9.8 DNA mutations Flashcards
UV radiation can cause chemical binding of adjacent _________. The most common mutant structure of DNA damage is the _________.
pyrimidines
thymine dimer
chemical mutagens have a direct effect on the _________ of the base, changing it’s normal base pairing
chemical structure
define conservative mis-sense mutation
a single amino acid change caused from a single base change, however, it changed to a similar amino acid
mutation called when you have a single amino acid change caused from a single base change. The single base change in the coding region of a gene can alter the codon so it becomes a different amino acid. This can range in severity depending on where the change is.
mis-sense mutation
for inversion mutations? what could happen if the break occurs in the middle of a gene? what if it encompasses the entire gene?
if in the middle, could be disastrous
if entire gene, could still function normally
in the disease __________ ___________, there are defects in the DNA repair mechanism for thymine dimers from UV damage.
Xeroderma pigmentosum
what is the mutation called when you put in new termination codon (NO amino acids beyond this point). Protein synthesis will stop at the new termination codon, truncated polypeptide. Generate premature stop codons.
nonsense mutations
addition or deletion of a single base, alter the reading frame
frame shift mutation
mutations that generate pre-mature stop codons:
nonsense mutations
NO more protein
transposons and retroviruses are an example of _______.
insertions
they spontaneously insert themselves into DNA
define non-conservative mis-sense mutation
a single amino acid change caused from a single base change, however, it changed to a completely characteristic of amino acid.
what form of large-scale mutations genes occur when there was a break in the DNA - and it got flipped when repair mechanisms came in. Inverted. Scrambled gene
inversions
chemical mutagens alter _____ _______
base pairing
point mutations contrast from large-scale mutations. what are 3 types of point mutations?
mis-sense, nonsense, frameshift
what can cause deletions in DNA?
ionizing radiation, X-rays, anything that physically breaks DNA
In Xeroderma pigmentosum, there is a defect in _________ for dimers, leading to a high rate of:
DNA repair
skin cell death, high rate of skin cancers
what main form of large-scale mutations occurs when after a break, something gets added.
insertions
Burkitt’s lymphoma is caused by _________ of a proto-oncogene next to a _____________, which is very active
translocation
Ig heavy chain gene
in insertions, what happens if something is inserted into a coding region or regulatory region?
may completely destroy gene function
due to UV damage, once ________ are linked, they are no longer able to __________ correctly
thymines
base pair
what are common sources of radiation exposure?
CT (even higher than spending an hour on a power plant)
X-ray is really small
________________ is a cancer of lymphocytes, Occurs because during translocation, the c-myc proto-oncogene is ___________ next to Ig heavy chain region. Since the Ig is really active, it activates the myc gene.
Burkitt’s
translocated
what main form of large-scale mutations occurs when DNA is physically broken and then rejoins?
deletions
tens to millions of base pairs can be removed
main type of large-scale mutation where a whole piece of the chromosome is added or swapped with a whole piece of another chromosome?
translocations.
