Chapter 7 pt 2 Flashcards
Fusion of membranes causes the polymerization of actin to form the _______
fertilization cone
Fusion of membranes forms a _______ between the gametes and the further polymerization of actin in both cells expands this bridge allowing the sperm nucleus and tail to enter the egg cytoplasm
cytoplasmic bridge
The fusion of membranes is an _______ process
active
- requiring energy input
_______: The entrance of more than one sperm into the egg
polyspermy
Polyspermy results in non-viability of the embryo due to the presence of too much _______ and too many _______ by the mitotic spindle due to the presence of extra centrioles
DNA
axis of division
Normally in _______, the sperm contributes its haploid nucleus and centriole
monospermy
The _______ of the sperm combines with the egg nucleus to form the diploid nucleus
nucleus
the sperm _______ divides to form the two poles of the mitotic spindle. What happens to the egg’s _______?
centriole
- egg centriole is degraded
What are the stages in the 2-stage mechanism that prevents multiple sperm entry after a single sperm has penetrated the egg?
1) fast block: electrical changes
2) slow block: mechanical changes
Sperm entry triggers a rapid change in _______ within the egg
membrane potential
- electrical
Prefertilization, the egg’s membrane potential is _____, right after fertilization, the membrane potential is _____. What causes this change?
-70mv
+20mv
(caused by influx of Na+ ions only lasts a minute)
Sperm cannot bind to a ______ charged membrane
positively
The mechanical change (slow block) to polyspermy is the _______ reaction
cortical granule
- occurs within 1 minute following fertilization
Sperm entry triggers the release of _______ from the ER into the cytoplasm
Ca2+
One of the effects of increased Ca2+ is stimulating thousands of _______ positioned just below the cell membrane to fuse with the membrane and release their contents into the space between the membrane and vitelline layer
cortical granules
_______ cleaves protein posts that connect to vitelline envelope to the cell membrane, cleaves off bindin attaching any remaining sperm
Cortical Granule Serine Protease (CGSP)
_______ increase osmotic gradient, drawing water into the space between the vitelline envelope and cell membrane. Water fills the space, forming the fertilization envelope
Glycosaminoglycans
The fertilization envelop is stabilized/hardened by _______ and _______
1) peroxidases
2) transglutaminase
What are the 2 types of peroxidases?
1) ovoperoxidase
2) Udx1
_______: crosslinking enzymes that form covalent bonds
transglutaminase
_______: a large acidic protein released by granules and forms a coating around the egg
hyaline
- forms hyaline layer that modifies ECM of egg
Aequorin and Fura2/3 are _______ activated _______ that can be used to monitor intracellular changes during fertilization
Calcium (Ca2+) activated dyes
luminescence
A traveling wave of Ca2+ release is _______ meaning if released in one area it causes release in adjacent areas
self-stimulating
In fusion of genetic materials, the sperm contributes what? (2)
1) haploid nucleus
2) centriole
_______ in the egg reduces the DNA wound up by protamines with numerous disulfide bonds
glutathione
In fusion of genetic materials, the egg contributes what? (3)
1) haploid nucleus
2) maternal mitochondria
3) cytoplasmic determinants and organelles
Ca2+ oscillations activated _______ which promotes DNA synthesis and _______ allowing the egg pronuclei to resume division
MAP kinase
proteolysis of cyclins
- needs deactivation of MAP kinase in order to resume cell cycle
_______ happens independently in sperm/egg pronuclei as they approach one another
DNA synthesis
_______ from male centrosome orients the 2 pronuclei and pulls them together
asters
Two nuclear membranes break down, DNA does not fuse yet, but condenses into _______ attached to a common mitotic spindle
- when 2 pronuclei are super close
chromosomes
_______ initiates major changes to the metabolism within the egg cell, initiating the events of development
Union of egg/sperm
Regarding egg metabolism: Ca2+ stimulates _______ of protein synthesis and _______ of cell cycle
removal of inhibition (activation)
resumption
In mammals, a soluble factor released from the sperm at its entry activates _______ that subsequently activates ________
tyrosine kinase
Phospholipase C (PLC)
In sea urchins, sperm proteins bind to the egg surface receptors changing their conformation, this activates _______ and then _______
Src (tyrosine kinase)
Phospholipase C (PLC)
What is the difference between mammal and sea urchin activation of IP3 pathway?
Mammals have sperm bind and use regular Tyrosine kinase (TK)
Sea urchins have sperm bind to receptor, which activates Src (TK)
Explain the IP3 pathway for Ca2+ release and Na+/H+ exchange
1) PLC cleaves PIP2 into IP3 and DAG
2) IP3 stimulates Ca2+ release from ER
3) DAG activates PKC which activates Na+/H+ antiporter
_______ activates NAD+ Kinase
Ca2+
NAD+ kinase converts _______ into _______
NAD into NADP+
- reduction
_______ is used as a coenzyme for lipid synthesis, required for cell membrane formation
NADP+
_______ burst is initially used to crosslink fertilization envelope
Oxygen
The increase in _______ stimulates the resumption of protein synthesis
pH
What does PIP2 stand for?
Phosphotidyl-inositol-4,5-bisphospate
In mammals, fertilization occurs in the _______ of the oviduct
ampulla
Large number of sperm are _______
heterogenous
- only about 200 reach the egg
The oocyte will not be moved into the oviduct unless supporting _______ cells are present
cumulus
_______ and _______ move the oocyte-cumulus complex to the proper placement in the ampulla of the oviduct
cilia beating
muscular contractions
Sperm are actively transported to the ampulla by _______ of the uterus
muscular contractions
Sperm are not capable of fertilizing the egg but are altered during their trek towards the egg, these changes are called _______
capacitation
5 major outcomes of sperm capacitation:
1) _______ is removed from the sperm cell membrane
2) _______ are lost from the sperm cell membrane
3) membrane potential becomes more _______
4) protein _______
5) outer acrosomal membrane changes and comes in close contact with _______ preparing for fusion
1) cholesterol
2) proteins and/or carbohydrates (repressors)
3) negative (loss of K+ for Ca2+ entry)
4) phosphorylation (for signaling, heat shock proteins)
5) sperm cell membrane
cholesterol is removed from the sperm cell membrane by female _______ proteins
albumin
_______ is the enzyme that allows for protein phosphorylation needed for sperm capacitation
Sperm Adenylate Cyclase enzyme (SPCY)
