Lecture 3 (Mutations, mitosis, meiosis) Flashcards
gene
a region of DNA that had enough instructions to make a polypeptide or RNA
mutation
there HAS to be a change in the sequence of DNA for it to be a mutation
a point mutation
a change in just one base pair of the gene
wild type
the normal or healthy version of the sequence
What could cause a mutation?
- In the S phase of the cell cycle, replication occurs. Sometimes DNA pol will make a mistake and it’ll not be corrected
- Exposure to radiation, x-ray, sun, and any harmful chemicals
Mistakes to DNA
Substitution - substitute one base for another
Insertion- insertion of an extra base
Deletion - deletion of a base
What is the most harmful mistake to DNA?
insertion or deletion because it can cause a frameshift
frameshift
caused by an insertion or deletion and it changes the way you read the sequence
silent
if the substitute doesn’t change the amino acid
missense
if the substitution changes the amino acid
nonsense
if the substitution changes the amino acid to a STOP
where are mutations are most dangerous?
polypeptide- N terminus
RNA- 5’
DNA- 3’
Which is the MOST dangerous effect?
nonsense
what are homologous pairs?
they are a pair of chromosomes. they are the same length and possess the same genes for the same characteristics at corresponding loci. you get one from mom and dad
where can you find homologous pairs?
diploid cells
