Chapter Four: Sex Chromosomes

Question 1

Walter sutton studied meiosis in ___

Answer 1

grasshoppers

Question 2

cells in the testes that will eventually go through meiosis to become sperm are maintained by ___

Answer 2

mitosis

Question 3

two types of sperm formed after meiosis

Answer 3

half have X and have have Y

Question 4

type of ehh formed after meiosis

Answer 4

all have X

Question 5

does an XX chromosome always indicate a female for every animal

Answer 5

no

Question 6

what did Sutton conclude about X and Y chromosomes

Answer 6

they are sex chromosomes that determine sex

Question 7

children receive a ___ chromosome from their mother and a ___ chromosome from their father

Answer 7

X
X or Y

Question 8

there is approximately a ___ ratio of females:males

Answer 8

1:1

Question 9

the primary determinant of maleness is a single gene called ___

Answer 9

SRY (sex determining region of Y)

Question 10

___ helped provide evidence implicating that the SRY gene determines male gender

Answer 10

sex reversal (XX males and XY females)

Question 11

SRY is ___ in XX males
SRY is ___ in XY females

Answer 11

present
nonfunctional

Question 12

human sex chromosomes also contain genes that are ___

Answer 12

unrelated to sex

Question 13

the end regions of sex chromosomes that contain genes which enable sex chromosomes to pair during meiosis one

Answer 13

pseudoautosomal regions (PARs)

Question 14

in Drosophila (flies), the ___ determines gender

Answer 14

ratio of X chromosomes to autosomes, number of sex chromosomes

Question 15

in humans, the ___ determines gender

Answer 15

presence or absence of a Y chromosome

Question 16

why can humans tolerate extra X chromosomes

Answer 16

extra X chromosomes become nonfunctional in an XX female anyway, so the extra X chromosomes also become nonfunctional; may cause some issues but the individual is still viable

Question 17

what is the nonfunctional X chromosome called

Answer 17

Barr body

Question 18

complete absence of an X chromosome is ___ for humans and flies

Answer 18

deadly

Question 19

effect of additional Y chromosomes in humans or flies

Answer 19

has little effect

Question 20

the Y chromosome in flies does not determine ___, but it is necessary for ___. an XO male is ___

Answer 20

maleness
male fertility
sterile

Question 21

sex with two different kinds of gametes (XY)

Answer 21

heterogametic

Question 22

sex with one type of gamete (XX)

Answer 22

homogametic

Question 23

in some species (lizards and turtles), sex is determined by ___, specifically ___

Answer 23

environment
temperature

Question 24

specialized diploid cells set aside during embryogenesis that will eventually form gametes

Answer 24

germ line

Question 25

gamete formation

Answer 25

gametogenesis

Question 26

in humans, oogenesis produces ___ from each ___

Answer 26

one ovum primary oocyte

Question 27

in humans, spermatogenesis produces ___ from each ___

Answer 27

four sperm primary spermatocyte

Question 28

diploid germ cells in ovaries of female embryos

Answer 28

oogonia

Question 29

oogonia divide via ___ to become ___ and arrest in prophase one before entering meiosis one

Answer 29

mitosis primary oocytes

Question 30

after puberty, one primary oocyte per month resumes meiosis at ___

Answer 30

ovulation

Question 31

completion of meiosis one in oogenesis produces ___ and ___

Answer 31

a large secondary oocyte small first polar body

Question 32

secondary oocyte arrests in ___

Answer 32

metaphase of meiosis two

Question 33

at ___, meiosis two is completed to produce ___ and ___

Answer 33

fertilization mature ovum second polar body

Question 34

polar bodies ___

Answer 34

disintegrate

Question 35

long meiotic arrest may contribute to ___

Answer 35

chromosome segregation errors

Question 36

there are about ___ eggs in females, and they release about ___ in their lifetime

Answer 36

300,000-400,000 300-400

Question 37

diploid germ cells found only in testes

Answer 37

spermatogonia

Question 38

spermatogonia divide via ___ to form ___

Answer 38

mitosis primary spermatocytes

Question 39

after puberty, ___ begins to form sperm

Answer 39

maturation

Question 40

primary spermatocytes undergo meiosis one to produce ___

Answer 40

two haploid secondary spermatocytes

Question 41

secondary spermatocytes undergo meiosis two to produce ___

Answer 41

two spermatids

Question 42

spermatids mature into ___

Answer 42

sperm

Question 43

___ of X and Y sperm are produced

Answer 43

equal numbers

Question 44

spermatogenesis occurs throughout ___ of males

Answer 44

adult life

Question 45

entire process of spermatogenesis takes about ___

Answer 45

48-60 days

Question 46

___ of sperm produced over a male lifetime

Answer 46

billions

Question 47

why is it not smart for males to reproduce later in life

Answer 47

the occurrence of chromosome anomalies increases with age

Question 48

the wild type allele for flies is denoted with ___

Answer 48

superscript +

Question 49

the recessive mutant allele for flies is denoted with ___

Answer 49

lowercase letter

Question 50

gene symbol for white eye genes in flies is ___, for red eye gene is ___

Answer 50

w w+

Question 51

a dominant mutant allele for flies is denoted with ___

Answer 51

uppercase letter

Question 52

gene symbol for normal eye in flies is ___, for abnormal eyes is ___

Answer 52

Bar+ Bar

Question 53

the drosophila white eye gene is located on the ___

Answer 53

X chromosome

Question 54

when daughters inherit the phenotype of their father and sons inherit the phenotype of their mother

Answer 54

crisscross inheritance

Question 55

crisscross inheritance occurs with ___ traits

Answer 55

X linked recessive

Question 56

because males only have one X chromosome, they have ___ as females with two X chromosomes

Answer 56

half the number of alleles

Question 57

reduced allele number due to sex-linkage and possession of a single sex chromosome rather than heterozygosity of autosomal alleles

Answer 57

hemizygosity

Question 58

a ___ mutation led to 1/2000 male progeny of flies of white females having red eyes

Answer 58

nondisjunction

Question 59

successfully predicting the movement of chromosomes based on phenotypes in drosophila provided compelling evidence that ___

Answer 59

specific genes exist and are transmitted via specific chromosomes

Question 60

chromosome theory explains that mutations can be heritable is they occur ___

Answer 60

in germ cell lines

Question 61

red-green colorblindness is inherited as ___ trait

Answer 61

X linked recessive

Question 62

x linked recessive traits never pass from ___

Answer 62

father to son

Question 63

daughters of affected males of a x linked recessive trait are ___, ___ of those daughters son's will inherit the trait

Answer 63

carriers 1/2

Question 64

an x linked dominant trait is seen ___

Answer 64

in every generation

Question 65

a male affected with an x linked dominant trait will produce ___ daughters and ___ sons

Answer 65

affected unaffected

Question 66

y linked traits show up in ___

Answer 66

only males

Question 67

hemophilia is a ___ triat

Answer 67

x linked recessive

Question 68

the first in a family tree to demonstrate a trait

Answer 68

proban

Question 69

hypophosphatemia is a ___ trait

Answer 69

x linked dominant

Question 70

in the early female embryo, each cell independently inactivates ___

Answer 70

one X chromosome (could be from mom or dad in each cell)

Question 71

___ in females arises from this independent inactivation of an X chromosome

Answer 71

mosaicism

Question 72

affect a structure or process found in only one sex

Answer 72

sex-limited traits

Question 73

appear in both sexes but hormonal differences may cause difference between the sexes

Answer 73

sex-influenced traits