Genetics

Question 1

Which direction is DNA read in?

Answer 1

5’ => 3’

Question 2

How is variation introduced during meiosis?

Answer 2

Crossing over,

Independent assortment

Question 3

Are introns or exons transcribed onto mRNA?

Answer 3

Exons

Both transcribed onto pre-mRNA - spliced for form mRNA

Question 4

What is a polymorphism?

Answer 4

Any variation in human genome with >1% frequency

Question 5

What are the tops of the arms of chromosomes called?

Answer 5

Telomeres

Question 6

What os the difference between balanced and unbalanced chromosome rearrangement?

Answer 6

Balanced: all chromosome material is present
Unbalanced: there is extra or missing chromosome material (poorer outcome)

Question 7

What is Robertsonian translocation?

Answer 7

2 chromosomes (from different pairings) stuck end to end 
Not a risk until pregnancy (games will have extra or missing chromosomes)

Question 8

What is trisomy 18?

Answer 8

Edwards syndrome

Question 9

What is Turners and Klinefelters syndrome?

Answer 9

Turners: 45 X
Klinefelters: 47 XXY

Question 10

How does trisomy 14 present?

Answer 10

Miscarriage

Question 11

What does microarray detect?

Answer 11

Missing or duplicated pieces of chromosome (unbalanced chromosome rearrangement) - first line for paediatric referrals

Question 12

What are SNPs?

Answer 12

Single nucleotide polymorphisms

Question 13

How are point mutations identified?

Answer 13

PCR and next generation sequencing (can sequence whole genome or just specific section)

Question 14

What indicates the start and end points for transcription?

Answer 14

Start: promotor sequence
End: stop codon

Question 15

What is retinoblastoma?

Answer 15

A tumour suppressor gene (if both copies lost, tumour develops)

Question 16

What is the two hit hypothesis?

Answer 16

Must have 2 copies of a mutant gene to show the effects. One can be inherited and the other a somatic mutation, or both can be somatic mutations (hit twice by a mutation)

Question 17

What is FISH used for?

Answer 17

To indicate the presence or absence of specific genes