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exam 4 1510 - G1 is the most valuable phase for cell...

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G1 is the most valuable phase for cell reproduction If you took a cytoplasm from an actively dividing egg and inject cytoplasm from active mitotic cycle, that cell with start mitosis (MPF) Proteins called cyclins , maturation promoting factor or MPF where cyclin was required Cyclin is a single , in yeast, in higher eukaryotes (similar structures, not identical) MPF is a complex between a protein kinase and a cyclin The MPF is cyclin dependent , protein kinase or Cdk protein ( only active when complexed with cyclin) MPF is what starts the process of cell division G1/S is the primary point at which the cell decides whether or not to divide G2/M checkpoint makes sure that DNA has been sucessffuly replicated Spindle checkpoing makes sure that all of the chromosomes are attached to the spindle in preparation for anaphase Kinases phosphorylate enzymes and can phosphorylate themselves and downstream factor CDK can phosphorylate and they drive the cell cycle Dephosphorylation determines whether the kinase is activate or deactivated Phosphorylation will change the conformation of a protein If synthesis is not complete or DNA is badly damaged, cell undergoes uptotsis or cell death If DNA is repairable a cascade is initiated that will activate DNA repair systems depending on the damage Spindle checkpoint that occurs during mitosis , anaphase (APC) APC triggers anaphase itself because the sister chromatids are still attached in metaphase , inhibitors are produced to destroy cohesin At metaphase the chromosomes are supposed to be lined up accordingly while spindle is disintegrating G2 reorganization of microtubules Normal cells have contact inhibition that tells them to stop growing
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P53 is active is normal P53 not active due to mutation P53 is involved in repairing DNA which is a check point between G2 and M If p53 is damaged it will not be able to prevent cancer The longer you live the higher of chances of DNA damage Anchor genes – they are normal genes required for normal development Embryo happens thru cell division Important in growth development and differentiation Protoanchor genes become mutated are converted to anchor genes, mutation is due to translocation on chromosome because it started making the product that it shouldn’t These genes are receptors for growth factors and others contain proteins that start phosphorylation cascades Genetic recombination occurs in metaphase 1 CHAPTER 11 – SEXUAL REPRODUCTION Gametes are sperm and egg (sex cells) that are produced in the ovaries and testis We have 23 pairs of chromosomes, so if you’re a diploid organism Somatic cells contain 4 chromosomes while games contain 2 chromosomes When you have fertilization or syngamy (diffusion of egg and sperm) you will get a diploid (zygote) The outcome of meiosis is haploid Gametes are haploid while somatic cells are diploid
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