Class Notes (810,677)
Canada (494,204)
York University (33,691)
BCHM 2021 (13)
Lecture 17

Biochemistry- Lecture 17.docx

5 Pages
Unlock Document

York University
BCHM 2021
Julie Clark

Biochemistry- Lecture 17 Mitosis: M-cdk activation causes all early events of mitosis Activate M-cdk: 1. Increase M-cyclin gene expression M-cyclin levels - cdk-acitvativity CAK activate - weel kinase inactivates 2. Activation of cdc25 phosphatase removes inhibitory- p -positive feedback -M-cdk inhibits weel -activates cdc25 - all-or-nothing switch - cdc 25 activation -? -M-cdk phosphorylates proteins -assembly of mitosis spindle break down of nuclear envelope -lamins - it causes re-arrangements of the actin cytoskeleton + golgi chromosome condensation -condensin + activates -Mcdk Phosphorylates proteins -assembly of mitotic spindle -break down of nuclear envelope lamins -re-arrangements of actin -cytoskeleton and Golgi -chromosome condensation -condensin -condenses chromosomes -M-cdk phosphoylates -condensin and activates Mitotic Spindle -bipolar array of microtubules -minus ends poles 3 Kinds of Tubules 1) Interpolar -antiparallel 2) Kinetochrore -attached to the sister chromatids at the kinetochore 3) Astral -outward from centrosome to cell cortex **Video 17.7: Mitotic Spindle* Formation of Spindle -G1/S-cdk triggers centrosome -duplication and S phase -Beginning of mitosis: -M-cdk phosphorylates MAP, microtubules become shorter and more dynamic -phosphorylation of centrosome -γ-tubulin ring complex more in centrosome -more microtubules form -M-cdk phosphorylates motor proteins Motor Proteins -dyneins: minus end directed pull tubules to cortex -centrosomes move apart -pulling them apart -Kinesin 5: plus end directed -pushing the poles apart -kinesin-14: minue end directed -pull poles together -balance opposing forces -Kinesin 4,10 to plus end  carry chromosomes Question: It is estimated that as many as 25% of kinetochore microtubules and 75% of interpolar microtubules are NOT anchored to the centrosomes. In spite of that, all microtubules are focused tightly at the spindle pole Why don’t the microtubules that weren’t nucleated by centrosome splay out away from the poles Answer: Microtubules that are not directly connected tho the centrosomes are held in place by minus- end-directed motors, which link them to the other microtubules...[internet] -kinetochore: attachment site on a chromosome -proteins at heterochromatin at centromere -2 kinetochores per pair of chromatids = 92 humans -microtubules capture chromosomes -chromatids attached to opposite poles -line up on metaphase plate Anaphase -Activate APC/C Triggers anaphase -coh
More Less

Related notes for BCHM 2021

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.