DNA Mutation

Question 1

why is mutation important

Answer 1

• source of new genes
• source of diversity
• can cause death and errors

Question 2

why are mutations rare?

Answer 2

• DNA is stable
• it is geometrically tight
• the bases are protected in sugar-phosphate backbone
• usually quickly repaired my DNA polymerase during replication

Question 3

extragenic vs intragenic mutations

Answer 3

ex = not within a gene, no effect
intra = in a gene - could or could not impact organism

Question 4

how frequent are mutations

Answer 4

1 in 10^4 to 10^6 per generations (humans)

Question 5

how to calculate mutation numbers

Answer 5

need mutation rate and number of cells
- number of cells/mutation rate = mutants

Question 6

what are some causes of mutations

Answer 6

non-induced:
- random chance
- polymerase doesn’t repair it (damaged genes)
- short generation times
induced:
- natural sunlight/factors
- exposure to mutagens - chemical, physical, biological
- man-made mutations

Question 7

somatic vs germinal mutation

Answer 7

• som = som cells, affect individual, unusual cell growth
• germ = gamete cells, passed to
  offspring only, genetic/chromosomal disorder (all cells affected)
  e.g. CF

Question 8

Types of mutations

Answer 8

1. DNA level/small scale
   - frameshift (missence, nonsence, silent)
   - In and Del
   - substitution
   - transition and transversion
2. large scale - chromosomal leve;
   - duplication’
   - inversion
   - translocatoon
   - Del

Question 9

what is transition vs transversion in DNA mutations

Answer 9

• transition = pyramdine to purine or other way
• transversion = swapped for one of the same kind of bases (purine to purine)

Question 10

What do frameshift, missence, nonsense and silent mutation do

Answer 10

1. frameshift = codons shift so all codons become incorrect (addition or deletion) -> VERY BAD effects
2. missence = substitution of base only changes one AA.
3. nonsense -> substitution cause stop codon
4. silent -> substitution does not change AA coded for since genetic code is redundant

Question 11

What is aneuploidy vs polyploidy?

Answer 11

an = addition deletion of one chromosome
polyploidy = addition of chromosome to all sets

Question 12

explain deletion, duplication, transloaction and inversion (chroms)

Answer 12

1. deletion = section of one chromosome deleted
2. duplication = a region of a chromosome is duplicated and put back on chromosome
3. translocation = swapping of same section of two chroms
4. inversion = a reigion flips 180°