Genetics

Question 1

Which technique is best suited to monitor viral load (RNA) in blood

Answer 1

polymerase chain reaction

Question 2

What is currently considered the first genetic investigation of choice for an inherited disorder associated with developmental delay and learning difficulties

Answer 2

chromosomal microarray analysis as this has greater resolution than a karyotype

Question 3

What is the most likely explanation for a woman being affected by an x-linked mutation that they are a carrier of

Answer 3

skewed x-inactivation

Question 4

What is the best technique to identify a balanced translocation mutation

Answer 4

karyotyping - a chromosomal microarray cannot detect balanced chromosome translocations

Question 5

what is the significant advantage of using DNA technology to identify bacteria from a patient sample using its 16s gene sequence

Answer 5

this allows identification of microbes that cannot be grown under normal laboratory conditions

Question 6

Analysis of transcripts within bone marrow cells from a haematology department focuses on what material

Answer 6

RNA

Question 7

What is the best technique for testing multiple genes for single base variants

Answer 7

next generation sequencing

Question 8

What is the sequence of events that occurs during transcription

Answer 8

RNA polymerase binding
DNA chain separation
Transcription initiation
Elongation
Termination

Question 9

What can chromosomal microarray testing be used to identify

Answer 9

Unbalanced chromosomal alterations

Question 10

When is conventional cytogenetic used

Answer 10

to investigate a suspected balanced chromosomal translocation

Question 11

What is the first step in the central dogma of making a protein from a gene

Answer 11

transcription

Question 12

What is the most likely explanation for why a single base mutation in an exon has no effect on protein sequence

Answer 12

codon usage shows redundancy

Question 13

If someone possesses a gene mutation and a health condition but their son has the mutated gene without the health condition, what is the most likely explanation

Answer 13

The mutation has variable penetrate

Question 14

Why does next generation sequencing of genes have an advantage over conventional sequencing

Answer 14

it allows sequencing of a much larger number of genes

Question 15

Why is aCGH preferred over karyotyping as a first test for chromosomal analysis

Answer 15

it is high resolution

Question 16

What characteristic of a cancer cell is central to it acquiring new characteristics

Answer 16

genomic instability

Question 17

What is the best first lien investigation for detecting unbalanced chromosomal rearrangements

Answer 17

aCGH

Question 18

What is penetrance

Answer 18

the likely hood of having a disease if you possess the gene mutation

Question 19

What karyotype can be identified in someone diagnosed with Turner syndrome

Answer 19

45 X - this syndrome affected females only

Question 20

How many hydrogen bonds from between cytosine and guanine

Answer 20

3

Question 21

How many hydrogen bonds form between adenine and thymine

Answer 21

2

Question 22

In what ways can DNA be damaged during replication (3)

Answer 22

DNA strand breaks
Chemical cross-linking
Mismatched bases

Question 23

What is a polymorphism

Answer 23

A change in the genome that does not cause a disease in its own right, but can predispose an individual to a common disease

Question 24

What pattern of inheritance do classic genetic disease cause

Answer 24

Mendelian inheritance

Question 25

Describe multi factorial diseases

Answer 25

when multiple polymorphisms cause risk of diseases

Question 26

What is a missense mutation

Answer 26

a point mutation that causes a change to a single amino acids Substitution

Question 27

What is a nonsense mutation

Answer 27

one resulting in a premature stop codon: the polypeptide will be shorter

Question 28

What are the possible types of insertion/deletion mutations (2)

Answer 28

In frame Out of frame

Question 29

Which type of insertion/deletion mutation causes a frame shift

Answer 29

out of frame

Question 30

What is the result of promoter and splice site sequence changes (2)

Answer 30

terminates transcription or abnormal splicing

Question 31

Balanced chromosome rearrangement

Answer 31

when all chromosomes are present after rearrangement

Question 32

Unbalanced chromosome rearrangement

Answer 32

when some of the chromosomes/parts of chromosomes are missing after rearrangement Causes major developmental problems/miscarriages

Question 33

Aneuploidy

Answer 33

whole extra or missing chromosome

Question 34

Which type of aneuploidy is better tolerated and why

Answer 34

X chromosome aneuploidy Due to x inactivation

Question 35

What is the definition of translocation

Answer 35

rearrangement of chromosomes

Question 36

What is robertsonian translocation

Answer 36

when two acrocentric chromosomes are stuck end to end

Question 37

reciprocal translocation

Answer 37

two broken off chromosome pieces from non-homologous chromosomes are exchanged

Question 38

What chromosome is associated with Down’s syndrome

Answer 38

21

Question 39

Which chromosome is associated with miscarriage when mutated

Answer 39

14

Question 40

Which chromosome is associated with Edward’s syndrome

Answer 40

18

Question 41

What is the karyotype of Klinefelter syndrome

Answer 41

47 XXY

Question 42

What is FISH

Answer 42

a technique that uses fluorescent probes that bind only to parts of a nucleic acid sequence with a high degree of sequence complementarity Can be used in genetic counselling

Question 43

Each human has how many pairs of chromosomes

Answer 43

23

Question 44

Which chromosome looks like a teddy bear

Answer 44

22

Question 45

What is the short arm of a chromosome represented by

Answer 45

P

Question 46

What is the long arm of a chromosome represented by

Answer 46

q

Question 47

What is a meta centric chromosome

Answer 47

a chromosome whose arms are both roughly the same length

Question 48

What is an acrocentric chromosome

Answer 48

a chromosome whose p arm is so short it is hard to observe

Question 49

What is a telomeric chromosome

Answer 49

a chromosome whose centromere is located at the terminal end of the chromosome

Question 50

What is monosomy

Answer 50

when there is a missing chromosome from one pair

Question 51

What is trisomy

Answer 51

When there is an extra chromosome in a pair

Question 52

Monosomy of the sex chromosome causes what

Answer 52

Turner’s syndrome

Question 53

Describe the inheritance of mitochondrial disease

Answer 53

the diseased mitochondria is passed from mother to child

Question 54

What is mosaicism

Answer 54

when cells within the same individual have different genetic makeup

Question 55

What is epigenetic variation

Answer 55

functional modifications to the genome

Question 56

What does methylation inhibit

Answer 56

DNA transcription

Question 57

What is imprinting

Answer 57

when variations occur in gene expression depending on which parent you inherit the gene from

Question 58

What is heteroplasmy

Answer 58

when different daughter cells contain different proportions of mutant mitochondria

Question 59

How many copies of the tumour suppressor gene are required to be mutated for cancer to occur

Answer 59

two copies