Ch. 6 - Heredity

Question 1

Homologous chromosomes: a pair of chromosomes that contains ____ (gene for gene). Each parent contributed ____ of the chromosome in the pair and thus different alleles may exist for a gene (dominant and recessive or incomplete dominance (color blending) / co-dominant such as blood type).

Answer 1

____
same genetic material
1

Question 2

law of segregation: one member of each chromosome pair migrates to an ____ so that each gamete is ____ (aka each gamete has only one copy of each allele), occurs in ____.

Answer 2

opposite pole
haploid
anaphase I

Question 3

Law of independent assortment: migration of homologues within one pair of homologous chromosomes ____ influence
the migration of homologues ____ (independent assortment of alleles)

Answer 3

does not

of other homologous pairs

Question 4

incomplete Dominance: ____ of expressions of alleles (e.g. R red, R’ white, RR’ comes out pink) (unique hetero phenotype)

Answer 4

blending

Question 5

Codominance: Both inherited alleles are ____ (e.g. blood types A and B or both can show up as AB if expressed)

Answer 5

completed expressed

Question 6

Multiple alleles: Blood groups have ____, the codominant A and B and the O, leading to 4 possible genotypes (phenotypes?): AO (A type), BO (B type), AB (codominant AB type), OO (O type)

Answer 6

3 possible alleles

Question 7

Epistasis: one gene affects phenotypic expression of ____. ____ (one gene controls (turn on/off) the production of pigment, and 2nd gene controls color or amount). If 1st gene codes for ____ => 2nd gene has no effect.
CCBx => black fur in mice ccxx => ____

Answer 7

2nd gene
pigmentation
no pigment
no pigment

Question 8

Pleiotropy: single gene has ____ (gene in pea plants that expressed seed texture also influences phenotype of ____ and water uptake; ____ leads to different health conditions).

Answer 8

more than 1 phenotypic expression
starch metabolism
sickle cell anemia

Question 9

Polygenic inheritance: the interaction of ____ to shape a ____ w/ continuous variation (____, skin color).

Answer 9

many genes
single phenotype
height

Question 10

Linked genes: two or more genes that reside on the same chromosomes and thus cannot separate ____ because they are physically ____ (inherited together). Linked genes exhibit recombination about ____ of the time.

In a cross of BbVv x bbvv (says that BV and bv are linked and each is in a homologues). We only get BV or bv and no Bv or bV. However, if there is ____, we may get 18% of Bv and bV.

• Greater recombination frequencies (18% above) means ____ of genes apart on the same chromosome.

Answer 10

independently
connected
18%

recombination

farther distance

Question 11

Sex-linked: refers to ____ resides on sex chromosome; when male (XY) receives an X from ____, whether it is dominant or recessive will be expressed because there is no copy on the Y chromosome.

Answer 11

single gene

mother

Question 12

Sex-influenced: can be influenced by ____ carrying trait (e.g. Bb female not bald, Bb male is)

Answer 12

sex of individual

Question 13

Penetrance: ____ an organism with a specific genotype will express a ____

Answer 13

probability

particular phenotype

Question 14

Expressivity: term describing the ____ for a specific genotype

Answer 14

variation of phenotype

Question 15

X-inactivation: during embryonic development in female mammals, one of two X chromosomes does not ____ => dark and coiled compact body chromosome (____) => cannot be ____. Thus, only the genes on the other X chromosome will be expressed. Either one can be inactivated => genes in the female will not be expressed similarly, so all cells in a female mammal not necessarily ____ (calico cats).

Answer 15

uncoil into chromatin
barr body
expressed
functionally identical

Question 16

Hemophilia: cannot form blood clot. XHXh is a normal carrier. But if XH is ____ => Xh is expressed. (female x-inactivation)

Answer 16

inactivated

Question 17

Nondisjunction: failure of one/more chromosomes pairs or chromatids to ____ during ____ (failure of two chromatids of a
single chromosome during anaphase) or ____(homologous chromosomes to separate during Meiosis I or sister chromatids to separate during Meiosis II; result in ____ or ____; ex Down syndrome) – note: specifically during ____!

Answer 17

separate
mitosis
meiosis
trisomy
monosomy

Question 18

Mosaicism in cells that undergo ____ in ____ during embryonic development; fraction of body cells have extra or missing chromosome

Answer 18

nondisjunction

mitosis

Question 19

Polyploidy: all chromosomes undergo ____ and produce gametes with ____ the number of chromosomes. Common in ____.

Answer 19

meiotic nondisjunction
twice
plants

Question 20

Point mutation: single nucleotide changes causing substitution, insertion, deletion (latter 2 could cause frameshift). - ____ mutation: Purine to purine or pyrimidine to pyrimidine
- ____ mutation: purine to pyrimidine or vice versa

Answer 20

transition

transversion

Question 21

Aneuploidy: genome with ____ chromosome XO ____, physically abnormal; ____ (XXY); Down Syndrome (Trisomy 21)

Answer 21

extra/missing
nondisjunction
trisomy 21
sex chromosome
sterile
klinefelter

Question 22

Chromosomal abberations: chromosome segments are changed.

• Duplications: chromosome segment is repeated on ____.
• Inversions: chromosome segments are rearranged in ____.
• Translocation: segment is moved to ____. Can be ____ (two non-homologous chromosomes swap chunks) or ____ (one chromosome from a pair becomes attached to another from a pair – e.g. an extra chromosome 21 attached to 14 can cause Downs as well, ____)

Answer 22

same chromosome
to another chromosome
reciprocal
robertsonian
tripled 21 chunk

Question 23

Chromosomal Breakage – spontaneous or induced (mutagenic agents, Xrays). Deficiency = ____

Answer 23

lost fragment

Question 24

Mutagenic agents include cosmic rays, Xrays, UV rays, radioactivity, chemical compounds include ____ (inhibits ____ causing polyploidy), mustard gas. Mutagenic agents are generally also ____.
- Proto-oncogenes stimulate normal growth; if mutated become ____  cancer.

Answer 24

colchiline
spindle formation
carcinogenic
oncogenes

Question 25

PKU (inability to product proper enzyme for ____; degradation
product ____ accumulates), cystic fibrosis (____ in tracts)

Answer 25

phenylalanine breakdown
phenylpyruvic acid
fluid buildup

Question 26

Tay-sachs (____ defect; can’t breakdown ____ for normal brain fxn)

Answer 26

lysosome

lipids

Question 27

sickle-cell (defective hemoglobin due to ____ mutation)

Answer 27

substitution

Question 28

Huntingtons (____ nervous system disease)

Answer 28

degenerate

Question 29

hemophilia (abnormal ____)

Answer 29

blood clotting

Question 30

Turner’s doesn’t typically cause ____, but Downs, Kline, and Cri Du Chat (deletion on ____) do

Answer 30

mental retardation

chromosome 5

Question 31

Extranuclear inheritance: extranuclear genes are found in ____ and ____. Defects in mito DNA can ____
cell’s ATP production. Mitochondria passed to zygote all come from ____, so all related diseases are ____.
Note that mitochondria have their own ____ that make mitochondrial proteins w/in mitochondrial matrix!

Answer 31

mitochondria
chloroplasts
reduce cell's ATP production
mother
mother inherited
~70S ribosomes

Question 32

Homozygous: two copies of the same allele (AA or aa). Heterozygous: different alleles of the same gene (Aa).
Note that mitochondria have their own ____: one single copy of a gene instead of two. (male has XY sex chromosome
Note that mitochondria have their own ____).

Answer 32

hemizygous

hemizygous

Question 33

• Lethal gene: cross between Aa and Aa, we get AA:2Aa:aa. If “aa” was lethal, we would have AA and Aa as ____ ratio.

Answer 33

1:2

Question 34

f the phenotype “skips” generations be suspicious of an ____ disorder. If no skip, most likely an ____ disorder. Be suspicious for ____, if a father doesn’t have the phenotype, none of his ____ display it.

Answer 34

autosomal recessive
autosomal dominant
x-linked recessive
daughters

Question 35

Mitochondrial DNA is an exception to the ____

Answer 35

universality of genetic code