Cell division is essential but must be controlled.
- Mitosis is division of the nucleus into two genetically identical daughter nuclei.
- Chromosomes condense by supercoiling during mitosis.
- Cytokinesis occurs after mitosis and is different in plant and animal cells.
- Interphase is a very active phase of the cell cycle with many processes occurring in the nucleus and cytoplasm.
- Cyclins are involved in the control of the cell cycle.
- Mutagens, oncogenes and metastasis are involved in the development of primary and secondary tumors.
Cell division: is the process by which a parent cell divides into two or more daughter cells.
Mutation: random changes to the base sequence of genes
-A mutation interrupts what produces normal cell cycle control, which produces uncontrolled cell cycling (oncogene)
Mutagens: agents that produce changes in genes involved in controlling the cell cycle, causing uncontrolled cell division.
-Chemicals
-UV lights
Metastasis: movement of cells from a primary tumor to set up secondary tumors in other parts of the body.
Reasons Why Cells Divide:
-To become smaller cells
-Growth of organism
-Replace dead, damaged or infected cells
-Asexual reproduction
Chromosome: DNA + proteins
Chromatid: one of two copies of DNA
Sister chromatids: two identical copies of DNA
Centromere: region on chromosome that joins sister chromatids
Spindle fiber: microtubules that move chromosomes during cell division
Centriole: microtubule organizing center
Mutation: random changes to the base sequence of genes
-A mutation interrupts what produces normal cell cycle control, which produces uncontrolled cell cycling (oncogene)
Mutagens: agents that produce changes in genes involved in controlling the cell cycle, causing uncontrolled cell division.
-Chemicals
-UV lights
Metastasis: movement of cells from a primary tumor to set up secondary tumors in other parts of the body.
Reasons Why Cells Divide:
-To become smaller cells
-Growth of organism
-Replace dead, damaged or infected cells
-Asexual reproduction
Chromosome: DNA + proteins
Chromatid: one of two copies of DNA
Sister chromatids: two identical copies of DNA
Centromere: region on chromosome that joins sister chromatids
Spindle fiber: microtubules that move chromosomes during cell division
Centriole: microtubule organizing center
Stages of the Cell Cycle:
-Interphase:
G1: growth, protein synthesis, increase in the number of mitochondria and/or chloroplasts
S: DNA replication
G2: growth, protein synthesis, preparation for mitosis/cytokinesis
-Mitosis: nuclear division
Prophase
Metaphase
Anaphase
Telophase
-Cytokinesis: cellular division
Prophase:
-Chromosomes become visible to microscopic view
-Centrioles move to opposite poles
-Nucleolus disappears
-Nuclear membrane disappears
-Microtubular spindle apparatus forms at each pole
Metaphase:
-Spindle microtubules attach to chromosome centromeres
-Chromosomes align in the center of the cell
Anaphase:
-Centromeres split the chromosomes to each side of the cell
-Sister chromosomes move to opposite poles and microtubules shorten
Telophase:
-Sister chromosomes reach opposite sides
-Spindle disappears
-Centrioles replicate
-Nuclear membrane reforms and becomes visible
-Nucleolus becomes visible
-Chromosomes become chromatin
-Interphase:
G1: growth, protein synthesis, increase in the number of mitochondria and/or chloroplasts
S: DNA replication
G2: growth, protein synthesis, preparation for mitosis/cytokinesis
-Mitosis: nuclear division
Prophase
Metaphase
Anaphase
Telophase
-Cytokinesis: cellular division
Prophase:
-Chromosomes become visible to microscopic view
-Centrioles move to opposite poles
-Nucleolus disappears
-Nuclear membrane disappears
-Microtubular spindle apparatus forms at each pole
Metaphase:
-Spindle microtubules attach to chromosome centromeres
-Chromosomes align in the center of the cell
Anaphase:
-Centromeres split the chromosomes to each side of the cell
-Sister chromosomes move to opposite poles and microtubules shorten
Telophase:
-Sister chromosomes reach opposite sides
-Spindle disappears
-Centrioles replicate
-Nuclear membrane reforms and becomes visible
-Nucleolus becomes visible
-Chromosomes become chromatin
Stem Cells: the ability that this mother cells have to divide and differentiate within different situations is essential for embryonic development.This characteristic also provides the cell with therapeutic use. The most commonly treated disease with stem cells is the Stargardt's disease which affects the retina in children between the ages of six and twelve causing loss of vision, this can be treated with implanting stem cells and by this improving the sense of sight for the individual.
A number of scientific discoveries are claimed to be incidental or serendipitous. To what extent might some of these scientific discoveries be the result of intuition rather than luck?
Most scientific discoveries are due to intuition rather than luck. Since most scientific discoveries are the cause of experiments done by scientists, almost all discoveries are created after effort of reaching an answer to a theoretical question of science. There are also a small number of experiments that were experienced due to luck; such as the british housekeeper who realized that cells had membranes after placing soap and milk in the same plate.