Exam 1- lectures 1 & 2

Question 1

How much of the genome codes for proteins?

Answer 1

2%

Question 2

how much of the genome is “junk DNA”?

Answer 2

50%

Question 3

how much “difference” do we see in people?

Answer 3

0.1%

Question 4

locus

Answer 4

the position of an allele on a chromosome

Question 5

allele

Answer 5

a variant of a gene

Question 6

central dogma

Answer 6

DNA->mRNA->protein

Question 7

what DNA is inherited?

Answer 7

DNA in gametes

Question 8

4 types of SNP mutations

Answer 8

silent, conservative missense, non-conservative missense, nonsense

Question 9

conservative missense mutation

Answer 9

amino acids are similar and the protein function is similar

Question 10

silent mutation

Answer 10

leads to the same amino acid

Question 11

non-conservative mutation

Answer 11

amino acids are different, so chaped & function of protein will change

Question 12

nonsense mutation

Answer 12

codes for a stop codon

Question 13

most clinically impactful mutations

Answer 13

nonsense & non-conservative

Question 14

incomplete dominance

Answer 14

both traits are expressed; blended-> pink

Question 15

co-dominance

Answer 15

not blended; both expressed equally-> red & white spots

Question 16

mendelial genetics

Answer 16

monogenic

Question 17

quantitative traits

Answer 17

(expressivity) traits that vary in the extent to which they are expressed in each individual (i.e. height & weight)

Question 18

incomplete penetrance

Answer 18

not every individual who has the genotype expresses the phenotype; other genes may affect the phenotype

Question 19

multifactoral traits

Answer 19

both environment and genetic components (hemochromatosis)

Question 20

genetic switching

Answer 20

fly eyes

after the genes have already been made, change due to environmental factor & new gene will be passed on to offspring

Question 21

how many deleterious genes does each person carry?

Answer 21

estimated 5-8

Question 22

pleiotropism

Answer 22

a mutation in a single gene can lead to many effects

Question 23

genetic heterogeneity

Answer 23

mutations at several genetic loci may produce the same trait

Question 24

huntington’s diease

Answer 24

autosomal dominant
triplet repeat on chromosome 4
dysfunctional protein builds up -> toxic GABA neurons
hyperkinesis, parkisonian rigidity, bradykinesia, death w/in 15 years

Question 25

familial hypercholesterolemia

Answer 25

autosomal dominant defective LDL receptor-> inability to bind LDL & transport atheroscleosis, MI by 20 yo

Question 26

autosomal dominant diseases

Answer 26

huntington's disease | familial hypercholesterolemia

Question 27

autosomeal recessive dieases

Answer 27

PKU, cystic fibrosis sickle cell anemia

Question 28

phenylketonuria (PKU)

Answer 28

defective phenylalanine hydrocylase | phenylalanine is not catabolized-> build up in CNS-> severe mental retardation

Question 29

cystic fibrosis

Answer 29

defective Cl ion channel-> thickened mucus secretions | resp. infections, pancreatic dysfunction, impaired male fertility

Question 30

sickle cell anemia

Answer 30

defective HbS | sickling of RBCs-> blockage of blood vessels-> tissue hypoxia

Question 31

x-linked recessive diseases affect who most?

Answer 31

males bc X is inherited from mother

Question 32

x-linked recessive dseases

Answer 32

hemophilia A & B GPPD deficiency diabetes insipidus

Question 33

hemophilia A & B

Answer 33

defect in clotting factors 8 & 9 | -> prolonged bleeding due to inability to form a fibrin clot

Question 34

G6PD deficiency

Answer 34

usually asymptomatic until triggered (drugs, infection, fava beans)-> RBC unable to repaid

Question 35

diabetes insipidus

Answer 35

mutation in AVPR2 gene-> defective vasopressin receptor

Question 36

what is the most common enzyme deficiency in humans?

Answer 36

G6PD

Question 37

polygenic traits

Answer 37

height, intelligence, BP, skin color, metabolic parameters

Question 38

polygenic continuous diseases

Answer 38

HTN, DM

Question 39

polygenic congenital malformations

Answer 39

cleft lip & palate, pyloric stenosis, anencephaly, congenital heart disease

Question 40

polygenic discontinuous diseases

Answer 40

manic-depressive psychosis, rheumatoid arthritis

Question 41

diseases due to non-disjunction

Answer 41

down's syndrome (trisomy 21) turner's syndrome (X0) klinefeiter's syndrome (XXY)

Question 42

positive selection examples

Answer 42

``` alcohol tolerance lactose tolerance sickle cell anemia- heterozygous protects against malaria CF- protects against thyoid tay sachs- protects against TB type AB blood- resistant to cholera ```

Question 43

gene-environment interaction examples

Answer 43

multiple sclerosis, asthma, factor V leiden & OCPs

Question 44

multiple sclerosis

Answer 44

higher incidence far from equator (US, Canada, N. Europe)

Question 45

increased risk of venous thrombosis in oral contraceptive users who are carriers of what mutation?

Answer 45

factor V leiden mutation

Question 46

what is the most common cardiovascular event in young women?

Answer 46

venous thrombosis

Question 47

factor V Leiden mutation

Answer 47

ARG replaced by GLN at 506 R506 is the cleavage site for aPC R506Q is not cleaved, there fore factor V is not inactivated overproduction of thrombin & fibrin-> excessive clotting

Question 48

ACMG recommendations when to do genetic testing for Factor V Leiden mutation & OC use

Answer 48

-<50, MI and smoker

Question 49

routine genetic screening

Answer 49

trisomy 21, trisomy 12, sick cell, GALT, CF, G6PD, PKU, Beta-thelassemia, etc