Exam II Flashcards
(187 cards)
1
Q
What the stages of oogenesis?
A
Primordial germ cell
Mitosis
Oogonia
Mitosis
Small primary oocyte
growth and vitellogenesis (cell differentiation)
large primary oocyte
Meiosis I
Secondary oocyte + first polar body
Meiosis II
Ovum + second polar body
Mature Egg
2
Q
What do the polar bodies get rid of?
A
excess DNA
3
Q
What are 3 similarities between oogenesis and spermatogenesis?
A
- Meiosis
- Morphological differentiations
- Limited life span
4
Q
What are 4 differences between oogenesis and spermatogenesis?
A
- Mitotic divisions
- Meiotic rest points (oogenesis has them)
- Timing of differentiation
- Developmental rate
5
Q
Talk me through human nuclear maturation
A
Nuclear envelope breakdown > onset of microtubule nucleation > growing microtubule aster > early bipolar spindle > initial chromosome congression > stable chromosome alignment > anaphase > polar body abscission > bipolar MII spondle
6
Q
Where does nuclear maturation arrest in oogenesis?
A
Prophase I
7
Q
Define cytokinesis
A
Dividing of cytoplasm
8
Q
Define Karyokinesis
A
Separating of chromosomes
9
Q
Define Parthenogenesis
A
Development of offspring without need of a male
10
Q
What are two examples of animals that use parthenogenesis for reproducing?
A
Bee
Desert grassland whiptail lizard
11
Q
Talk me through bee reproduction
A
Queen bee > haploid egg > haploid bee > male bee
Male bee > mitosis > haploid sperm > egg + sprem > diploid bee > female
12
Q
What kind of egg does the desert grassland whiptail lizard produce?
A
A diploid egg because the chromosomes double prior to meiosis
13
Q
Talk me through regulation of nuclear maturation in a starfish
A
Radial nerve of starfish > RF (radial nerve factor) > targets ovarian follicle cells > ovarian follicle cells release MIS (maturation inducing substance) > oocyte surface > signal is transfers to cytoplasmic MPF (maturation promoting factor) > meiosis resumes > GVBD (germinal vessicle breakdown)
14
Q
Talk me through the regulation of nuclear maturation in starfish at the cellular level starting with ovarian follicle cells
A
Reproductive season > ovarian follicle cells are receptors for gonadostimuline (GS) > MIS (maturation inducing substance) > G protein > beta/gamma subunits breakdown cAMP > activation of MPF (maturation promoting factor) > GVBD (germinal vessicle breakdown)
15
Q
Talk me through the regulation of nuclear maturation in amphibians (specifically frogs)
- Hypothalamus to CSF
- Fertilization to resumption of mieosis II
A
Hypothalumus > Gonadotropin Releasing Hormone > gonads > progesteron > c-mos > phosophylation cascade > phosphorylation of p34 = subunit of MPF (p34 +Cyclin) > activation of MPF > releases hold that is a diplotene arrest > egg enters into meiosis II and stops at anaphase (metaphase block) because CSF is inhibiting APC (anaphase promoting complex)
APC -| securin -| separase > destruction of cohesion rings (required for anaphase)
Fertilization > increase in cytoplasmic Ca > activation of calmodulin > breakdown CSF > activation of APC > ubiquitination and degradation securin > activation of separase > destruction of cohesion rings > resumption of mieosis II
16
Q
What happens 15 hours, 20 hrs, 35 hrs, and 38 hrs after the ovulatory surge of LH and FSH in humans?
A
0 hrs = ovulatory surge of LH and FSH
15 hrs = GVBD
20 hrs = First meiotic metaphase
35 hrs = Second meiotitc metaphase
38 hrs = ovulation
17
Q
Talk me through the resumption of meiosis in humans
A
- Normally: active GC > increased cGMP > travels through granulosa cells into oocyte > activatate AC > increase cAMP & increase cGMP
- Resumption: Increase in LH > activate LHR-G5-AC complex > increase cAMP > increase LH > activate GMP PDE (phosphodiesterase) > breakdown of cGMP > gap junctions close between outer granulsa and oocyte > decrease cGMP in oocyte > activate PDE3A > decrease cGMP & decrease cAMP -| PKA C -| Wee1 + no inhibition on CdC25 > MPF activation
high levels of cAMP > PKA C -| CdC25 > MPF
high levels of cAMP > wee1 -| MPF
18
Q
What are the 8 important pieces that make up the egg?
A
- Haploid nuclease
- Ribosomes & tRNA
- Enzymes
- mmRNAs
- Morphogeneic factors
- Protective chemicals (esp needed for eggs released into the environment)
- Extracellular coats
- Yolk
19
Q
What is the jelly layer? Do human eggs have one?
A
Protects the egg and attracts sperm
We do not have a jelly layer
20
Q
What is the vitelline envelvope? Is it specific to mammals?
A
Surroinds the eggs
Zona polusoa
Mamalian specific
21
Q
What is mmRNA?
A
Maternal mRNA
22
Q
What are the 3 egg types based on yolk?
A
- Oligolecithal (little yolk) ex us, sea urchins
- Mesolecithal (middle yolk) ex amphibians
- Telolecithal (large yolk) ex fish, birds
23
Q
What is an additional structure that teloecithal eggs will have?
A
Germinal disc
24
Q
What is the cumulus? What structure does it stem from?
A
A layer of granulosa cells outside of the egg post ovulation
Corona radiate become cumulus after ovulation
25
What is the cumulus offerus?
Stalk?
26
When do females have the highest egg count? What is it?
16-18 weeks after conception
6.5 x 10,000,000
27
How many eggs do females have at birth?
1-2 million
28
How many eggs do females have at the start of puberty?
30-40,000
29
How many eggs will a female ovulate in her life?
400 (all the others will die off)
30
What does cohesin do?
Keeps chromosomes together for migration
31
How does the amount of cohesion in the eggs of a young mouse and old mouse differ?.
There is less cohesion in the old mouse
32
What is a trisome? What is an example?
When the egg ends up with 3 copies of a chromosome instead of 2
ex. Down Syndrome (Trisomy 21)
33
At what age do trisomies begin to escalate rapidly?
32
34
What age is considered "advanced maternal age"
35
35
What percentage of fertilized eggs fail to develop leading to spontaneous abortion?
50%
36
What does trisomy 16 result in most of the time? What makes it different form trisomy 21?
Leads to a spontaneous abortion
This trend is linear (not exponential after a certain age)
37
Primordial follicle and primary follicle both fall under the umbrella of what stage of oogenesis?
Primary oocyte
38
What is the difference between a primordial follicle and a primary follicle? What life stages do they occur at?
```
Primordial = not well-developed follicle cells, what you have at birth
Primary = follicle/theca cells arise, transcription begins, grow in size, what you have at puberty
```
39
What are the characteristics of a intermediate/secondary follicle?
Increase in layers of granulosa cells
Theca cells split into 2 layers (externa and interna)
40
What is the basal lamina?
Exists between the theca and granulosa cels of a developing oocyte
41
What are the characteristics of a early tertiary/antral follicle?
FSH drives development
Follicle grows
Antrum start to appear (individual cavities) filled with liquor follicular to bath the egg in proteins and hormones for development
42
What are the characteristics of a late tertiary/antral/graffian follicle?
1 large cavity (antrum)
43
How many days does it take for complete mammalian folliculogenesis?
355 days
44
What are the stages of folliculogenesis?
Primoridal (primary follicle and secondary follicle)
Growth (preantral, early antral)
Selection (antral, antral)
Matruation (antral, preovulatory)
45
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Oogenesis
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Nuclear Maturation in Humans
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Nuclear Maturation in Humans
Prophase I arrest
GVBD
-
Polar Bodies
48
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Polar Bodies of invertebrates
49
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Shoes spindle portiens, eccentric spindle appartues, first polar body
50
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Mature Graafian Follicle
51
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The egg
52
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Amphibian Egg
53
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Amphibian Egg
54
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Amphibian Egg Polarity
55
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Oocyte with corona raidata
Prior to ovvulation
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Ovulated egg with cumulus and cumulus ooserus
57
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Oogenesis throughout the life of the woman
58
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Staining of cohesion of oocytes in diplotene arrest
There is less cohesion in the old mouse
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Malformations at diplotene arrest
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Graafian Follicle
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Primordial follicle
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Primary Follicle
63
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Intermediate/secondary follicle
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Early tertiary / antral follicle
65
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Late tertiary/antral/graffian follicle
66
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Mature Graafian Follicle
67
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Mammalian Folliculogenesis
68
What are the two types of ovulation?
1. Relex (cervical stimulation) ex rabbits
2. Periodic (cyclic release) ex us
69
What are the two main types of cycles?
1. Estrous
2. Menstraul
70
What is the estrous cycle? What are the 4 phases?
Characterized by pronounced period of sexual receptivity
1. Diestrus: quiescence, small follicles, if prolonged, called anestrus
2. Proestrus: follicular stimulation, uterine lining proliferation
3. Estrus: period of receptivity and ovulation
4. Metestrus: follicles develop into corpora lutea (uterine lining recycled if no fertilization)
71
What are the 3 cycles of the menstrual cycle?
1. Ovarian Cycle: mature and release ovum
2. Uterine cycle: provide an environment for implantation
3. Cervical cycle: allow movement of sperm into reproductive tract only at appropriate time (mucus keeps bacteria and sperm out and thins when egg is present in the uterus)
72
What is the hypothalamic-pituitary-gonadal axis?
Hypothalumus \> GNRH \> anterior pituitary \> FSH & LH \> granulosa & theca interna
73
What is the corpus luteum?
Endocrine producing structure = produces progesterone
74
What do the spinal arteries do during menstruation?
They close off so you don't have continuous bleeding when the uterine lining is sloughing off
75
During what stage of menstration does the endometirum increase in size?
Luteal
76
The ovulatory spike refers to a spike in what hormone?
Luteinizing hormone (LH) (primarily)
Follicular stimulating hormone (FSH)
77
What occurs 15 hrs, 20 hrs, 35 hrs, and 38 hrs after ovulatory spike?
15: break down of ovulatory vesicle
20: meiosis I completed
35: meiosis II completed
38: ovulation
78
What occurs 24 hours after estrogen spike?
Ovulation
79
How do the levels of estrogen effect the levels of FSH and LH?
Low estrogien = supresses FSH and LH
High estrogen = does not suppress FSH and LH
80
What phase of the mentraul cylce varies in length?
Proliferative phase
81
Approximately how many days does each phase in the menstrual cycle take?
Menstrual phase: 5 days
Proliferative phase: 5-9 days
Luteal phase: 14 days
82
If the embryo implants into the uterine lining what hormone is produced? What does that hormone do?
HCG \> feedback to corpus luteum \> corpus leuteum remains and produces steady levels of progesterone and estrogen \> decreased levels of FSH and LH \> uteren lining stays
83
Pregnancy tests measure what hormone?
HCG
84
What is the start of menopause?
No period for one year
85
What occurs in your body for menopause to start?
Loss of gonadotropin sensitivity (the follicles FSH and LH target are gone)
86
What are some evolutionary hypotheses about why menopause occurs?
Grandmother hypothesis: help DNA offspring survive rather than introduce new DNA offspring
87
How do you go from 5-10 follicles at the start of development to 1?
Increae in estrogen \> 1. decreased levels of FSH & 2. increase in the number of FSH receptors \> cells are able to response to lower and lower levels of FSH \> finally one follicle is able to respond to the signals and the others drop off
88
What are the 6 major types of birth control for females?
1. Oral Contraceptive Pills
2. Nuva Ring
3. Xulane
4. Depo-provera
5. Nexplanon/Implanon
6. Mirena
89
What are the two types of oral contraceptive pills? How many placebo pills are there? What does progesterone do? What does the
1. Progesterone + estrogen
2. Progesterone
7 placebo for mensus
Progesterone helps keep cervical mucus thick
Prevents ovulation
90
What is the nuvaring?
Places right around cervix that delivers hormones
Have it in for 3 weeks, remove it for 1 week
Pro: lower hormone concentration because they are closer to its target
91
What is Xulane?
aka the patch
hormone system (3 weeks in, 1 week out)
92
What is Depo-provera?
Shot
Injects hormones in matrix that gets delivered (12 weeks)
93
What is Mirena?
IUD
Used to be Cu with cotton string, now with different string and hormones
94
What are the two types of morning after pills?
1. Plan B, Next Choice (progestin only)
2. Ella (ulipristal acetate) (spike of progesterone)
Both push back ovulation so the sperm will die off waiting of the egg
95
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Menstual Cycle
96
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3 phases of the menstrual cycle
1. Proliferation
2. Luteal
3. Mensus
97
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In depth image of myometrum on bottom and endometrium on top
98
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Overlapping view of menstrual cycle
99
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Wave of hormones during follicular development
100
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Ovarian targets of hormones
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Ovarian targets of hormones
102
What 4 things does the LH (ovulation) spike cause?
1. Collagenase: break down of collagen in the ovary wall
2. Prostaglandin: smooth muscle contraction
3. Water comes in \> increase in pressure
4. Proteases: breakdown wall
103
What is a stigma?
When the egg is protruding out of the ovarian follicle
104
Talk me through oocyte pickup?
Fimbrea (finger-like projections that pulse with your heartbeat) sweep along the surface of the ovary and pick up the egg as it is released (sits on stalk until then)
105
What do the cilia lining the fallopian tubes do?
Help move the egg into the uterus
106
What is sperm capacitation?
It means the sperm is able to undergo acrosome reaction
occurs via the female reproductive track
107
What are the 5 changes in sperm that occur during capacitation?
1. Cholesterol removed from the membrane
2. Membrane proteins/carbohydrates lost (unmasking)
3. Membrane potential drops
4. Protein phosphorylation
5. Acrosomal & plasma membranes conact
108
Why does the cholesterol get removed from the membrane during capacitation?
Allows the 2 lipid bilayers to fuse becoming a fusogenic membrane
109
Why is unmasking necessary during capacitation?
Sperm is fragile and needs protection so it is covered in proteins and corbaosydres when in the epididymis and during ejaculation
The proteins are removed so the sperm can interact with the egg during capacitation
110
Why does the membrane potential drop during capacitation?
Negative charge inside the sperm \> signaling events
111
What protein phosphorylation events occur during capacitation?
Albumin from female binds to cholesterol efflux in sperm membrane \> bicarb influx & K outflux \> change in potential \> ca channels open \> cAMP production \> PKA \>\>\>\> phsophoyrlation cascade \> hyperactivation = "sprint!"
112
What are the 5 steps of fertilization?
1. Approach
2. Recognition and Binding
3. Sperm penetration into the egg
4. Egg activation
5. Amphimixis
113
Fertilization: Approach
Bring sperm and egg into same relative proximity (chemotaxis, spermatophores)
114
What are the two types of External Fertilization? Define them
1. Broadcast Spawning (release eff and sperm into water)
2. Spermatophores (mass of gelatinous sperm that sticks to the underside of female and female releases eggs onto mass)
115
What is internal fertilization?
When fertilization occurs inside the female reproductive tract proper
116
What is chemotaxis?
aka chemoattraction
egg releases chemicals to attract sperm
It is a species specific process
117
What role does the jelly layer play in broadcast spawners?
It make the egg a bigger target
118
What chemical do Urchins use for chemotaxis? What does it cause the sperm to do?
Resact (14 aa peptide from egg)
Increases motility and respiration
Taxonomically specific (only sperm from a species that also produces Resact will find the Resact producing egg)
119
What happens with Resact binds to sperm surface?
Resact \> RGC \> converts GTP to cGMP \> open ca channels \> increase ca \> sperm swims towards egg
120
What is seminal fluid comprised of fluid from(2 big things)?
Epidiymus (60%): Fructose (energy), prostaglandins, coagulating gel, immunosuppressives
Prostate (25%): protease
121
How long can sperm be viable after ejaculation? How about the egg after ovulation?
1-6 days
1 day
122
Why is "the fastest" sperm not always the one to fertilize the egg?
Sometimes it only takes sperm 30 min to reach the ovaduct, but they didn't swim there - they got beat up by the cilia and are not going to be able to fertilize the egg
123
Fertilization: Recognition and Binding
Acrosome reaction
Sperm binding to vitelline envelope
124
Fertilization: Sperm penetration into egg
Sperm-egg membrane fusion
Fertilization cone (forms at site where sperm in drawn to egg)
125
Fertilization: egg activation
Jump start development - gets to metaphase II \> boom become active start processes for development and block other sperm entry
126
Fertilization: Amphimixis
Syngamy (fusion of the male and female chromatin, the ultimate fertilization event)
127
To the female body, sperm are foreign materials. What does this mean?
The female immune system will start attacking the sperm
The vagina has a low pH to prevent pathogen entry but serves a dual purpose because sperm also don't like it
128
How does seminal fluid help the sperm get past the acidic vagina?
Seminal fluid alters the pH, fights the immune system
Coagulating gel prevents back flow (~30% sperm will come back out of the vagina due to gravity)
129
What are three concerns for sperm when trying the pass the cervix?
1. Cervical mucus which inhibits sperm (progesterone increases thickness)
2. Folds in the wall of the cervix create resistance (only the best sperm will get past the folds = way for fe to select sperm (2 headed sperm will not make it past folds))
3. Antibodies
130
In comparison to vaginal deposit, transport through the uterus occurs quickly
True
There are two places sperm can be deposited: vagina or uterus (depends on animal (we do vagina))
131
How do neutrophil levels change at 12, 24, 36, and 48 hours post-insemination?
Withing 6-12 hours after introduction of sperm into the uterus, there is a massive infiltration of neutrophils into uterus lumen
Begin to drop after 12 hours, nearly gone by 48 hours
132
What would a uterus split into horns signify?
The animal will reproduce in litters
Multiple babies in both horns
133
What is the oviductal sperm reservoir?
Sperm reservoir at the oviductal junction where sperm bind to epithelium/lining of ovaduct
134
What are the 3 possible functions for oviductal sperm reservoir?
1. Helps prevent polyspermy (not all that bind will be released)
2. Timing (bind and hang out until ovulation)
3. Capacitation & hyperactivation (complete both)
135
How do the sperm bind to the oviduct?
Similar to the sertoli cells in the testes
136
What do we know about human sperm storage?
1. Sperm last longer when attached to female reproductive tract
2. Location is unkown
137
What is the site of capacitation?
Occurs in the oviductal isthmus
138
What are the 8 steps of sperm attachment and detachment?
1. Sperm reservoirs at uterotubual junctions (isthmus)
2. Sperm lectins bind to glycoconjugates of epithelium of reproductive tract
3. Isthmus narrowing and mucus may aid in binding
4. Binding increases survival time and slows capacitation
5. Ovulaiton
6. Oviductal secretions increases capacitation
7. Sperm lectin losses adhesiveness
8. Hyperactivation of flagella helps release sperm
139
Talk me through the loss of sperm from vagina to ampullae
10^7 sperm in vagina
10^5 make it through uterus
10^4 make it to ovaduct
10^2 make it to ampullae
140
Is there chemoattraction in humans?
Uuknown
We do know that the majority of sperm will swim to the correct ovaduct
Possibly pojesteron which will open ca changes and direct sperm swimming
141
Do we use thermotaxis?
Yes
The ampullae is 2C warmer than the rest of the ovaduct
142
Oocyte transport of egg
1. Oocyte capture ( by fimbriae off extended mucus stalk)
2. Oocyte transport to ampullae (by cilia)
143
Why would it be unlikley that a sperm would swim past the egg?
Cumulus expansion makes the egg bigger so it fills the lumen of the ovaduct
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Ovary Rupture
145
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Mammalian Ovulation
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Oocyte Pickup
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Sperm Capacitation
The capaciated sperm have less cholesterol
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Clustering of sperm due to urchin chemotaxis
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Split uteri into horns
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Oviductal Sperm binding
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Human Sperm Storage
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Site of Capacitation
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Summary of Fertilization
154
Acrosome reaction I (Urchin)
Fucose sulfate polymer on the jelly of the egg binds to the SURej receptor on sperm \> acrosomal exocytosis
1. Soluble components (enzymes) are releases \> breakdown jelly layer
2. Influx of calcium from internal and external sources \> promotes fusion
3. Sodium proton exchange
155
Induction of the acrosome is species dependent
True
156
Acrosome Reaction II (Urchin)
Globular actin polymerizes and forms filament that exposes inner acrosomal membrane
157
What molecule is responsible for Urchin acrosomal binding?
Bindin which is located on the inner acrosomal membrane
158
How do we know that arcrosomal binding is species specific?
Green species with green species
This is significant because you can create a new species by modifying the surface proteins (SURej, binding, etc)
159
What is the receptor to Bindin?
EBR1 on the egg binds to Bindin on Sperm
160
What are the two evens that help the sperm penetrate the cumulus?
1. Sperm Hyperactivated (bull its way through the cumulus layer)
2. Hyaluronidase on the surface of sperm break down GPI between granulosa cells
161
When does the sperm arosome reaction in humans?
Not exaclty sure
Sometime during its penetration through the cumulus layer
162
How are human and urchin acrosome reactions different?
Humans do not produce an acrosomal filatment
We just exposes the inner acrosomal membrane
163
What exactly does the human sperm bind to?
ZP2
Zona Pelucida has 3 main components
ZP 2,3 = structural
ZP 1 = cross link
164
What is gamete fusion?
The fusion of the sperm and egg membranes which really allows the sperm to get into the egg
165
What is a unifying theme across gamete fusion?
The use of microvilli
166
What is one difference between the way human and mouse sperm bind to the egg?
Human sperm bind perpendicularllly
Mouse sperm go in sideways
167
What are the 3 main steps of gamaete fusion?
Adhesion
Deydration (get rid of water)
Hemifusion (outer leaflet binds to outer leaflet)
Pore opening and expansion (inner leaflet binds to inner leaflet)
168
What are fusogenic proteins?
Proteins that aid in gamete fusion (we don't know what they are specifically)
169
What is unilateral or bilateral gamete fusion?
Unilateral = 1 cell provides the fusogenic proteins
Bilaterial = both cells provide fusogenic proteins
170
What two proteins are bound together for human gamete fusion?
Izumo on the sperm
Juno on the egg
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Urchin Fertilization
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Mouse Fertilizaiton
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Human Fertilization
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Acrosomal Reaction I
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Acrosomal Reaciton I is species specific
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Acrosomal Reaction II
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Urchin Bindin
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Urchin - species specific binding
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Binding to the VE Bindin
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Acrosomal Binding is specieis specific
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Summary of Urchin Fertilization
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Zona Pellucida of Egg
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Sperm bind to ZP 2
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Possible pathways for mouse fertilizaiton
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Sea urchin gamete fusion
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Human gamete fusion
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Summary of Mammalian Fertilization Sequence
