Fertilization: Beginning a New Organism Flashcards
sperm develops from a
classical cell
the head of a sperm cell is known as the
acrosome
the acrosome of a sperm cell is derived from the
Golgi apparatus
the head of sperm cells contains
- vesicle of digestive enzymes
- nucleus of DNA
what is the function of the vesicle of digestive enzymes in the acrosome?
to penetrate into the egg
the sperm is made of what 3 subsections?
- head
- midpiece
- flagella
the midpiece of a sperm cell contain aggregates of
mitochondria
mitochondria in the midpiece of a sperm cell is used for
- ATP production
- motility
the flagella of a sperm cell is referred to as the
axoneme
the axoneme is a _______ arrangement of ____________ containing ____________.
- 9+2
- microtubules
- dynein
dynein is a
ATPase enzyme
dynein hydrolyzes ATP as an energy source for
movement of the flagella
what is known as the maturation process of sperm
capacitation
capacitation occurs in the
reproductive tract
capacitation is achieved under the control of
chemical signals from the egg
what medical condition results from the lack of dynein enzyme?
Kartagener’s Syndrome
the lack of dynein enzymes results in
- decreased sperm motility
- infertility
extreme cases of Kartagener’s Syndrome exhibit the absence of
flagella & cilia
- leads to respiratory infections
some individuals w/ Kartagener’s will also present w/
situs inversus
define situs inversus
mirror image layout of anatomical structures
polyspermic fertilization is when
more than 1 sperm penetrates the egg cytoplasm
polyspermia results in
- excess genetic material
- loss of embryo
during egg development it accumulates
cytoplasm during oogenesis or formation
during sperm cell development it
loses volume
the cytoplasm of the egg contains
- proteins
- ribosomes
- mRNA
- paracrine factors
- transcription factors
- enzymes
what is the function of the enzymes in the cytoplasm?
repair minor DNA defects
where is the fusing site for sperm?
the egg cell membrane
the extracellular envelope contains sperm/egg
recognition sites
the recognition sites on the EC envelope are used for
species specific recognition
in invertebrates the extracellular envelope is known as
vitelline envelope
in vertebrates the extracellular envelope is known as
zona pellucida
define cumulus
the ovarian follicular cells outside the zona pellucida
what is the innermost layer of cumulus cells known as?
corona radiata
the cortex is the
inside of the cell membrane
the cortex contains
actin filaments
the actin filaments form
microvilli
microvilli on the cortex aid in
sperm entry
what are cortical granules?
proteolytic enzymes used to prevent polyspermia
where does fertilization occur?
in the upper third of the fallopian tube near the ampulla region
at what stage is fertilization considered?
Carnegie stage 1: day 1
translocation is known as the movement of sperm through
regions of the reproductive tract
translocation is aided by
smooth muscle contraction in the myometrium of the uterine wall
where does the maturation and motility of sperm increase?
in the fallopian tube
increasingly warmer temperatures up the fallopian tube creates…
this is an example of…
- hyperactive motility
- thermotaxis
what aids translocation?
this is an example of
- chemical signals from the cumulus region
- chemotaxis
zona pellucida proteins bind the
acrosomal region of sperm
binding of the zona pellucida proteins initiates ________ second messenger to open ____________ ___________.
- G-protein
- calcium channels
a calcium influx causes the
release of enzymes from the acrosomal region
the release of enzymes from the acrosomal region is for
digesting/entering through the zona and egg cell membrane
the events of
- calcium influx
- release of enzymes
- sperm entry through zona and cell membrane
stimulates…
this prevents…
- cortical granules to release all sperm cells bound to ZP3 proteins
- polyspermia
what could potentially inhibit the binding of sperm to the zona layer?
this could potentially lead to…
- anti-sperm antibodies
- infertilization
gamete fusion is when the
side of the sperm head fuses w/ the egg membrane
what facilitates the recognition and binding process during gamete fusion?
microvilli binding regions
list 2 major points in the importance of the zona pellucida encircling the developing embryo
- early release can cause embryo attachment to the fallopian tube
- failure of release can prevent embryo adhesion to the uterine wall
embryo attachment to the fallopian tube can lead to
ectopic pregnancy
in the uterine space if embryo fails to adhere to the uterine wall this can lead to
miscarriage or spontaneous abortion
the egg nucleus has been arrested in
metaphase of meiosis II
when does the egg resume the meiosis process?
upon entry of the sperm into the egg cytoplasm & Ca2+ influx
once the sperm enters the egg the egg is
haploid completing meiosis
the joining of genetic material is aided by the formation of
microtubules that draw the pronucleus of the sperm and egg together
define zygote
fertilized egg
