chp 9 prt 2

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

enviromental developmental

What is the name of the specialized plasmid that directs conjugation in gram-negative cells? In bacterial conjugation, a recipient cell having no F (fertility) DNA is considered F-.

f factor

In bacterial conjugation, a donor cell with a F (fertility)--- located in the cytoplasm is considered F+.

factor

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

ongogenic

What is a small circular segment of DNA found in the cytoplasm of prokaryotes that is capable of independent replication and usually contains nonessential genes?

plasmid

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

point

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

mutations

Which type of mutation is due to random mistakes in replication?

spontaneous mutation

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

start

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

t

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

repressor

Which type of RNA is transcribed from a DNA template?

all types of rna

The --- test is used to determine the carcinogenic potential of a chemical

ames

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

Transformation

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

competent

R factors are specifically associated with which mechanism of recombination? in bacteria refers to horizontal gene transmission via pili.

conjugation

During which method of gene transfer are bacterial cells in direct contact? True or false: Bacterial conjugation is a sexual process.

conjugation f

Proteins that remove incorrect bases and replace them with correct ones are termed ______ repair enzymes.

excision

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

f

Conjugation in gram-negative cells is directed by a plasmid called the ---

ferility factor

---- are DNA sequences found within a gene that do not encode the protein corresponding to the gene.

introns

The --- subunit of the ribosome holds tRNAs and catalyzes peptide bond formation by means of a ribozyme.

large

Random portions of host DNA are transferred by bacteriophage during ---transduction.

generalized

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

photoactivation

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

redundancy

The ---- protein is capable of repressing an operon.

regulator

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

regulatory

True or false: R-factors or "resistance factors" can be shared between bacteria through conjugation to help them survive the effects of antibiotics.

t

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 an structural genes

During translation initiation, the ----ribosomal subunit binds to a specific site on the mRNA and places the start codon in correct alignment with the P site.

small

Due to the separation of prophage DNA from the bacterial chromosome, a specific, adjacent part of the host genome is transferred during ---transduction.

specialized

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

spontaneous

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

start

What binds with an inactive repressor to make an active repressor?

copressor

Which occur during posttranslational modification?

Cofactors are added to proteins destined to become enzymes. Proteins join with other proteins to form quaternary structures. Removal of formyl-methionine from the start of the polypeptide chain

In bacterial conjugation, which term refers to a recipient cell that does not have a fertility plasmid?

F-

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

Hfr

Which of the following is the genetic pattern of viral genomes?

Single or double stranded DNA or RNA

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

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

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

anticodon codon

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

mutation

The mechanisms of ---- transformation involve genes that can regulate cellular genomes and control the onset of cell division. Several DNA viruses are known to be initiators of cancers and are thus termed

oncogenic

Alterations to a protein made after translation, such as removal of f-met, addition of cofactors and joining with other proteins for quaternary structure, are referred to as --- modifications.

posttransitional modification

RNA polymerase binds to the --- region to initiate transcription.

promoter

Which recombination method involves transfer of DNA via bacteriophages?

transduction

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

transformation

--- are able to shift from one part of the genome to another. known as jumping genes

transposons

--- 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

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

recombination

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

f