Ch.9

Uracil, the nitrogenous base unique to RNA molecules, pairs with the nitrogenous base ___

Adenine

Which of the following are true of RNA viruses compared to DNA viruses?

Enter host cell in RNA form Smaller genomes Virus cycle occurs in cytoplasm

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: Several codons code for the same amino acid, which is called the redundancy of the code.

True

Transduction occurs through

bacteriophage

Any nitrogen-containing molecule found in DNA and RNA that provides the basis for the genetic code is a nitrogenous ____

base

The three types of RNA are ___RNA, ____RNA, and _____RNA.

mRNA tRNA rRNA

A ___ mutation changes an amino-acid-producing codon into a stop codon, leading to premature termination of a protein.

nonsense

Any alteration in DNA that occurs as a consequence of exposure to chemical or physical mutagens is a(n) mutation.

induced

Transcription of the structural genes of the lac operon will be inhibited when

lactose concentration is low and glucose concentration is high.

Transcription of the structural genes of the lac operon will be greatest when

lactose is present in high concentrations but glucose is absent.

A ___ is the basic unit of DNA structure.

nucleotide

The basic unit of DNA structure is the

nucleotide

Several DNA viruses are known to be initiators of cancers and are thus termed

oncogenic

Which viruses insert their DNA into the host genome increasing the risk of cancer?

Herpesvirus Hepatitis B virus

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

Hfr

Which are components of an operon in a sequence of DNA?

operator structural genes

Gene expression in prokaryotes is regulated through _______.

operons

Prokaryotic DNA is arranged into systems called

operons

The site on a chromosome where DNA replication begins is called the ___ of replication.

origin

The place where DNA replication is initiated is called the ______.

origin of replication

An enzyme that is named for its ability to build strands of DNA is DNA ________.

polymerase

RNA polymerase binds to the ____ region to initiate transcription.

promoter

DNA polymerases are responsible for

proofreading/repair. building the DNA chain.

In DNA, a purine always combines with

pyrimidine

Which of the following types of RNA delivers the amino acids to the growing peptide chain in translation?

tRNA

The region of DNA that signals the end of an RNA transcript is the ____ sequence.

termination

Which best describes the flow of genetic information in a cell?

DNA encodes RNA which encodes protein

Genetic inheritance in microorganisms is best defined by which term?

Heredity

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

Triplet

Which of the following are physical, as opposed to chemical, agents that can cause mutations?

X-rays Ultraviolet light

The _____ , or continuous, strand is replicated without segments during DNA replication

leading

A DNA nucleotide is composed of a(n) , a(n) sugar, and a(n) base.

phosphate deoxyribose nitrogenous

Mutations that involve the addition, deletion or substitution of no more than a few bases are referred to as ___ mutations.

point

DNA _______ is the enzyme responsible for building strands of DNA.

polymerase

Two subunits of the ____ come together to perform protein synthesis.

ribosome

Which type of organisms have their DNA arranged into operons?

Prokaryotes

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

Promoter

The first three events of translation in the correct order are ____ ,_____ ,_____ followed by protein folding and processing.

initiation elongation termination

The newly forming DNA strand that is discontinuously replicated in segments (Okazaki fragments) is called the ___ strand.

lagging

The newly forming DNA strand that is discontinuously replicated in segments (Okazaki fragments) is called the _____ strand.

lagging

The final sealing of nicks in a newly synthesized DNA strand is catalyzed by the enzyme __

ligase

Which of the following types of RNA is the transcribed version of a structural gene in DNA, that is later read for translation into protein?

mRNA

In protein synthesis, eukaryotic and prokaryotic cells show similarities in all of the following EXCEPT the

number of proteins encoded on a single mRNA. use of formyl-methionine as the first amino acid.

A ________ serves as the vector for transduction in bacteria.

phage

Mutations that involve the addition, deletion or substitution of one or a few bases are referred to as _______ mutations.

point

The enzymes responsible for building the DNA strand, proofreading newly produced DNA strands, and removing the RNA primer are DNA ____ I and III.

polymerase

In DNA, adenine pairs with _____ , whereas cytosine pairs with _____

thymine guanine

In DNA, adenine pairs with _____, whereas cytosine pairs with _____

thymine guanine

Which type of RNA comprises ribosomal subunits?

rRNA

Which strand is replicated discontinuously in segments during DNA replication?

The lagging strand only

Which is the correct order of events in transcription?

1. initiation 2. elongation 3. termination

Guanine and ______ are purine bases found in DNA.

Adenine

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

2

In a chromosome, the DNA is composed of ______ strands.

2

DNA polymerase ___ is the enzyme responsible for building the DNA strand.

3

DNA polymerase ______ is the enzyme responsible for building the DNA strand.

3

Nucleotides can only be added to the ____ end of a growing chain.

3

All new DNA strands are synthesized from

5' to 3'

If a codon of mRNA reads 5'-UUG-3', the tRNA that delivers the amino acid to this location during translation will have an anticodon of 3'-_____-5'.

AAC

Which of the following are parts of a nucleotide in DNA?

Phosphate Nitrogenous base Deoxyribose sugar

Genes are made up of ______, a macromolecule made up of nucleotides.

DNA

DNA polymerase ____ is the main enzyme involved in the building of the new DNA chain, whereas DNA polymerase ____ is involved mostly with removing the primers and repairing damaged DNA.

III / I

The enzyme involved in replicating a new DNA strand is DNA polymerase _____, and DNA polymerase _____ is involved in removing the RNA primer, closing gaps, and repairing mismatched bases.

III, I

How does RNA differ from DNA in bacteria and eukaryotes?

In RNA, uracil replaces thymine RNA is single-stranded

Where are the chromosomes of yeast cells located?

In the nucleus

___ operons are usually turned on by the substrate of the enzyme for which the structural genes code.

Inducible

Which type of operon is typically in the "off" position until the appropriate substrate is present?

Inducible operon

Which is the correct order of events when a protein is made in the process of translation?

Initiation, elongation, termination

Which strand is replicated continuously without segments during DNA replication?

Leading

Which enzyme completes the final sealing of nicks in a newly synthesized DNA strand?

Ligase

Which of the following are chemicals that can cause mutations?

Nitrous acid Ethidium bromide Acridine dyes

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

Okazaki

_____ fragments are formed during DNA replication of the lagging strand.

Okazaki

Gram-positive cells conjugate and transfer genetic material through which component?

Proteins activated during cell adhesion

The large enzyme complex involved in synthesizing RNA from a DNA template is called ___ ____

RNA polymerase

The large enzyme complex involved in synthesizing RNA from a DNA template is which of the following?

RNA polymerase

The main enzyme responsible for transcription is

RNA polymerase

Which are parts of the lactose operon?

Structural locus Regulator Control locus

What region of DNA signals the end of a RNA transcript?

Terminator

What is the purpose of the Ames test?

To determine the carcinogenic potential of a chemical

What are the two stages needed for protein synthesis?

Transcription Translation

___ and ____ are the two stages involved in protein synthesis.

Transcription Translation

Which of the following are functions of RNA polymerase?

Unwinds the DNA so that transcription can take place Synthesizes an RNA molecule from DNA template

In RNA, which nitrogenous base pairs with adenine?

Uracil

Unlike DNA, RNA contains the nitrogenous base ___

Uracil

The purine nitrogenous bases found in DNA are guanine and

adenine

The purine nitrogenous bases found in DNA are guanine and _____

adenine

The four nitrogenous bases in DNA are ___ ,_____ ,_____ , and _____.

adenine guanine cytosine thymine

The nitrogenous bases found in DNA include:

adenine, cytosine, guanine, thymine

The ___ of a tRNA is complementary to a ____ of mRNA.

anticodon codon

The ____ of a tRNA is complementary to a ____ of mRNA.

anticodon codon

Plasmids can be found in both ___ and ____ .

bacteria fungi

Plasmids are found in which type(s) of organisms?

bacteria and fungi

DNA polymerase III is responsible for:

building the DNA chain

Viral DNA inserted into the host genome may cause the transformation of the host cell into a ___cell.

cancer

A ____ is a discrete cellular structure composed of a neatly packaged DNA molecule.

chromosome

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

conjugation

Which of the following is NOT a type of RNA?

dRNA

Pentose sugar found in DNA

deoxyribose

Which pentose sugar is found in DNA?

deoxyribose

A nucleotide is oriented 5' or 3' depending on the location of the _______ on the strand of DNA.

deoxyribose carbons

The flow of genetic information in a cell is a process starting with ____ which encodes _____ which encodes protein.

dna rna

The DNA of a chromosome is ____ -stranded.

double

Transcription involves initiation,____ , and termination.

elongation

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

fork

A(n) ______ is a sequence of DNA nucleotides that codes for one functional protein or RNA.

gene

Control mechanisms ensure that _____ are active only when their products are required.

genes

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

genome

During eukaryotic protein synthesis, ______ ribosome(s) are used to translate mRNA that contains ______ gene(s).

many, one

The RNA form that contains the transcribed code for a protein from the original DNA strand is ____ RNA.

messenger

An organism that has a mutation is called a

mutant

The ___________ bases are either purines or pyrimidines.

nitrogenous

The ____ of the genetic code results in several codons encoding the same amino acid.

redundancy

the ___ is the gene that codes for a protein capable of repressing the operon.

regulator

During semiconservative ______ the DNA is duplicated prior to binary fission.

replication

What must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s)?

replication

Retroviruses contain the enzyme

reverse transcriptase

The pentose sugar found in RNA is

ribose

Which pentose sugar is found in RNA?

ribose

RNA virus genomes are usually than DNA virus genomes.

smaller

___ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.

sponetnous

The ___ codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.

start

The ____ codon AUG of mRNA is associated with the tRNA anticodon UAC and the amino acid methionine.

start

The mRNA sequence AUG, specifying the first amino acid in protein sequences, is called the ___ codon.

start

The RNA type that transfers amino acids to the growing peptide chain in translation is ____ RNA.

transfer

During the process of ___ a competent bacterial cell may accept soluble DNA from the surrounding environment.

transformation

The term ___ , or codon, is a sequence of 3 nucleotides in DNA that encodes an amino acid.

triplet

The nitrogenous base thymine is only found in DNA, while _____ is only found in RNA.

uracil

Which nitrogenous base is found in RNA but not found in DNA?

uracil