Class Notes (808,765)
Canada (493,382)
BIOL 1000 (60)
Lecture 22

BIOL 1000 Lecture 22: Biology Lecture 22

3 Pages
Unlock Document

University of Manitoba
Biological Sciences
BIOL 1000
Kevin G.Scott

Biology Lecture 22: Division in meiosis occurs in the same four phases except they have 1 attached to them in the first part and 2 in the second part. It is in meiosis that you go from 2n to n. Prophase I: Prophase I typically occupies more than 90 percent of time Chromosomes begin to condense In synapsis, homologous chromosomes loosely pair up, aligned gene by gene** E.g eye colour and toe nail genes lined up side by side In crossing over, non sister chromatids exchange dna segments Each pair of chromosomes form a tetrad a group of 4 chromatids Each tetrad usually has one or more chiasmata, Xshaped regions where crossing over occurred Homologues pair of chromosome lining up is called a tetrad**** Chiasmata is the crossing over of part of the two chromosomes in a homologous pair Metaphase I: Tetrads line up at metaphase plate with one chromosomes facing each pole Microtubules from one pole are attached to the kinetochore of one chromosomes of each tetrad Microtubules from the other pole are attached to the kinetochore of the other chromosome Spindle apparatus is attached and connected to pole and connected to a kinetochore of a chromosome Anaphase I: Pairs of homologous chromosomes separate One chromosome moves toward each pole guided by the spindle apparatus **Sister chromatids remain attached at the centromere and move as one unit toward the pole Telophase I and Cytokinesis: In beginning each half of cell has a haploid set of chromosomes, each chromosome still consists of two sister chromatids Cytokinesis usually occurs simultaneously forming two haploid daughter cells 2 cells formed will have 1n double stranded. So we went from 2n double stranded to 1n double stranded. In animal cells a cleavage furrow and in plants cells a cell plate forms.
More Less

Related notes for BIOL 1000

Log In


Don't have an account?

Join OneClass

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

Sign up

Join to view


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.