Fertilization Mechanism

Question 1

shell around human egg

Answer 1

zona pellucida (ZP1-4)

Question 2

The _____ releases the egg from the germinal vesicle and completes meoisis I

Answer 2

LH surge

Question 3

____ cells surround the ZP

Answer 3

cumulous cells

Question 4

Capacitation

Answer 4

process that ensures sperm can fertilize an egg –> e.g. motility increase due to cAMP, loss of cholesterol from plasma membrane, chang ein surface charge, change in ion conductance, elevation of intracellular pH

Question 5

With the help of _____, a cell surface _____, capacitated sperm penetrate the cumulus oophorus

Answer 5

PH20 –> surface hyaluronidase

Question 6

ZP ___ is most crucial for egg/sperm interaction

Answer 6

ZP3

Question 7

Only after ____ can the sperm fuse with the egg plasma membrane

Answer 7

acrosomal reaction

Question 8

____ releases GPI linked proteins from the sperm surface and inner acrosomal matrix in the process of enzymatic hydrolysis of the ZP.

Answer 8

angiotensin converting enzymes

Question 9

T/F penetration of the ZP requires motile force from sperm.

Answer 9

T –> in addition to enzymatic hydrolysis

Question 10

____ plane of the sperm head attaches to the plasma membrane of the oocyte during adhesion and membrane fusion

Answer 10

equatorial plane –> 3 hours

Question 11

Fertilization induced calcium oscillations

Answer 11

early event is increase in egg cytosolic calcium –> triggered by PLC

Question 12

_______ are released after fertilization to prevent other sperm from penetrating.

Answer 12

cortical granules

Question 13

At the ___ stage, cell boundaries are not visible anymore due to ____

Answer 13

morula –> compaction

Question 14

Frequency of polyspermy after ovulation

Answer 14

1-2%

Question 15

T/F polyspermy may be 30% if mating is delayed after ovulation/aged eggs

Answer 15

T

Question 16

In humans, where is the block to polyspermy?

Answer 16

level of ZP as well as membrane

Question 17

Can oocyte activation occur without sperm?

Answer 17

Yes –> parthenogenesis due to mechanical trauma, temperature shock, ICSI, etc.

Question 18

intrauterine insemination

Answer 18

seminal fluid washed out –> sperm in alkaline buffer for capacitation –> intrauterine insemination

Question 19

Approximately how long after LH surge will ovulation take place?

Answer 19

36 hours

Question 20

Indication for intrauterine insemination

Answer 20

mild to moderate male factor infertility

Question 21

Intracytoplasmic sperm injection (ICSI)

Answer 21

sperm injected into egg directly