Advanced Biology

 Cell – The basic structural and functional unit of all living organisms  Cell Theory – One of the fundamental ideas of modern biology and includes the following three principals: 1) All living organisms are composed of one or more cells 2) Cells are the basic unit of structure and organization of all living organisms 3) Cells arise only from previously existing cells, with cells passing copies of their genetic material on to their daughter cells

 Plasma Membrane – Special boundary that helps control what enters and leaves the cell.  Organelle – Specialized structures that carry out specific cell functions  Eukaryotic Cells – Contain a nucleus and other organelles that are bound by membranes  Nucleus – A distinct central organelle that contains the cell’s genetic material in the form of DNA  Prokaryotic Cells – Cells without a nucleus or other membrane-bound organelles

 Selective Permeability – The membrane allows some substances to pass through while keeping others out  Phospholipid Bilayer – Two layers of phospholipids arranged tail-to-tail in the cell membrane  Transport Proteins – Move needed substances or waste materials through the plasma membrane  Fluid Mosaic Model – The plasma membrane with components constantly in motion, sliding past one another within the lipid bilayer

 Cytoplasm – Semifluid material found inside the plasma membrane  Cytoskeleton – Supporting network of long, thin protein fibers that form a framework for the cell and provide an anchor for the organelles inside the cell  Ribosomes – Organelles that help manufacture proteins  Nucleolus – Site of ribosome production inside the nucleus

 Endoplasmic Reticulum – (ER) A membrane system of folded sacs and interconnected channels that serve as the site for protein and lipid synthesis  Golgi Apparatus – A flattened stack of membranes that modifies, sorts, and packages proteins into sacs called vesicles  Vacuole – Sac used to store food, enzymes, and other materials needed by a cell  Lysosomes – Vesicles that contain substances that digest excess or worn-out organelles and food particles

 Centrioles – Organelles made of microtubules that function during cell division  Mitochondria – Energy generators that convert fuel particles into usable energy  Chloroplast – Organelles that capture light energy and convert it to chemical energy through a process called photosynthesis  Cell Wall – A thick, rigid, mesh of fibers that surrounds the outside of the plasma membrane, protecting the cell and giving it support

 Cilia – Short, numerous projections that look like hairs  Flagella – Projections that move with a whiplike motion; Longer and less numerous than cilia  Diffusion – The net movement of particles from an area where there are many particles of the substance to an area where there are fewer particles of the substance  Dynamic Equilibrium – Continuous movement of particles but no overall change to the concentration occurs

 Facilitated Diffusion – The use of transport proteins to move ions and small molecules across the plasma membrane  Osmosis – The diffusion of water across a selectively permeable membrane  Isotonic Solution – Water enters and leaves the cell at the same rate  Hypotonic Solution – The net movement of water through the plasma membrane is into the cell because the solute concentration is lower outside the cell

 Hypertonic Solution – The net movement of water is out of the cell because the solute concentration is higher outside the cell  Active Transport – The movement of substances across the plasma membrane against the concentration gradient; Requires energy from the cell  Endocytosis – The process by which a cell surrounds a substance in the outside environment, enclosing the substance in a portion of the plasma membrane

 Exocytosis – The secretion of materials at the plasma membrane