5.1 variation / mutatiom

Question 1

environmental variation

Answer 1

piercings, glasses, tatoos

Question 2

genetic variation

Answer 2

eye colour, blood group, prescence of genetic disorders

Question 3

how many genes control a genetic disorder

Answer 3

one

Question 4

continuous data

Answer 4

a characteritic can be any value between a min-max
e.g. height
- range of values
genetic or environmental
multiple genes

Question 5

discontinuous data

Answer 5

distinct groups of characteristics eg blood type - A, B, AB, O
- one (or few) genes
genetic only

Question 6

why is variation essential for survival

Answer 6

cruical to evolution - each species in a stable environment is there because it has adapted to be there

Question 7

genetic vaariation is the result of

Answer 7

• mutations
• sexual reproduction (2random gametes fuse)
• meiosis (all gametes genetically diff - random pairing + switching of genes)

Question 8

what is a mutation

Answer 8

• change in the sequence of bases in DNA
• occur randomly
• can occur if DNA isnt replicated correctly
• some substances eg ethanol + ionising radiation increase chance of mutation
  lead to ALLELES

Question 9

mutation effects

Answer 9

harmful - affect person/offspring eg cancer
neutral - dont benefit nor harm eg attached earlobes
beneficial - eg tall neck for giraffes

Question 10

substitution mutations

Answer 10

• silent - results in triplet code that codes for same amino acid
• nonsense - results in a stop - shorter protein made
• missense - diff amino acid coded for - diff shape if enzyme diff active site

Question 11

types of mutation

Answer 11

• substitution - one base changed to another
• insertion- base added - to gene
• deletion - base deleted - alters all triplet code downstream

Question 12

non coding sections of DNA

Answer 12

• specific sequences of dna before a gene which trigger transcription
• if mutation occurs here - transcription factors cant bind - gene not turned on - gene not transcriped - proteins not produced