ch 9

All new DNA strands are synthesized from

5' to 3'.

Guanine and ______ are purine bases found in DNA.

Adenine

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

DNA RNA/mRNA

Which is true regarding DNA replication?

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

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

Where are the chromosomes of yeast cells located?

In the nucleus

HOMEWORK

QUES

Which type of plasmids confer the ability of an organism to survive treatment by antibiotics?

R factors

Which of the following are functions of RNA polymerase?

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

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

anticodon codon

DNA polymerases are responsible for

building the DNA chain. proofreading/repair.

A mutation that causes a change in a single nucleotide in DNA

changes the corresponding nucleotide in mRNA, resulting in a different codon.

In eukaryotic cells, what cellular structure is composed of a neatly packaged DNA molecule?

chromosome

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

competent

A ____ binds to an inactive repressor to make an active repressor.

corepressor

The arginine operon is a repressible system. When arginine accumulates, it acts as a __________ by binding to a repressor protein, thus halting transcription of more arginine biosynthetic genes.

corepressor

Which of the following is NOT a result of transposon activity in bacteria?

correction of ultraviolet radiation mutations

In eukaryotic cells, gene expression is regulated in response to ____ stimuli such as nutrient and toxin levels, and also during growth and _____.

environmental development

True or false: Bacterial conjugation is a sexual process.

false

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

fork

All of the following are methods for detecting mutant bacteria, except __________.

gram staining

The __________ subunit of the ribosome is the site of peptide bond formation.

large

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

leading

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

A ______ is the basic unit of DNA structure.

nucleotide

In a protozoal or fungal cell, chromosomes are located in the ____

nucleus

Two components of an operon include the ______ that acts as an on/off switch, and the ____ gene sequences

operator structural

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

operator structural genes

A(n) __________ is a section of prokaryotic DNA that contains one or more genes along with a corresponding operator to control transcription.

operon

Which process repairs DNA that has been damaged by ultraviolet radiation using visible light?

photoactivation

________ 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

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

redundancy

______ RNA may exert control on several levels in both prokaryotes and eukaryotes.

regulatory

The protein product which binds to the operator to stop transcription is called the ____.

repressor

Retroviruses, such as the human immunodeficiency virus (HIV), carry their genetic information as RNA and convert it to DNA using the enzyme

reverse transcriptase.

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

ribosome

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

semiconservative

In bacteria, as transcription begins the promoter is recognized by the ________ , a subunit of RNA polymerase. Promoter sequences tend to be rich in _______and ________ base pairs, which facilitates opening of the DNA duplex.

sigma factor adenine thymine

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

start

The enzyme __________ is responsible for compacting the DNA molecule in prokaryotes.

topoisomerase

The acceptance by a bacterial cell of small DNA fragments from the surrounding environment is termed __________.

transformation

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

transformation

"Jumping genes" are known as

transposons

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

true

Vancomycin-resistant enterococci (VRE) arise when, through genetic transfer, a MRSA strain acquires the ____ operon located within a ____.

vanA transposon

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

2

Duplication of chromosomes starts at a specific site called the origin of replication. What is the composition of bases normally found at the origin? Why does it make sense for it to be these bases?

The origin of replication is usually rich in adenine and thymine. It makes sense for it to be these bases because they are held together by only two hydrogen bonds and are easier to separate than cytosine and guanine bonds.

Describe the process by which transcription begins in bacteria. How does RNA polymerase know where to start? How does it know where to stop?

Transcription has 3 main stages: initiation, elongation, termination. RNA polymerase starts when it recognizes a gene called the promoter region. The sigma factor then guides the RNA polymerase to its correct position on the promoter. RNA polymerase stops when it recognizes a site on DNA near the end of the gene that signal separation and release of the completed mRNA.

Genetic transfer of ______ to a methicillin-resistant Staphylococcus aureus (MRSA) strain produces vancomycin resistant enterococci (VRE).

a transposon containing the vanA operon