Fertilization

gonads

the anatomical reservoir of germ cells

germ

sperm and egg are — cells

germ layers

ectoderm, endoderm, and mesoderm are —

zygote

fertilized egg

Contact, recognition

Events of fertilization:

1. — and — of sperm and egg

2. regulation of sperm entry into the egg

3. fusion of genetic material from sperm and egg

4. activation of egg metabolism to start development

sperm entry

Events of fertilization:

1. Contact and recognition of sperm and egg

2. regulation of — into the egg

3. fusion of genetic material from sperm and egg

4. activation of egg metabolism to start development

fusion

Events of fertilization:

1. Contact and recognition of sperm and egg

2. regulation of sperm entry into the egg

3. — of genetic material from sperm and egg

4. activation of egg metabolism to start development

egg metabolism

Events of fertilization:

1. Contact and recognition of sperm and egg

2. regulation of sperm entry into the egg

3. fusion of genetic material from sperm and egg

4. activation of — to start development

23

the egg and sperm each have — chromosomes

Meiosis

— is a type of cell division in which one diploid cell divides to produce four haploid cells, each with half the original number of chromosomes. It is essential for sexual reproduction.

interphase

— is when chromosomes replicate

meiosis I

— is when homologous chromosomes separate

meiosis II

— is when sister chromatids separate

acrosomal vesicle

An — is a small membrane-bound vesicle in a developing sperm cell that forms the acrosome.

flagellum

C. elegans sperm do not have —

nutritive proteins

the egg contains — for a supply of energy

mRNA

the egg contains — because transcription occurs before fertilization!

ribosomes, tRNA

the egg contains — and — so it can immediately begin making proteins

morphogenetic factors

the egg contains — to direct the differentiation of different cell types

protective chemicals

the egg contains — like antibodies, UV filters, and DNA repair enzymes

Nurse cells

— are specialized cells that support and nourish developing germ cells, especially developing eggs.

cytosol

All of the — from nurse cells gets transferred to oocyte

4

Mature oocyte carries — cells worth of cytosol, trna, ribosomes, mrna, etc

1

a single germ cell (oogonium) gives rise to — oocyte

4

a single germ cell (spermatogonium) gives rise to — sperm

jelly layer

The — is the outer, gelatinous coating of the egg that elps with sperm attraction and provides protection.

vitelline envelope

• Protein-rich layer just outside the egg's plasma membrane.

• Contains molecules involved in sperm recognition.

• After fertilization, it is modified to help prevent polyspermy.

cell membrane

• The actual membrane of the egg cell.

• Sperm–egg fusion occurs here.

cortical granules

• Vesicles located inside the egg, immediately beneath the plasma membrane.

• After sperm fusion, they release their contents by exocytosis.

• This modifies/hardens the vitelline envelope, producing the fertilization envelope and helping prevent additional sperm from entering.

chemotaxis

how do sperm find the egg in external fertilization

acrosome reaction

the — releases enzymes to digest a path to the egg membrane

acrosome process

the — contacts the surface of the egg to initiate a species-specific binding

Bindin

— binds to specific receptors on the egg's vitelline envelope

acrosomal process

The — is a long, thin projection that extends from the sperm head during the acrosome reaction.

-70, +20

the membrane potential of the egg shifts from —mv to — mv after binding of the first sperm

fast

the — block to polyspermy involves change in membrane potential

open, into

when the sperm bind to the egg, sodium channels (open/close) and sodium moves — the cell

lower

(higher/lower) Na+ conc. in the media surrounding an egg prevent the change in membrane potential and allows polyspermy

fertilization envelope

The — is a protective layer that forms around the egg immediately after fertilization. Its main function is to prevent polyspermy.

Ca+2

when — rises in the egg, cortical granules release their components

cortical granules

when Ca+2 rises in the egg, — release their components

viteline envelope

the — becomes the fertilization envelope

a wave of Ca+2 release is the — blovk to polyspermy