Genetics

Question 1

What happens in mitosis?

Answer 1

1 diploid parent cell –> 2 identical diploid daughter cells

Question 2

What happen in meiosis?

Answer 2

1 diploid parent cell –> 4 haploid daughter cells

Question 3

What is a polymorphism?

Answer 3

Any variation in the human genome that has a population frequency of greater than 1% (does not cause disease in its own right)

Question 4

What does aneuploidy mean?

Answer 4

Whole extra or missing chromosome

Question 5

What is translocation?

Answer 5

Rearrangement of chromosomes

Question 6

What is Down’s syndrome?

Answer 6

Extra chromosome 21

Question 7

What are the chances of a woman who already has a child with Down’s syndrome having another?

Answer 7

1%

Question 8

What are the stages of the cell cycle?

Answer 8

G1 - cell grows in prep for DNA replication
S - DNA replication
G2 - make sure DNA replication occurred properly
M - mitosis - cell division

Question 9

What is trisomy 18 called?

Answer 9

Edwards syndrome

Question 10

What is trisomy 13 called?

Answer 10

Patau syndrome

Question 11

What is 47XXY called?

Answer 11

Klinefelter syndrome

Question 12

2 main types of translocation

Answer 12

Balanced

Unbalanced

Question 13

What is robertsonian translocation?

Answer 13

An entire chromosome has attached to another at the centromere

Question 14

What is a reciprocal translocation?

Answer 14

Where segments from 2 different chromosomes have been exchanged

Question 15

Syndromes caused by deletion

Answer 15

DiGeorge’s syndrome
William’s syndrome
Cri du chat syndrome

Question 16

What is amniocentesis?

Answer 16

Needle used to obtain sample from unborn child in utero

Question 17

Treatment for Philadelphia chromosome?

Answer 17

Tyrosine kinase inhibitor: imatinib

Question 18

What does autosomal dominant mean?

Answer 18

1 faulty copy of gene causes disease

50% risk

Question 19

What does autosomal recessive mean?

Answer 19

2 faulty copies of the gene are needed to cause disease

25% risk if parents are carriers

Question 20

What does x linked mean?

Answer 20

Disease carried on X chromosome
Female carrier - 1/2 male kids affected, 1/2 female kids carriers
Make affected - male kids normal, female kids carriers

Question 21

What does mitochondrial inheritance mean?

Answer 21

Mitochondria always come from mother

Question 22

What are single nucleotide polymorphisms?

Answer 22

Any variation in the human genome that does not cause a disease in its own right but may predispose to a common disease

Question 23

What are copy number variations?

Answer 23

Extra or missing stretches of DJA

Question 24

What is penetrance?

Answer 24

The likelihood of having the disease if you have the mutation

Question 25

What is expression?

Answer 25

The variation in disease severity if you have the mutation

Question 26

What is mosaicism?

Answer 26

When different cells have a different genetic constitution within one individual

Question 27

When does somatic mosaicism occur?

Answer 27

When the somatic cells of the badly are of more than one genotype

Question 28

What is gonadal mosaicism?

Answer 28

A special form of mosaicism where some gametes (i.e. Either sperm or oocytes) carry a mutation but the rest are normal

Question 29

3 outcomes if the cell cycle is arrested

Answer 29

DNA repair Apoptosis Cancer

Question 30

What is DNA methylation?

Answer 30

Epicene tic mechanism that cells use to control gene expression

Question 31

What is Angelman's syndrome?

Answer 31

Neuro genetic disorder

Question 32

What is myotonic dystrophy?,

Answer 32

I a chronic, slow progressing, inherited multi systemic disease

Question 33

Clinical features of myotonic dystrophy

Answer 33

``` Muscular dystrophy Cataracts Heart conduction defects Endocrine changes Myotonia (slow relaxation of muscles after contraction) ```

Question 34

What is huntingtons disease?

Answer 34

Neurodegenerative genetic disorder that afters muscle coordination and leads to cognitive decline and psychiatric problems

Question 35

What is anticipation?

Answer 35

Where disease symptoms become more severe from generation to generation and may become onset at a much earlier age

Question 36

What is heteroplasmy?

Answer 36

Different daughter cells contain different proportions of mutant mitochondria (similar to mosaicism)

Question 37

What are the symptoms of mitochondrial disease?

Answer 37

``` Myopathy Diabetes Deafness Optic atrophy Stroke-like episodes Encephalitis (inflammation of the brain) ```

Question 38

4 methods by which oncogenes are activated?

Answer 38

Duplication of the gene Activation of the gene promoter Change in amino acid sequence Phosphorylation of the gene