Mutations (2/23)

Question 1

What are the two sources of variation within a species?

Answer 1

1. ) Mutation

2. ) Recombination (occurs during sexual reproduction)

Question 2

What has a higher rate of point mutations, bacteria or higher eukaryotes?

Answer 2

Bacteria!

Question 3

What are Types of “Point Mutations” Within a DNA Sequence?

Answer 3

a. ) Substitution: switches the sequence in only one spot
b. ) Insertion: moves the whole line of codons down a letter
c. ) Deletion: moves the whole line of codons back one letter

Question 4

Is evolution a random process?

Answer 4

No! Mutations happen at random but natural selection is the filter!

Question 5

Synonymous Codons

Answer 5

mutations that do NOT change the meaning of a triplet

Question 6

Non-Synonymous Codons

Answer 6

mutations that result in the replacement of one amino-acid for another

Question 7

What is the ratio of Synonymous Codons and Non-Synonymous Codons found in nature?

Answer 7

It is expected to be 3:1, but in nature it is actually 1:3 because natural selection purges non-synonymous mutations that alter the amino acid sequence of a protein while it is more permissive of synonymous mutations

Question 8

What are “Pseudogenes”?

Answer 8

“Use it or Lose it”; fossil genes that no longer serve a function

• they arise because certain genes become useless as organism evolve, but those genes still remain conserved within the genome

Question 9

Mutagenic Chemical Agents

Answer 9

exposure to mutagenic agents may cause mutations (UV Radiation, Tobacco Smoke, etc.)

Question 10

Recombination as a Source of Variation

Answer 10

sexual reproduction increases the variability in a population;

• permits a wider range of evolutionary response
• permits a more rapid evolutionary response
• offspring bear a new combination of alleles

Question 11

Crossover Between Chromosomes During Meois

Answer 11

partial exchange of genetic information between two homologous chromosomes can reshuffle allele combinations