Question | Answer |
What are the three processes of tissue homeostasis? | 1. Cell proliferation by mitosis
2. Cell differentiation
3. Cell death |
Define neoplasia. | Uncontrolled cellular division and proliferation (i.e. tumor) |
What are 3 possible causes of an imbalance in tissue homeostasis? | 1. Tissue atrophy
2. Functional insufficiency
3. Neoplasia |
What are the ordered stages of the cell cycle? | G1, S, G2, M, G0 |
What is occurring during the G1 stage? | The cell is stimulated to proliferate and is making components for DNA |
Cyclin D partners with CDK4/6 and Cyclin E partners with CDK2 during which phase? | G1 |
What is occuring during the S stage of the cell cycle? | DNA synthesis |
Cyclin A partners with CDK 2 during this phase? | S phase |
G2 Phase of the cell cycle is preparing the cell to undergo what? | Mitosis |
M phase represents what? | The mitotic phase |
What is the cell doing during the G0 phase? | The cell is leaving the cycle |
What are the 4 ordered stages of mitosis? | Prophase, Metaphase, Anaphase, Teleophase |
What does Cdk stand for and what do they do? | Cyclin Dependent Kinases phosphorylate proteins. |
CDKs must be complexed with these in order to be active? | Cyclins |
Cells receive (internal or external) signals that result in the increase of Cyclin (A, B, D, or E) | External; D |
What maintains control over cell cycle activity? | Kinase levels |
Kinase activity is determined by the synthesis and degradation of what? | Cyclin partners |
Name the 3 inhibitor of CDKs that bind cyclins of G1 and S phase. | p21, p27, p57 |
Which 4 inhibitors inhibit CDK4/6 only? | p15, p16, p18, p19 |
DNA damage is checked for at which cell cycle checkpoint? | G1 Checkpoint |
What does the S-phase checkpoint check for? | Accuracy of DNA replication |
If DNA is unreplicated and damaged, which checkpoint would catch this? | G2-M checkpoint |
Chromosomal alignment is checked at what checkpoint? | Metaphase checkpoint |
What is the most commonly mutated gene in human cancer? | P53 |
What 4 actions happen with P53 synthesis is induced? | 1. p21 upregulated
2. CDC25 phosphatase inhibited
3. proapoptotic BAX induced
4. anti-apoptotic Bcl-2 inhibited |
What is the overall goal of p53 synthesis after a damaged cell is discovered at the G1 checkpoint? | To stop cell growth and division allowing time for DNA repair or apoptosis. |
What occurs during the G2-M checkpoint that does not allow the cell to progress towards mitosis? | Phosphorylation of CDK1 |
How does the p53 gene mutation correlate to cancer? | If mutated, this allows damaged DNA to continue through mitosis and make more abnormal cells |
What are the 4 possible outcomes for a cell? | 1. Senescence
2. Terminally differentiated
3. Neoplastic transformation
4. Apoptosis |
Cell death occurs in what 2 different ways? | 1. Necrosis - cell murder
2. Apoptosis - cell suicide |
Which form of cell death involves the orderly breakdown of a cell, shrinkage, and phagocytosis. | Apoptosis engulfs apoptotic bodies formed through the orderly breakdown of a cell. |
What occurs during necrosis? | A cell enlarges and lysis occurs |
The (intrinsic or extrinsic) pathway of apoptosis is initiated by mitochondria in response to stress. | Intrinsic pathway |
What are responsible for orderly dismantling of a cell? | Caspases |
IAP stands for? | Inhibitor of apoptosis proteins |
Bcl-2 proteins (inhibits or promotes) apoptosis? | Inhibits |
BAX dimers (inhibit or promote) apoptosis? | Promote |
What does the R point represent in the cell cycle? | R defines a point in the cell cycle after which the cell no longer depends on extracellular signals but is committed to completing that cell cycle independent of further mitogenic stimuli. |
What is the role of apoptosis in the hematopoietic system? | 1. Selection of appropriate T/B cells
2. Cytotoxic function of T cells and NK cells
3. Regulate the # of mature cells
4. Platelet production
5. Final RBC maturation |
What does CAK do? | CAK stands for Cdk Activating Kinase and activates phosphorylation of all the kinases in the cell cycle. |