Mitosis Flashcards
(17 cards)
How can the stages of mitosis be observed under a microscope?
The stages of mitosis can be observed under a light microscope in onion and garlic root tips. A small slice of the root tip is placed on a microscope slide and broken down with a needle. A stain is added to make the chromosomes visible, and the cover slip is pushed down to squash the tip to achieve a single layer of cells.
List the three main stages of the cell cycle.
The three main stages of the cell cycle are interphase, nuclear division, and cytokinesis.
What is the longest stage of the cell cycle?
Interphase is the longest stage of the cell cycle.
During which stage of the cell cycle does DNA replication occur?
DNA replication occurs during the interphase stage of the cell cycle.
Define malignant tumors and their characteristics.
Malignant tumors are cancerous because they grow rapidly, can spread to other tissues in the body, and often have their own blood supply.
How do chemotherapy treatments work to prevent cancer cell division?
Chemotherapy treatments work by preventing rapidly dividing cells from entering mitosis. Some drugs target the spindle fiber formation in metaphase to prevent mitosis from happening. This prevents the cancer cells from dividing further.
Describe the process of binary fission in prokaryotic cells.
In binary fission, the circular DNA and plasmids replicate. The cytoplasm then divides to create two daughter cells, each with a copy of the circular DNA and plasmids.
How can mutations in genes affect Mitosis?
Mitosis is a gene-controlled process, but mutations in the genes that control when cells divide can result in uncontrollable mitosis, which can lead to conditions such as cancer.
Define the Mitotic Index and explain how it is calculated.
The Mitotic Index is a measure of the proportion of cells in a population that are undergoing mitosis. It can be calculated by counting how many cells are visible in the field of view and the number of cells visible that are in a stage of mitosis. The formula used is: Mitotic index = (the number of cells in mitosis / the total number of cells) x 100.
Describe the process of cell division in eukaryotic cells.
Eukaryotic cells enter the cell cycle and divide by mitosis or meiosis. The cell cycle comprises three key stages: interphase, nuclear division, and cytokinesis. During interphase, the organelles double, the cell grows, and DNA replicates. Nuclear division can be either mitosis, creating two identical diploid cells, or meiosis, creating four genetically different haploid cells. Cytokinesis is the final stage, which is the division of the cytoplasm to create the new cells.
Explain the process of Telophase in Mitosis.
In Telophase, the chromosomes are now at each pole of the cell and become longer and thinner again. The spindle fibers disintegrate, and the nucleus starts to reform. The final stage in the cell cycle is when the cytoplasm splits in two to create the two new genetically identical cells.
Describe the process of Anaphase in Mitosis.
In Anaphase, the spindle fibers start to retract and pull the centromere and chromatids they are bound to towards the opposite poles. This causes the centromere to divide in two, and the individual chromatids are pulled to each opposite pole. These separated chromatids are now referred to as chromosomes. This stage requires energy in the form of ATP, which is provided by respiration in the mitochondria.
What is the role of the spindle apparatus in cell division?
The spindle apparatus, created by the centrioles in animal cells, is responsible for the movement and separation of chromosomes during cell division. Spindle fibers attach to the centromere and chromatids on the chromosome, aiding in their alignment and separation.
How does the process of mitosis differ from meiosis?
Mitosis results in the creation of two identical diploid cells, which is used for growth and repair. On the other hand, meiosis results in the creation of four genetically different haploid cells, which are used to create gametes.
What happens during the metaphase stage of mitosis?
During metaphase, the chromosomes align along the equator of the cell. The spindle fibers released from the poles now attach to the centromere and chromatid.
Define the role of centrioles in mitosis.
In animal cells during prophase, the centrioles separate and move to opposite poles of the cell. The centrioles are responsible for creating spindle fibers which are released from both poles to create a spindle apparatus. These will attach to the centromere and chromatids on the chromosome in later stages.
How do prokaryotic cells and viruses replicate?
Prokaryotic cells replicate by binary fission. Viruses, being non-living, do not undergo cell division. They replicate inside the host cells they invade by injecting their nucleic acid into the cell to replicate the virus particles.
