Module 2 Control of the Cell Cycle

The Tumor suppresors (3)

Typical cell cycle duration in Human Cell Maintained in culture G1 (GAP 1) G0 S (DNA Synthesis) G2 (GAP 2) M (Mitosis)

Cell turnover: early embryonic cells epithelial cells Specialized cells

Examples of specialized cells (2)

Regulation by external events: Both the ___ and ____of cell division are triggered by events external to the cell when it is about to begin the replication process.

Regulation by external events: Whatever the source of the message, the cell receives the ____ a series of events within the cell allows it to proceed into ____ Moving forward from this ____ point, every parameter required during each cell cycle phase must be met or the cycle cannot progress.

Regulation by external events: The ____ of a nearby cell The release of ____ hormones such as ____ ____ of cells can also inhibit cell divisions The ____ of the cell can also initiate cell division. This is because the cell becomes inefficient thanks to its ____ ratio wherein it needs to eventually divide.

____ are proteins that stimulate cell division

Regulation by external events: A lack of HGH or Human Growth Hormone can result in ____ An excess of HGH or Human Growth Hormone can result in ____

Regulation by Internal Checkpoints: Mistakes in the duplication or distribution of the chromosomes lead to ____ that may be passed forward to every new cell. To prevent this, there are ____ that operate at _____.

Regulation by Internal Checkpoints: ____ one of the several points in the eukaryotic cell cycle at which the progression of a cell to the next stage in the cycle can be halted until conditions are favorable Location of these occur at the (3)

Regulation by Internal Checkpoints: The integrity of the DNA is assessed at the ___ Proper _____ is assessed at the ____ Attachment of each ____ to a _____ is assesed at the ____

G1 checkpoint: Also called ____(in yeast) determines whether all conditions are favorable for cell division to proceed It is a point where the cell ____ to the cell division process

G1 checkpoint: Checks the following: Adequate ___ and ___ Check for ___ at the G1 checkpoint which is then regulated by the ___ protein causing ____

G1 checkpoint: If failed to meet the conditions, the cell cannot fo into the ____ The cell can halt the cycle and attempt tor emedy the condition or it can advance into ___ and await when conditions improve

G2 checkpoint: Bars entry into the ____ phase if certain conditions are not met. This checkpoint ensures that all of the ____ have been duplicated without damage Upon failure it either attempts to complete ___ or ___ it

M checkpoint: Occurs near the ___ stage of ____ It is also known as the ____ because it determines whether the ___ are attached correctly to the ____

In addition to the checkpoints, there are ___ that regulate the cell cycle. They either promote progress of the cell into the next phase called ____ Or they halt the cycle called ____

Regulatory molecules: The failure of a single regulator may have almost no effect on the cell cycle, especially if more than one mechanism controls an event However, the effect of a deficient or ____ can be wide-ranging ang possibly fatal if multiple processes are involved

Positive regulation: There are two types of proteins which are responsible for the progress of the cell through various checkpoints However, the ___ only regulate when bound to the ___ A ____ is an enzyme that transfers a phosphate group onto a protein through phosphorylation

Initiation of Mitosis: ____ The protein complex which initiates the mitotic phase of the cell cycle It is made up of : ____ Oscillates in quality during the cell cycle. High concentrations necessary to enter M phase, low concentration necessary to leave M phase _____ Constant quantity and encoded by the ___ gene. Only functional when bound to its cyclin.

Initiation of Mitosis: Once mitosis has been initiated, the ___ decrades the Cyclin B protein of the Mitosis Promotion Factor It also causes the separation of ___ at the start of ___

Negative regulation: Best understood ____ are (3): ___ a group of tumor-suppresor proteins common in many cells The number designations refer to the functional molecular masses of the proteins known as _____

Negative regulation: A faulty copy of a regulatory protein may cause cells to replicate uncontrollably becoming ____ Rb, p53, p21 primarily act at the ____