2. Genes and Genetic Diseases

Question 1

insertion or deletion of 1 or more base pairs

Answer 1

frameshift mutation

Question 2

RNA directs synthesis of a polypeptide at a ribosome

Answer 2

translation

Question 3

RNA is synthesized from DNA template and form messenger RNA (mRNA)

Answer 3

transcription

Question 4

silent, missence, and nonsense are all what type of genetic mutation

Answer 4

base pair substitution

Question 5

What is seen in Down syndrome?

Answer 5

intellectual disability, distinctive facial features, and increased risk of leukemia

Question 6

only 1 gene needed for expression; genders equal

Answer 6

autosomal dominant

Question 7

cells w/ compete extra sets of chromosomes

Answer 7

polyploidy (usually spontaneous aborted or stillborn)

Question 8

exchange of material between 2 non-homologous chromosomes

Answer 8

reciprocal translocation

Question 9

mutation -> new codon -> new AA

Answer 9

missense mutation

Question 10

On what chromosomes do Robersonian translocations occur?

Answer 10

13, 14, 15, 21, and 22

Question 11

What AD disease is known for its delayed age of onset (about 40 y/o)?

Answer 11

Huntington’s disease

Question 12

harmful agent that increases risk of chromosomal breakage

Answer 12

clastogen (ionizing radiation, viral infection)

Question 13

long arms of 2 non-homologous chromosomes combine at the centromere to form a single chromosome and the short arms are usually lost

Answer 13

Robertsonian translocation

Question 14

List 3 examples of autosomal dominant disorders

Answer 14

Huntington’s disease, Von Willebrand’s disease, and Marfan’s syndrome

Question 15

genes position along a chromosome

Answer 15

locus

Question 16

Chromosomes and pairs of gametes

Answer 16

23 chromosomes as singles (haploid)

Question 17

Example of expressivity

Answer 17

neurofibromatosis

Question 18

Fragile X Syndrome

Answer 18

gap on long arm of X chromosome

Question 19

certain number of factors/genes must be affected before phenotype is expressed

Answer 19

threshold of liability

Question 20

any agent known to increase frequency of mutation

Answer 20

mutagen

Question 21

Turner Syndrome

Answer 21

Monosomy X

Question 22

What role does the ribosome play in forming a polypeptide?

Answer 22

provides an enzyme that catalyzes the formation of covalent peptide bonds between adjacent AA -> growing polypeptide chain

Question 23

What chromosome is cystic fibrosis linked to?

Answer 23

chromosome 7

Question 24

Cri-du-chat syndrome

Answer 24

Chromosome 5 - deletion of short arm

Question 25

What is seen in Klinefelter syndrome?

Answer 25

breast development, small testicles, typically sterile and some intellectual impairment

Question 26

Klinefelter Syndrome

Answer 26

XXY condition

Question 27

cells w/ a multiple of the normal number of chromosomes

Answer 27

euploid cells

Question 28

describe the chromosomes in triploidy and tetraploidy cells

Answer 28

- triploidy = 3 complete sets of chromosomes - tetraploidy = 4 complete sets of chromosomes

Question 29

Patau syndrome

Answer 29

trisomy 13

Question 30

Edward's syndrome

Answer 30

trisomy 18

Question 31

aneuploidy is a result of what?

Answer 31

nondisjunction - homologous chromosomes or sister chromatids fail to separate during mitosis or meiosis

Question 32

Name 4 types of abnormalities in chromosome structure

Answer 32

- deletion - duplication - inversion - translocation

Question 33

List 3 examples of AR diseases

Answer 33

cystic fibrosis, sickle cell anemia, and albinism

Question 34

range of phenotypes that vary between patients and specific genotype

Answer 34

expressivity

Question 35

what is the recurrence of autosomal dominant

Answer 35

50%

Question 36

traits in which variations are caused by combined effect of multiple genes (polygenic)

Answer 36

multifactorial inhertence

Question 37

different forms of a gene

Answer 37

alleles

Question 38

List 3 examples of X-linked inheritance

Answer 38

color blindness, Duchenne muscular dystrophy, and hemophilia A

Question 39

RNA sequences that are spliced out are called ___ and sequences that become mRNA to code for proteins are called \_\_\_

Answer 39

introns; exons

Question 40

Newborns w/ trisomy of what chromosomes can survive?

Answer 40

trisomy 13, 18, 21, or X

Question 41

Down Syndrome

Answer 41

Trisomy 21

Question 42

mutations located on the X chromosome; females usually carriers; males affected

Answer 42

X-linked Inheritance

Question 43

name 2 types of aneuploidy cells and which type is worse

Answer 43

monosomy and trisomy; monosomy is worse due to the lack of genetic material

Question 44

What molecule includes the site where the AA attaches during translation?

Answer 44

the tRNA

Question 45

What is the recurrence of autosomal recessive?

Answer 45

50% carrier, 25% normal; 25% affected

Question 46

Chromosomes and pairs of somatic cells

Answer 46

46 chromosomes in 23 pairs (diploid)

Question 47

a cell that does not contain a multiple of 23 chromosomes (missing or additional individual chromosomes)

Answer 47

aneuploidy

Question 48

What is expressivity influenced by?

Answer 48

environment, genes at other loci and mutations at different points on loci

Question 49

What is a common example of incomplete penetrance

Answer 49

retinoblastoma - about 90% who carry the gene will get the disease (90% penetrance)

Question 50

What is seen in cri-du-chat syndrome?

Answer 50

low birth weight, severe intellectual disability, microcephaly, heart defects, and characteristic high pitched cry

Question 51

% of individuals w/ a genotype who also exhibit the expected phenotype

Answer 51

penetrance

Question 52

a locus that has 2 or more alleles that each occur with an appreciable frequency in a population

Answer 52

polymorphic

Question 53

mutation -\> new codon -\> same AA

Answer 53

silent mutation

Question 54

mutation -\> new codon -\> stop codon

Answer 54

nonsense mutation

Question 55

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

Answer 55

partial trisomy

Question 56

What is seen in Turner syndrome?

Answer 56

short stature, neck webbing, spaced nipples, usually sterile, but no intellectual disability

Question 57

individuals w/ disease-causing genotype but not the phenotype

Answer 57

incomplete penetrance

Question 58

What is seen in Fragile X syndrome?

Answer 58

more common in males; causes intellectual disability (2nd most common under Down syndrome)

Question 59

2 copies of the genes needed to influence the phenotype; genders equal

Answer 59

autosomal recessive