ch 12- reproduction Flashcards
binary fission
unicellular organisms
prokaryotes
mitochondria
chloroplasts
DNA replicated and migrates to ends of cells and SEPTUM forms
Budding
DNA replicated and deposited into bud
hydra and yeast do this
what does regeneration
hydra and planaria and fungi
parthogenesis
Unfertilized egg develops to a
viable organism (e.g., honeybees exhibit
haplodiploidy (males haploid, females diploid)).
spermiogenesis
final stage of spermatogenesis
haploid spermatids differentiate into mature motile spermatozoa (mature sperm cells)
NO CHANGE IN AMOUNT OF GENETIC MATERIAL
spermatogenesis
is the formation of mature
spermatozoa from spermatogonium. In this process,
diploid germ cells (spermatogonium) become haploid
gametes (spermatozoa).
produces four spermatids
seminiferous tubules
of testes are the site of
spermatogenesis (sperm production) and
contain:
● Sertoli cells: Surround and nourish sperm.
Produce inhibin (inhibits FSH - negative
feedback).
● Spermatogenic cells: Produce spermatozoa.
what activates sertoli cells
FSH
where are not mature sperm tranpsorted
from the seminiferous tubules to the epididymis via peristalsis
the epididymis is a duct around the testes
here the sperm are stored and matured
where does sperm go after the epididymis
Sperm moves through vas deferens (group of tubules) to ejaculatory duct (where vas deferens meets seminal vesicles) which propels sperm into
urethra and leads to ejaculation out of penis as semen (sperm + accessory gland secretions).
sperm parts
● Head: Contains nucleus and acrosome.
● Midpiece: Mitochondria (ATP production).
● Tail: Long flagellum (microtubules) to propel sperm.
seminal vesicle
accesory gland
Secrete fructose (nutrients to
produce ATP), viscous mucus (cleans and
lubricates urethra), and prostaglandins (causes
urethral contractions which propels sperm).
prostate gland
Alkaline secretions (basic) to
counteract uterine acidity.
accessory gland
bulbourethral gland
Viscous mucus (cleans and
lubricates urethra).
accessory gland
blastocyst
fertilized egg
what produces estrogen and progesterone
ovary
oogenesis steps
- Many oogonia produced, majority die via
apoptosis, small fraction remain and differentiate
to primary oocytes (begin meiosis but are
arrested in prophase I until puberty). - At puberty: one egg per month ovulates,
completing meiosis I, which produces a large
secondary oocyte (arrested in meiosis II during
metaphase II) and a polar body. - If fertilization occurs: meiosis II is completed.
- At the end of meiosis II: 2-3 polar bodies
(non-viable) and 1 oocyte (viable, contains majority
of cytoplasm, mitochondria, and nutrients for
fetus) are produced.
when is meiosis I and II completed for eggs
I- puberty during ovulation one egg per month
-also produces polar body
II- after fertilization
-2-3 polar bodies by the end of meiosis II
FSH
Follicle stimulating hormone (FSH): Stimulates
follicles in the ovary to develop and production
of estrogen and progesterone.
● Follicles are fluid filled sacs on the ovaries that contain an immature egg (arrested at meiosis I). The corpus luteum is a temporary endocrine structure formed by the dominant follicle after ovulation of the egg.
LH
Stimulates ovulation
of egg, corpus luteum formation, which produces
estrogen and progesterone. The ovulated egg is
released from a dominant follicle to complete
meiosis I.
birth control pills
release
synthetic estrogen and progesterone, inhibiting
GnRH production during the menstrual cycle through
negative feedback and thus preventing the
menstrual cycle from causing ovulation.
temp dependent sex determination pattern 1 and 2
● Some reptiles determine their sex in
development not by chromosomes, but by
temperature.
○ Pattern I development results in males in
cold temperatures, and females in warm
temperatures (eg, turtles).
○ Pattern II development results in females
in low and high temperatures, and males
in intermediate temperatures (eg,
crocodiles).
factors influencing development- apoptosis
Programmed cell death is important for
normal development of the fetus (eg,
removing webbing between fingers) and
adults (preventing cancer).
factors influencing development- egg cytoplasm determinant
If egg cytoplasm is unevenly distributed
(creating animal and vegetal poles), an axis is created, influencing how the embryo divides during cleavage.
factors influencing development- homeotic genes
master controller
homeotic genes
homeobox
hox genes
master controller
turns different gene
expressions on/off.
homeotic genes
decide which part of the
embryo develops into what structures.
○ This is carried out through regulating the
formation of the body axes and body
structures in the proper location during
early embryonic development.
homeobox
is a common DNA sequence
homologous across organisms that contains
homeotic genes.