meiosis, development and aging Flashcards
First cell that leads to development of a new individual is a fertilized ovum.
zygote
Zygote is formed when a sperm cell forms a male and an oocyte (also called an egg cell) from a female join.
fertilization
they are produced in the reproductive system
gametes
- oocyte
- sperm
each reproductive have…
pair structures called gonads
tabular structures:
male - vas deferens
female - fallopian tube
hormones and secretion tht control the reproduction
The seminiferous tubules are packed into paired, oval organs.
testes
it bends behind the bladder and joins the urethra
ductus deferens
vas deferens
it is a tube that carries the sperm and urine out of the body through the penis
urethra
how many does the penis ejaculates and delivers
200 to 600 million sperm cells
Female sex cells develop in paired organs in the abdomen.
ovaries
Once a month, one ovary releases the most mature oocyte.
puberty
muscular saclike organ
uterus or womb
uterine tubes
aka fallopian tube
cilia sweeps the mature oocyte into the fingerlike projections of one of 2 uterine
carries oocyte inot the uterus
A genetically overlord cell with more than 2 sets of chromosomes.
polypoid
what are the 2 division of genetic material
reduction division (meiosis I)
- reduces the no. of replicated chromosomes from 46 to 23
equational division (meiosis II
- produces 4 cells from the 2 cells formed in the first division by splitting the replicated chromosomes
The formation of sperm cells begins in diploid stem cells called a spermatogonium.
spermatogenesis
why does the gametes of older people are more likely to have new mutations (that is, not inherited mutations) than the gametes of younger people
this happens because the cells go through more divisions and can accumulate more mistakes over time
briefly explain the “paternal age effect” usually causes dominant single-gene diseases.
This refers to the fact that older fathers are more likely to pass on new mutations to their children, especially in genes that cause dominant single-gene diseases.
These are diseases where just one copy of a mutated gene (from one parent) is enough to cause the condition. This happens because sperm cells in older men divide more often, leading to mutations.
parental development
index card
Result from the fertilization of two separate
eggs with two different sperm during the
same pregnancy.
fraternal twins aka dizygotic twins
a rare situation where two eggs from the same woman are fertilized by sperm from two different men during the same ovulation cycle. This happens when a woman releases two eggs and has sexual intercourse with two different men within a short period of time. As a result, she can become pregnant with twins that have different fathers.
Heteropaternal superfecundation
how many days can a sperm and oocyte survive in a woman’s body
sperm - up to 3 days
oocyte - can be fertilized for the next 12 to 24 hours after ovulation (release of an egg cell)
a process that chemically activates the sperm and the oocytes secrete a chemical that attracts the sperm
capacitation
a week after fertilization, it nestles into the uterine lining
implantation
after implantation, the outermost cells of the blastocyst is called? which secretes?
trophoblast
secretes hCG - human chorionic gonadotropin
