Lec 5. Sex determination and sex linked characteristics

Question 1

What gene determines sex?

Answer 1

SRY gene

Question 2

What protein determines sex?

Answer 2

TDF

Question 3

How many pairs of chromosomes do platypus’s have?

Answer 3

5 pairs. 5 Xs 5Ys or 10Xs

Question 4

What is heteromorphic?

Answer 4

X and Y are called heteromorphic

Question 5

What is the primary testis initiation gene in therian mammals?

Answer 5

SRY

Question 6

Define sexual reproduction

Answer 6

Alternates between haploid and diploid states

Question 7

What does Fertilization produce?

Answer 7

a diploid zygote

Question 8

What does Meiosis produce?

Answer 8

Haploid gametes

Question 9

Define heterogametic

Answer 9

sex produces 2 different gamete types -with 2 different sex chromosomes

Question 10

True or False? Most organisms have two sexual phenotypes, male and female.

Answer 10

True

Question 11

Define Parthenogenesis

Answer 11

reproduction without males

Question 12

In mammals, the X and Y chromosomes usually do what during meiosis?

Answer 12

pair even though they are not homologous

Question 13

How many genes are on the Y chromosome?

Answer 13

around 30

Question 14

How many genes are on the X chromosome?

Answer 14

more than the Y a lot.

Question 15

What are autosomes?

Answer 15

Non-sex chromosomes.

Question 16

What are the sex chromosomes for insects?

Answer 16

XX (f)-XO (m)

Question 17

What are the sex chromosomes for birds and reptiles?

Answer 17

ZW (f) -ZZ (m)

Question 18

What is the role of the X sex chromosome?

Answer 18

contains genetic info essential for both sexes. At least one copy of an X is required

Question 19

What is the role of the Y chromosome?

Answer 19

male-determining gene is located here.

Question 20

Where are the X and Y chromosomes only homologous in?

Answer 20

pseudoautosomal regions

Question 21

In the Haplodiploidy system: Haploid set is

Answer 21

Male (unfertilized)

Question 22

In the Haplodiploidy system: Diploid set is

Answer 22

Female (union of sperm and egg)

Question 23

What is the genic sex-determining system and where is it found?

Answer 23

No sex chromosomes, only sex-determining genes. Found in plants, fungi, fish.

Question 24

What is an example of environmental sex determination?

Answer 24

aquatic snail, limpets position in stack determines sex

Question 25

What is another example of environmental sex determination?

Answer 25

Alligators temperature-dependent sex determination

Question 26

what is the genotype for Turner syndrome?

Answer 26

XO. Females

Question 27

What is the genotype for Klinefelter syndrome?

Answer 27

XXY, XXXY or XXXXY or XXYY. Males

Question 28

What are the signs and symptoms of a person with Turner Syndrome?

Answer 28

Short, high arched palate, retrognathia, webbed neck, droopy eyes, lazy eye, broad chest

Question 29

What are the signs and symptoms of Klinefelter syndrome?

Answer 29

After 5 years of age, boys are taller and fatter around belly, clumsy, slow motor skills.

Question 30

In what way could the SRY gene not function?

Answer 30

Androgen-insensitivity syndrome

Question 31

What happens if the SRY gene gets translocated onto the X?

Answer 31

XX, male phenotype with testicular disorder of sex development.