540 likes | 550 Views
A detailed guide on cell reproduction processes, focusing on mitosis and meiosis. Learn about the cell cycle, chromosome structure, mitotic stages, and regulation mechanisms. Explore asexual reproduction types and understand meiosis phases for sexual reproduction.
E N D
Ch 10 and 11 Cell Reproduction, Mitosis
Limits on Cell Size • Diffusion • DNA • Surface area to volume ratio
Cell Cycle Cell Growth The sequence of growth and division of a cell Divided into Stages: Interphase Mitosis http://www.cellsalive.com/cell_cycle.htm
INTERPHASE Divided into Stages G1 stage (Growth) Rapid growth High protein production S stage (synthesis) DNA made Chromosomes replicates G2 stage (Growth) Other organelles are made Cell prepares for mitosis Majority of the cell’s life is spent in Interphase
CHROMOSOME Homologous Pair 2 Main Parts Sister Chromatids Two halves of the doubled structure of a chromosome Centromere Structure that holds sister chromatids together Centromeres (DNA) nonSister Chromatids Sister Chromatids
What is Mitosis? • Cell reproduction in which 2 identical cells or daughter cells are made from 1 parent cell • Mitosis results in the growth and repair of the body cells or somatic cells (such as skin, bone, muscles, or liver cell). • http://www.cellsalive.com/mitosis.htm
Prophase Centrioles Centrioles pull apart Spindle fibers form Nuclear membrane disappears Nuclear envelope Spindle fibers
METAPHASE centrioles Chromosomes attach the spindle fibers Chromosomes line up at the center of the cell chromosomes fibers
ANAPHASE centrioles Spindle fibers Centromeres spilt and sister chromatids are pulled to opposite poles Cytoplasm pinches inward Sister chromatids
TELOPHASE Nuclear envelope Spindle fibers break down Nuclear membrane reappear 2 identical cells formed Cytokinesis occurs (cell splits)
Regulation of the Cell cycle Enzymes (proteins) monitor a cell’s progress from phase to phase during the cell cycle
Enzymes are necessary to begin and drive the Cell cycle Enzyme production is directed by genes located on the chromosomes
Internal Regulation-proteins that respond to events inside the cell; they allow the cell cycle to proceed only when certain processes have happened inside the cell properly Ex: prevents anaphase until all chromosomes are attached to the mitotic spindle
External Regulation- proteins that respond to events outside of the cell; they speed up or slow down the cell cycle Example: prevents excess growth of the cell by using chemical messengers (signals) such as hormones (proteins)
Causes of Cancer Cancer is the result of uncontrolled cell division Can be both genetic & environmental
air pollution; water pollution & exposure to ultraviolet radiation can cause Cancer Cancer may also be caused by viral infections
Cancer Prevention Diets low in fat & high in fiber content reduce the risk of cancer Vitamins & minerals may also help prevent cancers Daily exercise & not smoking
TYPES of ASEXUAL REPRODUCTION 3rd set of ch 10 and 11 notes
Asexual Reproduction is the production of new organisms without the fusion of nuclei of two specialized sex cells Mitotic Cell Divisions – the new organisms are genetically identical to the parent 1Diploid Cell(2n) 2 Diploid Cells(2n)
Binary Fission (evenly) Ex: amoeba, paramecium, (protists) The nucleus divides by mitosis along with cytoplasm to make 2 daughter cells that have the same # of chromosomes
Budding The division of cytoplasm is unequal so 1 daughter cells is larger than the other Ex: hydra, yeast
Sporulation Spores are made in large amounts that surround themselves with tough coats, large #s Ex: bread mold, fungi, bacteria
Vegetative Propogation-new plants are made from roots, stems, or leaves of the parent plant Cutting-new plants develop from cut end of plant, plant stem Ex: coleus, geraniums
Bulb-underground stem made from existing bulbs Ex: onions, tulips, lilys
Runner-horizontal stem close to the ground Ex: Strawberry
Grafting- cut twig attached to trunk or branch of another Ex: flowers, seedless fruits
Regeneration (unspecializes=invertebrates) Replacement or regrowth of lost or damaged body parts Ex: lobster, starfish
Ch 11 Meiosis 4th set of notes
MEIOSIS Process of nuclear division that reduces the # of chromosomes by half It is involved in SEXUAL reproduction It results in haploid(1n) eggs and sperm (animals) and spores that later lead to egg and sperm (plants) [gametes]
MEIOSIS It has 2 nuclear divisions : Meiosis I and Meiosis II Also called Gametogensis(Spermatogenesis – sperm (testes) and Oogenesis-eggs (ovaries))
Phases of Meiosis IProphase I Nuclear membrane and nucleolus disappears Synapsis occurs (pairing of homologous chromosomes) & crossing-over occurs Tetrad forms (packets of 2 chromosomes) tetrad Crossing-over
Metaphase I Homologous chromosomes attach to spindle fibers and move to the equator of the cell
Anaphase I Disjunction occurs (homologous chromosomes separate and move to opposite poles)
Telophase I Cytokinesis occurs 2 daughter cells form Nuclear membrane reappears
Phases of Meiosis IIProphase II Centrioles reappear Similar to mitosis
Metaphase II Chromosomes attach to spindle fibers and move to equator of cell
Anaphase II Chromosomes split at centromere Chromosomes move to opposite poles
Telophase II Cytokinesis occurs in both cells Nuclear membrane reappears 4 cells formed Males – 4 sperm cells Females-1 egg cell & 3 polar bodies
Fertilization and Development 5th set of notes for ch 10 and 11
Fertilization and Development Fertilization is the union of a monoploid (n) sperm nucleus with a monoploid (n) egg nucleus to form a zygote (2n) cell, the fertilized egg
2 Types of Fertilization: Internal fertilization is the union of sperm and egg in the moist reproductive tract of the female. External fertilization is the union of sperms and egg outside the body of the female; usually done in water.
Stages of development: Development begins when the zygote undergoes a rapid series of mitotic cell divisions called cleavage.
4. 8 cells 3. 2. 5. Ball of cells-stem cells 6. Blastula 1.
Blastula the formation of a hollow ball made up of one single layer of cells. Gastrulation the process in which one side of the blastula pushes inward or indents; resulting in an embryonic stage called the gastrula
Gastuala consists of 3 germ layers: Enduderm inner layer that gives rise to the organs Ectoderm outer layer that gives rise to the skin and nervous system Mesoderm middle layer that forms bonds between the ectoderm and endoderm; gives rise to the muscles, bone, and blood.