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Genetics > Exam 1- My Q's > Flashcards

Exam 1- My Q's Flashcards

(83 cards)

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1
Q

What does each chromosome have that distinguishes them from others?

A

a characteristic centromere position and unique length and shape

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2
Q

karyotype

A

display of the chromosome complement of a cell or individual

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3
Q

homologous chromosome pair

A

same length, shape, centromere position, identical genetic potential, not genetically identical

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4
Q

How many autosomes do humans have

A

22

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5
Q

why can sex chromosomes interact even though they are different sized and shaped

A

can behave as homologous because of their pseudoautosomal regions

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6
Q

haploid or diploid?
egg
zygote
adult

A

egg: n
zygote: 2n
adult: 2n

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7
Q

What are germ cells?

A

they are cells in the sex organs testis and ovaries that can divide my meiosis to produce gametes

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8
Q

Key words for prophase 1
metaphase 1
anaphase
telophase

A

prophase: crossing over, condensation, synapsis (pairing of homologous pairs)
metaphase: line up at equator of cell
anaphase: disjunction
telophase: splitting cell into 2, cleavage

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9
Q

What are the results of prophase 1

A

4 chromatids- tetrad

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10
Q

where and when does crossing over happen?

A

chiasma during prophase 1

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11
Q

what are chromosomes like in prophase 1

A

consist of 2 sister chromatids. still attached

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12
Q

what is the main event of phase 1 and 2 of meiosis

A

phase 1: reduces ploidy of original germ cell from diploid to haploid
phase 2: recombines genetic info further now that chromosomes have crossed over

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13
Q

disjunction, what is it when does it happen

A

movement to opposite poles in cell, anaphase I and II

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14
Q

What is the difference between telophase 1 and 2

A

in telophase 2 the chromatids are mosaic, mixed info between mom and dad

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15
Q

What is the final result of meiosis phase 2

A

4 genetically unique daughter cells

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16
Q

how many cells mature in spermatogenesis vs oogenesis

A

sperm: 4
ovum: 1

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17
Q

What are mendel’s 3 proposals

A

1: there are recessive and dominant traits
2: there are unit factors or genes that are passed from parent to offspring. these unit factors exist in alternative forms
3: 2 alleles segregate during gamete formation, there is an equal probability that a gamete receives 1 allele from each gene

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18
Q

What is mendel’s 4th proposal

A

segregating pairs of alleles assort independently from one another.

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19
Q

Autosomal recessive inheritance

A

the trait appears in progeny of unaffected parents. appears equally in both sexes

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20
Q

Autosomal dominant inheritance

A

trait almost always appears in each generation, usually at least 1 affected parent. more common in heterozygotes than homozygotes

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21
Q

wildtype allele

A

most common phenotype, usually dominant

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22
Q

mutant allele

A

has a mutation, usually recessive

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23
Q

polymorphic allele

A

more than 1 wildtype allele of a given gene that coexist

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24
Q

haplosufficiency

A

when a single functional allele is sufficient to bring about a function

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25
complete dominance
an allele is expressed whenever present
26
incomplete dominance
neither allele is fully dominant, forms a new intermediate phenotype
27
codominance
2 alleles are both dominant, forms a new phenotype where both are present, spotted.
28
Lethal alleles
mutations in genes whose proteins are essential for survival, the organism can die from it
29
recessive lethal allele
homozygotes don't survive, 2 copies allele needed to kill
30
dominant lethal allele
only 1 allele needed to kill, very rare
31
pleiotropy
expression of an allele that has multiple phenotypic effects. can be expressed at different developmental stages
32
x linked recessive
more males affected, no sons receive it. affected females pass it to all sons
33
x linked dominant
affected males pass to all daughters but not sons
34
dosage compensation
females have the potential to make twice the x linked genes but have gene inactivation randomly. preventing the expression of x linked genes every single time
35
epistasis
2+ genes influence a trait and one overrides the other
36
recessive epistasis
the homozygous genotype prevents the expression of another
37
dominant epistasis
a dominant allele of one gene overrides the expression of another gene
38
gene interaction
2 or more genes influence a single trait
39
complementary gene interaction
at least 1 dominant allele of each gene is needed to produce a certain phenotype. 1 allele is stronger than the other
40
euploidy
having an exact multiple of complete chromosome sets | ex: haploid, diploid
41
aneuploidy
having an extra or missing individual chromosome
42
monosomic
loss of a single chromosome | 2n-1
43
trisomy
gain of a single chromosome | 2n+1
44
why are triploids usually sterile?
because they cant be equally distributed into their own cells, they produce aneuploidy gametes.
45
What are the ways chromosomes numbers can be varied?
nondisjunction, complete nondisjunction, mitotic slippage, hybridization
46
nondisjunction
during meiosis I or II, chromosomes don't correctly separate
47
what are the results of nondisjunction
offspring with one extra or one missing chromosome, anueploidy
48
complete nondisjunction
no cell separation, one daughter cell empty in meiosis 1, cell separates only in meiosis 2
49
mitotic slippage
mitosis fails and never happens, cell never separates results in tetraploid cell
50
1:1
Test cross
51
3:1
F1xF1 single trait- normal expected results
52
9:3:3:1
dihybrid normal results, 2 traits
53
1:2:1
incomplete dominance
54
1:1:1:1
codominance
55
2:1
recessive lethal
56
9:3:4
recessive epistasis (albino scenario)
57
12:3:1
dominant epistasis
58
9:7
complementary interaction/ duplicate recessive epistasis (at least 1 capital of each gene to give a certain phenotype)
59
down syndrome
2n+1 autosomic
60
patau
2n+1 autosomic
61
edward
2n+1 autosomic
62
turner
sex linked 2n-1 (X)
63
klinefelter
sex linked 2n+1 (XXY)
64
triplox
sex linked 2n+2 to + 4, extra x
65
what are the consequences of aneuploidy
can cause abnormal phenotype due to imbalance of gene expression
66
how does a trisomy express
excessive amounts of gene products
67
how does a monosomy express
deficient amounts of gene products
68
what can non disjunction lead to
aneuploidy
69
what can complete nondisjunction cause
autopolyploidy, like a triploid
70
what can mitotic slippage lead to
autopolyploidy
71
what can hybridization lead to
allopolyploidy, sterility
72
allopolyploidy
more than 2n (polyploidy) with 2 different but similar species
73
autopolyploidy
more than 2n all chromosomes from the same species.
74
Which hybrids are sterile and which arent
if there is a nondisjunction, then there are 2 copies of each chromosome (amphidiploid) then those hybrids are viable offspring. If 2 species mate but meiosis performs like normal, the gametes are non viable because there are not even pairs.
75
What causes deletion and duplication
unequal crossover
76
What is intercalary and terminal deletion
intercalary- deletion in interior | terminal-deletion at the end
77
what happens if there is a deletion on a very short chromosome
hypoploidy: under representation of a gene
78
what happens if there is a duplication
hyperploidy: over representation of a gene
79
what is paracentric and pericentric inversion
para- does not include centromere | peri-includes centromere
80
What are some of the possible effects of inversion
could affect fertility, causes loop formation, a fragment is lost
81
What are the consequences of translocations
reduced fertility
82
What if translocation happens during meiosis
1 chromosome can be homologous to more than one other, creates cross or diamond type formation gametes are duplicated and deficient
83
robertsonian translocation
the extreme of short chromosomes attach to longer chromosomes. usually on acrocentric (centrosome near end)

Genetics (8 decks)

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