Unit 7 : Gene mutation and regulation
RNA interference
(RNAi) a technique used to silence the expression of selected genes. RNAi uses synthetic double-stranded RNA molecules that match the sequence of a particular ene to trigger the breakdown of the gene's messenger RNA.
mutation
A change in the nucleotide-base sequence of a DNA molecule.
mutagen
A chemical or physical agent that interacts with DNA and causes a mutation.
polyploidy
A chromosomal alteration in which the organism possesses more than two complete chromosome sets. A beneficial mutation which occurs in plants, usually resulting in larger and stronger plants.
Which mutation typically causes a bigger problem and why?
A frameshift mutation changes every amino acid after the mutation so causes a bigger change in a protein.
frameshift mutation
A mutation caused by an insertion or deletion within a gene sequence. This causes a shift in the reading frame. This can change every amino acid downstream of the mutation.
silent mutation
A mutation that changes a single nucleotide, but does not change the amino acid created.
nonsense mutation
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.
gene mutation
A mutation which involves a single gene. (Includes substitutions, insertions, and deletions)
substitution or point mutation
A single nucleotide is changed, usually changing no more than one amino acid.
promoter
A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA.
chromosomal mutations
Changes in a DNA sequence that affect an entire chromosome or multiple chromosomes. (These include deletions, duplications, inversions, and translocations.)
differentiation
Is the development of a cell from an unspecialized to a specialized state. Genes are turned on or off depending on the cell.
If a gene had 180 nucleotides but had a frameshift mutation at 175, how many amino acids would be affected?
Only the last 2 amino acids would be affected. The first 58 would be normal.
Most mutations...
do NOT effect the health of an individual.
How many nucleotides are needed to code for 5 amino acids?
15 (3 nucleotides per amino acid)
