of this polypeptide, how many amino acids entered through the A site of the ribosome? a. 1 b. 9 c. 50 d. 99 e. 100

D

A transducing phage contains _________. a. no DNA b. only viral DNA c. host cell DNA d. only mRNA

D

Addition or deletion of bases that changes the reading of mRNA codons a. spontaneous mutation b. induced mutation c. substitution mutation d. frameshift mutation

D

HFr refers to a cell that has... a. integrated the F plasmid into its cytoplasm. b. integrated the F plasmid into its cell wall. c. integrated the F plasmid into its sex pilus. d. integrated the F plasmid into its genome. e. refused to integrate the F plasmid into the cell.

D

In eukaryotic cells, what cellular structure is composed of a neatly packaged DNA molecule? a. gene b. genome c. genotype d. chromosome e. histone

D

In specialized transduction a. any random bacterial gene can be transduced b. only genes on a plasmid can be transduced c. only phage genes near the site of the recipient bacteria integration site can be transduced d. only bacterial genes near the site of integration of the phage DNA can be transduced

D

Semiconservative replication of DNA means a. only one strand is used as a template b. a double-stranded DNA is split into two single-stranded DNAs c. only half the genes are copied into the new cells d. each DNA made contains one old strand and one new strand on DNA

D

The Shine-Dalgarno sequence is found on the ________. a. small ribosomal subunit b. large ribosomal subunit c. initiator tRNA d. mRNA e. IF3

D

Translation is characterized by... a. a messenger RNA molecule synthesized from the DNA molecule in the nucleus. b. a transfer RNA molecule synthesized from the DNA molecule in the nucleus. c. a ribosomal RNA molecule synthesized from the DNA molecule in the nucleus. d. the blueprint of the RNA molecule used to bind amino acids together to form proteins. e. the binding of enzymes to their substrates to produce products.

D

When the defective phage enters a. a new bacterial cell only phage DNA integrates into the chromosome of the new host cell b. only bacterial DNA from the previous bacterial host integrates into the chromosome of the new host cell c. both phage DNA and bacterial d. DNA integrate into the chromosome of the new cell host e. the DNA is destroyed

D

Which of the following DNA molecules is the most stable? a. CTGCATAC GACGTATG b. GAAATTTC CTTTAAAG c. AGTCGAAT TCAGCTTA d. GCGTGCAC CGCACGTG e. GGATCCTG CCTAGGAC

D

Which of the following does NOT occur during bacterial conjugation? a. direct contact between donor and recipient cells b. shortening of the pilus c. enzymatic cleavage of one strand at the origin of transfer d. unidirectional transfer of both DNA strands e. recipient cell becomes a donor cell after conjugation

D

Which of the following is NOT a result of transposon activity in bacteria? a. changes in traits such as colony morphology, pigmentation, and antigenic characteristics b. replacement of damaged DNA c. transfer of drug resistance in bacteria d. correction of ultraviolet radiation mutations

D

Which of the following is a characteristic of double-stranded DNA? a. 2 nanometers in width b. 10 base pairs per turn c. 0.34 nanometers per basepair d. All of these are characteristic of DNA.

D

Which of the following is not involved in the initiation of translation? a. mRNA b. ribosomal subunits c. initiator tRNA d. RNA polymerase e. all of the above are involved

D

Which of the following is not part of the lac operon? a. lacO b. lacZ c. lacA d. lacl e. lacP

D

Which of the following is not true about transposons? a. they are capable of shifting from one cell to another b. they can move into the host genome c. they can move from one site in the host genome to another site d. is able to leave the host genome via a vector e. replicate themselves before moving

D

Which of the following is required to replicate the lagging strand of DNA? a. okazaki fragments b. primase c. DNA ligase d. all of these are required

D

Which of the following statements about peptidyl transferase is TRUE? a. it catalyzes the formation of peptide bonds b. it is present in the 50S ribosome subunit c. it is an enzyme d. all of these are true

D

in a tautomeric shift a. it is always adenine that is changed b. final bonding of nucleotides remain unchanged c. adenine is changed so it can no longer form base pairs d. hydrogen atoms move to form a base with altered hydrogen properties e. carbon atoms move to form a base with altered properties

D

transposons are... a. segments of messenger RNA b. transposable elements c. plasmids d. segments of DNA e. segments of transfer RNA

D

Before the lagging strand can begin assembling new DNA nucleotides, which of the following must occur? a. DNA polymerase III adds deoxyribonucleotides. b. DNA polymerase I removes some material and replaces it with DNA. c. OH bonds must be broken between the two strands of DNA. d. DNA ligase forms a phosphodiester bond between the 3' OH of the growing strand and the 5' phosphate in front of it. e. RNA primase constructs a short RNA primer.

E

If one donor cell is mixed with 20 recipient cells, eventually ________ cells will become donors. a. 2 b. 5 c. 10 d. 15 e. 20

E

In the absence of tryptophan, the trp repressor is a. active and can bind to the operator. b. active and cannot bind to the operator. c. inactive and cannot bind to the promoter. d. inactive and can bind to the operator. e. inactive and cannot bind to the operator.

E

In the presence of tryptophan, tryptophan binds to the a. operator b. promoter c. RNA polymerase d. trp genes e. trp repressor

E

The enzyme that unwinds a segment of the DNA molecule is... a. DNA polymerase b. DNA ligase c. RNA primase d. DNA polymerase III e. helicase

E

The lac repressor is inactivated by binding to which of the following? a. lactose b. betagalactosidase c. transcription factors d. glucose e. allolactose

E

The trp operon consists of ________ structural genes. a. one b. two c. three d. four e. five

E

Which of the following best describes translation? a. DNA--DNA b. DNA--RNA c. DNA--Protein d. RNA--DNA e. RNA--Protein

E

Which of the following is NOT a nitrogen base found in DNA? a. adenine b. cytosine c. guanine d. thymine e. uracil

E

Which of the following occurs as a result of translocation? a. the tRNA that was in the A site moves into the E site b. the tRNA that was in the P site moves into the A site c. the tRNA that was in the E site moves into the P site d. the tRNA that was in the E site moves into the A site e. the tRNA that was in the P site moves into the E site

E

transposons are... a. transported by transduction b. transported by a sex pilus c. transported by conjugation d. transported by bacteriophages e. transported by plasmids

E