Highlighted content wk 1

Question 1

1) Define aneuploid.
2) When is this term usually used?

Answer 1

1) Wrong number of copies
2) In relation to one chromosome in an individual

Question 2

1) Define autosomes
2) Define sex chromosomes

Answer 2

1) Non-sex chromosomes
2) X and Y

Question 3

mRNA is transported from the nucleus to the cytoplasm where the encoded information is translated into the amino acid sequence of a protein. Does this occur before or after processing?

Answer 3

After

Question 4

What requires the interaction of mRNA, ribosomes (rRNA), tRNA molecules, amino acids, enzymes, and energy sources?

Answer 4

Translation

Question 5

Methylation is an example of what?

Answer 5

Genetic imprinting (the parental “tagging” of alleles that prevent transcription)

Question 6

Are mitochondrial genes are inherited exclusively maternally, paternally, or from both?

Answer 6

Exclusively maternally

Question 7

What type of genetic disorder’s defect is due to an excess or a deficiency of the genes contained in whole chromosomes or chromosome segments?

Answer 7

Chromosome disorders

Question 8

What causes single-gene disorders?

Answer 8

Mutations in individual genes

Question 9

“disease is the result of multiple different genes acting together, often in concert with environmental factors” describes what kind of genetic disorder?

Answer 9

Multifactorial inheritance

Question 10

The primary oocyte undergoes ______________________ and then waits until puberty

Answer 10

prophase I

Question 11

What occurs during prophase I?

Answer 11

Homologues are condensed and separated

Question 12

Mutations in individual genes can result in what kind of disorder?

Answer 12

Single-gene disorders

Question 13

Define polymorphism

Answer 13

Two or more versions of an allele, with each comprising at least 1% of the population

Question 14

What does locus relate to?

Answer 14

location

Question 15

Alternative versions of a locus on the DNA code are called what?

Answer 15

Alleles

Question 16

1) Define genotype
2) Define phenotype

Answer 16

1) The genetic material in a person – in a specific locus the two alleles occupying that locus on two homologues
2) The expressed physical traits of the genotype

Question 17

The alterations that wind up on the _________ strand are the mutations we are talking about

Answer 17

protein

Question 18

True or false: SNPs only involve a single location

Answer 18

True

Question 19

Frameshift mutations: When the insertion / deletion number of nucleotides is not a multiple of three, what happens?

Answer 19

Everything downstream is messed up

Question 20

Dynamic mutation:
Often the wild type allele is polymorphic with varying number of tandem repeats, however, the _____________ expands as it is passed down in some families, causing abnormalities of gene expression

Answer 20

number

Question 21

How do you track the rate of disease-causing gene mutations: what 3 things make the frequency traceable?

Answer 21

1) You have to look at incidence of new cases not present in mom or dad
2) Disease has to be caused by single mutation
3) Has to be evident in baby

Question 22

Achondroplasia:
1) FGFR3 binds to _______________________ factors
2) What is the cause of achondroplasia?

Answer 22

1) fibroblast growth factors
2) Proliferation of chondrocytes at growth plate is inappropriately inhibited due to constitutive activation of FGFR3

Question 23

Delayed motor involvement, dental crowding, OSA, otitis media, hydrocephalus, and foramen magnum stenosis are all potential complications of what genetic condition?

Answer 23

Achondroplasia

Question 24

1) Define homozygous
2) Define heterozygous
3) Define compound heterozygous
4) Define hemizygous and give an example

Answer 24

1) Having a pair of identical alleles
2) Having two different alleles – one mutant and one wild type
3) Having two mutant alleles
4) Only one allele (MC a male with the mutant allele on single X chromosome)

Question 25

List the 3 typical patterns single gene disorders tend to follow

Answer 25

Autosomal recessive Autosomal dominant X-linked

Question 26

Define Penetrance

Answer 26

probability that mutant allele or alleles will have any phenotypic expression at all

Question 27

When frequency of expression is less than 100% - in other words, when at least someone with the genotype completely fails to demonstrate disease – it is said to show what kind of penetrance?

Answer 27

“reduced” or “incomplete”

Question 28

True or false: the baby's sex doesn't matter for autosomal genes mendelian inheritance

Answer 28

True

Question 29

A disease demonstrates “incomplete dominance” when ________________ dominant individuals suffer more severely from autosomal dominant disease than their _______________ counterparts

Answer 29

homozygous; heterozygous

Question 30

True or false: most diseases are incomplete dominant

Answer 30

True

Question 31

65 highlight edit this card to simplify 1) Hemochromatosis is a disease of iron overload resulting in mutation of the ____________ gene. 2) What is its penetrance and expressivity? 3) What inheritance pattern does it have?

Answer 31

1) HFE 2) Incomplete penetrance; variable expressivity 3) Autosomal recessive

Question 32

1) What absorbs iron in the body? 2) What two things determine iron stores in the body?

Answer 32

1) Enterocytes in small intestine 2) Dietary absorption and release of iron from macrophages that phagocytize RBC’s

Question 33

1) Does hepcidin block or enable further iron absorption? 2) How is hepcidin affected by a mutant HFE gene?

Answer 33

1) Block 2) Hepcidin signaling is inhibited, allowing the release of iron

Question 34

What are the two types of hereditary hemochromatosis?

Answer 34

Homozygous and compound heterozygous

Question 35

True or false: with hereditary hemochromatosis, homozygosity does not always lead to dz

Answer 35

True (b/c penetrance varies)

Question 36

____________________, as an example, is incompletely dominant, because it is usually fatal when homozygous

Answer 36

Achondroplasia

Question 37

Male-limited precocious puberty: 1) What type of genetic disorder is this an example of? 2) What is mutated? 3) What does this mutation do? 4) What are the physical Sx? 5) Do heterozygous women get this?

Answer 37

1) Sex-linked autosomal dominant 2) LCGR gene which encodes receptor for luteinizing hormone 3) Mutations constitutively activate receptors signaling luteinizing hormone even in the absence of hormone 4) Affected boys develop secondary sex characteristics with growth spurt at 4 years of age; epiphyseal fusion occurs early and adults have short stature 5) No

Question 38

Give an example of a factor deficient in hemophilia A

Answer 38

Factor VIII (8)

Question 39

Who can hemophilia A be inherited from?

Answer 39

Either mom or dad

Question 40

With X-linked dominant conditions, affected females are roughly twice as common as affected males, but they typically have milder expression of the phenotype Why?

Answer 40

Incomplete dominance

Question 41

Why are Mitochondrial DNA disease so rare?

Answer 41

Because energy production is so fundamental and ubiquitous to all cellular function

Question 42

Achondroplasia: 1) What do is the risk of inheritance in *subsequent* children of unaffected parents? 2) How about offspring of affected individual?

Answer 42

1) Same odds you started with (small) since you're not a carrier 2) 50%

Question 43

Pedigrees: 1) What do empty squares and circles mean? 2) What do fully filled in squares and circles mean? 3) What do squares and circles with dots in the middle mean?

Answer 43

1) Unaffected male (square) and female (circle) 2) Affected male and female 3) They carry the disease but don't show it ("obligate carrier")

Question 44

Autosomal recessive disorder are typically seen in siblings and potential offspring of the proband – not in parents, offspring, or other relatives. Why?

Answer 44

Autosomal recessive patterns manifest by skipping generations as the affected are usually children of unaffected carriers. (answer is from google)

Question 45

Autosomal Dominant Inheritance: 1) In what generations does the phenotype usually appear? 2) True or false: Each affected person has an affected parent. Explain your answer and list any exceptions. 3) Any child of affected heterozygous parent has ____% chance of having disease 4) Who are equally likely to give it to children of either sex: males, females, or both?

Answer 45

1) In every generation 2) True; exceptions are due to incomplete penetrance, variable expressivity, and new mutations 3) 50% 4) Males and females equally likely to give it to children of either sex

Question 46

Sex-limited Autosomal Dominant Disease: Male-limited precocious puberty 1) What gene is mutated? 2) What does this mutation do? 3) What are the physical Sx?

Answer 46

1) LCGR gene which encodes receptor for luteinizing hormone 2) Constitutively activate receptors signaling luteinizing hormone even in its absence 3) Affected boys develop secondary sex characteristics with growth spurt at 4 years of age; epiphyseal fusion occurs early and adults have short stature

Question 47

True or false: Women heterozygous for male-limited precocious puberty do not get it

Answer 47

True