Genetics

Question 1

Transcription

Answer 1

DNA copied into messenger RNA(mRNA) in the nucleus

Question 2

Translation

Answer 2

mRNA attaches to ribosome, transfer RNA 9tRNA) carries amino acid to the ribosome and binds to a matching sequence in the mRNA

Question 3

3 main chromosomal tests

Answer 3

1. karyotype
2. FISH
3. microarray

Question 4

Karyotype genetic testings can detect (6 types)

Answer 4

aneuploidy
large chromosome deletions
large chromosome duplications
unbalanced translocations
balanced translocations
inversions

Question 5

Microarray will pik up__
will not pick up___

Answer 5

will pick up chromosome imbalancec, will not pick up chromosome thats balanced.

Question 6

Chromosomal microdeletions and microduplicaitons can be detected by

Answer 6

1. FISH (fluorescence in situ hybridizations (targeted to a specific chromosome region)
2. Microarray

Question 7

main gene-base tests

Answer 7

single gene sequencing
multiple gene sequencing (gene panels)
Whole exome sequencing (WES)
whole genome sequencing

Question 8

Trinucleotide Repeat Disorders

Answer 8

Due to abnormal expansion of repetitive DNA sequences
Examples:
Fragile X syndrome
Huntington disease
Friedrich Ataxia

Question 9

CVS

Answer 9

chorionic villus sampling
12-14 weeks
1% risk of miscarriage

Question 10

amniocentesis

Answer 10

after week 16
0.1-0.3% risk of miscarriage/early delivery

Question 11

NSO

Answer 11

newborn screening Ontario (heel prick)
1. metabolic disease
2. endocrine disease
3. sickle cell disease
4. cystic fibrosis
5. severe combined immune deficiency
6. spinal muscular atrophy

Question 12

DNA polymerase

Answer 12

enzyme that travels along the single DNA strand, adding the correct nucelotides to the free end of the new strand and checking to ensure that its base is actually complementary tot he template base, DNA proofreading

Question 13

How many different types of amino acids

Answer 13

20

Question 14

sequence of how many bases to form a codon

Answer 14

3 nitrogenous bases

Question 15

explain silent mutations

Answer 15

because the redundancy fo the genetic code, such mutations do not change the amino acid sequence

Question 16

missense mutaton

Answer 16

produce a change in a single AA

Question 17

nonsense mutation

Answer 17

produce on the three stop codons (UAA, UAG, UGA)

Question 18

frameshift mutation

Answer 18

insertion or deletion of one or more base pairs of the DNA

Question 19

karyotype

Answer 19

an ordered display of chromosomes

Question 20

polyploid cell

Answer 20

euploid cell has more than the diploid number of chromosome e.g. liver, bronchial, epithelial tissues

Question 21

aneuploidy

Answer 21

a cell that does not contain a multiple of 23 chromosomes

Question 22

nondisjunction

Answer 22

an error in whcih homologous chromosomes or sister chromatids fail to separate normally druing meiosis or mitosis

Question 23

partial trisomy

Answer 23

only an extra portion of a chromosome is present in each cell

Question 24

Turner’s Syndrome

Answer 24

Monosomy of X

Question 25

Klinefelter’s Syndrome

Answer 25

XXY condition

Question 26

Principle of Segregation

Answer 26

homologous genes separate from one another during reproduction and that each reproductive cell carries only one copy of a homologous gene

Question 27

Penetrance

Answer 27

% of individuals with a specific genotype who also exhibit the expected phenotype

Question 27

Principle of independent assortment

Answer 27

hereditary transmission of one gene does not affect the transmission of another

Question 28

Expressivity

Answer 28

extent of variation in phenotype associated with a particular genotype

Question 29

Empirical risks

Answer 29

direct observation of large numbers of families, used to estimate recurrence risks for multifactorial dieses

Question 30

Threshold of liability

Answer 30

disease that do not follow a normal distribution, probably polygenic or multifactorial, certain threshold before the disease is expressed