Mutations Lesson Review Flashcards
Review from the Mutations lesson or U3L6 (17 cards)
What are MUTATIONS?
- There are errors in the DNA sequence that are inherited.
- They may have negative, positive or no known side effects.
- Diploid organisms may have the error masked in a phenotype as it has 2 copies of each gene.
What are POINT mutations, and what are the 2 general types?
- It is a mutation that occurs at a specific base pair in a genome.
- Base Subtitution
- Frameshift
What is a BASE SUBTITUTION mutation, and what are the THREE types?
- It is a replacement of one base in a DNA sequence with another base.
- Silent
- Missense
- Nonsense
What is a SILENT mutation?
- It does not result in a change in the amino acid coded for.
- It does not result in a phenotypic change.
- It primarily occurs in the introns.
- Could be due to redundancy of genetic code.
What is a MISSENSE mutation?
It is a single substitution of one base in a codon, which results in a different amino acid. Ex includes: Sickle Cell Anemia.
What is NONSENSE mutation?
- It is a single substitution of one base in a codon that causes a stop codon to replace a codon specifying an amino acid.
- It is the ONLY part of protein produced during translation.
- It can be LETHAL to the cell.
What causes FRAMESHIFT mutations?
- Causes changes in the reading frame.
- Caused by an insertion.
- Caused by a deletion.
What is an INSERTION?
It is an addition of one or more base pairs in a DNA sequence.
What is a DELETION?
It is the removal of one or more base pairs in a DNA sequence.
What is a TRANSLOCATION?
It is the transfer of a fragment of DNA from one site in the genome to another location.
Where does TRANSLOCATION usually occur, and what is the result?
- It occurs between two nonhomologous chromosomes.
- It results in a fusion protein with an altered function.
What is INVERSION?
It is the reversal of a segment of DNA within a chromosome.
What could happen during inversion?
- No gain or loss of genetic info.
- Though a gene may get disrupted.
What are TRANSPOSABLE ELEMENTS?
- AKA “jumping genes”.
- There are certain fragments of DNA that consistently move from one location to another.
- If they are added to a coding region of a gene, it will leave it inactive.
What are some CAUSES of genetic SPONTANEOUS mutations?
- It can be caused by errors within DNA replication.
- DNA polymerase I rereads duplicated DNA for errors.
What are some CAUSES of INDUCED mutations?
- Caused by mutagenic agents.
- Mutagenic agents include UV radiation, or other radiations and certain chemicals.
What are some CAUSES of genetic mutations?
- Cancer (a genetic disease because it is always a result of a mutation in the genetic sequence).
- Oncogenes (genes that control cell growth and division).
