General
The cell cycle consists of alternating phases of...
Interphase and Mitosis
Name the stages of Interphase in sequence
G1 --> S --> G2
Name all the phases of mitosis in sequence.
Prophase --> Prometaphase --> Metaphase --> Anaphase --> Telophase and Cytokinesis
What are the three major checkpoints in the cell cycle?
G1 Checkpoint, G2 Checkpoint, and M (Spindle) Checkpoint
What is genome?
All of the cell's genetic information (DNA)
What is the longest phase in the cell cycle?
Interphase
What occurs in the G1 and G2 phases?
In the G1 phase, the cell grows and carries out normal cellular functions. In the G2 phase, the cell undergoes its final growth and prepares for Mitosis.
In which phase of Mitosis does the nuclear envelope fragment?
Prometaphase
What are the two types of cells that do not leave the G0 phase?
Muscle/Nerve Cells
What are the differences between Haploid and Diploid cells?
Haploid cells contain only one set of chromosomes, while Diploid cells contain two sets of chromosomes.
What is the Cell Cycle?
Cell Cycle is the life of a cell from its formation until its division
What happens in the S "synthesis" phase? Why is this phase important?
In the S phase, DNA replication and chromosomes duplication occur. This is important because it is required for the initiation of mitosis.
Why are microtubules important to the M phase?
Microtubules attach to each kinetochore (in Metaphase) and due to Microtubules shortening sister chromatids separate and move to opposite ends of the cells (in Anaphase).
What is apoptosis? In which checkpoint would this occur?
Apoptosis is programmed cell death. Apoptosis occurs in the G2 checkpoints given that detected damage can not be repaired.
What roles do actin filaments play in cell division?
In animal cells' cytokinesis, a cleavage furrow appears due to the contractile rings made of actin filaments
Why is it necessary to condense Chromosomes before division?
Chromosomes are condensed for easier replication and division of chromosomes.
Why is Interphase important in the survival of an organism?
Interphase is important because the cell grows up and performs regular functions required for the survival of the organism. The interphase also allows the replication of DNA and duplication of the chromosomes and prepares the cell for Mitosis (cell division).
Describe the different ways cytokinesis takes place in animal and plant cells.
In animal cells, a cleavage furrow appears due to a contractile ring made of actin filaments.
In plant cells, vesicles produced by the Golgi travel to the middle of the cell and form a cell plate
What is one possible consequence of abnormal cell cycle regulation?
- Abnormal Cell Division such as the spread of cancerous cells
- Apoptosis
- Abnormal/ broken chromosomes from spindle event
The difference between Benign and Malignant Tumors are...
Benign Tumors are cells that are abnormal but are not considered to be cancerous. (Remains at only the tumor site and doesn't spread)
However, Malignant tumors are mass of cancerous cells that lose their anchorage dependency and can leave the tumor site
List the properties of somatic cells
Somatic cells are body cells, divide using mitosis, and are diploid (consist of two sets of chromosomes).
What are the some events that happen before cytokinesis?
- The sister chromatids have to be at the opposite poles of the cell.
- Two Daughter nuclei reappears.
- Chromosomes become less condense.
If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis?
10 chromosomes. During Anaphase, sister chromatids separate and move to opposite ends of the cell due to microtubules shorthing. A centrosome holds one set of sister chromatids. If there is 20 centrosomes, there will be 40 sister chromatids and once separated by microtubules, each pole will contain 20 sister chromatids. A chromosome has a pair of sister chromatids meaning that there will be 10 chromosomes.
What are the two components of the Internal Cell control system? Give a brief Description of the components and their interactions.
Cyclin and Cyclin Dependent Kinases (CDKs);
Cyclin is a protein, that is synthesized and degraded at specific stages of the cell cycle. CDKs are special enzymes that are constantly present through each phase of the cell cycle.
When specific cyclins are present cyclins are present the CDKs activates. CDK complexes phosphorylate target proteins which help regulate key events in the cell cycle
Briefly describe two external cell cycle regulators.
Growth Factors - hormones released by cells that stimulate growth by activating Signal Transduction Pathways associated with CDKs.
Contact (Density) Inhibition - Cell surface receptors recognize contact with other cells which initiates signal transduction pathway that stops the cell cycle in G1 phase
Anchorage Dependence - Cell rely on attachment to other cells or the extracellular matrix to divide