exam 3 chapter 10

Question 1

inheritance of characters by a single gene may deviate from simple Medelian patterns when…

Answer 1

1. incompletely dominant or codominant
2. multiple alleles
3. pleiotropy
4. epistasis
5. nature and nurture

Question 2

codominance

Answer 2

2 dominate alleles affect phenotype in separate distinguishable ways

Question 3

incomplete dominance

Answer 3

a blend of phenotypes

Question 4

multiple alleles

Answer 4

most genes have MORE THAN 2 allelic forms

example ABO blood I^A I^B i

Question 5

Pleiotropy

Answer 5

a gene with multiple phenotypes example sickle cell and cystic fibrosis

Question 6

epistasis (a)

Answer 6

two or more genes, a gene at one locus alters the phenotypic expression of another gene at a different locus
example:coat color of mice depends on two genes (one determining pigment and one determining if it will be deposited)

Question 7

symptoms of cystic fibrosis

Answer 7

European decent

results in defective or absent chloride transport channels in plasma membranes

mucus buildup in internal organs and inadequate absorption of nutrients in the intestine

Question 8

symptoms of sickle cell

Answer 8

African decent

oxygen content of an affected individual is low, the hemoglobin molecules aggregate and deform into this shape

clump and clog blood vessels to cause physical weakness, pain, organ damage, paralysis and even death

caused by the substitution of a single amino acid in the hemoglobin protein in red blood cells

Question 9

epistasis (b)

Answer 9

two or more genes: polygenic inheritance
when two or more genes have an additive effect
example skin color in humans

Question 10

nature (genotype) and nurture (environment)

Answer 10

some phenotypes depend on both the genotype and the environment
called MULTIFACTORAL because the factors collectively influence phenotype
example: heart disease, diabetes, obesity, cancer
AND hydrangea color depending on soil acidity

Question 11

why are humans not good subjects for research

Answer 11

1. generation time is too long
2. only few offsprings are produced
3. breeding is immoral

Question 12

Pedigree

Answer 12

a family tree that describes the interrelationships of parent and children across generations
inheritance patterns of particular traits can be traced using these

Question 13

name 3 recessively inherited traits

Answer 13

1. albinism
2. cystic fibrosis
3. sickle cell disease

Question 14

albinism

Answer 14

recessive condition characterized by lack of pigmentation in hair

Question 15

carrier

Answer 15

heterozygous individuals that carry the recessive allele but are phenotypically normal

Question 16

some genetic anomalies are cause by ______ alleles

Answer 16

dominant

Question 17

_______ alleles rarely cause a lethal disease, most of the __________ are mild and not life threatening

Answer 17

dominate, abnormalities

Question 18

achondroplasia

Answer 18

form of dwarfism caused by a rare dominant allele

Question 19

hexadactyly

Answer 19

another anomaly cause by a dominate allele where you have 6 fingers or toes

Question 20

chromosomal alterations often lead to ______ or cause a variety of ________ disorders

Answer 20

miscarriages, developmental

Question 21

nondisjunction

Answer 21

pairs of homologous chromosomes do not separate normally during meiosis

one gamete receives two off the same type of chromosomes and another game receives none

leads to ANEUPLOIDY

Question 22

aneuploidy

Answer 22

results from the fertilization of games in which nondisjunction occurred

may result in a trisomic or monosomic zygote

Question 23

trisomic zygote

Answer 23

3 copies of a specific chromosome

Question 24

monosomic zygote

Answer 24

one copy of a particular zygote

Question 25

Down syndrome

Answer 25

an aneuploid condition seen in individuals that inherit 3 copies of chromosome 21

affects 1 in 700 children born in the us

Question 26

aneuploidy of sex chromosomes

Answer 26

nondisjunction of sex chromosomes that can result in Klinefelter syndrome or monosomy (turner syndrome)

Question 27

klinefelter syndrome

Answer 27

caused by an extra X chromosome in males, making their genotype 44 + XXY

Question 28

monosomy (turners syndrome)

Answer 28

caused by one missing X chromosome in females among their genotype 44 + X

Question 29

breakage of a chromosome can lead to 5 types of changes

Answer 29

1. insertion
2. deletion
3. duplication
4. inversion
5. translocation

Question 30

insertion

Answer 30

adds a chromosomal segment

Question 31

deletion

Answer 31

removed a chromosomal segment

Question 32

duplication

Answer 32

repeats a segment

Question 33

inversion

Answer 33

reverses a segment within a chromosome

Question 34

translocation

Answer 34

moves a segment from one chromosome to another

Question 35

fetal testing

Answer 35

to determine if the unborn offspring is carrying any genetic disease or abnormality, certain techniques and tests are preformed on the fetus in the mothers womb

Question 36

amniocentesis

Answer 36

the amniotic fluid (liquid that bathes the fetes) is collected by a syringe and tested for genetic abnormalities

Question 37

chorionic villus sampling (CVS)

Answer 37

a sample of the placenta (embryonic tissue) is removed with the help of suction tube and tested for genetic abnormalities