Study Guide Exam 4 PDF

Study Guide Exam 4 Chapter 18  Cyclin dependent protein kinases (Cdks) are present during all phases of the cell cycle. For example, S-Cdks, M-Cdks, G1-S-Cdks are present during all phases of the cell cycle.  Centromere protein A (CENP-A) recruit proteins to the centromere to for...

Study Guide Exam 4 Chapter 18  Cyclin dependent protein kinases (Cdks) are present during all phases of the cell cycle. For example, S-Cdks, M-Cdks, G1-S-Cdks are present during all phases of the cell cycle.  Centromere protein A (CENP-A) recruit proteins to the centromere to form the kinetochore  Cyclins regulate cell cycle progression by activating Cdks.  The Gap 2 to M phase transition (G2-M checkpoint or transition) checks the status of DNA replication and DNA integrity.  Mitotic cyclin- Mitotic-Cdk also known as mitosis promoting factor (MPF) is active when it is singly phosphorylated.  The ubiquitin-proteasome pathway controls the degradation of regulatory proteins during the cell cycle.  The phosphorylation of condensin (by M-cyclin-M-Cdk) is directly required for chromosome condensation  Cyclin synthesis and degradation, Cdk phosphorylation, and Cdk dephosphorylation regulate mitotic Cdk activity  After DNA replication, the sister chromatids are held together by cohesins.  Condensins assemble or associates with DNA when phosphorylated by M-Cdk.  DNA damage results in elevated levels of p53 within cells. Elevation of p53 results in the expression of Cdk inhibitor proteins such as p21  S-Cdk phosphorylates cdc6 and inactivates it so that DNA replication only occurs once during each cell cycle.  Progression through the cell cycle requires a cyclin to bind to a Cdk. The binding of a cyclin to Cdk is required for Cdk enzymatic activity.  During anaphase, sister chromatids separate because securins are degraded and destroyed due to ubiquitination by APC.  The Gap 1 DNA damage checkpoint inhibits cyclin-Cdk complexes by p21 (p21 is a protein that muffles signaling from the cyclin-Cdk complex)  The concentration of M-cyclin falls at about the end of M phase because of ubiquitination and degradation  The retinoblastoma (Rb) protein blocks cells from entering the cell cycle by inhibiting cyclin transcription.  M-Cdk stimulates or promotes the activity of APC. The APC promotes the degradation of proteins that regulate M phase and it inhibits M-Cdk activity  Phosphorylation of mitotic Cdk by the inhibitory kinase (Wee1) makes the Cdk inactive, inhibiting the Cdc25 phosphatase will delay the G2/M transition and the activating phosphatase (Cdc25) removes the two phosphates from mitotic Cdk that were added by Wee1, so that MCdk will be active.  Cells in Gap zero (G0 ) are non-proliferative and do not divide  Genomic, nuclear DNA is replicated in Synthesis phase (S-phase) of interphase of the cell cycle  Cells grow mostly in the Gap one phase (G1 phase) of interphase of the cell cycle  During interphase cells grow in size, the DNA is replicated, and the centrosomes are duplicated  A eukaryotic cell G2-M checkpoint evaluates the status of DNA replication.  The generation time is the time it takes a cell to progress through a complete cell cycle  The sequential order of the stages/phases of mitosis are prophase, prometaphase, metaphase, anaphase and telophase.  Chromosome condensation is a sign that a cell has entered prophase  The centrosome is the microtubule organizing center (MTOC) in animal cells. The centrosome contains a pair of centrioles.  Nuclear envelope breakdown or fragmentation occurs in prometaphase  The mitotic spindle and sister chromatids appear to be still and inactive during metaphase but in reality, each sister chromatid is being pulled toward its respective pole  Anaphase is the shortest stage of mitosis. During anaphase A, each chromosome is pulled to its respective spindle pole as its kinetochore microtubules shorten. During anaphase B, the spindle poles are pushed further apart as interpolar or polar microtubules lengthen. Anaphase B may coincide with or follow anaphase A, depending on the cell type.   During cytokinesis in a plant cell phragmoplast align Golgi-derived vesicles in the center of the dividing cell, Golgi-derived vesicles fuse to form the cell plate and vesicles with non-cellulose components assemble to form the primary cell wall. No abscission occurs in plant cells.  Raf (MAPKKK or MAP3K) activates MEK (MAPKK or MAP2K). MEK (MAPKK or MAP2K) activates MAPK (ERK).  Rho proteins play a central role in regulating the assembly and activation of the contractile ring during cytokinesis in animal cells  Extracellular signals that encourage cell division are called mitogens. Extracellular signals that regulate cell growth or proliferation are called growth factors Chapter 13  Glycolysis is an anaerobic process used to catabolize glucose. It occurs in the cytosol. “Anaerobic” means that no oxygen is required for glycolysis.  The final metabolite produced by glycolysis is pyruvate  The net number of activated carrier molecules produced in glycolysis from one molecule of glucose (number and type of molecules produced minus the number of those molecules used as input) is 2 molecules of ATP and 2 molecules of NADH  The conversion of pyruvate to acetyl CoA in aerobic cell respiration includes the production of carbon dioxide  In oxidative phosphorylation a phosphate group is added to ADP to produce ATP  In oxidative phosphorylation, molecular oxygen serves as a final electron acceptor, FADH2 and NADH become oxidized as they transfer a pair of electrons to the electron- transport chain and the electron carriers in the electron-transport chain toggle between reduced and oxidized states as electrons are passed along. (Glycolysis (glucose to pyruvate) is not the same as oxidative phosphorylation)  In the electron transport chain NADH dehydrogenase, cytochrome c reductase and cytochrome c oxidase act as proton pumps whereas cytochrome c does not act as a proton pump   Cytochrome c oxidase, a component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen Chapter 14  Apoptosis differs from necrosis in that necrosis causes cells to swell and burst, whereas apoptotic cells shrink and condense.  Programmed cell death or apoptosis is an intracellular suicide program.  Apoptosis can be promoted by the release of cytochrome c into the cytosol from mitochondria.  Mitochondrial division is mechanistically like prokaryotic cell division.  The mitochondrial outer membrane is permeable to molecules with molecular mass as high as 5000 daltons.  The mitochondrial inner membrane contains transporters for ATP molecules.  The mitochondrial intermembrane space contains proteins (cytochrome c) that are released during apoptosis  The mitochondrial matrix contains enzymes required for the oxidation of fatty acids.