CELL CYCLE-LAB_merged.pdf

CELL CYCLE & CELL DIVISION Cell Multiplication o Increase in the number of cells for What is Cell Cycle? growth, development and repair Series of events that tak...

CELL CYCLE & CELL DIVISION Cell Multiplication o Increase in the number of cells for What is Cell Cycle? growth, development and repair Series of events that take place in a cell TYPES OF CELLS leading to its division and DNA replication Somatic Cells Make up all the body tissues and organs Interphase Diploid Chromosomes Period of the cell between cell divisions Undergo Mitosis Preparatory stage for cell division Germinal Cells G1 PHASE Gametes o Between Mitosis and DNA synthesis Reproductive cells o Growing cell: organelles are duplicating Haploid Chromosomes o Metabolically active cell Undergo Meiosis o Lasts up to 11 hrs. What are Haploid and Diploid Chromosomes? G0 PHASE Haploid Chromosomes o Quiescent stage One copy of genetic material o Metabolically active cell subdivided into o Not dividing cell chromosomes S PHASE Diploid Chromosomes o DNA replication Two copies of genetic o Increase in DNA content material subdivided into o Last up to 8 hrs. chromosomes G2 PHASE o Protein synthesis What are Homologous and Sister o Check point: damaged DNA, Chromosomes? unreplicated DNA Homologous Chromosomes o Lasts up to 4 hrs Have alleles for same genes at specific loci M - PHASE Similar but NOT identical Cell Division: Mitosis, Meiosis Sister Chromosomes Lasts for 1 hr. Have the same alleles for each gene Identical chromosomes What is Cell Division? Biological Basis of life o Reproduction: to produce new individual of the same kind Maintains the genome Cells that don’t enter cell division o Keeps the genomic information consistent between generations MEIOSIS Meiosis I: Prophase I Chromosomes become visible Meiotic spindle forms Nuclear envelope disappears 1. Leptotene Condensation of chromosomes Shortening and thickening of chromosomes Doubled chromosomes 2. Zygotene Pairing of homologous chromosomes Synapsis begins 3. Pachytene Bivalent formed Crossing-over occurred 4. Diplotene Coiling stage Chiasmata holds the homologous chromosomes 5. Diakinesis Recondensation Tetrad chromosomes are visible Terminalization: chiasmata at the ends End of Prophase I Nucleolus vanishes Nuclear membrane breaks down Meiosis I: Metaphase I Chromosomes are: Attached to the meiotic spindle Arranged at the metaphase plate Meiosis I: Anaphase I Separation of homologous chromosome, each moving to opposite poles Sister chromosomes remain attached Meiosis I: Telophase I Property Mitosis Meiosis Homologous chromosomes reached the DNA Occurs during Occurs during poles Replication interphase interphase Nuclear envelopes form before mitosis before meiosis Cytokinesis follows begins. begins. Number of One Two Meiosis II: Prophase II divisions Synapsis of Does not Occurs along Nuclear envelope breaks down homologous occur. with crossing Spindle apparatus forms chromosomes over between non-sister Meiosis II: Metaphase II chromatids in Chromosomes are: prophase I. Attached to fully formed spindle Number of Two diploid 4 haploid (n) On the metaphase plate daughter cells (2n) daughter daughter cells, and genetic cells that are each Meiosis II: Anaphase II composition genetically containing half Centromeres separate identical to the as many Sister chromatids are now individual parent cell. chromosomes chromosomes as the parent Chromosomes move toward the poles cell. Daughter cells are genetically Meiosis II: Telophase II different from Nuclear envelope forms around each set of the parent cell chromosomes and each Cytokinesis occurs other. Formation of 4 daughter cells, each with Role in the Produces cells Produces haploid set of chromosomes animal body for growth and gametes and repair. assures genetic diversity in sexual reproduction. What is a CELL?  Bilayer Phospholipid  Structural unit and functional unit of life  Phosphate layers: polar heads;  Performs all life processes hydrophilic What is CYTOLOGY?  Lipid layers: non-polar tails; hydrophobic  Science about the cell  Semi-permeable Example of Cell  Selects materials that pass through it  Animal Cell  Regulates the movement of materials o Human blood smear showing RBC and  Fluid Mosaic Model WBC  Contains various materials or molecules  Plant Cell Phospholipids o Hydrilla leaf cell emphasizing the Cholesterol chloropasts Proteins  Protozoa o Amoeba an example of protozoa Cell Wall  Bacterial Cell None in animal cells o E. Coli seen under SEM  Freely Permeable Discovery of the Cell  Porous  Anton van Leeuwenhoek  NO direct effect on the movement of o Made a simple and single-lens materials in and out the cell microscope  Components depend on the organism: o With magnification of about 275x Plants: with cellulose  Robert Hooke Fungi: with chitin o Discovered the cell  Rigidity o Coined the name “cell”  Gives support and protection o Used cork of plant o Observed tiny boxes that look like the Cytoplasm rooms in monastery Also called Protoplasm 2 Basic Cell Types Inside of the cell 1. Eukaryotic Cell  "Living Substance"  “True” Nucleus  Contains the organelles that perform all the  Membrane-bound & non-membrane physiological properties of the cell bound organelles  Multicellular Organism  Gel-like Material Plants & Animals  Sol: semi-liquid 2. Prokaryotic Cell  Gel: semi-solid  “False” Nucleus  Non-membrane bound organelles  Cytosol  Unicellular Organism  70% of the cytoplasm Bacteria  Mixture of cytoskeleton filaments, dissolved What are the 3 Basic parts of the Cell? materials and water  Plasma Membrane Endoplasmic Reticulum  Cytoplasm System of membranous tubules and sacs  Nucleus  "Circulatory System of the Cell" What are Organelles?  Internal Transport System  Basic cell parts that perform the physiological  Allows molecules in the cell to move from activities of the cell one part to another Cell Membrane  Rough ER (rER)  Also called Plasma Membrane  Lined with ribosomes  Separates the cell from its external environment  For protein synthesis and transport  Envelope  Covers and protects the cell  Gives shape to the cell   Smooth ER (SER)  Vesicles and fused with the Golgi body for  No ribosomes Transports other materials secretion via exocytosis other than protein  Transport Agent  Involved in the distribution of lipids around Ribosomes the cell Most common organelles in almost all cells  Lysosome Builder Not surrounded by a membrane  Lysosomes are vesicles with protein  Protein Micro-machines enzymes pinched off by Golgi body to the  Sites for protein synthesis cytoplasm  Free Ribosomes  Floating in the cytoplasm Centrioles  Size 70S Organizing centers for microtubule  In prokaryotes Contain 2 bundles of microtubules at right angle to  Polysome/Polyribosome each other  Group of 80s ribosomes working together  Cell Division translating mRNA to polypeptides  Form the spindle fibers for the separation of  Attached Ribosomes chromosomes  Line the membranes ofendoplasmic  Centrosomes reticulum  House the centrioles  Size 80S  In eukaryotes Lysosome Tiny sac produced by Golgi body Mitochondria  Digestive Plant "Powerhouse of the Cell"  Contains digestive enzyme to help in the Large organelles second to nucleus and process of digestion chloroplasts  Keeps the cell clean  ATP Manufacturer  Also digests excess and worn out organelles,  Manufacture energy in the form of ATP and engulfed bacteria or viruses  Metabolize carbohydrate and fatty acid to  Suicide Sac generate energy  When the cell is damaged, the lysosome  Semi-autonomous Organelles bursts, releases enzyme and digests own  Have own DNA, so can produce by itself by cell dividing  Aerobic Respiration Peroxisome  Mitochondria act like a digestive system to Formerly known as a microbody breakdown nutrients to produce energy rich  Oxidative Organelle molecules  Contains enzymes that oxidizes fatty acids  Double-membrane Organelles and amino acids  Smooth outer membrane  Byproduct is hydrogen peroxide  Folded inner membrane   Cristae: infoldings  Chemical Detoxification  Oversees reactions that neutralize free Golgi Apparatus radicals, which cause cellular damage and Also called Golgi complex or Golgi body Processing cell death and Packaging Plant, and Secretory Vesicle  Cisternae Vacuole  Fused flattened sacs or folds Storage bubbles found in cells  Also called dictyosome Membrane bound fluid sac  Protein Collector & Dispatcher  Storage Sac  Protein synthesized in the ER packed into  Stores large amount of various materials, like the organic and inorganic molecules   Subordinate Role  Chromosomes  Assisting in exocytosis and endocytosis  Houses the genes (DNA) Hereditary  Transporting Agent material: contains instructions for traits and  Transports needed materials into the cell via characteristics endocytosis, and waste materials out of the  Nucleolus cell via exocytosis  Spherical body in the nucleus for the synthesis of protein Cytoskeleton Complex network of interlinking filaments or tubules FYI: All eukaryotic cells have nucleus, except for the "Cell Skeleton" Red Blood Cells or Erythrocytes that lose their nuclei 3 Structures: as they mature 1. Microfilaments:  Contractile: made of actin [from ppt]  For cell movement and cytokinesis 2. Microtubules:  Rigid, hollow tubes: made of tubulin  Maintain cell shape  Form the centrioles (spindle fibers) 3. Intermediate Filaments  Provide strength and support Chloroplasts None in animal cells Sites of photosynthesis  Thylakoids  Flattened membranous sacs that contain chlorophyll  Stroma  Spaces in grana for the exchange of materials  Grana  Pile of thylakoids Flagella and Cilia For Cell Movement  Cilia  Short  Hair-like  Numerous in number  Flagella  Long  Thread-like  Fewer in number. Nucleus Normally the largest organelle "Brain of the cell"  Nuclear Envelope  Double membrane with many pores  Controls the movement of material in and out the nucleus Cell Parts/Structures and Functions "Karyose" comes from a Greek word which means "kernel," as in a kernel of grain. In biology, we use this word root to refer to the nucleus of a cell. “Pro" means "before," and "eu" means "true," or "good." So "Prokaryotic" means "before a nucleus," &"eukaryotic" means "possessing a true nucleus." Prokaryotic (before nucleus)  Lack nuclei & other membrane-bound organelles  Classified into two domains Endomembrane System o Archaea & Eubacteria  Made up of lipid bilayer with proteins Eukaryotic (true nucleus) attached to either side or traversing them,  Larger & more complex; also provides a transport system, Have membrane-bound organelles;  It include plasma membrane, ER, nuclear  Have network of specialized structures membrane (not nucleus), lysosome, Golgi which are microtubules & microfilaments body, vacuoles & vesicles. organized into cytoskeleton giving shape & allows intracellular communication. Characteristic Prokaryotic Eukaryotic Nucleus Absent Present w/ nuclear envelope Chromosome Single circle Paired linear of DNA (DNA + Extra Plasmid Mitochondria, chromosomal, Chloroplast DNA Cell division Binary fission Mitosis  Phospholipid bi-layer form a barrier across Modern Version of Cell Theory which only lipid soluble molecules can  All energy flow of life occurs within cells migrate and to provide a framework for the (metabolism & biochemistry) membrane proteins.  Cell contain hereditary information which is passed from cell to cell during cell division. Importance of cholesterol in plasma membrane  All cells come from pre-existing cells.  It helps make membrane impermeable to small water soluble molecules & keeps the  All cells are basically the same in chemical membrane flexible over a wide range of composition. temperatures. Significance of Cell CHO unite with lipids = Glycolipids found on the  Reproduction surface of plasma membrane.  Growth CHO unite with proteins = Glycoproteins for  Function intercellular recognition.  Heredity Glycocalyx (cell coat) Two Types of ER  It refers to surface CHO & portion of the a. Smooth ER – lipid synthesis. The site of protein & lipids, w/c act as molecular lipid production, detoxification of a wide “fingerprints” for each cell types. variety of organic molecules & storage of  Necessary for cell to cell recognition, & calcium ions in muscle cells. behavior of certain cells. It is the key b. Rough ER – protein synthesis. It is a site component in coordinating cell behavior in for attachment of ribosomes. animals. 5. Golgi Apparatus – Consists of 3 to 20 golgi Protein Components of Cell membrane cisternae. Flattened sacs of membrane-  Embedded in the lipid bilayer linked to either bound cisternae (closed spaces serving as phosphatidylinositol, a minor phospholipid or fluid reservoir). It sorts, packages, & secretes a fatty acid chain. The integral proteins can proteins & lipids. Named after Italian be removed from the membrane only by microscopist Camillo Golgi who discovered it detergents that dissolve the liquid in 1898.  Peripheral proteins - Not embedded in the 6. Lysosomes – Lyso – dissolving; somes – bilayer but reside at one surface or the other, bodies. 60 kinds of powerful digestive. bound to an integral protein. Spherical organelles that contain “acid  Functions of Membrane Proteins hydrolases” that digest organic molecules o Intercellular Joining under acidic condition. This is the cells o Enzymatic Activity garbage disposal system. Isolated in 1950’s o Transport (Active/Passive) by Christian de Duve & associate. o Cell-Cell Recognition 7. Peroxisomes – Crystalline structure inside a o Anchorage/Attachment sac which also contains amorphous gray o Signal Transduction material. It function to rid the body of toxic substances using the enzyme “catalase”. Cytoplasm has several components 8. Mitochondria – Power Generator. Power 1. Cytosol – fluid portion of the cytoplasm house of the cell. Double membrane bound 2. Organelles – Tiny organs, Made of organelle that are spherical to elongate in macromolecules shape. 3. Ribosomes – “Protein workbenches” or the COMPONENTS OF MITOCHONDRIA site of protein synthesis. It contains protein a. Cristae – Inner membrane that folds into and rRNA (ribosomal RNA). Consists of a incomplete partitions small and larger subunit, which bind together b. Matrix – space between the cristae during Translation c. Outer membrane – Gives the Two Types of Ribosomes mitochondria its shape. a. Bound Ribosomes – attached to the d. Inner membrane – Site of ATP endoplasmic reticulum; produce proteins synthesis, & contains respiratory or for export or storage in membranes. electron transport chain, w/c release b. Free Ribosomes – float freely in the energy as electron pass through the cytoplasm; produce proteins for growth & System. maintenance of cell 9. Centrioles – Composed of nine tubes, each 4. Endoplasmic Reticulum (ER) – Production with three tubules; Involved in cellular & Transport. A complex membrane bound division; Lie at right angles to each other labyrinth of flattened sheets, sacs, & tubules Paired cylindrical organelles near nucleus; that branches & spread throughout the 10. Cytoskeleton – Network of several different cytoplasm. Series of channels that helps kinds of protein filaments that extend various materials to circulate throughout throughout the cytosol. Provides structural a cytoplasm, storage unit for enzymes & other framework for the cell Helps to determine the proteins & a point of attachment for cell’s shape and to organize the cellular ribosomes. contents TYPES OF CYTOSKELETON: a. Microtubules – It function in the movement of organelles such as secretory vesicles & chromosomes movement b. Intermediate Filaments – maintain shape of cell & the spatial organization of organelles c. Microfilaments – Solid strings of protein (actin) molecules. Actin microfilaments are mostly highly develop in muscle cells as myofibrils 11. Cilia & Flagella – Movement. 12. Vacuoles – Cell Maintenance. Membranous sacs that are part of the cytomembrane 13. Vaults – A newly discovered organelle. A single cell can contain thousands of vaults. cellular trucks. Its structure is consistent with the role in either subcellular transport or sequestering large nuclear protein assemblies. 14. Nucleus – The largest organelle, is the genetic information center of the cell. o Nucleolus – Visible as a dark spot in the nucleus, contains proteins & RNA and is the pre-assembly point for ribosomes. o Nuclear Membrane – separates the nucleus from cytoplasm & is continuous with the ER 15. Chromosomes – Rod- shaped structure that appears in nucleus of a cell during mitosis. It contains genes responsible for heredity. Chromatin – Nuclear material that give rise to chromosomes during mitosis. Complex of DNA, histones & non-histone proteins.