Mod 6 mutations Flashcards
What is Point Mutation?
is when a nitrogenous base is changed at a particular locus on a chromosome
What is a mutation?
A permanent change in the DNA structure.
Types of Electromagnetic radiation that can cause mutations
UV, X-Rays, Gamma Rays
What is a mutagen?
A mutagen is what causes a permanent change in base pairs of the DNA structure. For example, gamma rays.
Types of point mutation
substitution, insertion, deletion, duplication, neutral.
Types of substitution
Silent mutation (different nitrogenous base is added with no change in amino acid)
Missense mutation (a different amino acid is specified due to modified DNA sequence. A mutated protein will be formed)
Nonsense Mutation (a stop codon is produced due to a modified mRNA sequence. Results in the protein having a lower operational efficiency or unable to function completely)
Frameshift mutation
a type of mutation where a nitrogenous base is inserted or deleted from the DNA sequence, resulting in a shift in the reading frame of the ribosome on the mRNA during translation.
Types of Chromosomal Mutation
deletion, duplication, inversion, translocation, insertion.
Can lead to changes in chromosome numbers present in the gamete. occurs when the mutated chromosomes can’t cross over during meiosis.
duplication chromosomal mutation
when a chromosome section is copied creating a possible extra copy of the genes
Inversion chromosomal mutation
involves a chromosome section breaking off and recombining, in a reversed order, with the original chromosome. Can prevent crossing over.
Translocation chromosomal mutation
results in one chromosome section separating from a chromosome and combining with a non-homologous chromosome
Germ-line mutations
Starts in the gamete with the entire organism carrying the mutation. Occur in the organisms germinal cells. Can be inherited
Somatic mutations
Starts in the embryo. Can result in a change in the organism’s phenotype in affected area. Can’t be passed on as meiosis and fertilisation does not involve somatic cells.
Coding DNA
Accounts for 1% of the human Genome. Composes of exons which encodes for proteins.
Noncoding DNA
Does not encode for proteins
Exons and introns
Exons are sections in DNA that code for proteins.
Introns are sections in DNA that don’t code for proteins
