meiosis and mitosis

• Cell Division includes Mitosis and Meiosis.
• Mitosis is a type of cell division that produces daughter cells identical to the parent.
• Meiosis is a type of cell division that produces daughter cells different from the parent and from each other.
• The timing of replication and cell division is highly regulated in the Eukaryotic Cell Cycle.
• The Eukaryotic Cell Cycle consists of two major phases: Interphase (3 stages) and Mitosis (4 stages plus cytokinesis).
• Interphase is a non-dividing state with three sub-stages: Gap 1, Gap 2, and Synthesis.
• Gap 1 is when the cell grows in size and organelles are replicated.
• Gap 2 is the synthesis of proteins associated with mitosis.
• Sexual Reproduction is the fusion of two gametes to produce a single zygote, introducing greater genetic variation and allowing genetic recombination.
• A zygote has gametes from two different parents (except in cases of self-fertilizing organisms).
• Numerical anomalies in autosomes can lead to conditions such as Down syndrome, trisomy 21, Edward's syndrome, trisomy 18, Patau Syndrome, trisomy 13, and Turner syndrome, also known as Monosomy X.
• Numerical anomalies in sex chromosomes can lead to conditions such as Klinefelter Syndrome, where a male is born with an extra copy of the X chromosome, and Monosomy X, where a female is born with one X sex chromosome.
• Nondisjunctionis the failure of chromosome pairs to separate in meiosis stage 1 or stage 2,
• Meiotic non-disjunction can also results in a gamete known as a nullosomic gamete, which lacks one chromosome.
• Sex chromosome unbalance, such as in males (47, XYY) or females (XXX), may be without any symptoms but can result in a 10 - 15 points reduction in IQ compared to sibs.
• Mitosis is a type of cell division that produces daughter cells with the same genetic information as the parent.
• Meiosis is a type of cell division that produces daughter cells with half the number of chromosomes as a parent cell.
• Nondisjunction, or the failure of chromosomes to sort properly during meiosis, is common in humans and its frequency increases with maternal age.
• As a result of nondisjunction, one daughter cell has two chromosomes, and the other has none.
• The result of nondisjunction is a cell with an imbalance of chromosomes, known as Aneuploidy.
• Nondisjunction is the failure of homologous chromosomes to separate properly during cell division.
• A mosaic individual is made of two or more cells populations coming from one zygote.
• Inversion occurs when a segment of chromosome breaks, and rejoins within the chromosome effectively inverting it
• Polyploidy is a condition where cells contain more than two haploid sets of chromosomes.
• isochromosome is an unbalanced structural abnormality in which the arms of the chromosome are mirror image of each other images
• Tetraploidy have a 92 numbers of chromosomes
• a mosaic individual is made of 2 or more cell population coming from one zygote
• Mosaicism is usually due to a mitotic non-disjunction and can affect any type of cells, including blood cells and egg & sperm cells (gametes).
• triploidies have this type of chromosome XXX, XYY, XXY
• Ring formation is a break on each arm of a chromosome, two sticky ends on the central portion, and a reunion of the ends as a ring
• Deletion is the loss of a segment from a chromosome, either terminal or interstitial, and is an unbalanced rearrangement.
• Reciprocal is a mutual exchange between terminal segments from the arms of 2 chromosomes
• Daughter cells in Meiosis are different from parent cells and from each other
• sperm and ova are also called gametes
• 1. the first part of eukaryotic cell cycle
• third part of eukaryotic cell cyle

  mitotics cell division produces daughter cells identical to parent
• the timing of replication and cell division is highly regulated
• 2 major phases of the eukaryotic cell cycle are interphase and mitosis
• how many stages does the interphase have? 3
• in interphase DNA is not yet replicated