Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
27 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Heritable changes in genetic material |
*DNA sequence mutations *Chromosomal alterations |
|
|
|
The benefits of mutation |
*Leads to genetic variability within the species. *evolution needs variation *natural selection |
|
|
|
Types of DNA sequence mutations |
Spontaneous mutations (Part of normal cell processes) *DNA replication errors -put wrong base in *DNA repair errors -DNA repair mechanism can. miss *endogenous waste damage - waste products from metabolism can damage the DNA *nucleotide conversion -spontaneous. Loss of amino acid in a group can change cytosine to thymine. |
4 different types |
|
|
2 kinds of Mutagens |
Physical agents that damage DNA -ex. Radiation Chemicals that damage DNA -mutagenic chemicals |
|
|
|
Relationship between mutagens & carcinogens |
*All mutagens are carcinogens *not reverse....all carcinogens are NOT mutagens |
|
|
|
Average mutation rate: |
Average 1 mutation per 1 million base pairs. -rate varies from gene to gene -rate varies with exposure |
|
|
|
Limitations of estimating mutation rate of a gene from a pedigree |
*single gene trait *dominant gene *completely penetrate *certain of paternity *no environmentmental triggers (Cannot be multifactorial) |
|
|
|
Factors that effect mutation rate |
*size of the gene *repeats within gene *# of cytosines in gene sequence |
|
|
|
Point Mutations |
Change in one or two nucleotides in the DNA of a gene *base pair substitutions *frame shift mutations |
|
|
|
Types of base pair substitutions |
Silent, Nonsense, Missense |
|
|
|
Silent Mutations |
Nucleotide Change, but no amino acid change in the protein |
|
|
|
Nonsense mutations |
Nucleotide change from a specific amino acid to a stop codon. - protein becomes smaller than it should be. Reduced Function, non-function, or sometimes no effect depending upon where the mutation occurs. |
|
|
|
Missense Mutations |
Nucleotide mutation changes the amino acid which it codes for. -may have significant consequences or may be neutral. |
|
|
|
Frameshift mutations |
*Deletions or insertions *alters reading frame *protein is altered |
|
|
|
Types of physical mutagens |
Ex. UV, Radiation |
|
|
|
UV as a mutagen |
*absorbs directly by DNA *thymidine diners -deletions occur during replication |
|
|
|
Radiation as a mutagen |
Two types *direct hit * indirect -free radicals & electrons rem=radiation equivalent in man millirem= 1/1000 rem Radiation sickness @ 100rem |
|
|
|
Types of chemical mutagens |
*base analogs *base modifiers *DNA binders |
|
|
|
Base analogs |
*structure resembles nucleotides -may incorporate into DNA -may lead to wrong base pairing -ex. 5-BU (5 bromo-uracill) |
|
|
|
Base Modifiers (chemical mutagens ) |
*Chemicals that interact with bases. *change one base into another -ex. Nitrous Acid -C/G-->U/A-->A/T *nitrous acid will increase the rate of this mutation happening...processed meats like hot dogs, bacon, etc. Are high in nitrous acid. |
|
|
|
DNA binders (chemical mutagens ) |
*inserts into double helix *distorts the helix *leads to insertions or deletions - mutations occur during replication -ex. Ethidium Bromide |
|
|
|
Transition Mutation (additional mutation terminology) |
*purine to purine (A or G) *pyrimidine to pyrimidine (C, T, or U) |
|
|
|
Transversion Mutation |
Purine to Pyrimidine Pyrimidine to Purine -A & G---> C, T, or U. |
|
|
|
DNA replication repair errors |
Occasionally during DNA polymerase proof reading will put the wrong base in during S phase. |
|
|
|
DNA mismatch repair |
*mismatched bases missed by DNA polymerase *mute proteins scan for these replication mismatches *they are cut out and fixed during S phase. |
|
|
|
DNA damage repair /DNA excision repair |
*existing DNA duplex is scanned for mutations (usually at G1/S checkpoint ) *damage is cut out and repaired *many different repair enzymes |
|
|
|
Xeroderma pigmentosa |
*AR genetic disease *UV excision repair is affected -any of 8 different genes may be mutated *extreme sunlight sensitivity |
|
