Human Histo

• Cell


  Fundamental living unit of any organism
• Types of cells


  • Procaryotic cells
  • Eucaryotic cells
• Eucaryotic cell


  • Contains true nucleus

  
• Cell membrane


  • Also known as plasma membrane, cytoplasmic membrane, cellular membrane, cytolemma, plasmalemma
  • Mosaic composed of large molecules of proteins & phospholipids
  • Regulates the passage of nutrients, wastes products, & secretions into & out of the cell
  • Selectively permeable

  
• Nucleus


  • Controls the functions of the entire cell
  • "Command center of the cell"
• Components of the nucleus

  • Nuclear membrane
  • Nucleoplasm
  • Nucleolus
  • Genetic material
• Cytoplasm


  • Type of protoplasm
  • Semifluid (cytosol), gelatinous, nutrient matrix
  • Where most of the cell's metabolic reactions occur
• Components of the cytoplasm

  • Organelles
  • Inclusion bodies
• Endoplasmic reticulum


  Highly convoluted system of membranes, interconnected & arranged to form a transport network of tubules & flattened sacs

  
• Types of endoplasmic reticulum

  • RER (rough endoplasmic reticulum)
  • SER (smooth endoplasmic reticulum)
• Ribosomes


  • 18-22 nm in diameter
  • Consist of rRNA & proteins
  • Synthesis of proteins
  • With 2 subunits = 60S & 40S

  
• Golgi complex


  • Also known as Golgi apparatus or Golgi body
  • Stack of flattened, membranous sacs
  • Connects or communicates with endoplasmic reticulum
  • "Packaging plants"
• Lysosomes


  • Small vesicles that originate at the Golgi complex
  • Contain lysozyme & other digestive enzymes
  • Involved in phagocytosis and autolysis
• Peroxisomes


  • Membrane-bound vesicles in which H2O2 is both generated & broken down
  • Contain catalase

  
• Mitochondria


  • "Power plants", "powerhouses", "energy factories"
  • Where most of the ATP molecules are formed by cellular respiration
  • Another type of energy-producing organelle
• Plastids


  • Membrane-bound structures containing various photosynthetic pigments
  • Sites of photosynthesis
• Cytoskeleton


  • System of fibers including microtubules, microfilaments, and intermediate filaments
  • Strengthen, support, stiffen the cell, give the cell its shape
• Cell wall


  • External structure that provides rigidity, shape & protection
  • Composed of cellulose, pectin, lignin, chitin, mineral salts
• Flagella


  Long, thin structures for locomotion
• Cilia


  Hairlike projections, shorter, thinner & more numerous than flagella, for locomotion
• Gene expression


  1. Transcription (making a copy of a gene)

  2. Translation (converting that copied information into a protein)

  
• The ultimate expression of a gene is the production of a protein from the information contained in DNA

  
• The information encoded in a gene goes through a multi-step process in which it is copied, transported, read, and finally, used as a template for building proteins

  
• Gene expression contributes to the trait or 'phenotype' we observe
• Organization of living things

  • Cell
  • Tissue
  • Organ
  • Organ System
  • Organism
• Transcription


  1. First step in gene expression

  2. Takes place in the nucleus

  3. The process by which DNA is copied (transcribed) to mRNA, which carries the information needed for protein synthesis

  
• Cell


  Fundamental living unit of any organism
• Translation


  1. The synthesis of proteins based on the information in mRNA

  2. The mRNA formed in transcription is transported out of the nucleus, into the cytoplasm, to the ribosome (the cell's protein synthesis factory)

  
• Eukaryotes/Eukaryotic cell


  Contains true nucleus
• Interphase


  One of the two major phases of the cell life cycle
• Cell organelles and their functions

  • Plasma Membrane
  • Cytoplasm
  • Nucleus
  • Endoplasmic Reticulum
  • Mitochondria
  • Ribosomes
  • Lysosomes
  • Centrosome
  • Golgi Apparatus
  • Cytoskeleton
  • Cilia
  • Flagella
• Cell division


  The other major phase of the cell life cycle
• Plasma Membrane


  Selectively permeable membrane, providing shape and protects the inner contents of the cell
• What happens during interphase

  DNA replication

  
• Cytoplasm


  Contains enzymes, mainly responsible for controlling all metabolic activity taking place within the cell and are the site for most of the chemical reactions within a cell
• Chromatid


  Two genetically identical strands of chromatin
• Nucleus


  Monitors cellular activities including metabolism and growth by making use of DNA's genetic information
• Centromere


  Region on chromatids that joins two sister chromosomes
• Nucleoli


  Responsible in the nucleus for the synthesis of protein and RNA
• Centriole


  Forms spindle fibers to separate chromosomes during cell division