Cell Division Flashcards
(12 cards)
What are the stages of the cell cycle and what happens during each stage?
- Interphase: The cell prepares for division.
- Mitosis: The nucleus divides in two.
- Cytokinesis: The Cytoplasm divides into two to form two identical daughter cells.
What happens during interphase?
- G1- The cytoplasm grows and the organelles are duplicated.
- Synthesis- DNA replication.
- G2- The cell does more preparation for growth such as making proteins like tubulin that are used to make the spindle fibres.
Why is mitosis important?
- Growth.
- Repairing dead or damaged cells.
- Asexual reproduction.
Describe what happens during the prophase stage of mitosis. Draw what the cell will look like during that stage.
- The chromosomes condense and become visible under a microscope.
- The centrioles move to opposite poles of the cell, and spindle fibres form from them.
- The nuclear envelope starts to break down.
Describe what happens during the metaphase stage of mitosis. Draw what the cell will look like during that stage.
The chromosomes line up along the equator of the cell and the spindle fibres attach to the centromeres of the chromosomes.
Describe what happens during the anaphase stage of mitosis. Draw what the cell will look like during that stage.
The centromeres split into two producing two sister chromatids. The spindle fibres start to shorten and pull the sister chromatids to opposite poles of the cell.
Describe what happens during the telophase stage of mitosis. Draw what the cell will look like during that stage.
The chromatids reach the opposite poles of the cell, where they become chromosomes and then uncoil. The spindle fibres break down and the nuclear envelope starts to build back up.
What is cancer and how does it form?
Cancer is caused by a mutation in the gene that controls cell division leading to uncontrolled cell division and growth. This then forms a tumour that becomes cancerous when it invades neighbouring tissues.
How can chemotherapy kill cancerous cells?
- Synthesis stage: Radiation can be used to damage DNA, so when the cancerous cell checks the DNA and sees damage, it will go through with apoptosis.
- Metaphase: Cancer drugs interfere with the formation of spindle fibres, meaning the cells will no longer be able to divide.
Through what process do bacteria cells divide?
Binary fission
Describe how bacteria replicate by binary fission.
- The cell grows to prepare for division: The cytoplasm grows,, and the organelles duplicate.
- The circular loop of DNA duplicates and the plasmids replicate multiple times.
- The loops of DNA are pulled to opposite poles of the cell.
P4. A new cell wall starts to form which starts to divide the cytoplasm into two. - Once the cell wall is fully grown the cytoplasm divides into two to form two identical daughter cells.
How do viruses replicate?
The reverse transcriptase turns viral RNA into viral DNA. The viral DNA is inserted into the host cells’ DNA, and the cell transcribes that DNA to form viral mRNA which is translated to form viral proteins needed to make new viruses.
