Chapter 15 Flashcards
What did the Luria-Delbruck Flucation test show?
That mutations occur randomly, and are then subject to selection- they are not adaptive.
Explain somatic mutations.
Somatic mutations occur in any cell except germ cells and are NOT heritable.
Explain germ-line mutation.
Germ-line mutations occur in gametes and ARE inherited.
What is the outcome of a base substitution?
A point mutation
What is the outcome if there is an insertion or deletion?
A frameshift mutation.
Explain a missense mutation.
A missense mutation is a mutation that changes a codon into a codon that codes for a different amino acid.
Explain a nonsense mutation.
A nonsense mutation is a mutation that changes a codon to a stop codon and results in premature termination of translation.
Explain a silent mutation.
A silent mutation does not change the protein sequence.
What is a transition?
Transitions are pyrimidine replacing a pyrimidine or a purine replacing a purine.
What is a trasnversion?
Transversions are a purine and a pyrimidine interchanged.
What are purines?
A and G
What are pyrimidines?
C, T, and U
Mutations are typically classified according to their what?
Their phenotypic effects.
Such as: loss of function, gain of function, morphological, behavioral, nutritional, etc.
Mutations can occur spontaneously and it could be due to DNA polymerase inserting incorrect nucleotides. This is generally due to mispairing and a failure to proofread. What does this result in?
Point mutations
Explain Tauomeric Shifts.
Tautomeric shifts are shifts in bases that occur spontaneously and can induce mutations.
An example of this is Thymine bonding with Guanine, when it should be bonding with Adenine.