Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bio 303 > 3d and 3e > Flashcards

3d and 3e Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

PIP2 messenger system

A

-slow block to block polyspermy

how it works
1) Activation of bindin receptors activated phospholipase C (PLC)
2) PLC cleaves PIP2 in egg plasma, releasing IP3
3) IP3 released into egg cytoplasm
4) ip3 diffuses into ER. where it opens calcium channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Specifically how is phospholipase C (which is activated by bindin) activated

A

two ways, not sure which one
either
Soluble factors released from sperm membrane fusion
or
thorugh signal transduction by activation of receptor tyrosine kinase on egg membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

chromosome things fgor sea urchins

A

-female completed meiosis before fertilization
-sperm must decondense chromosomes by remvoing hisotones and adding female histones
-pronuclei of male and female migrate and fuse
-dna rep occurs after fusion of pronuclei
-SPERM centriole used to make mitotic spindle,
-sperm mitochondria and flagellum disintegrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mammalian Fertilization

A

-begins in oviduct with binding of free swimming sperm to the ovulated egg extracellular coat (zona pellucida)
-forms zygote (activated cell)

everal recognizable events include:

the sperm acrosome reaction (a form of cellular exocytosis)
penetration of the egg ZP by sperm
fusion of egg and sperm membranes
the egg cortical reaction
zona reaction (results in alteration of the ZP such that free-swimming sperm are unable to bind to fertilized eggs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three stages of human oogenesis

A

OOgenisis is theprocess of which eggs cells ar emade in the ovary

1) Meiotic prophase events of senapses and recombination which occurs in fetal ovary

2)Follicle formation: second tri of fetal develop

3)Oocyte growth: occurs in adult ovary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Oogina vs primary oocytes vs secondary oocyte

A

Oogina: undifferentiated ovarian germ cells that give rise to the oocytes

Primary oocytes: oogonia that have initiated meiosis

Secondary: completion of 1st meiotic division produces small cell called polar body and large secondart ooycte

Ova: egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

dictyotene stage

A

resting phase of the oocyte in mammals
-in humans can last from birth up to12-50 years depending on the time of follicle maturation and ovulation
-chromosomes condensed here
-primary oocytes are arrested in first meiotic prophase and remain here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Meiosis prophase 1 arrest vs metaphose 2 arrest

A

dictotene phase

metaphase 2 arrest is second arrest point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the order of mammalian oogensis

A

Primordial germ cell
oogina(entry into meiosis)
primary oocyte (m phase 1)
seocondary oocyte (meiosis 2 and growth)
ova

fertilization triggers completion of m phase 2 (2nd meiotic fividion)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sperm motility

A

-UTERINE MUSCLE CONTRACTION (needed to get sperm into oviduct (ampulla region)
-sperm becomes hyperactive in oviduct
-direction cues given from temperature gradient in oviduct
-chemical cues from cumulus or oocyte
-sperm become mature during voyage to oviduct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the ampulla region

A

oviduct, distal to uterus and near ovary where fertilization takes place

provides great environment for fertilization and helps transport gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What region may slow down sperm and release them slowly into ampulla

A

isthmus:narrow segment of the oviduct, next to uterus

found before ampulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is capacitation

A

-set of changes that allow sperm to become able to fertilize egg (become primed to undergo acrosomal rxn and primed to fuse to cell membrane)
when sperm become mature during voyage ti oviduct, if not wont be able to fertilize egg
-sperm released during ejaculation ar able to move but they vannot yet fertilize egg, need to be matured in reproductive tract
-this is because sperm is quiescent transcriptionally and translationally (means dormant) sothey rely on post translational modifications such as phosphorylation of proteins to control maturation process
-this occurs as sperm comes in contatt with natural conception lubrication
-this needed to be understood to have successful ivf treatments and stuff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how is oocytes moved

A

cumulus needed to :cumulus attaches to fimbria, which transports the ooycte to ampulla also through MUSCLE CONTRACTIONS AND CILIA BEATING (CILIARY LINING) those two points more important

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens during capacitation

A
  1. Albumin proteins (present in reproductive tract of females) remove cholestrol from sperm membrane
    -changes position of lipids that house receptors now allowing for it to be in right place
  2. Proteins and carbs are lost
  3. Membrane potential becomes negative (facilittes sperm fusion)
  4. Protein phosphorylation: two are phophorylated at sperm head, essential part of zona pellucida receptor
  5. Acrosomal membrane comes ont. contact with sperm cell membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Does increasing cholesterol increase membrane fluidity

A

NO increasing cholesterol decreases fluidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are three differences between capacitated sperm and uncapacitated

A
  1. Cap are hyperactive: swim faster
  2. Cap show thermotaxis (will move from cooler regions of isthmus to warmer amopulla)
  3. Cap show chemotaxis: will move towards molecules released by cumulus
  4. Cap can undergo acrosomal rxn: sucessful sperm undergo this rxn before they reach cumulus
    -higher progesterone levels near site may trigger acrosomal rxn
  5. Acrosomal rxn is final stage of cap, proteins that were once on inner membrane of acrsome are now on tip of sperm, these are needed to bind to zona pellucida
18
Q

What are the three major glycoproteins of the zona pellucida

A

ZP1, ZP2 , ZP3

bind with other proteins to form glycoprotein matrix (which binds sperm)

zona pellucida is like vitiline envelope but thicker and denser and binding to it is relatively species specific not absolutely

19
Q

Sperm membrane proteins bind to what proteins of oocute

A

ZP proteins

20
Q

Acromosal rxn in mammals old thoughts vs new thoughts

A

OLD:
1) sperm proteins bind to zp3 protein on zona pellucida

2)zp3 causes acromosal rxn to occur

3)enzymes released right where needed to digest thorugh zona pellucida

so zp3 protein was thought to be needed for acrosomal reaction to occur

HOWEVEAR NEW TOUGHT:
after imaging techniques, saw that sperm that binds to zona have already undergone acrosome reaction and can do this without zp3 gene

-so zp3 is not needed into acrosomal reaction but it is able to be

zp2 is sufficient for binding of sperm to human egg abd allows for movement

21
Q

Sperm is in what position to egg when sperm egg fusion occurs

A

lateral to egg membrane
fusion initiated at equitoral region

21
Q

In mammals is there a fast block to block for polyspermy

A

NO

three versions of slow block exist
1)fusion of cortical granules with egg membrane
-zona pellucida modified so that it can no longer bind sperm (zona rxn)

2) Zinc Shield
-after calcium splash when sperm enters, zin ions are released via exocytosis from oocyte (stored in cortex) and bind to zona pellucida, giving it a shield

3) OOcyte membrane protein JUNO
-can bind to any sperm in the previtilline space and prevent it from binding to any juno still on membrane
-also removed docking sites

22
Q

Wha does membrane fusion of eggand sperm intail

A

-IgG like protein found on INNER ACROSOMAL MEMBRANE called IZUMO
-also oocyte memrbane protein called JUNO

mutants of juno or izumo prevent fertilization

23
Q

Zona reaction

A

enzymes released when cortical granules bind to zona modify zp proteins and the sperm receptors on the zona pellucida so it cant bind

zp2 is cleaved by ovastacin

Nacetylglusoamine of ZP3 removed by nacetylglusoaminase

24
Q

What is ZP2 cleaved by

A

OVastacin, released when cortical granules bind to zona pellucida

necessary to block polyspermy in mammals

25
Q

Wat is necessary for the block to polyspermy in mammals

A

Cleaved Zp2

26
Q

Decondensing of sperm dna

A

must be decondensed, tightly packed with protamines, disulfide bonds must be reduced

egg cytoplasm contains glutathione, and maternal histones replace rprotamines

27
Q

Whattriggers the completeion of meiosis two in the oocyte

A

waves of calcium when sperm enters activates kinase that triggers the completion of meiosis 2 via degredatio of cuclin and securin (leads to degredation of chromatin cohesion)
-nuclear enveloped break down and the chromosomes of both assemble on shared mitotic spindle

28
Q

What is the first division called

A

gonomeric division
pronucleis dont fuse at this point but nuclear envelopes breakdown and first mitotic division occurs

29
Q

What is glutathione and why is it found in abundance in eggs

A

-reducing agent
-importnat antioxidant
-protects against damage due to reactive oxygen species
- so as disulfide bonds are reduced it is oxidized which is whythe cell has it in abundance because disulfide bonds are reduced when chromatin of sperm is condensed

30
Q

Does the sperm head disconnect from its flagellum

A

NO, the entire sperm cell in mammals (incliding mitochondria and flagellum) enter the egg at fertilization

sperms mitochondria gets degraded inside and sperm centriole used for the mitotic spindle

31
Q

Increase in Ca…

A

necessary for egg activation
-resumes meiosis, cortical granule exocytosis, release of stored mRNA inhibition

-released due to phospholipase C released IP3 which binds and releases ca from endo

32
Q

Where is there a single wave ca increase and where is there a series

A

Single wave: sea urchin
mammals: series of waves

causes released of metaphase 2 block
- release of the metaphase II block
- cortical granule exocytosis (= cortical granule reaction)
- release of mRNA inhibition (maternal stores)

33
Q

what is dependent on ca increase

A
  • release of the metaphase II block
    - cortical granule exocytosis (= cortical granule reaction)
    - release of mRNA inhibition (maternal stores)
34
Q

ip3 is the product of what

A

phosphlipase c cleaving PIP2

35
Q

What is the CA wave inducer

A

PLC zeta
expression induces ca oscillations

36
Q

cleavage divisions

A

-Mitotic divisions: divide egg into smaller nucleated cells known as blastomeres
-no cellular growth: overall cytoplasmic volume remains the same
-initiation of mitosis

early cleavage divison are INDEPENDENT OF EMBRYO GENOME and controlled by maternal stockpiles

37
Q

CDK

A

-mitosis promoting factor
-depends on association with cyclin B (regulated by accumulation or destruction of cyclin B)

38
Q

Mid blastula transition

A

Mid-blastula transition: The transition from the early rapid biphasic (only M and S phases) mitoses of the embryo to a stage characterized by
(1) mitoses that include the “gap” stages (G1 and G2) of the cell cycle
(2) loss of syncronicity of cell division
(3) transcription of new (zygotic) mRNAs needed for gastrulation and cell specification.

39
Q

Cleavage divisions

A

Karyokinesis: division of nucleus during mitosis
-rewuires mitotic spindle

Cytokenesis:
the division of cell during mitosis
-contractile ring of microfilaments needed

40
Q

Yolk cleavage divisions

A

eggs having little yolk that is equally distrubuted are isolecithal and generally undergo holoblastic cleavage –depending on orientation of mitotic spindles, holoblastic cleavage can be radial, spiral, bilateral, or rotational

eggs that have more yolk at one end than the other are mesolecithal and also undergo holoblastic cleavage – but cleavage rates are slower in the yolkier side (in frog embryos like Xenopus, the more active side is known as the animal hemisphere/pole and the less active yolky side is known as the vegetal hemisphere/pole)

eggs where only one small area is free of yolk are telolecithal and undergo meroblastic cleavage – in mammals and birds this type of meroblastic cleavage is called discoidal cleavage

eggs have much yolk in interior and are centrolecithal and display superficial cleavage – common in insects where a syncytial stage precedes the cellular blastoderm stage

41
Q
A

bio 303 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions