Bio 190 Ch 13

Consider a germ-line mutation that occurs in a sperm which fertilizes a normal egg to produce a zygote. In the individual that results from this zygote, _% of the cells will contain the mutation, and _% of the gametes produced by that individual will carry the mutation. Listen to the complete question

100, 50

How do point mutations affect DNA sequences?

By substituting, adding, or subtracting a base pair

Mutations outside a gene's coding sequence can affect gene expression. Which of the following sites, when mutated, would affect transcription?

Promoter and operator site

T/F? All living things possess mechanisms allowing them to minimize mutation.

True

T/F? New mutations are much more likely to be harmful than beneficial to the individual.

True

The effects of _ mutagens on DNA structure is varied. Some can alkylate bases, others act as base analogues, and a few can insert between bases in the double helix and cause additions or deletions.

chemical

Alkylation of bases and deamination of bases are ways that __ covalently modify the structure of nucleotides

chemical mutigens

A mutation may affect the amino acid sequence of a polypeptide only if it occurs within the...

coding sequence of a structural gene

Induced mutations are caused by...

environmental agents

What kind of mutation causes the amino acid sequence downstream of the mutation to be changed

frameshift mutation

Mutations can be divided into two main types. Spontaneous mutations result from abnormalities in biological processes, while _ mutations are caused by environmental agents that enter the cell and alter the structure of DNA. Listen to the complete question

induced

What kind of mutation causes one amino acid to be changed to another

missense mutation

X-rays and UV light are _ mutagens

physical

The base sequence within a gene is changed, a base pair is removed from a gene, and a nucleotide is added to a gene are all ways that _ mutations may alter a gene

point

At what mutation location is there a possible increase or decrease in the rate of transcription

promoter

At what mutation location is there a possible change in the ability of pre-mRNA to be properly produced

splice junctions

A site where two adjacent thymine bases become covalently cross-linked to each other

thymine dimer

How do the effects of germ-line mutations in a parent progress over the lifetime of an offspring receiving that mutation?

All of the cells of the individual's body, but only half of the gametes produced by that individual will carry the mutation.

The _ test, which was developed in the 1970s, is used to evaluate the ability of a substance to cause mutations.

Ames

In the Ames test, you expose S. typhimurium cells that cannot synthesize histidine to compound X, then plate them on a medium lacking histidine. The next day you observe a higher number of colonies on this plate versus the control plate, which has bacteria with no exposure. What reasonable conclusion can you draw about Compound X?

Compound X is a mutagen

In nucleotide excision repair in E. coli, which protein seals newly synthesized DNA to the original strand

DNA ligase

A spontaneous point mutation may be caused during DNA replication when the enzyme __ puts the wrong base in a newly-synthesized strand

DNA polymerase

In nucleotide excision repair in E. coli, which protein synthesizes new DNA to fill in the gap

DNA polymerase

T/F? Nonsense and frameshift mutations generally result in less dramatic changes to a polypeptide sequence than missense mutations

False

Where must a mutation occur if it is to directly affect an amino acid sequence?

The coding region of a structural gene

In nucleotide excision repair, what serves as the template for synthesis of new DNA to replace the damaged strand?

The complementary strand of DNA

In nucleotide excision repair in E. coli, which protein identifies a damaged site

UvrA/UvrB complex

In nucleotide excision repair in E. coli, which protein cuts DNA on both sides of the damaged site

UvrC

In nucleotide excision repair in E. coli, which protein removes the damaged region

UvrD

Repair in which an enzyme removes an alkyl group, thereby restoring the structure of the original base

direct repair

Mutations are essential for the long-term continuity of life because they supply the _ variation that is the foundation for evolutionary change.

genetic

At what mutation location is it not as likely to have an effect on gene expression

intergenic region

Breaks in one or both DNA strands and base deletions are effects of _ radiation

ionizing

Mutations in noncoding sequences...

may affect gene expression

A heritable change in genetic material is known as a(n)...

mutation

What kind of mutation causes an amino acid codon to change to a stop codon

nonsense mutation

Bacterial colonies can be transferred from a master plate to secondary plates in the same configuration using a transferring agent such as a sterile velvet cloth. This technique is known as...

replica plating

What is the process in which bacterial colonies are transferred from a master plate to secondary plates in the same configuration using a transferring agent such as a sterile velvet cloth?

replica plating

What kind of mutation has no effect?

silent mutation

Somatic mutations are not transmitted to an individual's offspring because...

they do not occur in the gametes

At what mutation location is there a possible change in the ability of protein to be produced from mRNA

translational regulatory element

_ are small segments of DNA that can insert at various sites in the genome. If they insert into a gene, they may cause a spontaneous mutation.

transposons

Thymine dimers are caused by...

ultraviolet radiation (nonionizing radiation)