ANAPHY

• Matthias Schleiden


  German botanist who in 1838 discovered that all plants are composed of cells
• Theodor Schwann


  Also in 1838, discovered that animals were made of cells
• Rudolf Virchow


  In 1855, German pathologist who discovered that humans are made up of cells
• Cell Theory


  • All living things are composed of a cell or cells
  • Cells are the basic unit of life
  • All cells come from preexisting cells
• Concepts of the Cell Theory

  • A cell is the basic structural and functional unit of living organisms
  • The activity of an organism depends on the collective activities of its cells
  • According to the principle of complementarity, the biochemical activities of cells are dictated by the relative number of their specific subcellular structures
  • Continuity of life has a cellular basis
• Cell size limits


  Cells will only grow so big; after that, they either remain the same size, or they divide into two smaller cells
• Cell Structure


  • Cell - basic unit of life; the human body has 500-100 trillion cells
  • Organelles - specialized structures
• Nucleus


  • Control center of the cell
  • Contains genetic material known as DNA
  • DNA is needed for building proteins and cell reproduction
  • Nuclear envelope (membrane) - Consists of a double membrane that bounds the nucleus; Contains nuclear pores that allow for exchange of material with the rest of the cell; Encloses the jellylike fluid called the nucleoplasm
  • Nucleolus - Nucleus contains one or more dark-staining nucleoli; Sites of ribosome assembly; Ribosomes migrate into the cytoplasm through nuclear pores to serve as the site of protein synthesis
  • Chromatin - Composed of DNA wound around histones (proteins); Scattered throughout the nucleus and present when the cell is not dividing; Condenses to form dense, rodlike bodies called chromosomes when the cell divides
• Plasma membrane


  • Cell membrane junctions - Desmosomes (anchoring junctions), Gap Junctions (allow communication between cells)
• Cytoplasm


  • The cellular material outside the nucleus and inside the plasma membrane
  • Site of most cellular activities
  • Includes cytosol, inclusions, and organelles
  • Cytosol: Fluid that suspends other elements and contains nutrients and electrolytes
  • Inclusions: Chemical substances, such as stored nutrients or cell products, that float in the cytosol
  • Organelles: Metabolic machinery of the cell that perform functions for the cell; Many are membrane-bound, allowing for compartmentalization of their functions
• Cell Diversity


  • Fibroblast - Secretes cable-like fibers
  • Erythrocyte (red blood cell) - Carries oxygen in the bloodstream
  • Epithelial cell - Packs together in sheets; Intermediate fibers resist tearing during rubbing or pulling
  • Skeletal muscle and smooth muscle cells - Contractile filaments allow cells to shorten forcefully
  • Fat cells - Lipid droplets stored in cytoplasm
  • WBC - Digests infectious microorganisms
  • Nerve cell (neuron) - Receives and transmits messages to other body structures
  • Oocyte (female) - Largest cell in the body; Divides to become an embryo upon fertilization
  • Sperm (male) - Built for swimming to the egg for fertilization; Flagellum acts as a motile whip
• Functions of the Cell

  • Cell metabolism and energy use
  • Synthesis of molecules
  • Communication
  • Reproduction and inheritance
• Cell Membrane


  • Outer boundary of the cell
  • Determine what enters and leaves the cells
  • Extracellular - substances outside the cells
  • Intracellular - substances inside the cell
  • Fluid-Mosaic Model - arrangement of molecules in the cell membrane
  • Selectively permeable - allows some substances to pass into or out of the cells
• Movement Through the Cell Membrane

  1. Diffusion - Movement of a solute from an area of higher to lower concentration gradient

  2. Osmosis - Diffusion of water across a selectively permeable membrane

  3. Carrier-Mediated Transport Mechanisms - Facilitated diffusion, Active transport, Secondary active transport (Cotransport, Counter transport)

  4. Endocytosis - Movement of materials into cells by formation of vesicles

  5. Exocytosis - Secretion of materials from cells
• Ribosomes


  • Site of protein synthesis
  • Found at two locations: Free in the cytoplasm, As part of the rough endoplasmic reticulum
• Endoplasmic Reticulum


  • Forms tubules/sacs throughout the cell
  • Rough E.R. - protein synthesis and modification; contains ribosomes
  • Smooth E.R. - lipid synthesis, detoxification, and Ca storage
• Golgi Apparatus


  • Modifies, packages, and distributes lipids and proteins
• Secretory vesicles


  • Transports and stores materials within cells
• Lysosomes


  • Membrane bound sacs containing hydrolytic enzymes
• Peroxisomes


  • Enzymes that digest fatty acids and amino acids, and catalyze the breakdown of hydrogen peroxide
• Proteasomes


  • Not bound by membranes, Digest selected proteins
• Mitochondria


  • Major site of ATP production
• Cytoskeleton


  • Holds organelles in place; enables the cell to change shape
  • Microtubules - support the cytoplasm; assist in cell division
  • Microfilaments - involved in cell movement
  • Intermediate filaments - provide mechanical support
• Centrioles and Centrosome


  • Centrosome - where microtubule formation occurs
  • Centrioles - specialized zone of the cytoplasm
  • Spindle fibers - involved in separation of chromosome during mitosis
• Cilia, Flagella, and Microvilli

  • Cilia - moves substances over the surface
  • Flagella - propel sperm cells
  • Microvilli - increase the surface area of cells; aids in absorption
• Gene Expression


  1. Transcription - making a copy of a gene

  2. Translation - converting that copied information into a protein
• Nucleotide Pairs


  Cytosine-Guanine, Thymine-Adenine, Uracil-Adenine
• Cell Life Cycle


  1. Interphase - non-dividing phase

  2. Cell Division - formation of daughter cells from a single parent cell
• Chromosomes


  • 46 Chromosomes - diploid no. of chromosomes
  • 2 X Chromosome = Female
  • X + Y Chromosome = Male
  • Autosomes - 22 remaining pairs of chromosomes
• Mitosis


  1. Prophase - chromatin condenses

  2. Metaphase - chromosomes align at the center

  3. Anaphase - chromatids separate at the centromere and migrate to opposite poles

  4. Telophase - chromosomes unravel to become chromatin
• Differentiation


  Cells develop specialized structures and functions
• Apoptosis


  Programmed cell death