UMass Amherst BIOLOGY 285 - Bio 285 SI Before Quiz 4 (4 pages)

Previewing page 1 of 4 page document View the full content.
View Full Document

Bio 285 SI Before Quiz 4



Previewing page 1 of actual document.

View the full content.
View Full Document
View Full Document

Bio 285 SI Before Quiz 4

32 views


Pages:
4
School:
University of Massachusetts Amherst
Course:
Biology 285 - Cellular & Molecular Biology

Unformatted text preview:

Bio 285 SI Notes Quiz 4 Cell cycle control system CDK enzyme called Cyclin dependent kinase o Cyclin is a binding partner o master cell cycle regulator o Any point in cell cycle that cells decide they need to stop inhibit CDK CDK is regulated in several ways o Cyclin regulation different cyclins for different phases of the cell cycle G1 cyclins telling CDK to target G1 proteins S phase cyclins M phase cyclins o Phosphorylation dephosphorylation by kinases and phosphatases 1 o CDK inhibitors CDKIs 2 Another way of regulation is the regulation of Cyclin levels 3 o Regulate the levels of the cyclin that binds CDK Cyclin levels rise and fall throughout cell cycle via o Transcription translation o Degradation through ubiquitin mediated proteolysis Difference between CDK and cyclin CDK is the car while cyclin is the key Cell cycle checkpoints G1 phase o Check for DNA damage before replication begins o Check for favorable environment o Must have enough material to create a duplication of the cell S phase o Check for errors incompletely duplicated DNA G2 phase o Damaged or incorrectly replicated DNA o Enough resources to continue M phase o Proper chromosome and microtubule attachment and arrangement If DNA gets messed up can stop it during those checkpoints S G2 do basically the same thing Summarize whole cell cycle by putting each step in each stage Overview of cell cycle G1 phase growth gap phase o Could duplicate organelles o Cell checks environment Growth factor signals present Enough nutrients Enough energy DNA check for damage o Restriction point START G1 checkpoint o Prepare for DNA replication prepare ingredients Make nucleotides Make proteins required for replication o Once replication starts cell now in S phase S phase synthesis phase o DNA replication G2 phase 2nd growth phase o Check for DNA damage o Finish replication o Prepare for M phase M phase chromosome segregation o Cytokinesis splitting of the cytosol G0 phase non dividing state o Stop replication o Cell damaged etc Control of the replicative cycle Goal is to set up where the replication begins Replication begins at origin of recognition site on DNA o Multiple ORCs that occur at same time Form the pre RC o How Get ORC to bind to origin of replication ORC then recruits Cdc6 which recruits CDT1 which recruits Mcm then Mcm Cdc6 CDT1 ORC complex makes up pre RC complex Still in G1 to S phase transition o Once pre RC complex together start replication Now in S phase Have more than one ORC not all fire at one time o Mcm is the helicase only protein from pre RC physically involved in replication o Cdc6 CDT1 ORC all ATPases Stop replication from happening a second time Phosphorylate ORC it can t call recruit Cdc6 or CDT1 again phosphorylate Mcm it leaves nucleus phosphorylate Cdc6 it gets degraded o S phase cyclin CDK phosphorylates all these o Have to do all three to stop replication o Do all



View Full Document

Access the best Study Guides, Lecture Notes and Practice Exams

Loading Unlocking...
Login

Join to view Bio 285 SI Before Quiz 4 and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Bio 285 SI Before Quiz 4 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?