fertilisation

Question 1

amphimixis

Answer 1

union of sperm and egg and the reconstitution of diploid genome

Question 2

activation of the egg

Answer 2

triggered for development of the embryo

Question 3

activation of the egg, resumption

Answer 3

of the cell cycle to start the development program

Question 4

activation of the egg, activate

Answer 4

the embryonic genome

Question 5

activation of the egg, block to polyspermy

Answer 5

blocks any other sperm from fertilizing the egg

Question 6

fertilization occurs in the

Answer 6

ampulla

Question 7

infundibulum is what

Answer 7

a proximal opening of the oviduct in the mouse, recieves ovulated egg with surrounding cumulus cells from ovary

Question 8

sperm reaches the ampulla by

Answer 8

muscular uterus contractions and by active propulsion

Question 9

sperm propulsion, the flagellum has

Answer 9

‘9+2’ microtubules

atp dependent sliding of microtubules pairs by dynein causing flagella propulsion wave

Question 10

flagellur movement propelling sperm

Answer 10

bond travelling down the sperm flagellum
can attach gold beads to see sliding apart and coming back together
energy from glucose used to form atp from midpiece

Question 11

axoneme structure

4 answers

Answer 11

9 microtubule doublets with 13+11 protofilaments each
alpha and beta tubulin dimers
nexin conects doublets
‘a’ tubulin carry inner and outer dynein arms

Question 12

what does dynein atpase do

Answer 12

‘puts on’ 1 set of outer microtubule pairs relative to the next outer pair, causing bonding motion of flagellum

Question 13

motile sperm are unable to do what

Answer 13

bind to the egg or fertilise

Question 14

sperm are capitulated by presence in the

Answer 14

female genital tract

Question 15

when sperm enters the female genitalia there is a

Answer 15

k+ efflux and hyperpolarisation of the sperm membrane, leading to ca2+ and HCO3- infulx and cAMP signalling

Question 16

cAMP signals by

Answer 16

adenylate cyclase - cAMP- PKA - protein tyrosine kinase - protein tyrosine phosphorylation

Question 17

fertilisation, sperm with egg what happens (ZP)

4 answers

Answer 17

activated by female tract
binds to zp3 zona glycoprotein (has zp binding proteins on membrane)
acrosome lysis the zona pellucidaby calcium influx via ca channels opening
after acrosome reacts ZP2 binding sites are exposed for further binding to zona.

Question 18

zona glycoprotein structure

Answer 18

strands of repeated zp2-zp3 dimers crosslinked by zp1

Question 19

what happens when the sperm binds to ZP3 carbohydrate domains

Answer 19

sperm binding to zona is inhibited in presence of ZP3 but not if carbohydrate removed

Question 20

ZP3 binding triggers what

Answer 20

acrosomal reaction

Question 21

zp3 binding to zp3 receptors in sperm plasmid membrane do what

Answer 21

open sperm Ca2+ channels

fusion of plasma membrane with acrosomal outer membrane

Question 22

ascorsomal reaction

Answer 22

release of lytic enzymes facilitates penitration of zona pellucida

Question 23

what happens after the acrosomal reaction

Answer 23

binding to ZP continues after the acrosome reaction
mediated by ZP2 receptors on inner acrosomal membrane (binding sites only exposed when the acrosomal reaction has occured)

Question 24

calcium wave at fertilisation what happens

Answer 24

increase in intracellular ca (1-3mins)

repeated ca oscillation

Question 25

calcium wave at fertilisation, sperm factor

Answer 25

phospholipid c zetahydrolysis PIP2 to IP3 and DAG

IP3 signals release of intracellular ca from ER stores

Question 26

ca oscillation causes ?

Answer 26

activation of development program

Question 27

ca oscillation at fertilisation activates the cell cycle doing what?

Answer 27

release oocyte from metaphase 2 arrest

egg forms zygote and 2nd polar body and enters interphase

Question 28

ca oscillation, activated cortical granules exocytosis,

5 answers

Answer 28

enzymes released
cause zona reaction
cleavage of sugars from ZP2 and 3 
stops polyspermy
activates embryonic gene activation

Question 29

cortical granules

Answer 29

triggered by ca

Question 30

development program

Answer 30

cleavage of blastocytes

and formation of embryonic ICM and extra cellular TE lineages