chapter 1 - the cell

• cell theory - unicellular + multicellular organisms

  • all living things are composed of cells
  • the cells is the basic functional unit of life
  • cells arise only from pre-existing cells
  • cells carry genetic info in the form of DNA
• magnification

  • increase in apparent size of an object
• resolution

  • ability to differentiate between two closely placed objects
• microscopes

  • compound light microscope - most commonly used
  • phase contrast microscope - visualization of living organisms
  • electron microscope - most powerful images (atomic level)
• autoradiography

  • uses radioactive compounds to track what is happening inside the cell
  • see how radioactive material moves and accumulates in the cell
• centrifugation

  • high speed spinning to separate components of a mixture based on density
  • denser - pulled to the bottom of the tube
  • less dense - pulled to the top of the tube
• prokaryotes - simplest of all organisms

  • cell wall is present
  • ribosomes (subunits = 30s+50s)
  • no membrane-bound organelles
  • unicellular
• eukaryotes

  • protists, fungi, plants, animals
  • cell wall in plants and fungi
  • ribosomes (subunits = 40s+60s)
  • membrane-bound organelles
  • unicellular or multicellular
• cytosol

  • aqueous part of cell
• cytoskeleton

  • the large network of proteins and other fibers that give the cell its shape and structure
• cholesterol

  • regulate the fluidity and stiffness of the cell
• nucleus

  • contains the cells genetic info (DNA)
  • direct protein synthesis
  • serve as genetic blueprint during cell replication
• ribosomes

  • factory of the cell for protein production
  • ship proteins to the endoplasmic reticulum
• endoplasmic reticulum

  1. smooth - ribosome studded - works on lipid synthesis and poison detox
  2. rough - ribosome free - works on protein production

  • responsible for production and distribution of the cell
• golgi apparatus

  • post office
  • directs material within the cell in membrane bound sacs
• lysosomes

  • garbage dump
  • remove old cellular components
• mitochondria

  • powerhouse of the cell
  • 2 layers

  1. inner - contains molecules and enzymes for electron transport chain
  2. outer - respiration

  semiautonomous - replicate independently via binary fission

  apoptosis - programmed cell death
• microbodies

  2 types

  • peroxisomes - creating hydrogen peroxide to break down fats into useable molecules
  • glyoxysomes - converting fats into useable fuels until plants can make their own energy
• simple diffusion

  no energy required

  • osmosis - water moves from low to high solute concentration
  • hypotonic - concentration of solutes inside > outside
  • isotonic - concentration of solute inside = outside
  • hypertonic - concentration of solutes inside < outside
• facilitated diffusion

  • also known as passive transport
  • movement of molecules along the concentration gradient with the help of proteins serving as channels
• active transport

  • net movement of solutes against concentration
  • requires energy - ATP
• endocytosis

  • cellular membrane engulfs material into the cell

  1. pinocytosis - small
  2. phagocytosis - large
• exocytosis

  • substrates are released from the cell out
• tissue

  1. epithelial - cover body and line cavities
  2. connective - framework for higher level interactions
  3. nervous - cellular signaling
  4. muscle - contractile ability and strength
• viruses

  • acellular structure composed of nucleic acids surrounded by a protein coat
  • capsid - protein coat
  • viruses cannot reproduce independently