chapter 13 - patterns of inheritance Flashcards

1
Q

chromosomes def

A

long molecules of DNA wrapped around nucleosomes…

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2
Q

what percentage of DNA codes for function protein in eukaryotes… what about prokaryotes?

A

Around 1% for eukaryotes, 90% for prokaryotes

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3
Q

how many chromosomes do humans have?

A

46, 23 pairs

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4
Q

how are human chromosomes arranged?

A

in the order of size, though the last one - #23 is the sex chromosome

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5
Q

human male chromosome

A

XY

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6
Q

human female chromosome

A

XX

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7
Q

homozygous def

A

same alleles

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8
Q

heterozygous def

A

different alleles

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9
Q

genotype def

A

the actual alleles inherited

ex: genes coding for flower color AA, Aa, or aa

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10
Q

phenotype def

A

the physical characteristics or traits of an organism

ex: purple flowers

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11
Q

who and when were the principles of genetics created [by]?

A

mendel in 1860s

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12
Q

how did mendel create these principles?

A

used pea-plants which self-pollinate, grow easily + quickly, and have 7 contrasting traits

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13
Q

principle of dominance

A

1 trait is ALWAYS expressed

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14
Q

principle of segregation

A

during meiosis homologous chromosomes separate into each cell

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15
Q

what is a cross?

A

making of 2 organisms

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16
Q

P = ?

A

parental generation

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17
Q

F1 = ?

A

first generation

18
Q

F2 = ?

A

second generation

19
Q

how can we predict results?

A

punnett squares determine probability or chances of a specific outcome

20
Q

principle of independent assortment

A

chromosomes segregate independently of one another during meiosis - only get 1 pair of each cell

21
Q

what other factors can affect offspring separate from predictions?

A

carrying capacity or amount of resources it can sustain:

I. food
II. water
III. habitat

22
Q

product rule

A

chance of 2 or more independent events occurring simultaneously = probability of each multiplied

23
Q

dihybrid cross def

A

2 traits, hybrid for both

24
Q

what kind of a trait is height? what is it influenced by?

A

Height is a multifactorial trait-

multifactorial inheritance is influence by more than 1 gene and the environment

25
can some alleles be neither dominant nor recessive?
yes
26
are traits only controlled by a single allele/gene?
no; many traits are controlling by multiple alleles or multiple genes
27
what are 4 exceptions to mendel's law?
I. Incomplete dominance II. Multiple alleles III. Codominance IV. polygenic traits
28
incomplete dominance def
the heterozygous phenotype is somewhere BETWEEN the two homozygous phenotypes AND NEITHER allele is COMPLETELY dominant OR COMPLETELY recessive ex: red + white flowers make pink
29
codominance def
both traits are fully and SEPARATELY expressed ex 1: red + white flowers make red and white speckled ex 2: blood type AB - fully A and fully B
30
what is blood type is an example of?
codominance AND multiple alleles multiple alleles - genes with more than 2 allele forms : A, B, and i codominance - blood type fully A and fully B
31
polygenic inheritance def
a trait produced by two or more genes, and usually shows a RINGE in phenotype ex: skin color, eye color, height, personality
32
what can occasionally in polygenic inheritance?
epistasis: one gene overshadows all of the others ex: labrador retriever fur colors, eye colors, and albinism [ bad gene(s) make bad traits, all bad people make bad society ]
33
pleitropy def
genetic effect of 1 gene on multiple phenotype traits- alleles at 1 locus may have effects on 2 or more traits ex: sickle cell [ 1 bad gene makes mANY bad traits, bad powerful person make bad... everything]
34
epistasis def
the interaction between genes at two or more loci.... the phenotype differs from what would be expected if the loci were expressed separately ex: polygenic
35
what mendel principle are linked genes an exception to?
principle of independent assortment
36
linked genes def
genes physically located on the same chromosome will be inherited together ex: blonde hair + blue eyes, red hair + freckles
37
how are linked genes separated?
only can be separated by crossing over ***the farther the distance between the genes, the greater chance of being unlinked***
38
sex-linked traits def
Y chromosome carry few genes X chromosome contains MANY genes that affect many traits ex: colorblindness
39
sex linked genes def
genes on sex chromosomes
40
x-linked genes def
genes on the X chromosomes are linked - females inherit the trait as normal and principle of dominance applies - males inherit the gene on the X but not the Y
41
how are x-linked genes passed through parents to children?
moms to sons; dads to daughters males only have one X, they express it whether it is dominant or recessive