Cell Cycle
What is S phase? What happens here?
S phase is the 2nd phase of interphase and stands for "Synthesis". DNA is synthesized/replicated here, to prepare for the division of the cell.
What is a diploid cell? What is the diploid number for humans?
A cell with two copies of each chromosome (2n). For humans 2n = 46.
What do you call compacted chromatin that is made up of two chromatids?
A chromosome.
What is the outcome of cell division (mitosis)?
Cell division through mitosis results in 2 genetically identical daughter cells
What is the purpose of mitosis?
For growth, repair, and development of an organism.
What is G2? What happens here?
G2 is the 3rd phase of interphase. In G2, the cell is rapidly growing - doubling all the organelles and buffing up its cytoplasm.
What is uncontrollable cell division diagnosed as?
Cancer
What are the four stages of mitosis in order?
1. Prophase 2. Metaphase 3. Anaphase 4. Telophase
Explain what happens during metaphase of mitosis.
The chromosomes line up at the equator of the cell, attached to spindle fibers at the centromere.
Explain what happens during anaphase of mitosis.
Sister chromatids pull apart toward the poles of the cell.
What happens if the cell does not pass any of the cell cycle checkpoints? Why does the cell do this?
If the cell does not pass the checkpoints, it goes through programmed cell death, called apoptosis. The cell does this to prevent itself from dividing/creating more mutated cells that can cause damage.
What is the job of the spindle fibers and where do they originate from?
The spindle fibers help organize the chromosomes during cell division. They are responsible for attaching to the centromeres at the equator and pulling sister chromatids apart during anaphase. The come from the centrosomes.
Explain what happens during prophase of mitosis (3 things).
1) Nuclear membrane dissolves
2) Chromatin coils into chromosomes
3) Centromeres appear with spindle fibers
Why is anaphase important? What would happen if anaphase did not occur correctly?
Anaphase is important because it allows the DNA to separate evenly. If it did not occur correctly, there would be an uneven amount of DNA between the two daughter cells.
How is mitosis different from cytokinesis?
Mitosis is nuclear division (the DNA dividing evenly and moving to opposite ends of the cell). Cytokinesis is cellular division; the cell itself divides into two.
Explain the purpose of interphase and what happens during this phase.
Interphase is where the cell spends most of its time. During interphase, the cell grows and develops and also replicates its DNA. The purpose of interphase is to prepare for cell division.
Explain the process of mitosis to a kindergartener and then to a 7th grader.
Kindergartener - Mitosis is how the parts of our body can grow in an organized way.
7th grader - Mitosis is a process that lets our cells create new cells that are genetically the same. Ex: how our bones can grow and create more bone cells.
What is the difference between sister chromatids and a homologous pair of chromosomes?
How is telophase/cytokinesis different in an animal cell from a plant cell?
In an animal cell, a cleavage furrow forms which leads to the separation of the cells. In a plant cell, a cell plate forms between the two cells from vesicles created from the Golgi.
When does cancer become malignant? When does it metastasize?
Name the three cell division checkpoints. What do they do?
G1 - Checks to see if the cell is the right size and DNA is suitable to be copied before the cell moves to S phase.
G2 - Checks after S phase to see if DNA replication occurred correctly before the cell moves to mitosis.
Mitosis - Checks after mitosis to see if DNA was evenly distributed and if mitosis occurred correctly.
How would you describe the state of DNA in interphase vs. in mitosis? Why is this difference important?
In interphase, the DNA is in chromatin form (loose). In mitosis, DNA is in chromosome form (high condensed). This is important because having DNA in chromosomes for cell division helps it stay organized and divide equally.
Explain the role of the nuclear membrane in cell division. WHEN does the nuclear membrane disappear and then reappear. WHY does it do this?
The nuclear membrane holds the DNA in the nucleus. It disappears during prophase 1 and reappears during telophase 1. It disappears so that the DNA is able to move around the cell.
What type of reproduction is mitosis? What is the biggest downfall to this type of reproduction?
Mitosis is asexual reproduction. The biggest downfall is that any cell created from this type of reproduction is genetically identical to the one before it. So if there is a mutation present, every cell that comes from that parent cell also has that mutation.
Explain the function of chromosomes in a cell and their purpose in cell division.
Chromosomes are structures that allow our DNA to stay organized during cell division. This organization allows for DNA to be evenly split between two new cells during division.