Cells - 2.4 91156

• Activation Energy


  The energy that an atomic system must acquire before a process (such as an emission or reaction) can occur
• Active Site


  The part of an enzyme or antibody where the chemical reaction occurs
• Active Transport


  Transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient; requires an expenditure of energy
• Adenine


  Purine base found in DNA and RNA; pairs with thymine in DNA and with uracil in RNA
• Aerobic


  Depending on free oxygen or air
• Anaerobic


  Living or active in the absence of free oxygen
• ATP


  A nucleotide derived from adenosine that occurs in muscle tissue; the major source of energy for cellular reactions
• Catalyst


  A substance that initiates or accelerates a chemical reaction without itself being affected
• Cell Membrane


  A thin membrane enclosing the cytoplasm of a cell
• Cell Wall


  A rigid layer of polysaccharides that maintain the shape of the cell and serves as a protective barrier
• Cellular Respiration


  The process where cells derive energy from glucose
• Cellulose


  A molecule consisting of many carbon, hydrogen and oxygen atoms
• Centriole


  One of a pair of small cylindrical cell organelles near the nucleus in animal cells
• Chloroplast


  Contained in plants that carry out photosynthesis
• Co-Enzyme


  A substance that enhances the action of an enzyme
• Co-factor


  A non-protein molecule that supports a biochemical reaction, with beneficial characteristics not typically present in amino acids
• Concentration Gradient


  A gradient in concentration of a solute as a function of distance through a solution
• Cisternae


  The complex network of interconnected flattened tubes in the endoplasmic reticulum
• Cristae


  A fold in the inner membrane of a mitochondrion
• Cytoplasm


  Full of proteins that control cell metabolism
• Cytosine


  A base found in DNA and RNA; pairs with guanine
• DNA


  Found in the nucleus of a cell, formed from nucleotides and shaped like a double helix; associated with the transmission of genetic information
• Denatured


  Unfolding or breaking up of the proteins
• Diffusion


  The process by which molecules can travel freely through the membrane
• Double Helix


  The shape of DNA
• Endoplasmic Reticulum


  A network of membranes found throughout the cytoplasm of cells, involved in processing proteins (rough ER) and lipids (smooth ER)
• Enzyme


  Any of several complex proteins produced by cells and act as catalysts in specific biochemical reactions
• Eukaryote


  An organism whose cells contain a nucleus
• Flaccid


  Not strong or robust
• Fluid Mosaic


  A flexible layer of lipid molecules that act as channels so other molecules can enter and leave the cell
• Golgi Apparatus


  A netlike structure in the cytoplasm of animal cells
• Grana


  Essential structural features of the chloroplast thylakoid network
• Guanine


  A purine base found in DNA and RNA; pairs with cytosine
• Inhibitor


  A substance that stops an activity
• Light Dependent Reaction


  A reaction part of photosynthesis, the goal is to collect energy from the sun and break down water molecules to produce ATP
• Light Independent Reaction


  Chemical reactions that convert carbon dioxide and other compounds into glucose; a reaction part of photosynthesis
• Lactic Acid


  A clear odourless hygroscopic syrupy carboxylic acid found in sour milk and in many fruits
• Lipid Bilayer


  Two layers of lipid molecules forming a thin membrane
• Lock And Key Theory


  An enzyme action; proposes that the enzyme's active site and the shape of the substrate molecule are complementary to one another
• Lysosome


  An organelle found in the cytoplasm of most cells