General Biology
MITOSIS
Mitosis, a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells. Strictly applied, the term mitosis is used to describe the duplication and distribution of chromosomes, the structures that carry the genetic information.
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PHASES OF MITOSIS:
1.Prophase
2.Metaphase
3.Anaphase
4.Telophase
MEIOSIS
Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. These cells are our sex cells – sperm in males, eggs in females.
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During meiosis one cell? divides twice to form four daughter cells.
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These four daughter cells only have half the number of chromosomes? of the parent cell – they are haploid.
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Meiosis produces our sex cells or gametes? (eggs in females and sperm in males).
Meiosis can be divided into nine stages. These are divided between the first time the cell divides (meiosis I) and the second time it divides (meiosis II):
PARTS OF A CELL
HIERARCHY OF LIFE
=Atoms -the basic units of matter and the defining structure of elements.
=Molecules -made up of atoms that are held together by chemical bonds.
=Macromolecule -a very large molecule, such as protein
=Organelle - one small part of a cell that has a very specific function or job
=.Cells -the basic unit of life.
= Tissue -makes up organs and other body parts.
=Organ -a self-contained group of tissues that performs a specific function in the body.
=System -a group of related parts that move or work together.
=Organism -a creature such as a plant, animal or a single-celled life form, or something that has interdependent parts and that is being compared to a living creature.
=Population -the whole number of people or inhabitants in a country or region.
=Community -a group of people living in the same place or having a particular characteristic in common.
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PROKARYOTES
Prokaryotes are unicellular organisms that lack organelles or other internal membrane-bound structures. Therefore, they do not have a nucleus, but, instead, generally have a single chromosome: a piece of circular, double-stranded DNA located in an area of the cell called the nucleoid. Most prokaryotes have a cell wall outside the plasma membrane.
EUKARYOTES
More advanced and developed than the prokaryotic cell, eukaryotic cells are those which have true or membrane-bound nucleus along with other nucleus bound cell organelles.
From unicellular organisms like protozoa and amoeba, all plants and animals, including human beings are made up of eukaryotic cells.
