ch20 study

Humans have ______ pairs of autosomal chromosomes.

22

A normal human cell contains ______ total chromosomes.

46

A fertilized egg is called a ______.

zygote

The genetic sex of an offspring is determined by the ______.

sperm

Females have two ______ chromosomes.

X

Males have one X and one ______ chromosome.

Y

A ______ body is found in female somatic cells but not in males.

Barr

______ imprinting allows for differing expression of alleles depending on parental origin.

genomic

Epigenetic changes involve modifications such as DNA ______.

methylation

Epigenetic changes ______ be passed on to offspring.

can

Silencing of a gene through methylation is considered an ______ change.

epigenetic

The Y chromosome contains genes important for ______ development.

male

The SRY gene is responsible for initiating development of the ______.

testes

Deletion of the SRY gene can cause a genetically male embryo to develop as a ______.

female

The presence of the SRY gene leads to development of ______.

testes

The primary sex hormone in males is ______.

testosterone

Testosterone is produced by ______ cells.

Leydig

Testosterone stimulates development of internal male reproductive ______.

ducts

Dihydrotestosterone (DHT) is important for development of ______ genitalia.

external

A lack of testosterone causes the genital tubercle to develop into a ______.

clitoris

Males with 5-alpha-reductase deficiency have male internal organs but more ______ appearing external genitalia.

female

Males lacking testosterone receptors may develop ______ external genitalia.

female

The first event in reproductive system development is the development of the ______ ducts.

Wolffian

The ______ ducts develop into male internal reproductive structures.

Wolffian

The ______ ducts develop into female internal reproductive structures.

Müllerian

Male development requires regression of the ______ ducts.

Müllerian

Female development requires regression of the ______ ducts.

Wolffian

Female accessory sex organs develop from the ______ ducts.

Müllerian

Estrogen plays a role in development of female reproductive structures especially during ______.

puberty

The embryonic urethral folds develop into the ______ in females.

labia minora

Leydig cells produce ______.

testosterone

Sertoli cells produce Müllerian ______ factor.

inhibiting

Müllerian inhibition factor causes regression of the ______ ducts in males.

Müllerian

Blocking DHT in a male fetus would primarily affect development of ______ genitalia.

external

Cryptorchidism refers to failure of the ______ to descend.

testes

Cryptorchid males still produce ______.

testosterone

Complete androgen insensitivity syndrome results in individuals with XY chromosomes but ______ appearing external genitalia.

female

Individuals with androgen insensitivity syndrome have normal chromosomal ______.

sex

Testosterone is essential for development of male ______ structures.

internal reproductive

DHT is essential for development of male ______ genitalia.

external

Sex differentiation depends on both ______ and hormone action.

genes