Cell bio Exam 3 - cell division

variable

CELLS DIVIDE AND FORM 2 DAUGHTER CELLS

Cell cycle is ____ in time

***Different cells replicate at different divisional times 

Methylation

DAUGHTER CELLS ALSO INHERIT GENE EXPRESSION PATTERNS AND DNA MODIFICATION STATES

• Cell “memory”

***_____ is a form of cell memory!!

• shorter

• longer

CELL CYCLE

• M phase much ____

• G1 much ____

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CHECK POINTS CONTROL WHEN A CELL ENTERS A DIFFERENT PHASE

• Think of these as “if/then” statements

• If DNA is fully replicated cell cycle can proceed

CDKS

• cyclin

• CDK

• phosphorylate; initiate

• interphase

• mitosis

____ INTIATE SPECIFIC STEP IN THE CELL CYCLE

• Cyclin dependent kinase

• Regulatory protein, _____, must bind to ____ for CDK to become active

• CDKs ______ specific proteins to ____ the next phase

• Amount of CDK changes through cycle

• ****Binds to cyclin to be active, then phosphorylates a bunch of stuff 

• ***Cyclin is made in interphase, and then activation ramps up in mitosis because cyclin can bind to CDKs 

• ***S cyclin is active at a certain point (____)

• ****M cyclin is active at another point (after ____) 

• Ubiquitination

• Dephosphotylation

• Binding of inhibitor

CDK INHIBITION

Different ways to inhibit CDKs

• ______

• ______

• ______

• Want to only do this when the cell needs it/its ready 

• Can ubiquitinated, phosphorylate (inhibitory phosphates), bring in another protein (binding of inhibitor) 

P53

• Tumor suppressor

• Phosphorylation

• p21

____ IS A TUMOR SUPRESSOR

• _______ - prevents tumors by stopping the cell cycle if something is wrong

• Stops the cell cycle if something is wrong 

• _____ prevents it from being degraded 

• Active p53 binds to ___ which inactivates

***Tumor suppressor → When functioning normally, cancer does not happen! When you break them, tumors happen

NUCLEAR MEMBRANE BREAKDOWN

MICROTUBULES

PHOSPHORYLATION CONTROLS _______ BREAKDOWN

_______ BIND TO THE KINETIC ORE

• ubiquitin; separase; securin

ANAPHASE REGULATION

• Get rid of cohesion (of sister chromatids) by ____ and protein ____ (which is inhibited by ____)

• Helps complete anaphase 

• DNA/RNA/protein

• daughter cell

BACTERIAL CELL SIZE SEEMS TO DEPENDENT ON NUTRIENT AVAILABILITY

• With more ability to make cell components bacterial cells get larger

• Ratio of ______ to cell size remains constant

• Timing of cell division vs growth determines size of ______

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EXTRACELLULAR SIGNALS CONTROL GROWTH IN LARGER ORGANISMS

• Saturation level of growth factors can control cells size

• Paracrine

• Local