Download DNA Repilication and Transmission

On the cellular level


Somatic Cells – Cells that make up
the body, excluding sex cells. Soma
is the Greek word for body.
Sex Cells – the cells in the testes of
men and ovaries of women that are
involved with reproduction.




Chromosomes are strands of DNA.
There are two types: autosomes and sex
chromosomes (allosomes).
The autosomes occur as homologous pairs, but
only a female’s allosomes are homologous.
The chromosomes of a person constitute one’s
karyotype.
A locus is the
location of a
given gene on a
chromosome



Mitosis involves the somatic cells.
The cell’s DNA is duplicated
without changes.
In infancy and childhood all types of
cells experience mitosis, excluding
brain cells.



In adulthood some cells undergo mitosis
continuously, others do not.
Mitosis is triggered by signaling proteins
called growth factors, that cause
transduction when they connect with
receptors on the surface of a cell.
Cancer occurs when the genes involved
in producing proteins involved in
transduction become corrupted.

Meiosis involves the sex cells.

The cell divides twice (meiosis I and II).

The DNA is duplicated during meiosis I
but is not during meiosis II.
Meiosis I
Spermatogenesis –
sperm production
Sperm
production
commences
at puberty,
and
continues
indefinitely.
Meiosis II
Gametes
Genetic Recombination – crossing over
♂
♀
♀
♂
♀
In the ovary
before ovulation
Prophase I
Metaphase I
In the uterine
tube
Gamete
Only happens if
fertilized




All of a woman’s follicles have been created 1822 weeks after conception.
Gametes are released singly once per month
following puberty.
The chromosomes of oocytes degenerate as
they age, markedly after age 30.
Gametes cease to be released with menopause.

Impregnation is difficult while women are
nursing.



Double standard with regards to attitudes
towards sexual behavior.
Exclusion from dangerous professions.
Attitudes towards violence directed towards
girls.