Matter Sex

Question 1

In _____ week, All embryos, developed two _________

Answer 1

5th week, All Embryos develop into two unspecialized gonads

Question 2

Triggers male development by signaling the indifferent gonads (undifferentiated reproductive organs).

Answer 2

SRY Gene

Question 3

Encodes a transcription factor – a protein that controls other genes.

Answer 3

SRY Gene

Question 4

Secrete Anti-Müllerian Hormone (AMH).

Answer 4

Sustentacular Cells (in testes)

Question 5

Destroys potential female reproductive structures during male development.

Answer 5

Sustentacular Cells (in testes)

Question 6

Secrete testosterone.

Answer 6

Interstitial Cells (in testes)

Question 7

Promotes development of male reproductive structures.

Answer 7

Interstitial Cells (in testes)

Question 8

It contains 1,500 genes, larger than the Y chromosome and acts as a homolog to Y in males

Answer 8

X chromosome

Question 9

It contains 231 genes, many of which are palindromes and may destabilize DNA

Answer 9

Y chromosome

Question 10

TRUE OR FALSE: Female are the homogenetic sex

Answer 10

TRUE: Males are the heterogametic sex (XY)

Question 11

SRY gene encodes a very important type of
protein called __________________

Answer 11

Transcription Factor

Question 12

It stimulates male development by sending signals
to the indifferent gonands.

Answer 12

Transcription Factor

Question 13

Hermaphroditism

Answer 13

Male and female stuff

Question 14

Presence of both types of structures but at different stages of life

Answer 14

Pseudohermaphroditism

Question 15

What term refers to individuals whose internal reproductive structures do not match their external sexual characteristics?

Answer 15

Intersex

Question 16

At what stage is chromosomal sex (XX or XY) determined in a developing human?

Answer 16

Fertilization

Question 17

When does the undifferentiated structure start developing into a testis or ovary during embryonic development?

Answer 17

6 weeks after fertilization

Question 18

What is the term for the stage when external and internal reproductive structures develop in response to hormones, and when does it occur?

Answer 18

Phenotypic sex; occurs 8 weeks after fertilization

Question 19

When do strong feelings of being male or female typically begin to develop?

Answer 19

From childhood, possibly earlier

Question 20

When does attraction to the same or opposite sex typically begin to emerge?

Answer 20

Sexual orientation usually develops from childhood.

Question 21

At conception

Answer 21

Primary sex ratio

Question 22

At birth

Answer 22

Secondary sex ratio

Question 23

At maturity

Answer 23

Tertiary sex ratio

Question 24

Sex ratios can change depends on the age TRUE OR FALSE

Answer 24

TRUE

Question 25

What combination of chromosomes results in a male zygote?

Answer 25

XY — formed when a Y-bearing sperm fertilizes the oocyte

Question 26

What combination of chromosomes results in a female zygote?

Answer 26

XX — formed when an X-bearing sperm fertilizes the oocyte

Question 27

What gene must be functional on the Y chromosome to initiate male development?

Answer 27

The SRY gene

Question 28

What is the role of the SRY gene in sex determination?

Answer 28

It triggers male development by activating the development of testes and male structures

Question 29

TRUE OR FALSE: Human male is considered hemizygous for x-linked traits because he has only one set of X-linked genes

Answer 29

TRUE

Question 30

What is the typical inheritance pattern for an X-linked recessive trait?

Answer 30

It passes from an unaffected heterozygous mother to an affected son.

Question 31

Who usually expresses X-linked recessive traits?

Answer 31

Males.

Question 32

Can females express X-linked recessive traits? If yes, under what condition?

Answer 32

Yes, if they are homozygous for the recessive allele, but it's very rare.

Question 33

How is an X-linked recessive trait typically passed to a son?

Answer 33

From a heterozygous or homozygous mother.

Question 34

What are the conditions for a female to be affected by an X-linked recessive trait?

Answer 34

She must have an affected father and a mother who is either affected or a heterozygote.

Question 35

What happens when a female inherits a dominant X-linked allele?

Answer 35

She will show the associated traits or illness.

Question 36

Why are males usually more severely affected by X-linked dominant traits?

Answer 36

Because they have only one copy of the X-linked allele.

Question 37

In how many copies is an X-linked dominant trait expressed in females?

Answer 37

In one copy.

Question 38

How do the effects of an X-linked dominant trait differ between males and females?

Answer 38

The effects are much more severe in males.

Question 39

What can result from early lethality of X-linked dominant traits in males?

Answer 39

High rates of miscarriage.

Question 40

How is an X-linked dominant trait passed from a male?

Answer 40

To all his daughters, but to none of his sons.

Question 41

Which X-linked dominant disorder causes yellow, pus-filled vesicles in newborn girls that turn into lifelong brown splotches and is typically lethal in males?

Answer 41

Incontinentia Pigmenti

Question 42

It affects a structure or function of the body that is present in only males or females

Answer 42

Sex-limited trait

Question 43

Sex-influenced trait

Answer 43

trait is dominant in one sex but recessive in another

Question 44

Why does a female body turn off (inactivate) one of the X chromosomes, and what is the name of the packed-up, turned-off X?

Answer 44

To stop the body from making too much stuff from the X, since girls have 2 X’s and boys only have 1. The turned-off X becomes a Barr body, which is a type of heterochromatin.

Question 45

In female mammals, both X chromosomes are initially active. However, during early development, one of the X chromosomes becomes inactivated in each cell. What is the biological purpose of this X inactivation, and what is the name of the structure formed by the inactivated X chromosome? A. To reduce gene expression in males; the inactivated X forms a euchromatin structure B. To prevent females from having a double dose of X-linked gene products; the inactivated X becomes heterochromatin C. To silence dominant alleles on the X chromosome; the inactive X becomes a nucleosome D. To allow both X chromosomes to express equally; the inactivated X becomes a Barr RNA

Answer 45

B. To prevent females from having a double dose of X-linked gene products; the inactivated X becomes heterochromatin 🧬 Quick breakdown: Females have two X chromosomes If both were active, they'd produce twice the amount of X-linked gene products than males (who only have one X). To balance this out, one X is randomly inactivated in each cell = dosage compensation. That inactivated X becomes tightly packed, silenced, and forms heterochromatin (aka Barr body).

Question 46

Controls the inactivation

Answer 46

XIST

Question 47

X-linked trait the expresses the phenotype

Answer 47

manifesting heterozygotes