VO 5 cell biology

• Cell adhesion and traction allow cells to pull themselves forward
• Members of the Rho protein family cause major rearrangements of the actin cytoskeleton
• Extracellular signals can activate the three Rho protein family members
• Chemotaxis is the process of cell movement in response to a chemical gradient
• Multiple layers of Cdk regulation allow tightly controlled and ordered cell cycle progression and adjustment of cell cycle transitions to intra- and extracellular signals.
• The A naphase P romoting C omplex (APC/C) is activated in mitosis by association with Cdc20, which recognizes amino acid sequences on cyclins.
• The eukaryotic cell cycle usually consists of four phases.
• Yeast (S. cerevisiae) is used as a model organism to study the cell cycle.
• The early embryonic cell cycle alternates between S and M phases without intervening G1 and G2 phases.
• The somatic cell cycle consists of four phases (G1, S, G2, and M).
• The cell cycle is the process of cell growth and division
• The control system blocks progression through Start, preventing cell division until conditions become favorable
• The cell cycle control system triggers the major events of the cell cycle
• If there is a malfunction, signals are sent to the control system to delay progression to M phase
• Cells treated with drug X are arrested in G2 phase
• The control system responds to information received back from the processes it controls
• The combination of methods helps dissect cell cycle progression defects
• The cell-cycle control system is robust and reliable due to backup mechanisms and other features.
• The cell-cycle control system is adaptable and can be modified to respond to specific signals.
• The switches in the cell-cycle control system are binary and launch events in a complete and irreversible fashion.
• In most eukaryotic cells, the cell-cycle control system governs cell-cycle progression at three major regulatory transitions: G1, Start, S, G2, and M.
• The cell-cycle control system is based on a series of biochemical switches that initiate specific cell-cycle events.
• There are multiple stages in cell-cycle progression
• Bivariate BrdU/DNA flow cytometric analysis can provide dynamic proliferative information such as S-phase transit rate and potential doubling time
• DAPI is a fluorescent dye used to stain all cells
• Anti-BrdU antibodies fused to a fluorescent dye can be used to detect incorporated BrdU
• BrdU can be used to label cells undergoing DNA replication (S-phase)
• Cell-cycle progression can be studied in various ways
• The cell cycle control system regulates the progression of the cell cycle
• Cells order cell cycle events through a series of chemical signals that can diffuse freely between the nucleus and cytoplasm.
• The G2 nucleus is resistant to S-phase promoting factor.
• The cell cycle proceeds in two steps: 1) the segregation of the cellular material, and 2) the actual division of the cell.
• G1 and G2 phases do not influence each other.
• Cell fusion experiments by Johnson and Rao in 1970 showed that the S-phase nucleus releases something that drives the G1 nucleus into S-phase.
• The experiments provided the first indication in mammalian cells that the sequential and unidirectional phases of the cell cycle are controlled by chemical signals.
• The only way to make a new cell is to duplicate a cell that already exists
• All living organisms are products of repeated rounds of cell growth and division.
• Requirements for a successful cell cycle include replication of genetic material, duplication of organelles, adaptation to cell growth and environment.
• The major chromosomal events of the cell cycle occur in S-phase (synthesis) and M-phase (mitosis).
• Cell division ensures the continuity of life and is a disorganized and discontinuous state.