FERTILIZATION Flashcards
____ Beginning of a New Organism
is the process where male and female gametes (sperm and egg) unite, typically occurring in the _____, which initiates the development of a new organism.
Purpose:
perpetuation of species through sexual reproduction.
determines the sex of the organism
Functions:
Transmit genes from parent to offspring
provides for recombination of paternal and maternal genes.
restoring the diploid chromosome number and ensuring genetic diversity.
Activates the egg to begin development
Fertilization
Uterine tube
Main Events During Fertilization:
- _____ between sperm and egg.
- Regulation of _____ into the egg.
- Fusion of ____
- Activation of ____ to start development.
Main Events During Fertilization:
Contact and recognition
sperm entry
Genetic Material
egg metabolism
STRUCTURE OF THE GAMETES: SPERM
____has hydrolytic enzymes for penetrating the egg
Cell body:
Contains _____
Neck:
_____
Tail:
_____ - core structure and contains: _____
______ ATPase causing flagellar bending
Acrosome
Cell body:
Pronucleus
Neck:
ATP/Mitochondria
Tail:
Axoneme contains: Tubulin
Dynein
Sperm parts (4)
Crucial part for the tail _____
Sperm parts (4)
acrosome
nucleus
mitochondria
tails
Axial filaments
The golgi apparatus forms the ______, which contains enzymes important for fertilization.
The ____ begin to migrate to one end of the cell, initiating flagellum formation.
acrosomal vesicle
centriole
Diagnosis of Kartagener’s syndrome:
Triad of symptoms (Characterics of KS 3):
Bronchiectasis
Chronic Sinusitis
Situs Inversus Totalis
Diagnosis of Kartagener’s syndrome:
_____ supports the diagnosis of Kartagener’s syndrome.
Moderate ____
Respiratory Failure Type 1 (Hypoxia without hypercapnia)
have a 50% chance that the heart is located on the ____ side of the body because of immotile cilia
Infertility
Airway Obstruction
right
Diagnosis of Kartagener’s syndrome:
Kartagener’s syndrome is a subset of ______ , a genetic disorder that affects the cilia. Because the cilia are immotile, they cannot perform their usual functions, leading to respiratory issues (due to mucus buildup in the lungs), chronic sinus infections, and issues with organ positioning (situs inversus).
Primary ciliary dyskinesia (PCD)
STRUCTURE OF THE GAMETES: EGG
All material necessary for the beginning of growth and development must be stored in the egg:
- _____ - like yolk (made in other organs; mostly liver)
- _____ burst of protein synthesis after fertilization
- _____ encodes proteins for use in the early stages of development.
Messages remain repressed until after fertilization - _____ direct the differentiation of cells into certain type
- Types of Protective chemicals (3)
STRUCTURE OF THE GAMETES: EGG
1. Nutritive proteins
- Ribosomes and tRNA
- mRNA
- Morphogenic factors
transcription factors, and paracrine factors - UV filters
DNA repair enzymes
Antibodies
Sea Urchin Egg:
- _____
Analogous to the mammalian zona pellucida, this is an extracellular matrix that forms a “fibrous” mat around the egg, playing a crucial role in sperm-egg recognition. - ______
Resides outside the vitelline envelope in some species; it attracts and activates sperm, aiding in the capacitation process. - _____
Located just inside the plasma membrane, these granules release enzymes that modify the vitelline envelope upon fertilization to prevent polyspermy. - _____
One sperm adheres to the egg cell membrane then the egg releases chemicals that drive the other sperms away from the egg and forms a fertilization barrier that cannot be penetrated. - _____
Provides the energy required for the egg’s metabolic activities post-fertilization.
Sea Urchin Egg:
- Vitelline envelope
- Egg Jelly
- Cortical Granules
- Plasma Membrane
- Mitochondrion
Mature (Vesicular) Follicle / Graafian Follicle:
- _____
Layers of cells that surround the follicle, playing roles in structural support and hormone production, respectively. - A fluid-filled cavity that forms within the follicle, which increases in size as the follicle matures.
- The actual gamete, arrested in metaphase of meiosis II until fertilization.
- A layer of cells that adheres to the oocyte and must be penetrated by the sperm prior to reaching the zona pellucida.
- Surround the oocyte and are involved in its nourishment and the production of sex steroids.
- A cluster of cells that anchors the oocyte to the follicle wall.
- A glycoprotein layer surrounding the oocyte, crucial for sperm binding and activation during fertilization.
Mature (Vesicular) Follicle / Graafian Follicle:
- Theca Externa and Theca Interna
- Antrum
- Secondary oocyte
- Corona radiata
- Granulosa cells
- Cumulus oophorus
- Zona pellucida
Recognition of Egg and Sperm
- _____ Sperm are attracted by soluble molecules secreted by the egg.
- _____ Of the acrosomal vesicle to release enzymes.
- _____ Of the sperm to the egg’s extracellular envelope.
- _____ Of the sperm through this envelope.
- _____Of egg and sperm cell membranes.
Recognition of Egg and Sperm
- Chemoattraction
- Exocytosis
- Binding
- Passage
- Fusion
EXTERNAL FERTILIZATION IN SEA URCHINS
Challenges:
1. How can sperm and eggs meet in such a dilute concentration?
- How can sperm be prevented from attempting to fertilize eggs of other species?
Solutions:
- Species-Specific Sperm Attraction
- Species-Specific Sperm Activation
Species-Specific Sperm Attraction:
- ______
sperm are attracted towards eggs of their species; following a gradient of chemical secreted by the egg
_____ (cnidarian)
regulates taxis (movement) and timing of sperm
chemotaxis occurs after _____
______ control the type of sperm they attract and the time at which they attract them.
1.Chemotaxis
Orthopyxis caliculata
2nd meiotic division
Oocytes
Sea Urchin:
motility acquired shortly after exposure to seawater
in testes, sperms are immotile because of low pH (pH____) by high CO2 content in the gonad
in sea water, sperm pH ~7.6 which results in activation of _____ (flagellar motor protein)
The ability to move does not provide the sperm with directions.
~7.2
dynein ATPase
Echinoderms:
Direction is guided by egg-derived peptides called ____:
sperm activation agent
sperm in sea water swim in circles
allows sperm to congregate (accumulation of sperm cells in a particular location)
_____- 14aa peptide isolated from egg jelly of Arbacia punctulata;
_____- specific for Strongylocentrotus purpuratus
Sperm-activating peptides (SAPs)
resact
speract