genbio 4th quarter

• Mitosis and meiosis are similar processes wherein both results in the production of new cells from the pre-existing ones.
• Cell division. It is a basic process of life that all organisms undergo, although it occurs in different ways in different species.
• There are two major types of cell division namely: mitosis and meiosis.
• Mitosis produces diploid (2n) daughter cells which have identical genetic content as the parent cell while meiosis produces haploid (n) gametes with half the number of chromosomes compared to the parent cell.
• Mitosis is a type of cell division that produces daughter cells that are genetically identical to the originally dividing cells (parent)
• meiosis occurs among somatic cells or the body cells and is the reason why our body is capable of growth and development
• In humans, there are 23 pairs of homologous chromosomes present in every nucleus of a normal cell
• mitosis process is responsible for the growth and development of an organism, repair and replacement of damaged cells and organelles, and helps in maintains the constant number of chromosomes in all body cells of an organism.
• There are four (4) stages under the process of mitosis: Prophase, Metaphase, Anaphase and Telophase.
• Prophase- the chormosomes appear condensed, and the nuclear envelope is not apparent
• Metaphase- thick, coiled chromosomes, each with two chromatids, are lined up on the metaphase plate
• Anaphase- chromatids of each chromosome have separated and are moving towards the pole
• Telophase- the chromosomes are at the pole and become more diffuse
• Meiosis has two divisions called Meiosis I and II
• cytokinesis- division into two diploids daughter cells
• MEIOSIS is a type of cell division that occurs only among gametes or reproductive cells.
• meiosis consists of two rounds of nuclear division
• the first division is called reduction-division wherein, it involves separation of homologous chromosomes resulting in two haploid nuclei.
• the second nuclear division is equational division, resulting in four haploid nuclei that are non-identical to the parents as a result of crossing over
• Meiosis is important for continuity of life in eukaryotes. It is essential in the production of sex cells/ gametes (gametogenesis); needed for the maintenance of an equal number of chromosomes in the offspring; responsible for the genetic variations in the next generation.
• prophase 1- synapsis and crossing over occurs
• metaphase 1- tetrads line up at the metaphase plate
• anaphase 1- homologous pairs separate and move to opposite poles
• telophase 1- the chromosomes have segregated into two clusters
• prophase 2- each nuclear envelope breaking down
• metaphase 2- chromosomes line up on the metaphase plate
• anaphase 2 - sister chromatids separate and move to opposite poles of the cell
• telophase 2- nuclear envelope reforms around the four sets of daughter
• cytokinesis 2- 4 haploid daughters are formed
• cytokinesis is where cytoplasmic division cells separate and ensure that each new cell contains all the metabolic machinery necessary for life
• chromatid is a strand of a double stranded chromosome
• mitosis and meiosis differ in that mitosis is a reduction- division while meiosis is equational division
• meiosis is important to a sexually reproducing organism because it reduces the number of chromosomes from diploid to haploid