CHAPTER SIX :)

What is a Holliday junction?

A four-stranded DNA structure that forms during homologous recombination.

The best term to describe the incorporation of a random mistake into the DNA sequence at a specific point is _____.

A point mutation

What are three methods to repair DNA damage?

Base Exision, Nucleotide Exision, and Direct Repairs

What are the three types of point mutations?

Base Substitutions, Insertions, and Deletions,

What bonds can ionizing radiation break?

Covalent Bonds

In DNA repair, what enzyme seals up broken parts of the DNA backbone?

DNA ligase

Which enzyme checks DNA for errors?

DNA polymerase

What is the correct order of the enzymes used in base excision repair?

Glycosylase, DNA polymerase, DNA ligase

Two types of point mutations that alter the length of the DNA strand are:

Insertion and deletion

Which type of mutations can result in a frameshift?

Insertions and deletions

Which type of mutagen could be compared to an extra plate shoving itself into the middle of a stack of plates?

Intercalating agent

What are the two types of radiation?

Ionizing and non-ionizing

Ionizing radiation can create:

Ions and free radicals

The eleventh amino acid of protein X should be serine, however, due to a mutation it now has the amino acid alanine in that position. Which type of mutation could have caused this change?

Missense

An environmental factor (chemicals) mutates fish in a nearby pond. The chemicals are an example of a:

Mutagen

Which type of double-strand break repair is the most likely to cause deletions or changes in the DNA sequence?

Non-Homologous End Joining

Which type of mutation results in an incomplete polypeptide because of an early stop signal?

Nonsense

The enzyme photolyase is used in what method of repair and why?

Photoreactivation because it uses light energy to break cross-linked bases.

Which type of mutation does NOT change the overall function of the protein?

Silent

How would a shift in the reading frame likely alter the resulting protein?

The protein would be greatly altered because multiple amino acids would be miscoded.

How can base analogs cause mutations?

These 'decoy' nucleotides are put into DNA instead of normal nucleotides and can then shape-shift, causing mispairing.

A purine (G) is substituted by mistake for a purine (A). What type of point mutation occurred?

Transition

A pyrimidine base (C) was substituted mistakenly for a purine base (G). What type of point mutation occurred?

Transversion