chapter 9

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

Which enzyme adds nucleoside triphosphates to a growing DNA strand?

DNA polymerase

True or false: A RNA template is a strand of RNA made from DNA.

False

True or false: A cell with an integrated F factor transmits its genes at lower frequency than does a cell with a free plasmid in the cytoplasm.

False

In bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?

Hfr

Which enzyme synthesizes primer sequences during replication initiation?

Primase

________refers to the transfer of genes from donor to recipient microorganisms, where the recipient strain shows a change in genetic makeup at the end.

Recombination

What is the function of mRNA?

Serves as a transcript of a gene sequence of template DNA

Which recombination method involves transfer of DNA via bacteriophages?

Transduction

_____involves the transfer of DNA via bacteriophages.

Transduction

horizontal gene transfer

Transfer of DNA from a source other than the parent organisms

Most bacterial plasmids carry an origin of replication and at most _____ genes.

a few dozen

______in bacteria refers to horizontal gene exchange via pili

conjugation

During conjugation, the donor cell generally retains a copy of the genetic material being transferred. This is termed a _____ process.

conservative

In DNA, the base that pairs with guanine is

cytosine

The science of heredity is called _______.

genetics

A permanent inheritable alteration in the DNA sequence of a cell is a(n)

mutation

Within a nucleotide, the_____ group is linked to the 5' carbon of the pentose sugar.

phosphate

Donor and recipient bacterial cells are connected by the sex ____during conjugation.

pilus or pili

The _____ of the lac operon is a gene that encodes a repressor protein.

regulator

During semiconservative____ the DNA is duplicated prior to binary fission.

replication

A _____ can transcribe DNA into RNA and then back into DNA for insertion in a new genomic location.

retrotransposon

During_____ DNA replication, the newly made double helices are composed of one parent template and one newly synthesized strand.

semiconservative

The antibiotic rifamycin can be used to treat tuberculosis because

the drug is more active against bacterial RNA polymerase than the human enzyme

True or false: The parent strands in a DNA molecule are used as a template to synthesize a complementary strand of DNA.

true

The pyrimidine nitrogenous bases found in DNA are cytosine and

tymine

How many replication forks are formed from opening a section of a circular DNA molecule during replication?

2

Which is the main event of translation termination? tRNA leaves the E site on the ribosome A nonsense codon is reached and the peptide is released from the ribosome A terminator sequence is reached and mRNA is released from the DNA template

A nonsense codon is reached and the peptide is released from the ribosome

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct? The exon-intron junction is recognized by a ribosome. A series of adenosines is added to the mRNA. Transcription occurs after splicing. Splicing to remove introns occurs in the nucleus.

A series of adenosines is added to the mRNA. Splicing to remove introns occurs in the nucleus.

The______ test is a method of detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria.

Ames

Which test is a method of detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria?

Ames

During translation elongation, peptide bonds form between

Amino acids

The genes of which microorganism(s) are arranged as operons?

Bacteria

Which is true regarding adenine and guanine?

Both are purines

A__________is a discrete cellular structure composed of a neatly packaged DNA molecule.

Chromosome

A bacterial cell described as______ can accept soluble DNA from the surrounding environment.

Competent

In the bacterium Escherichia coli, where is the chromosome located?

Cytoplasm

Which is the main enzyme in elongation of a DNA strand during replication?

DNA polymerase

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand

True or false: Bacterial conjugation is a sexual process.

False

True or false: Eukaryotic chromosomes are composed of DNA and RNA.

False

True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells.

False

True or false: Mutations are always harmful to cells.

False

True or false: Okazaki fragments are formed during DNA replication of the leading strand

False

True or false: Operons are found in fungi and helminths.

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False

True or false: The chromosome is a small circular segment of DNA found in the cytoplasm of prokaryotes that is capable of independent replication and usually contains nonessential genes.

False

True or false: Viral genomes are always composed of either single or double-stranded DNA.

False

is the study of the inheritance of living things.

Genetics

Which term represents all of the genetic information within a cell?

Genome

The purine nitrogenous bases found in DNA are adenine and

Guanine

The purine nitrogenous bases found in RNA are adenine and

Guanine

Which is a purine? Uracil Thymine Cytosine Guanine

Guanine

In DNA replication,_______ unwinds the double helix, primase synthesizes the short RNA primer, and DNA_____ adds nucleotides to the new chain.

Helicase polymerase

How does RNA differ from DNA in bacteria and eukaryotes? In RNA, uracil replaces thymine Ribose in RNA contains one less carbon than deoxyribose in DNA. In RNA, thymine is replaced with adenine RNA is single-stranded

In RNA, uracil replaces thymine RNA is single-stranded

Where are the chromosomes of yeast cells located?

In the nucleus

Which strand is replicated discontinuously in segments during DNA replication?

Lagging

Which strand is replicated continuously without segments during DNA replication?

Leading

Which is true regarding bacterial chromosomes? Located in the nucleoid region of the cytoplasm Enclosed in a membrane-bound organelle

Located in the nucleoid region of the cytoplasm

Which two of the following statements regarding plasmids are true? A typical bacterial plasmid will have a few hundred genes. Many bacteria carry plasmids in addition to their chromosome. Plasmids may contain genes that specify resistance to antibiotics. Plasmids are essential for bacterial survival.

Many bacteria carry plasmids in addition to their chromosome. Plasmids may contain genes that specify resistance to antibiotics.

In a protozoal or fungal cell, chromosomes are located in the______

Nucleus

In replication of DNA, the lagging strand is replicated in a discontinuous manner forming______ fragments.

Okazaki

____ ____are areas of the genome containing multiple genes which contribute to a new trait for the organism that increases its ability to cause disease.

Pathogenicity Islands

What are areas of the genome where multiple genes exist that are coordinated to give a new trait and make the bacterium more pathogenic?

Pathogenicity islands

The process of bacteria turning on or off a group of genes that changes its phenotype in a heritable manner is called ____ ___

Phase variation

Phase variation is a type of ________variation.

Phenotypic

In the central dogma, DNA encodes________ which encodes protein.

RNA

The antibiotic rifamycin, used to treat tuberculosis, binds and inhibits the activity of

RNA polymerase

Which enzyme transcribes DNA into RNA?

RNA polymerase

______ _______ is the enzyme that transcribes DNA into RNA.

RNA polymerase

Which is the main event of transcription initiation?

RNA polymerase binds to the DNA promoter.

Which is the main event of transcription termination?

RNA polymerase reaches a terminator region.

Which term refers to the transfer of genes from donor to recipient microorganisms?

Recombination

Which of the following is the genetic pattern of viral genomes? Single or double stranded DNA only Single or double stranded DNA or RNA Single stranded DNA only Double stranded DNA only

Single or double stranded DNA or RNA

Which two statements regarding eukaryotic transcription and RNA processing are correct? A series of thymines is added to the mRNA. The exon-intron junction is recognized by a spliceosome. Splicing to remove introns occurs in the cytoplasm. Transcription occurs before splicing.

The exon-intron junction is recognized by a spliceosome. Transcription occurs before splicing.

Which is a nitrogenous base found in DNA?

Thymine

vertical gene transfer

Transfer of DNA from parent organisms during reproduction

Which gene transfer method involves the uptake of free DNA by competent bacterial cells? Transformation Transduction Transposition Conjugation

Transformation

Which of the following are methods of gene transfer in bacteria? Transformation Transduction Translation Transcription Conjugation

Transformation Transduction Conjugation

_____ are capable of moving from one genomic location to another, including from one site in the chromosome to another site on the same chromosome.

Transposable elements

Which term, synonymous with codon, describes a trinucleotide sequence coding an amino acid in DNA?

Triplet

True or false: A bacterial cell described as competent can accept soluble DNA from the surrounding environment.

True

True or false: A mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.

True

True or false: A phage is a bacterial virus.

True

True or false: DNA replication must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s).

True

True or false: The structure of DNA is essential for providing variety since the order of nucleotides is responsible for the unique qualities of each organism.

True

True or false: Within a nucleotide, the phosphate group is linked to the 5' carbon of the pentose sugar.

True

In RNA, which nitrogenous base pairs with adenine?

Uracil

The pyrimidine nitrogenous bases found in RNA are cytosine and_____

Uracil

Unlike DNA, RNA contains the nitrogenous base_____

Uracil

The regulator of the lac operon is a gene that encodes

a repressor protein

The arginine operon is "on" when the cell is

actively growing

The purine nitrogenous bases found in DNA are guanine and_____

adenine

The purine nitrogenous bases found in RNA are guanine and

adenine

A nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a nitrogenous______

base

The genes of the lac operon in E. coli encode enzymes that

catabolize lactose

A(n)_______ is the specific sequence of 3 mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid.

codon

Donor and recipient bacterial cells are connected by the sex pilus during___

conjugation

The pyrimidine nitrogenous bases found in DNA are thymine and____

cytosine

DNA repair enzymes have as their substrate

damaged DNA

Ensuring that the DNA code will be maintained during cell growth and cell______ is one of the two essential effects of the structure of DNA.

division, replication, or reproduction

Most DNA damage is resolved by

enzymes

The structural locus of the lac operon has genes that encode an operator and promoter RNA polymerase enzymes to catabolize lactose the lac repressor protein

enzymes to catabolize lactose

A spontaneous mutation arises in DNA from

errors in DNA replication

The replication________ is the Y-shaped point on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNA.

fork

In _____ transduction, random fragments of host DNA are taken up by the bacteriophage during assembly.

generalized

The complete set of chromosomes and genes in an organism is referred to as the_______

genome

Select the enzymes that function in DNA replication. helicase DNA polymerase RNA polymerase reverse transcriptase ligase

helicase DNA polymerase ligase

___ gene transfer occurs when organisms acquire genes which did not come directly from parent organisms.

horizontal

The enzyme β-galactosidase, encoded in the lac operon, has an enzymatic activity to

hydrolyze lactose

The lac operon in E. coli regulates the metabolism of_______

lactose

A mutation that leads to cell death is termed a _____ mutation.

lethal

________is a copy of the DNA template corresponding to a protein-encoding gene.

mRNA

A small number of____ are considered beneficial in that they provide the cell with a useful change in structure or physiology.

mutations

A mutation that produced neither adverse nor helpful changes is termed a _____ mutation.

neutral

A nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a(n) ______.

nitrogenous base

The ______ DNA strand is the strand that is not directly used for transcription into mRNA during protein synthesis.

nontemplate

Building blocks of DNA, called______ , contain the same sugar and phosphate, but different nitrogenous bases.

nucleotides

When a cell is actively growing, the arg operon is _____, and arginine is _____.

on; actively synthesized

The _____ of the lac operon is a region of DNA that acts as an on/off switch for transcription.

operator

A_______ is a bacterial virus.

phage

A______ is a small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes.

plasmid

A mutation that affects only a single base pair in DNA is termed a _____ mutation.

point

A mutation that affects only a single base pair in DNA is termed a mutation.

point

During replication initiation, the enzyme______ synthesizes primer sequences.

primase

RNA polymerase binds to the_____ region of the DNA to initiate transcription.

promoter

RNA polymerase binds to the______ region to initiate transcription.

promoter

The _____ of the lac operon is a region of DNA that is recognized by RNA polymerase.

promoter

RNA polymerase binds to which region of DNA to begin transcription?

promotor

In _____ transduction, a particular part of the host genome is included in the virus.

specialized

Mutations that occur because of errors in DNA replication are termed

spontaneous

The _____ of the lac operon is comprised of three genes, each encoding a different enzyme needed to catabolize lactose.

structural locus

An insertion sequence consists of only two genetic elements: antibiotic resistance genes tandem repeats pathogenicity island origin of replication DNA encoding enzymes for transposition promoter

tandem repeats DNA encoding enzymes for transposition

The parent strands in a DNA molecule are used as_____ a to synthesize a complementary strand of DNA.

template

he ______ DNA contains the order of nucleotides that are transcribed into RNA.

template

The process of transcription ______ results in the release of a completed RNA transcript.

termination

Transposable elements are capable of moving from _____. a spliceosome to a plasmid the chromosome to a plasmid one site in the chromosome to another site in the chromosome a plasmid to the ribosome a plasmid to the chromosome

the chromosome to a plasmid one site in the chromosome to another site in the chromosome a plasmid to the chromosome

Conjugation is a conservative process, meaning that

the donor retains a copy of the genetic material being transferred

How do an Hfr cell and an F+ cell differ?

the plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell

All DNA nucleotides contain:

the same sugar and phosphate, but different nitrogenous bases

A codon contains how many nucleotides?

three

A retrotransposon can

transcribe DNA into RNA and then back into DNA for transposition

In general, a strand of RNA made from DNA is called an RNA______

transcript

The process of introducing foreign genes to a plant cell by adding the DNA directly to the cell medium is termed

transfection

The process of introducing foreign genes to a yeast cell by adding the DNA directly to the cell medium is termed

transfection

Conjugation,________ , and transduction are methods of gene transfer in bacteria.

transformation

______involves the uptake of free DNA by competent bacterial cells.

transformation

The enzyme lactose permease, encoded in the lac operon, has an enzymatic activity to

transport lactose

An insertion sequence is a type of

transposon

"Jumping genes" or ________, are insertion sequences that can lead to changes in genotype within a cell or between cells.

transposons

The term__________ is a sequence of 3 consecutive nucleotide bases in DNA that encodes an amino acid.

triplet