M: FERTILIZATION Flashcards
1
Q
_________ fuse to begin the formation of a new organism
A
Gametes
2
Q
____ is the combination of parental genes
A
Sex
3
Q
_________is the generation of a new organism
A
reproduction
3
Q
Process of Fertilization
A
- Contact and recognition between the sperm and egg
- Regulation of sperm entry into the egg
- Fusion of genetic material
- Activation of egg metabolism
3
Q
Sperm Structure: contains haploid nucleus and acrosome
A
Sperm Head
3
Q
contains enzymes that digests proteins and complex sugars
A
Acrosome
4
Q
originates from centriole, composed of axoneme structure of microtubules (tubulin)
A
Flagellum
4
Q
provides the tubulin force for sperm propulsion
A
Dynein
4
Q
contains rings of mitochondria
A
Midpiece
5
Q
-Final stage of sperm maturation
-maturation of the sperm during the travel from the vagina to the oviduct, accomplished after the sperm resides for some time in the female reproductive tract
A
Capacitation
5
Q
Storage of all necessary materials to begin growth and development (Nutritive proteins; ribosomes, tRNA; messenger RNAs; morphogenetic factors; and protective chemicals)
A
The egg
5
Q
The ______________ conserves most of its cytoplasm and accumulates more
A
oocyte (developing egg)
6
Q
contains glycoproteins and binds to the egg cell membrane; essential for species-specific binding of sperm
A
Invert: Vitelline envelope
Mammals: Zona Pellucida
6
Q
Many eggs have a layer of _________ outside the vitelline envelope
A
egg jelly
6
Q
Egg: The __________ is a gel-like cytoplasm that lies underneath the membrane containing globular actin molecules that form microfilaments during fertilization for cell division
A
cortex
6
Q
Egg: _______ aids for sperm entry
A
microvilli
6
Q
Egg: The cortical granules contains ______, ______, _______ and _______
A
proteolytic enzymes,
mucopolysaccharides,
adhesive glycoproteins,
hyaline proteins
6
Q
Zona pellucida is covered by the _________ made of ovarian follicular cells
A
cumulus
7
Q
The innermost layer of cumulus cells is called the ___________
A
corona radiata
8
Q
Process of Fertilization (more specific)
A
- Chemoattraction
- Exocytosis of sperm acrosomal vesicle
- Binding of the sperm to extracellular matrix
- Passage of the sperm
- Fusion of the egg and sperm cell membranes
9
Q
Sperm are attracted towards eggs of their species by ____________
A
chemotaxis
9
Q
Sperm motility is acquired after spawning due to ___________ in the gonads from high concentrations of CO2
A
low pH
10
Q
Upon contact with seawater, change in pH activates _____________ for flagellar movement
A
dynein ATPase
11
Q
____________ sperm have receptors in their cell membrane that bind resact
A
A. punctulata
12
A. punctulata: Upon binding , ______________is activated to produce more cyclic GMP which lets in Ca+ ions into the tail and activates mitochondrial ATP and dynein ATPase
Calcium channels are controlled by CatSper genes that also control direction
guanylyl cyclase
12
Sperm senses _____ and swim up the concentration gradient until they reach the egg
SAPs
13
The acrosome reaction: In sea urchins, it is initiated when sperm comes into contact with _____________________ in the egg jelly and releases proteolytic enzymes
species-specific sulfate-containing polysaccharides
14
In S. purpuratus, acrosome reaction is initiated by fucose sulfate that activates :
calcium transport channels,
sodium-hydrogen exchanger,
inositol 1,4,5 triphosphate (IP3)
14
a protein mediating egg recognition in sea urchins
Bindin
15
_________________isolated bindin from S. purpuratus and found it to be capable of binding to dejellied eggs of the same species
Vacquier (1977)
16
Bindin of closely related species of sea urchin have________________, implying specific bindin receptors on the vitelline membrane
different protein sequences
17
Closely related sea urchins have _______________; eggs will adhere only to the bindin of their own species
divergent bindin receptors
18
fastest evolving proteins known
Bindin and other gamete recognition proteins
19
Sperm-egg fusion polymerizes ______on the egg to form the _____________ - sperm nucleus and tail pass through here
-actin
-fertilization cone
20
one sperm enters the egg
Monospermy
20
During cleavage, centriole of sperm forms at the___________; centrioles of the egg degrade
two poles of the egg
21
entrance of multiple sperm; multiple chromosomes and centrioles divides the cell into four, randomized segregation of chromosomes
Polyspermy
21
-A change in electric potential of the egg cell membrane occurring immediately upon sperm entry
-Sodium (Na+) channels in the egg are closed, preventing sodium from entering the egg, resulting in a resting membrane potential of (-70 mV)
-After binding of the sperm, the egg membrane potential turns positive (20 mV) due to sodium channels reopening by NAADP - sperm cannot bind to positively charged egg
The Fast Block to Polyspermy
21
Sodium (Na+) channels in the egg are closed, preventing sodium from entering the egg, resulting in a resting membrane potential of __________
-70 mV
21
After binding of the sperm, the egg membrane potential turns __________ due to sodium channels reopening by NAADP - sperm cannot bind to positively charged egg
positive (20 mV)
22
-Cortical granule reaction removes sperm bound to vitelline envelope; activated after sperm and egg fusion
-Cortical granules are released between vitelline envelope and egg cell membrane; released with cortical granule serine protease
-Fertilization envelope is formed from the site of sperm entry and spreads around the egg
-Mucopolysaccharides absorb water and expands space between cell membrane and fertilization envelope, stabilized through crosslinking with adjacent proteins
-After this, a fourth set of cortical granule proteins, hyalin, produces the hyaline layer
The slow block to polyspermy
23
Slow Block (1): _______- reaction removes sperm bound to vitelline envelope; activated after sperm and egg fusion
Cortical granule
24
Slow block (2): Cortical granules are released between vitelline envelope and egg cell membrane; released with ______________
cortical granule serine protease
25
Slow block (3): _____________ is formed from the site of sperm entry and spreads around the egg
Fertilization envelope
26
Slow block (4):_____________ absorb water and expands space between cell membrane and fertilization envelope, stabilized through crosslinking with adjacent proteins
Mucopolysaccharides
27
Slow block (5): a fourth set of cortical granule proteins, _________, produces the hyaline layer
hyalin
28
Concentration of calcium ions in the egg ___________during fertilization
increases
29
Calcium as the initiator of the cortical granule reaction cam be monitored by ________
aqueorin
30
_________ is an ionophore drug that allows calcium to diffuse against the vitelline membrane
A23187
31
calcium is sored in _________________
endoplasmic reticulum
32
Membrane proteins that facilitate________________________ are connected to cortical granules
calcium-mediated exocytosis
33
Development can begin without the involvement of __________________ in sea urchin
parental nuclei
34
Activation of egg in Sea Urchin: Calcium release allows inhibited :
-mRNAs to be translated
-inhibition of nuclear division
35
Soluble factors from the sperm changes the ionic composition of the cytoplasm
Release of Intracellular Calcium Ions in Mammals
36
In sea urchins, oocyte mRNAs translate proteins for ________, ________, ________, and _____________ upon sperm entry due to pH increase and calcium elevation
-Histone
-tubulin
-actins
Morphogenetic factors
36
primary agent for calcium release
36
In mammals, ______ needs to be activated before fertilization can occur
cyclin
36
Fusion of genetic material in sea urchin: After fusion what happen to the sperm?
-sperm nucleus and centrioles separate from mitochondria and flagellum.
-mitochondria and flagellum disintegrate in egg cytoplasm
-Sperm nucleus rotates and forms microtubules to locate the egg
36
Sperm binds to receptors on the egg cell membrane and changes its conformation
Release of Intracellular Calcium Ions in Sea Urchins
37
_____________ are derived from the sperm centriole
Centrosomes
38
Fertilization in sea urchins occurs after the _______________
second meiotic division
38
Where does internal fertilization in mammals occur?
Oviduct of the female
38
Internal Fertilization in Mammals: Sperm population ejaculated into the female is _____________
hetergeneous
39
Translocation of sperm involves several processes:
(1) sperm motility,
(2) uterine muscle contractions, 1
(3) sperm rheotaxis
39
A mammalian oocyte just released from the ovaries is surrounded by ____________ to which the fimbriae attaches and transports the oocyte to the oviduct to be fertilized
cumulus cells
40
The molecular processes of the sperm during capacitation include:
1. Lipid Changes
2. Protein Changes
41
removal of cholesterol by albumin proteins
Lipid changes
42
particular proteins or carbohydrates are lost during capacitation (one particular effect is the phosphorylation of Izumo protein used for sperm-egg fusion)
Protein changes
43
activated by opening of calcium channels on the sperm flagellum, works with hyaluronidase enzymes to digest a path through the cumulus
Hyperactivation
44
directional cues due to the differences of temperature in the isthmus and ampulla
thermotaxis
45
oocyte and cumulus secrete molecules that attract capacitated sperm, such as progesterone and CRISP1
Chemotaxis
46
Mammalian zona pellucida is made of ________-
Z proteins
47
humans have four major glycoproteins - ZP1, ZP2, ZP3, and ZP4, _____-is critical for human sperm binding
ZP2
48
“Successful” sperm have already undergone the _________ prior to binding to the zona pellucida
acrosome reaction
49
Sperm binds to regions of the egg where _________ polymerizes
actin
50
The junction between the inner acrosomal membrane and the sperm cell membrane is called the ____________
equatorial region
51
On the acrosomal granule, __________ are found where mammalian egg-sperm cell membrane binding takes place, it binds with the oocyte protein Juno, their interaction recuits CD9 proteins
Izumo proteins
52
ZP2 is cleaved by ________ during fusion
Ovastacin
53
___________- reduces the disulfide bonds from the protamines that binds the sperm pronucleus
Glutathione
54
The mammalian sperm enters the oocyte while the oocyte is arrested in the __________
meiotic metaphase
55
Oscillation of calcium leads to the proteolysis of _______ and _________, resulting in a haploid female pronucleus
cyclin and securin
55
The chromatin of the male and female pronuclei condenses into chromosomes and orient themselves on a common ___________
mitotic spindle
56
A true diploid nucleus is seen in the ____________- in mammals
two-cell stage
57
_________________-- needed for egg activation comes from the sperm from the enzyme PLCζ
Mammalian Phospholipase C
58
Mammalian eggs are traversed by multiple waves of calcium ions, which bind to:
-Calmodulin-activated protein kinase
-MAP Kinas
-synaptotagmin
59
elimination of mRNA translation inhibitors
calmodulin-activated protein kinase
60
resumption of meiosis
MAP kinase
61
initiation of cortical granule reaction
synaptotagmin
