Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
|
What's the two main phases of the cell cycle? |
Mitotic Phase and Interphase |
|
|
What are the phases of interphase? |
Growth phase 1; synthesis phase; growth phase 2 |
|
|
Discuss growth phase 1 |
Replication of organelles; synthesis of cystolic components l; beginning of centrosome replication; takes between 8-10 hours |
|
|
Discuss the synthesis phase |
Takes 8 hours; DNA replication occurs |
|
|
Discuss growth phase 2 |
Take 4-6 hours; Replication of organelles; Synthesis of cystolic components; Centrosome replication; protein synthesis |
|
|
What are the 4 phases of the M phase? |
Prophase; Metaphase; Anaphase; Telophase |
|
|
What is Prophase? |
Chromatin fibres shorten and condense to form chromosomes. The nuclear membrane and nucleus disappear and centrioles begin to move towards the poles. As this genetic material was made in the S phase it is formed by the pairs of identical strands called chromatids which are held by a central body called the centromere kinetochore.
|
|
|
What is Metaphase? |
Chromosomes are led by the mitotic spindle fibres to line up along the metaphase plate which lies across the midline of the cell.
|
|
|
What is anaphase? |
The centromere and kinetochores allowing the individual chromatidssplit. They become chromosomes and then are pulled to opposite poles of thecells by the mitotic spindle fibres (microtubules). Microtubule connecting fromeither end of the cell extend and lengthen the cell in prep for cytokinesis. |
|
|
What is telophase? |
Final phase of mitosis. The nuclear membrane reforms and thenucleolus reappears and the chromosomes uncoil into chromatin. The microtubulescontinue to extend and split the cytoplasm.
|
|
|
What is the last phase of the cell cycle? |
Cytokinesis |
|
|
What is cytokinesis? |
A Contractual ring develops along the line previously occupied by the metaphase plate. This ring then pinches along the midline forming a cleavage furrow. The cleavage furrow depends and splits the cell into two parts.
|
|
|
How long does the cell cycle usually take? |
22 hours |
|
|
What are the three possible outcomes for a cell going through th cell cycle? |
It can grow and proliferate; remain alive in a resting state; or it can die |
|
|
What type of molecule is the cell cycle tightly controlled by? |
Cyclins (proteins) |
|
|
Briefly describe the concentration of cyclins throughout the cell cycle? |
The concentration of cyclins increases throughout the cell cycle but decreases rapidly towards the end. |
|
|
Explain how cyclins help control the cell cycle? |
Cyclins bind to an enzyme called cyclin dependant kinases (CDK) and causes an increase in CDK activity which drives the cell cycle.
When a CDK is bound to a cyclin the active site is only partially activated, so CDK catalyses the transfer of a phosphate group from ATP to a specific protein at different stages of the cell cycle. This initiates a cascade of events, allowing the cell cycle to progress to the next phase of the cell cycle. |
|
|
What are the three main cell cycle check points? |
G1/S checkpoint; G2/M checkpoint; Metaphase Checkpoint |
|
|
What is the G1/S Check point? |
It is known as the restriction point. This is where the cell will check if it has enough materials to fully replace its DNA- an unhealthy small cell will get stuck at this point |
|
|
What is the G2/M Check point? |
This is where the cell checks if it has enough cytoplasm and phospholipids for two daughter cells. TI also checks to see if it is the right time replicate. |
|
|
What is the Metaphase checkpoint? |
The cell checks that the spindle has properly formed and that all of the chromosomes are aligned at th espindle equator before anaphase begins. |
|
|
WHat molecule plays an important role in G1/S and G2/M checkpoints |
p53 |
