Genetics

Question 1

how many chromosomes does a somatic cell contain?

Answer 1

46 chromosome (23 pairs) 
it's diploid.

Question 2

How many chromosomes does a gamete have?

Answer 2

23 chromosomes

It’s a haploid (only contains one chromosome from a chromosome pair.)

Question 3

Meiosis

Answer 3

formation of haploid cells from diploid cells.

Question 4

autosomes

Answer 4

tells the cells everything but gender. first 22 of 23 chromosomes. homologous pairs.

Question 5

sex chromosomes

Answer 5

the 23rd pair of chromosomes.

Question 6

karyotype

Answer 6

ordered display of chromosomes.

Question 7

mutation

Answer 7

any inherited alteration of genetic material.

Question 8

base pair substitution

Answer 8

one base pair is substituted for another

Question 9

silent substitution

Answer 9

only one is affected. does not affect to where you can see of feel the mutation.

Question 10

frameshift mutation

Answer 10

insertion or deletion of one or more base pairs. Causes a change in the entire reading frame.

Question 11

spontaneous mutation

Answer 11

occurs in the absence of exposure to known mutagens.

Question 12

mutational hotspots

Answer 12

areas of the chromosomes that have high mutation rates. (C-G)

Question 13

Mutagen

Answer 13

agent known to increase the frequency of mutations.
-radiation
-chemicals
proliferating cells like bone marrow and GI are most affected by mutagens.

Question 14

Euploid Cell

Answer 14

cell has the normal number of chromosomes

-normal haploid and/or diploid

Question 15

polyploid cell

Answer 15

cell has a multiple of the usual diploid number. 
embryonic lethal (account for ~10% of known miscarriages)

Question 16

triploidy

Answer 16

three copies of each chromosome (93=3x23)

Question 17

tetraploidy

Answer 17

four copies of each chromosome. (92=4x23)

Question 18

Aneuploidy

Answer 18

a somatic cell that does not contain a multiple of 23 chromosomes. (trisomy and monosomy) It’s better to have too many than too few.

Question 19

trisomy (trisomic)

Answer 19

3 copies of one chromosome. infants can survive with trisomy of certain chromosomes.

Question 20

Monosomy (monosomic)

Answer 20

1 copy of any chromosome (match not there)

monosomy is lethal.

Question 21

aberrations

Answer 21

disjunction

nondisjunction

Question 22

disjunction

Answer 22

normal separation of chromosomes during cell division

Question 23

nondisjunction

Answer 23

usually the cause of aneuploidy. failure of homologous chromosomes or sister chromatids to separate normally during meiosis or mitosis.

Question 24

if a human fetus has 45 chromosomes in it’s cells it would be called:

Answer 24

Aneuploidy;monosomy

Question 25

trisomy 13

Answer 25

Patau syndrome

polydactyly (multiple digits), mental retardation, microcephaly (smaller head than normal)

Question 26

trisomy 18

Answer 26

Edward’s Syndrome

kidney malformations, protruding intestines, mental retardation, small size

Question 27

trisomy 21

Answer 27

Down Syndrome
1:800 live births
risk increases with parents age

Question 28

Sex Chromosome Aneuploidy: Trisomy X

Answer 28

little physical manifestation
lionization (formation of barbodies. every woman has one barbody but someone with trisomy x would have two)
Symptoms are variable: from no overt symptoms to sterility, menstrual irregularity, and/or mental retardation. Symptoms worsen with each additional X.

Question 29

Turner Syndrome

Answer 29

only one X chromosome
Characteristics:
underdeveloped ovaries (sterile) 
short stature
Webbing of the neck 
edema
underdeveloped breasts; wide nipples (shield chest) 
out turned arms at elbows
low hairline at back of neck

Question 30

Klinefelter syndrome

Answer 30

multiple Xs and one Y. 
Male appearance
fertile
possible breast development at puberty 
underdeveloped male genitals 
long limbs
Abnormalities increase with each X.

Question 31

Cri du chat syndrome

Answer 31

deletion of short arm of chromosome 5.
low birth weight, mental retardation, and microcephaly.
duplication in the same region as cri du chat causes mental retardation but no physical abnormalities

Question 32

inversions.

Answer 32

two breaks on a chromosome.
reversal of the gene order.
usually occurs from a breakage that gets reversed during reattachment.
will often affect offspring.

Question 33

translocations

Answer 33

the interchanging of material between nonhomologous chromosomes.
when two chromosomes break and the segments are rejoined in an abnormal arrangement.

Question 34

robertsonian translocation

Answer 34

most common example. Between chromosomes 14 and 21. It forms one trisomy because the really small one gets lost.
chromosomes 13,14,15,21&22 are most susceptible bc they have one long arm and one very short arm.
Carriers are usually normal but their offspring often have serious deletions or duplications.

Question 35

Fragile X syndrome

Answer 35

site on the long arm of the X chromosome. You lose the info.

Question 36

Locus

Answer 36

position of a gene along a chromosome. Location.

Question 37

Allele

Answer 37

a different form of a particular gene at a given locus.

Question 38

autosomal dominant disorders

Answer 38

abnormal allele is dominant and normal allele is recessive
no generation skipping
no carriers (all or nothing)
transmit to 50% of offspring

Question 39

autosomal recessive disorders

Answer 39

abnormal allele is recessive. must be homozygous for the trait to be expressed. Consanguinity(incest) increases possibility.

Question 40

true or false: the Y chromosome contains only a few dozen genes, so most of the sex-linked traits are located on the X chromosome.

Answer 40

true

Question 41

how many genes in the general population are associated with obesity?

Answer 41

32. it would only account for 22 lbs so obesity if a combination of genes and environment.

Question 42

epigenetics

Answer 42

changed in gene expression due to the environment and not changed in DNA.
usually occur after conception but before birth.
these changes can predict fact accumulation in children

Question 43

true or false: “common” obesity cannot be explained by epigenetics

Answer 43

false.

common obesity can likely be explained by epigenetics.

Question 44

what does leptin do?

Answer 44

controls hunger
induces lipolysis
increases brown fat 
increases insulin sensitivity(reduced ceramide)
increases mitochondiral biogenesis
induces weight loss when leptin is low.

Question 45

why dont leptin injections work on people?

Answer 45

because we already have a lot of leptin but are missing receptors so we are not using it right. They would work on people who dont produce leptin.

Question 46

MC4R mutation

Answer 46

Melano cortin 4 receptors.
most common monogenic cause of obesity.
when activated it tells the pancreas to turn off.

Question 47

Prader-Willi Syndrome

Answer 47

hypogonadotropic hypogonadism
mental retardation 
obesity 
hypotonia 
hyperphagia

Question 48

Bardet-Biedl Syndrome

Answer 48

learning diasability
polydactyly (6 fingers)
renal disorders
hypogonadism 
obesity