micro - bacterial genetics

When integrated F plasmid DNA in an Hfr cell is excised from the chromosome, an excision error can result in the removal of chromosomal DNA along with the F plasmid DNA, creating a plasmid called ______.

F'

Errors by DNA polymerase that incorporate the wrong nucleotide into replicating DNA can be repaired quickly by which two mechanisms?

Proofreading by DNA polymerase Mismatch repair

____ repair mechanism, which cannot always determine the correct nucleotide sequence, thus introducing mutations resulting from the repair process itself.

SOS

Which of the following types of radiation are mutagenic?

Ultraviolet rays X-rays

In conjugation in E. coli, an Hfr cell refers to ______.

a cell in which the F plasmid has been integrated into the cell chromosome

Cancer-causing chemicals are called

carcinogens

Chemicals that cause cancer are known as ______, and most of them are ______.

carcinogens; mutagens

The consequences of not repairing damaged DNA in cells include ______.

cell death cancer (in animals)

A bacterial cell described as can take up DNA from the surrounding environment.

competent

Cells that have the ability to take up DNA from the environment are called ______ cells.

competent

In bacteria, conjugationBlank 1Blank 1 conjugation , Correct Unavailable refers to DNA transfer requiring cell to cell contact.

conjugation

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

conjugation transformation transduction

A plasmid that can directs its own transfer from donor to recipient cells is called a(n)

conjugative plasmid

Conjugation in bacteria requires ______.

contact between donor and recipient cell

The genes that are present in all strains of a given species are called the ______.

core genome

Selecting penicillin-resistant mutants by plating them on a medium containing penicillin is an example of ______ selection.

direct

Mutants that can grow under conditions in which the parent (wild type) cells cannot are easily isolated by

direct selection

Mutant cells in bacterial cultures can be isolated by ___ selection and ____selection methods.

direct, indirect

Two methods used to identify mutants in a culture are ______ and ______ selection.

direct, indirect

During repair of oxidized guanine, which enzyme removes the damaged nucleobase from the sugar-phosphate backbone?

dna glycolysase

An auxotroph can be isolated from a prototrophic parent strain by ______ selection.

indirect

selection is used to isolate an auxotroph from a prototrophic parent strain, because no selective medium exists to inhibit the parent.

indirect

Mutations that are caused by external influences such as radiation or chemicals are called ______ mutations.

induced

mutations are genetic changes caused by factors from outside of the cell such as radiation or chemicals.

induced

____ is a change in the nucleotide sequence of DNA that is passed on to daughter cells.

mutation

Genetic change in bacteria occurs through which two mechanisms?

mutation horizontal gene transfer

Organisms most fit to survive in a given environment will predominate because they can reproduce more rapidly than others. This phenomenon is called

natural selection

The process by which organisms best adapted to a given environment will predominate in that environment is called _______.

natural selection

Which type of DNA repair is shown in this figure?

nucleotide excision repair

are circular pieces of bacterial DNA that do not usually encode information essential to the life of a cell.

plasmids

Repair of nucleotide incorporation errors during the process of DNA replication is accomplished by ___ by DNA polymerase and by ____

proofreading mismatch

_______ is the transfer of bacterial DNA from a donor to recipient via a bacteriophage.

tranduction

The mechanism by which bacterial DNA is moved from one bacterium to another by a bacteriophage is called

transduction

The genetic transfer mechanism shown here is called

transformation

Which mechanism of gene transfer involves the uptake of "naked" DNA by competent bacterial recipient cells?

transformation

Mutagens that are DNA segments that can insert into genes and thereby inactivate them are called ______.

transposons

Segments of DNA that can move to new positions within the genome of a single cell are called

transposons

Restriction-modification systems were discovered ______.

while studying why certain bacterial strains are relatively resistant to phage infection

Which of the following are systems bacteria can use to protect against invading DNA?

restriction-modification CRISPR

CRISPR systems involve ______.

retained segments of phage DNA used by bacteria to recognize and destroy future invading DNA

______ repair is activated by extensive DNA damage and uses a polymerase that lacks proofreading ability, ultimately resulting in mutations.

sos

Mutations that arise naturally during cellular metabolism, and not as a result of exposure to mutation-causing agents, are called

spontaneous mutations

Random genetic changes that result from normal cellular processes are ______.

spontaneous mutations

Base ______ mutations occur when an incorrect nucleotide is incorporated in place of another during DNA synthesis.

subsitutions

The most common type of mutation is base ____, , where an incorrect nucleotide is incorporated during DNA replication.

substitution

In humans, two of the genes associated with the development breast cancer encode enzymes involved in ______.

DNA repair

Which of the following statements about transformation is correct?

Transformation is the uptake of naked DNA from the environment.

______ are segments of DNA that can move from one location to another in a cell's genome.

Transposons

Because CRISPR systems involve bacteria using retained segments of DNA to identify and destroy future invading phage DNA, these systems are a form of ______.

adaptive immunity

Many bacteria are able to recognize and destroy invading DNA. It is thought this ability evolved ______.

asa defense against phages

involves the uptake of "naked" DNA by competent bacterial recipient cells.

bacterial transformation

Chemical mutagens can cause two types of mutations:

base subs frameshift mutations

When an excision errors produces a plasmid containing both chromosomal and F plasmid DNA, the resulting plasmid is called a(n)

f' plasmid

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

false

True or false: Ultraviolet rays are chemical mutagens.

false

True or false: A point mutation always leads to a shift of the reading frame from the point of mutation downstream.

false - frameshift mutation does

mutation results from an insertion or deletion of nucleotides, leading to a shift of the reading frame from the point of mutation downstream.

frameshift

Which of the following are caused by chemical mutagens?

frameshift mutations base substitutions