Class Notes (837,548)
United States (325,103)
BIOSC 0160 (73)
Nilson (19)
Lecture 12

BIOSC 0160 Lecture 12: Biology 2 Lecture 2.2: Animal Developmental Processes
Premium

2 Pages
30 Views
Unlock Document

Department
Biological Sciences
Course
BIOSC 0160
Professor
Nilson
Semester
Spring

Description
Biology Week 8 Lecture 2.2 Segmentation genes: subdivide embryo into smaller areas, demarcating the embryo segments and eventually specifying the identityrole of each segment o Bicoid and other maternal effect genes are at the top of a regulatory gene of hierarchy of these Hox genes occur in two clusters on chromosome 3 o Order on chromosome is the same order of position expressed in embryo o Highly conserved in animals where they specify position of structures Homeotic mutations: altered Hox genes that result in drastic transformations to the body plan Morphogens: maternally expressed gene products Evodevo: field of biology which studies how changes in the expression of developmentally important genes can lead phenotypic diversity and the formation of new species o Highly conserved tool kit genes like Hox genes (direct pattern formation) o Genetic switches (DNA regulatory regions, transcription factors, signaling transduction molecules) regulate tool kits determine where, when, and how they are expressed in development o Modularity: independence of developmental processes (module changes without changing the whole organism) results from multiple switches o Heterometry: amount of expression o Heterochrony: time of expression o Heterotropy: location of expression Fertilization: initial developmental event in sexual reproduction o Union of male and female gametes o Restores diploid number o Sperm entry establishes polarity in the zygote o Polyspermy: fertilization of the egg by more than one sperm Increases number of centrile and chromosome number Fast block: begins shortly after egg contact with fertilization sperm and lasts about 60sec. Plasma membrane is depolarized when NA+ channels are opened and Na+ enters the cell, which prevents additional sperm from entering (dont know why this works) Slow block: cortical reaction and fertilization membraneenvelope formation Ca2+ are released from intracellular stores triggering the formation of the fertilization membrane which removes excess sperm Ca2+ release triggers cortical reaction o Enzymerich cortical granules fuse with the cell membrane, release their contents outside the plasma membrane vis exocytosis (between cell membrane and vitelline layer) o Enzymes digest sperm receptors, water rushes into the space because of the release of solutes, and the fertilization envelope is pushed away from the egg removing the sperm o Species recognition: external fertilization
More Less

Related notes for BIOSC 0160

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit