Chapter Fifteen: Ploidy

Question 1

many plants and some animals can tolerate having multiple ___

Answer 1

chromosome sets

Question 2

more than two sets of chromosomes

Answer 2

polyploidy

Question 3

three sets of chromosomes

Answer 3

triploidy

Question 4

complete chromosome set

Answer 4

euploid

Question 5

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

Answer 5

aneuploid

Question 6

calculation for euploidy

Answer 6

2n

Question 7

an individual lacking one chromosome

Answer 7

monosomy

Question 8

an individual with one extra chromosome

Answer 8

trisomy

Question 9

calculation for nullisomy

Answer 9

2n-2

Question 10

calculation for monosomy

Answer 10

2n-1

Question 11

calculation for trisomy

Answer 11

2n+1

Question 12

aneuploidy usually results in ___ or ___

Answer 12

multiple abnormalities or lethality

Question 13

autosomal monosomy is usually ___

Answer 13

lethal

Question 14

most trisomies are ___, a few result in ___

Answer 14

lethal
characteristic syndromes

Question 15

sex chromosome aneuploidy is ___ due to ___

Answer 15

tolerated
X-chromosome inactivation

Question 16

___ of births have some sort of genetic anomaly

Answer 16

0.4% (1/250)

Question 17

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

Answer 17

pseudoautosomal (PAR)

Question 18

X-chromosome aneuploidy causes ___

Answer 18

infertility

Question 19

aneuploidy is caused by ___

Answer 19

nondisjunction

Question 20

nondisjunction is the failure of chromosomes to ___

Answer 20

segregate normally

Question 21

when can nondisjunction occur

Answer 21

meiosis I, meiosis II, and mitosis

Question 22

failure of sister chromatids to separate during anaphase of mitosis

Answer 22

mitotic nondisjunction

Question 23

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

Answer 23

chromosome loss

Question 24

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

Answer 24

true

Question 25

aneuploid cells can survive and undergo ___, producing ___

Answer 25

further rounds of mitosis clones of aneuploid cells

Question 26

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

Answer 26

normal and aneuploid

Question 27

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

Answer 27

gynandromorph

Question 28

are all euploid species diploid

Answer 28

no

Question 29

the number of chromosomes in a single, complete set

Answer 29

basic chromosome number (x)

Question 30

for diploid species, x = n = ___

Answer 30

the number of chromosomes in the gametes

Question 31

for polyploid species, X ___ n

Answer 31

does not equal

Question 32

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

Answer 32

7 42 21

Question 33

monoploid and polyploidy are ___ observed in animals

Answer 33

rarely

Question 34

polyploidy in humans is ___

Answer 34

lethal

Question 35

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

Answer 35

diploid germ cells

Question 36

treated cells divide into a mass called an ___

Answer 36

embryoid

Question 37

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

Answer 37

plant hormones

Question 38

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

Answer 38

spontaneous events

Question 39

4 uses of monoploid plants

Answer 39

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

Question 40

___ prevents spindle formation and results in doubling of chromosome numbers

Answer 40

colchicine treatment

Question 41

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

Answer 41

metaphase arrest

Question 42

triploid plants result from the union of ___ and ___

Answer 42

monoploid and diploid gametes

Question 43

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

Answer 43

4x defects in meiosis

Question 44

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

Answer 44

unbalanced two copies one copy

Question 45

fertilization with gametes for triploid organisms usually produces ___

Answer 45

unviable offspring

Question 46

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

Answer 46

X is small

Question 47

tetraploid cells occur during mitosis in a diploid when ___

Answer 47

chromosomes fail to separate into two daughter cells

Question 48

if tetraploidy occurs in gamete precursors, ___ are produced

Answer 48

diploid gametes

Question 49

union of two ___ produces a tetraploid organism

Answer 49

diploid gametes

Question 50

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

Answer 50

autopolyploid

Question 51

pairs of synapsed homologous chromosomes

Answer 51

bivalents

Question 52

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

Answer 52

balanced genes

Question 53

tetraploids generate ___ mendelian ratios

Answer 53

unusual

Question 54

___ of all known flowering plant species are polyploid

Answer 54

1/3

Question 55

polyploidy often results in increased ___ and ___ in plants

Answer 55

size and vigor

Question 56

many polyploid plants have been selected for ___

Answer 56

agricultural cultivation

Question 57

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

Answer 57

allopolyploid

Question 58

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

Answer 58

infertile pair and segregate properly

Question 59

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

Answer 59

amphidiploid

Question 60

sterile F1 from crossing cabbages and radishes

Answer 60

raphanobrassica

Question 61

F1 hybrid of wheat and rye, allopolyploid

Answer 61

triticale

Question 62

duplication of whole genomes are useful for ___

Answer 62

evolution

Question 63

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

Answer 63

whole genome duplication

Question 64

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

Answer 64

homologous gene sequences