Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
10 Cards in this Set
- Front
- Back
Cytoplasmic Determinant
|
Early embryonic cells become different because of the uneven distribution within the unfertilized egg of maternal substances.
|
|
cell differentiation
|
specialization of cells in their structure and function. communication of instructions, tells cell what and when to do something.
|
|
Morphogenesis
|
an animal takes shape and the differentiated cells end up in the appropriate locations.
|
|
Fertilization
|
Sperm penetrates the plasma membrane of the secondary oocyte.
|
|
Steps of fertilization:
|
Recognition, Penetration, formation of the fertilization membrane, completion of meiosis II in the secondary oocyte, fusion of nuclei and replication of DNA.
|
|
Recognition:
|
the sperm secretes a protein that binds with special receptor molecules that reside on a glycoprotein layer surrounding the plasma membrane of the oocyte. (vitelline layer/zona pellucida) insures that fertilization occurs only between egg and sperm of the same species.
|
|
penetration
|
the plasma mebranes of the sperm and oocyte fuse, and the sperm nucleus enters the oocyte.
|
|
formation of the fertilization membrane
|
the vitelline layer forms a fertilization membrane which blocs the entrance of additional sperm.
|
|
completion of meisosi II in the secondary oocyte
|
sperm penetration triggers meiosis II in the oocyte, producing ovum a dpolar body. the polar body is discharged trhoug the plasma membrane.
|
|
fusion of nuclei and replication of dna
|
the sperm and ovum nuclei fuse, forming a zygote nucleus consting of 23 pairs of chormosomes(inhumans) each chromosome replicates so that it consists of two identical chromatids
|