Biology

• Organic compounds


  • Carbohydrates
  • Proteins
  • Lipids
  • Nucleic Acids
• Carbohydrates


  Major source of energy, include sugars and starches, made up of carbon, hydrogen, and oxygen with a 2:1 ratio of hydrogen to oxygen, plants and animals use for maintaining structure within cells
• Proteins


  Nitrogen-containing compounds made up of chains of amino acids, 20 amino acids can combine to form a great variety of protein molecules, can compose enzymes, hormones, antibodies, and structural components
• Lipids


  Water-insoluble (fats and oils), made up of carbon, hydrogen and oxygen, composed of glycerol and fatty acid, provide insulation, store energy, cushion internal organs, found in biological membranes, can be saturated or unsaturated
• Nucleic Acids


  Direct the instruction of proteins, genetic information an organism receives from its parents, two types: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)
• Cell Organelles


  • Chloroplast
  • Golgi Body
  • Lysosomes
  • Mitochondria
  • Nucleus
  • Ribosome
  • Vacuole
  • Cell (plasma) membrane
  • Cell wall
  • Cytoplasm
  • Endoplasmic Reticulum
• Chloroplast


  Capture solar energy for photosynthesis (plant cells, some algae)
• Golgi Body


  Package, distribute products
• Lysosomes


  Digest excess products and food particles
• Mitochondria


  Transform energy through respiration
• Nucleus


  Contains DNA which controls cellular activities
• Ribosome


  Produce proteins
• Vacuole


  Store substances
• Cell (plasma) membrane


  Phospholipid bilayer that protects and encloses the cell, controls transport, maintains homeostasis
• Cell wall


  Rigid second layer that protects and encloses the cell (plant cells and some bacteria)
• Cytoplasm


  Fluid-like substance that contains various membrane-bound structures (organelles) that perform various functions
• Endoplasmic Reticulum


  Site of chemical reactions, rough ER contains ribosomes, smooth ER produces lipids
• Cytoskeleton


  Provides internal structure, includes microfilaments and microtubules
• Cell Types


  • Unicellular
  • Multicellular
  • Prokaryote
  • Eukaryote
• Unicellular


  Organism that exists as a singular, independent cell
• Multicellular


  Organism that exists as specialized groups of cells, cells are organized into tissues that perform the same function, tissues form organs and organs make up an organ system
• Prokaryote


  Has nuclear material in the center of the cell, but is not enclosed by a nuclear membrane, no membrane-bound organelles, found in bacteria and blue-green bacteria
• Eukaryote


  Contain a clearly defined nucleus enclosed by a nuclear membrane and membrane-bound organelles, found in plants, animals, fungi, and protists
• Cell Theory


  • The cell is the basic unit of life
  • All organisms are composed of cells
  • All cells come from pre-existing cells
• Cell Specialization


  • cells
  • tissues
  • organs
  • organ systems
  • organism
• Cell Specialization


  Each cell performs a specific function for each tissue or organ, as cells mature they shape and contents change, as cells become specialized they may contain organelles that are NOT common to all cells, design and shape of a cell is dictated by its function and the conditions under which it works, multicellular organisms exhibit greater cellular specialization, such as red blood cells, nerve cells, and gland cells
• Passive Transport


  • Diffusion
  • Osmosis
  • Facilitated Transport
• Diffusion


  Movement of substances across the plasma membrane from an area of high concentration to an area of low concentration
• Osmosis


  Diffusion of water across the plasma membrane from areas of high concentration to areas of lower concentration
• Facilitated Transport


  A carrier molecule embedded in the plasma membrane transports a substance across the plasma membrane following the high-to-low concentration gradient
• Active Transport


  • Endocytosis
  • Exocytosis
• Endocytosis


  Large particles are brought into the cell
• Exocytosis


  Large particles leave the cell
• Homeostasis


  Internal equilibrium, the plasma membrane regulates what enters and leaves the cell, a selectively permeable membrane only allows certain substances to pass through
• Effect of Concentration on a Cell

  • Hypotonic
  • Hypertonic
  • Isotonic
• Hypotonic


  Water moves in, cell bursts
• Hypertonic


  Water moves out, cell shrivels
• Isotonic


  No net movement, cell maintains equilibrium
• Homeostasis


  Self-regulating mechanism that maintains internal conditions (with individual cells and within organs, systems), example: body temperature, respiration, nutritional balance, cells communicate their needs to each other mainly through their cell membranes by releasing chemical messengers that, ultimately, tell the hypothalamus gland in the brain that a change needs to be made in the interstitial fluid
• Negative Feedback


  Glucose / Insulin levels in cells