Chapter Fifteen: Ploidy Flashcards

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1
Q

many plants and some animals can tolerate having multiple ___

A

chromosome sets

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2
Q

more than two sets of chromosomes

A

polyploidy

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3
Q

three sets of chromosomes

A

triploidy

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4
Q

complete chromosome set

A

euploid

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5
Q

missing one or more chromosomes from a set, or have extra chromosomes

A

aneuploid

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6
Q

calculation for euploidy

A

2n

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7
Q

an individual lacking one chromosome

A

monosomy

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8
Q

an individual with one extra chromosome

A

trisomy

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9
Q

calculation for nullisomy

A

2n-2

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10
Q

calculation for monosomy

A

2n-1

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11
Q

calculation for trisomy

A

2n+1

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12
Q

aneuploidy usually results in ___ or ___

A

multiple abnormalities or lethality

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13
Q

autosomal monosomy is usually ___

A

lethal

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14
Q

most trisomies are ___, a few result in ___

A

lethal
characteristic syndromes

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15
Q

sex chromosome aneuploidy is ___ due to ___

A

tolerated
X-chromosome inactivation

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16
Q

___ of births have some sort of genetic anomaly

A

0.4% (1/250)

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17
Q

phenotype of X-chromosome aneuploidy is largely due to ___ genes

A

pseudoautosomal (PAR)

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18
Q

X-chromosome aneuploidy causes ___

A

infertility

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19
Q

aneuploidy is caused by ___

A

nondisjunction

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20
Q

nondisjunction is the failure of chromosomes to ___

A

segregate normally

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21
Q

when can nondisjunction occur

A

meiosis I, meiosis II, and mitosis

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22
Q

failure of sister chromatids to separate during anaphase of mitosis

A

mitotic nondisjunction

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23
Q

lagging chromatid that is not pulled to either spindle pole at mitotic anaphase

A

chromosome loss

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24
Q

true or false: nondisjunction can occur in meiosis I, meiosis II, and mitosis

A

true

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25
Q

aneuploid cells can survive and undergo ___, producing ___

A

further rounds of mitosis
clones of aneuploid cells

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26
Q

there can be side-by-side existence of ___ cells and ___ cells

A

normal and aneuploid

27
Q

drosophila that has equal parts male and female tissue after loss of X chromosome in first mitotic division

A

gynandromorph

28
Q

are all euploid species diploid

A

no

29
Q

the number of chromosomes in a single, complete set

A

basic chromosome number (x)

30
Q

for diploid species, x = n = ___

A

the number of chromosomes in the gametes

31
Q

for polyploid species, X ___ n

A

does not equal

32
Q

bread wheat has 42 chromosomes: 6 nearly identical sets each containing 7 chromosomes
therefore: x=___, 6= ___, and n=___

A

7
42
21

33
Q

monoploid and polyploidy are ___ observed in animals

A

rarely

34
Q

polyploidy in humans is ___

A

lethal

35
Q

can create monoploid plants from ___ species with special treatment of ___

A

diploid
germ cells

36
Q

treated cells divide into a mass called an ___

A

embryoid

37
Q

subsequent exposure to ___ enables the embryoid to develop into a monoploid plant

A

plant hormones

38
Q

monoploid plants may also arise from rare ___ in large, natural populations

A

spontaneous events

39
Q

4 uses of monoploid plants

A
  1. visualize recessive traits directly, without crosses to homozygosity
  2. introduce mutations into individual monoploid cells
  3. select for desirable phenotypes (like herbicide resistance)
  4. hormone treatment to grow cells into monoploid cells
40
Q

___ prevents spindle formation and results in doubling of chromosome numbers

A

colchicine treatment

41
Q

colchicine is good for ___ to observe chromosomes for things like karyotyping

A

metaphase arrest

42
Q

triploid plants result from the union of ___ and ___

A

monoploid and diploid gametes

43
Q

diploid gametes may arise from a ___ parent or from a diploid with ___

A

4x
defects in meiosis

44
Q

meiosis in a triploid organism will almost always be ___, with ___ of some chromosomes and ___ of others

A

unbalanced
two copies
one copy

45
Q

fertilization with gametes for triploid organisms usually produces ___

A

unviable offspring

46
Q

if ___, occasionally a meiosis of triploid organisms will produce balanced gametes

A

X is small

47
Q

tetraploid cells occur during mitosis in a diploid when ___

A

chromosomes fail to separate into two daughter cells

48
Q

if tetraploidy occurs in gamete precursors, ___ are produced

A

diploid gametes

49
Q

union of two ___ produces a tetraploid organism

A

diploid gametes

50
Q

polyploids in which all chromosome sets are derived from the same species

A

autopolyploid

51
Q

pairs of synapsed homologous chromosomes

A

bivalents

52
Q

in a tetraploid, pairing of chromosomes as bivalents results in ___

A

balanced genes

53
Q

tetraploids generate ___ mendelian ratios

A

unusual

54
Q

___ of all known flowering plant species are polyploid

A

1/3

55
Q

polyploidy often results in increased ___ and ___ in plants

A

size and vigor

56
Q

many polyploid plants have been selected for ___

A

agricultural cultivation

57
Q

hybrids in which chromosome sets come from distinct, but related species

A

allopolyploid

58
Q

all-polyploids are usually ___ because different chromosomes sets cannot easily ___

A

infertile
pair and segregate properly

59
Q

type of allopolyploid produced by mating of two different diploid parental species

A

amphidiploid

60
Q

sterile F1 from crossing cabbages and radishes

A

raphanobrassica

61
Q

F1 hybrid of wheat and rye, allopolyploid

A

triticale

62
Q

duplication of whole genomes are useful for ___

A

evolution

63
Q

plant biologists think that around 90 million years ago, an ancient diploid plant with 5 chromosomes underwent a ___

A

whole genome duplication

64
Q

in the rice genome, many blocks of ___ are found on two different chromosomes

A

homologous gene sequences