Ch. 1

Question 1

What is a phenotype?

Answer 1

expression of a genotype

Question 2

What are autosomes?

Answer 2

pairs of chromosomes that are not sex-determining

Question 3

What is a mitochondrial chromosome? What genes does it encode for?

Answer 3

small circular chromosomes in mitochondria; encodes for all tRNA, rRNA, and proteins involved in oxidative metabolism

Question 4

How are mitochondrial chromosomes passed down?

Answer 4

from cytoplasm of fertilized ovum = maternal in origin

Question 5

What is somatic mutation?

Answer 5

mutation that occurs AFTER conception

Question 6

What is chromosomal aberration?

Answer 6

change in physical structure of chromosome

Question 7

What is aneuploidy?

Answer 7

extra or less than 46 chromosomes

Question 8

What are the 3 types of aneuploidy?

Answer 8

monosomy, trisomy, and polysomy

Question 9

What is monosomy?

Answer 9

one chromosome of a pair is present = missing other pair = incomplete (ie: X0)

Question 10

What is trisomy?

Answer 10

a chromosome pair has 1 extra chromosome = 3 chromosomes

Question 11

What is polyploidy?

Answer 11

there is 4+ copies of a chromosome

Question 12

What is translocation?

Answer 12

rearrangement of chromosome arms

Question 13

What is inversion?

Answer 13

chromosomal region reoriented 180 degrees

Question 14

What is a degenerate?

Answer 14

amino acid corresponds to more than 1 codon

Question 15

What is a truncated protein?

Answer 15

protein isn’t full length or proper form = cannot fully function properly

Question 16

What are 6 health problems associated with Down’s Syndrome?

Answer 16

heart defects | GI issues | vision | hearing | infections | intellectual

Question 17

What is mosaicism?

Answer 17

person has two or more genetically different sets of cells in their body

Question 18

Why is Trisomy 21 considered mosaic?

Answer 18

affected individuals have both trisomic (42,XX/Y and XXX) and euploid (44,XX/Y)cell lines.

Question 19

What is the life expectancy of Down Syndrome?

Answer 19

55 yrs

Question 20

What is the screening done for a newly pregnant woman for Down Syndrome?

Answer 20

blood test either 1st trimester w/ cell free DNA or 2nd trimester

Question 21

What is Klinefelter syndrome?

Answer 21

when an XX ovum is fertilized with a Y sperm = XXY = sterile male

Question 22

What is Turner Syndrome?

Answer 22

monosomy disorder with a sex-empty ovum (0) gets fertilized with a sperm (X) = X0 = female appearance and sterile

Question 23

What is penetrance?

Answer 23

how much of the genotype is phenotypically showing

Question 24

What is variable expressivity?

Answer 24

same genes but differ in characteristics or symptoms displayed with varying intensity or presentation (ie: same painter’s palette, different pictures)

Question 25

What is consanguinity?

Answer 25

both partners descended from a common ancestor

Question 26

What is the definition Mendelian?

Answer 26

phenotypes due to alterations at a single gene

Question 27

What is Mendelian disorders?

Answer 27

monogenic human diseases

Question 28

What is inborn errors of metabolism?

Answer 28

autosomal recessive phenotypes associated with deficient activity of an enzyme

Question 29

What is Mendelian genetics?

Answer 29

genes passed from generation to generation ; dominance vs recessive alleles; heterozygous vs homozygous

Question 30

What is a missense mutation?

Answer 30

changes to a different protein by changing a single nucleotide

Question 31

What is a nonsense mutation?

Answer 31

codes for a premature stop codon

Question 32

What is a silent mutation?

Answer 32

changes the codon but no effect on protein product

Question 33

What is a frameshift mutation?

Answer 33

deletion or insertion of an amino acid = shifts the sequence = codons read differently

Question 34

What type of mutation is observed in Edward's syndrome?

Answer 34

trisomy 18 and is a germinal mutation

Question 35

What is mitochondrial inheritance?

Answer 35

comes from maternal mitochondria

Question 36

What kind of diseases do mitochondrial inheritance commonly entail?

Answer 36

affecting oxidative metabolism

Question 37

What is cytogenetics?

Answer 37

studying chromosomes via light microscopy

Question 38

Explain fluorescence in situ hybridization

Answer 38

obtain gene --> make a probe (tag) for a specific target sequence --> tag finds target sequence --> match = glow

Question 39

What is fluorescence in situ hybridization used for?

Answer 39

localization of genes on specific chromosomes

Question 40

What is the limitations of karyotyping?

Answer 40

identifies sex NOT gender ; atypical/mutated genes are not visualuzed

Question 41

What is karyotyping?

Answer 41

staining chromosomes --> rearranged from longest to shortest

Question 42

What is karyotyping used for?

Answer 42

observing chromosome structure and quantity

Question 43

What is DNA analysis?

Answer 43

understanding gene expression via study of DNA sequences on chromosomes

Question 44

What test is used for DNA analysis?

Answer 44

Polymerase Chain Reaction

Question 45

What is PCR?

Answer 45

amplifies gene of interest

Question 46

What is PCR used for?

Answer 46

observing a gene of interest via amplification

Question 47

Simple steps of PCR

Answer 47

denature = open up DNA --> primers bind = Taq polymerase copies template || NEED control DNA to compare and determine if sample has disease of interest

Question 48

What is biochemical analysis?

Answer 48

determine presence/absence of certain protein ; looks for enzymatic defects

Question 49

Phenylketonuria (PKU)

Answer 49

disorder = inability to convert phenylalanine into tyrosine

Question 50

What causes PKU?

Answer 50

absence/defect of enzyme phenylalanine hydroxylase (PAH)

Question 51

What effect does PKU have on an affected individual?

Answer 51

severe intellectual disability unless treated in infancy and childhood by a low-phenylalanine diet

Question 52

What are the 3 stages of embrology?

Answer 52

pre-embryonic; embryonic, and fetal