chapter 9 learnsmart

Which is the main event of translation termination?

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

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

RNA polymerase

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

Recombination

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

catabolize lactose

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

mutations

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

triplet

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct?

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

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

Which two of the following statements regarding plasmids are true?

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

In the central dogma, DNA encodes ___ which encodes protein.

RNA

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 of the following is the genetic pattern of viral genomes?

Single or double stranded DNA or RNA

Which of the following are methods of gene transfer in bacteria?

Transduction Conjugation Transformation

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

a few dozen

The arginine operon is "on" when the cell is

actively growing

The science of heredity is ______.

genetics

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

genome

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

mutation

Phase variation is a type of __ variation.

phenotypic

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

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

replication

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

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

Bacteria

in bacteria refers to horizontal gene exchange via pili.

Conjugation

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

Genome

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

Unlike DNA, RNA contains the nitrogenous base .

Uracil

True or false: Mutations are always harmful to cells.

false

The lac operon in E. coli regulates the metabolism of

lactose

All DNA nucleotides contain ______.

the same sugar and phosphate, but different nitrogenous bases

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

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

Which two statements regarding eukaryotic transcription and RNA processing are correct?

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

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

point

is the study of the inheritance of living things.

Genetics

Conjugation is a conservative process, meaning that

the donor retains a copy of the genetic material being transferred

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

on; actively synthesized

The antibiotic rifamycin can be used to treat tuberculosis because

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

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

Most DNA damage is resolved by

enzymes

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

True or false: Bacterial conjugation is a sexual process.

False

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

False

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

amest

During translation elongation, peptide bonds form between:

Amino acids

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

False

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

Horizontal

How does RNA differ from DNA in bacteria and eukaryotes?

In RNA, uracil replaces thymine RNA is single-stranded

Which enzyme transcribes DNA into RNA?

RNA polymerase

is the enzyme that transcribes DNA into RNA.

RNA polymerases

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

Triplet

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

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

conjugation

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

conservative

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

A spontaneous mutation arises in DNA from

errors in DNA replication

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

nucleotides

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

phase variation

Mutations that occur because of errors in DNA replication are termed

spontaneous