Chapter Thirteen: Mutation, DNA Repair, and Cancer Flashcards
Mutations are permanent and…changes to the DNA
heritable
What kind of mutation (Point or Chromosomal)?
- changes to nucleotide sequence of individual genes
Point Mutations
What kind of mutation (Point or Chromosomal)?
- changes to the gene order of chromosomes
Chromosomal Mutation
In Substitution Mutations, one nucleotide is replaced with…
another
When one Nucleotide is substituted for another, one…in the resulting RNA will be altered
codon
Typically in substitution mutations after the nucleotide is substituted, the altered RNA will alter one amino acid in the resulting…
protein
The change of one…could produce little to no effect, or a lethal one in substitution mutations
amino acid
In substitution mutations, it is also possible that the codon could be changed to a stop…and end the Protein prematurely
codon
When a codon is changed to a stop codon, ending the Protein prematurely, it would most likely destroy the Protein’s…
function
In Substitution Mutations, it is possible, due to the redundancy of the Genetic Code that the new codon would code for the same…
amino acid
What is this called?
When a base substitution is present but the protein would not be changed and would function normally
Silent Mutation
What is this called?
- add one or more nucleotides to a gene
Additions
What is this called?
- delete one or more nucleotides from a gene
Deletions
Both Additions and Deletions produce…
Frameshift Mutations
Frameshift Mutations shift the…reading frame of the codons
triplet
Mutations outside the Region Coding for the Nucleotides of the…can also have effects
RNA
Only mutations in the…line cells will be passed on to individuals of the next generation
Germ
Mutations in…(or body) cells are not passed on to individuals of the next generation
Somatic
…Mutations, like cancers, can have serious effects for the individual, but only that individual, not their children
Somatic
Mutations may be of natural cause (spontaneous) or from outside factors (…)
induced
…are chemicals or physical factors that alter the structure of DNA
Mutagens
….are chemicals and can enter into reactions which convert them to something other than the normal four bases of DNA
Nucleic Acids
Nitrous Oxide (found in smoked meats) can remove the amino group from Cytosine or Adenine, replacing it with a carbonyl group to produce Uracil and…
Hypoxanthine
Cytosine normally pairs with Guanine, but when converted to Uracil, pairs with…
Adenine
C-G pair is converted to a U-A (T-A) pair in a…
substitution mutation
Adenine normally pairs with Thymine, but when converted to Hypoxanine, pairs with…
Cytosine
An A-T pair is converted to a H-C (G-C) pair in a…
substitution mutation
…are similar enough to the “real” DNA bases to be incorporated into DNA, but they don’t have the same faithfulness in pairing
Base Analogues
Base Analogues produce…mutations
substitution
The Causes of Mutations:
Ionizing Radiation (X-rays) physically…DNA which may not be repaired correctly
cut
The Causes of Mutations:
Bases could be…
removed
The Causes of Mutations:
Strands could be…
cut
The Causes of Mutations:
UV light has high enough energy to promote covalent linkages between adjacent…bases (T-T dimers)
Pyrimidine
The Causes of Mutations:
…does not recognize the T-T dimer as a normal base and will randomly insert one
DNA Polymerase
The Causes of Mutations:
Substitution mutations are…
promoted
DNA Repair:
…Excision Repair is one of the more widespread and better understood mechanisms
Nucleotide
….Complex scans DNA looking for errors, such as Thymine dimers
UvrABA
DNA Repair:
When dimer is found, UvrB releases UvrA and recruits…
UvrC
DNA Repair:
…cuts the sugar-phosphate backbone on either side of the mutation
UvrC
…(a helicase) is recruited to remove the damaged section from one cut to the other
UvrD
DNA Repair:
Finally, …replaces the damaged removed section, using the intact, undamaged strand as a template
DNA Polymerase
What is used to close the final gap in DNA Repair?
DNA Ligase
