Part 5 Flashcards
(14 cards)
What role do cohesins and condensins have in chromatin condensation?
Which kinases regulate chromatin condensation.
What structural changes occur between G2, prophase and metaphase? (see figure 17.23)
Cohesins: Holds sister chromatins together
Codensins: Help pack chromatin into condensed chromosomes
Auroa B kinase, and Polo like kinase (PLK1)
G2: Chromatin loosely packed
Prophase: Chromatin condenses nuclear envelope starts breaking
Metaphase :Chromosomes fully condensed aligned at the metaphase plate.
What type of remodeling occurs at the nuclear envelope during mitosis and what are the enzymes and structural proteins involved?
Nuclear envelope remodeling in mitosis:
Breaks down in prophase, reforms in telophase
Enzymes: Cyclin dependent kinase (CDK1)
Structural proteins: Lamins (Phosphorylation causes disassembly)
Compare the differences between embryonic and typical eukaryotic cell cycles.
What could account for the different cell cycle times?
Embryonic cells: Rapid, no G1/G2/ phases, mainly 2 and M phases
Typical eukaryotic cells: full cycle (G1, 2, G2, M) slower
Cell type developmental stage, externals signals, and nutrients availability
How is progression of animal cells regulated through the cell cycle?
What occurs at each phase during the cell cycle?
Cyclins and CDKs: control phase transitions
Checkpoints: Ensure proper progression
G1: growth, checkpoint before DNA replication
S: DNA replication
G2: Preparation for mitosis, another checkpoint
M: Mitosis, cell division
How is regulation of the cell cycle for budding yeast controlled?
At what point in the cycle is regulation primarily controlled and how?
CDKs, and cyclins regulate transitions
G1/S transition (start point decides if the cell enters the cycle based on nutrients and signals.
Compare the difference between plant and animal cytokinesis.
Animals: cleavage furrows (actin myosin contractile ring)
Plants: Cell plate formation (Golgi vesicles)
How is the centromeric region maintained during chromatin condensation?
How are cohesins replaced by condensins?
Specialized chromatin structure and proteins (CENP-A) maintain centromeres
Cohesions removed by separase condensins then help compact DNA
Learn the difference between endothelial cells and epithelial cells.
What is the role Vascular Endothelial Growth Factors (VEGF) in cell proliferation?
Endothelial: line blood vessels
Epithelial: cover body surfaces and organs
Stimulates blood vessel growth (angiogenesis)
What are the steps leading up to replacing damaged cells that have shed from the surface epithelium?
What type of cells are involved in this process?
1)Stem cell activation
2)Proliferation of new cells
3) Migration to damages area
4) Differentiation into mature epithelial cells.
Stem cells and transit amplifying cells
What is ‘hematopoietic stem cell transplantation’ and how is it applied to the treatment of cancer?
A medical procedure where blood-forming stem cells from bone marrow are transferred to a patient to replace damaged or destroyed bone marrow
Application to cancer treatments: Replaces blood forming cells destroyed by chemotherapy/radiation
What are ‘Induced Pluripotent Stem Cells’
How are ‘Induced Pluripotent Stem Cells’ made?
Why was it necessary to make ‘Induced Pluripotent Stem Cells’?
Adult cells reprogrammed to behave like embryonic stem cells
Transcription factors (Oct4, Sox2, Klf4-cMyc) reprogram adult cells
Harvested from fibroblasts on skin cells or peripheral blood cells
Avoids ethical issues of using embryonic stem cells.
What is ‘Transdifferentiation’?
What is the medical significance of ‘Transdifferentiation’?
Direct conversion of once cell into another without going through a stem cell stage
Potential for regenerative medicine repairing damaged tissues directly
What are the medical applications of stem cell therapy (note: there are a number of them mentioned within the text)?
Treats blood disorders, spinal injuries, Parkinsons, diabetes and heart diseases
What role do phagocytes play in the removal of apoptotic cells?
What interactions take place between apoptotic cells and phagocytes?
Engulf and digest dead cells to prevent inflammation
Eat me signals (Phosphatidylserine exposure) attract phagocytes
