variation

Question 1

genetic mutation

Answer 1

inherited change in genetic information

its the only means by which new genetic variation is created

caused by :

• copying errors
• exposure to mutagens ( radiation or chemicals )
• virus or virus-like sequences

Question 2

point mutation

Answer 2

a mutation involving a change in a single base pair

Question 3

chromosomal mutations

Answer 3

eliminate, duplicate, or rearrange segments

Question 4

whole genome events

Answer 4

duplication of entire genomes ( e.g ploidy changes )

Question 5

substitutions ( point mutation )

Answer 5

one base is simply substituted for another

two types :

1. transitions
   purine to purine
   pyrimidine to pyrimidine
2. transversions ( G-C , C-A , A-T , T-G )
   purine to pyrimidine
   pyrimidine to purine

Question 6

natural mutation ( substitution )

Answer 6

happens in non-coding sequence

Question 7

synonymous/silent mutation ( substitution )

Answer 7

the single mutation results in the same amino acid being coded for

AAA = lysine
AAG = lysine

Question 8

non-synonymous / coding mutation ( substitution )

Answer 8

the single mutation results in a different amino acid being coded for
- change protein primary structure

Question 9

non-sense mutation ( substitution )

Answer 9

mutation causes a amino acid codon to change to a stop codon

Question 10

deletions ( point mutation )

Answer 10

one or more nucleotide (s) are deleted from the DNA sequence

Question 11

insertions ( point mutation )

Answer 11

one or more nucleotide (s) are inserted into the DNA sequence

Question 12

frameshift mutations

Answer 12

A frameshift mutation is a genetic mutation caused by a deletion or insertion in a DNA sequence that shifts the reading frame

( deletions and insertions )

Question 13

slippage

Answer 13

misalignment of DNA strands during the replication of repeated DNA sequences

common in highly repetitive sequences

Question 14

gene duplications ( larger scale mutations )

Answer 14

can be brought about by copying errors or transposable elements

duplicate gene (s)
1. pseudogenes 
  ( not expressed )
2. (multi) gene families 
  ( expressed )

Question 15

chromosomal rearrangements ( larger scale mutations )

Answer 15

a mutation that is a type of chromosome abnormality involving a change in the structure of the native chromosome

caused when chromosomal alignment and pairing during meiosis malfunctions

major force of evolution

Question 16

aneuploidy ( larger scale mutations )

Answer 16

a change in the number of individual chromosomes

e.g monosomy, trisomy, tetrasomy

Question 17

polyploidy ( larger scale mutations )

Answer 17

one or more complete sets of chromosomes is added, wither from the same species ( autopolyploids ) or as a result of hybridisation between two different species ( allopolyploids )

Question 18

chromosomal inversion ( chromosomal rearrangments )

Answer 18

a chromosome rearrangement in which a segment of a chromosome is reversed end-to-end

Question 19

chromosomal translocation ( chromosomal rearrangments )

Answer 19

occurs when a chromosome breaks and the (typically two) fragmented pieces re-attach to different chromosomes

Question 20

horizontal gene transfer

Answer 20

the non-sexual movement of genetic information between genomes

Question 21

‘molecular clock’

Answer 21

a figurative term for a technique that uses the mutation rate of biomolecules to deduce the time in prehistory when two or more life forms diverged