Chapter 2 – Microbiology Test Questions – Flashcards
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| Biosphere |
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| that part of the earth- including the air, soil, and water- where life occurs |
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| Cellular Chemistry |
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| the chemical reactions between atoms and molecules that provide for the unique metabolism found in microbial cells |
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| Matter |
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| Anything that occupies space and has a mass |
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| Chemical Element |
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| the most basic forms of matter and they cannot be broken down into other substances by ordinary chemical means -6 of the most important elements to humans: 1. Carbon 2. Hydrogen 3. Nitrogen 4. Phosphorus 5. Sulfur 6. Oxygen CHNOPS -other important elements include: Sodium, Calcium, manganese, iron, copper, zinc |
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| Atom |
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| the smallest unit of an element having the properties of that element, it cannot be broken down further without losing the quality of the element |
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| Atomic Nucleus |
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| an atom consists of a positively charged core, which contains most of its mass and two kinds of particles neutrons and protons |
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| Mass |
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| The quantity of matter in a sample |
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| Proton |
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| positively charged particles |
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| Neutron |
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| neutral particles |
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| Atomic Number |
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| the number of protons in the atom |
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| Mass Number |
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| the number of protons and neutrons combined |
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| Electrons |
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| in a cloud surrounding the atomic nucleus, negatively charged, the number is equal to the amount of protons |
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| Electron Shell |
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| spaces where electrons are located and where each shell represents a different energy level |
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| Isotopes |
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| Atoms of the same element that have different numbers of neutrons |
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| Radioisotope |
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| unstable isotopes that give off energy in the form of radiation and are useful in research and medicine |
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| ion |
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| an atom that has acquired electrostatic charge |
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| Anion |
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| a negatively charged ion |
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| Cation |
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| a positively charged ion |
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| Electron Placement in Electron Shell |
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| the shell closest to the nucleus can accommodate two electrons, while the second and third shells each can hold 8, other shells have a max numbers but usually no more than 18 are presented in those outer shells |
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| Chemical Bond |
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| the force holding two or more atoms that are linked together -they can interact electrostatically or uncharged atoms can share electron with one or more other atoms |
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| Ionic Bond |
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| one atoms gives up its outermost electrons to another |
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| Salts |
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| - typically formed through ionic bonding Including: calcium (Ca+2) potassium (K+2) Magnesium (Mg+2) iron (Fe+2 or Fe+3) |
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| Compound |
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| when two or more different elements interact with one another to achieve stability, each has its own formula and set of properties |
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| Covalent Bonds |
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| a bond where electron achieve stability by sharing electrons between atoms (CHNOPS elements) |
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| Structural Formula |
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| chemical diagrams showing the order and arrangement of atoms |
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| Molecule |
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| two or more atoms held together by covalent bonds |
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| Molecular Formula |
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| the kinds and amounts of atoms (the subscript) in a molecule |
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| Hydrocarbons |
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| molecules consisting solely of hydrogen and carbon (ie: methane) |
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| Nonpolar Molecules |
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| the “equal sharing” of electron pairs, there are no electrical charges (poles) and the bonds are called nonpolar covalent bonds |
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| Polar Molecules |
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| electrically charged poles (ie: water) |
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| Hydrogen Bonds |
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| involves the attraction of a partially positive hydrogen atom that is covalently bonded to one polar molecule toward another polar molecule having either a partially negative oxygen atom or nitrogen atom, weaker than covalent bonds, but they hold water molecules together |
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| Chemical Reaction |
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| a process in which atoms or molecules interact to form new bonds |
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| Dehydration Synthesis (Condensation) Reaction |
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| a process of bonding two molecules together by removing the products of water and joining the open bonds |
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| Hydrolysis Reaction |
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| A process in which a molecule is split into two parts through the interaction of H+ and (OH-) of a water molecule |
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| Solvent |
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| the liquid doing the dissolving to form a solution |
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| Solute |
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| the substance dissolved in the solvent |
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| Hydrophilic |
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| referring to a substance that dissolves in or mixes easily with water |
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| Hydrophobic |
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| referring to a substance that does not dissolve in or mix easily with water |
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| Aqueous Solution |
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| one or more substance dissolved in water |
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| Acid |
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| a chemical substance that donates H+ to a solution, they have a sour taste (ie: acetic acid in vinegar, citric acid in citrus fruits, and lactic acid in sour milk products) (ie: strong acids: hydrochloric acid (HCl), sulfuric acid (H2SO4) nitric acid (HNO3)) Weak acids- carbonic acid (H2CO3) |
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| Base |
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| a substance that combines with H+ in solution, they have a bitter taste (strong base = Potassium Hydroxide (KOH) |
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| pH |
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| the power of hydrogen ions |
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| pH scale |
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| numerical scale extends from 0 (extremely acidic, high H+) to 14 (extremely basic and alkaline, low H+) and is based on actual calculations of the number of hydrogen ions present when a substance mixes with water; it is logarithimic; that means every time the pH changes by one unit, the [H+] changes 10 times |
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| Neutral |
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| a substance having a pH of 7 like pure water |
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| Acidic |
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| solutions that releases H+ and have a pH lower than 7 |
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| Basic |
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| solutions that lose H+ and have a pH greater than 7 |
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| Daltons |
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| units to measure the weight of atomic particles or molecules; equivalent to atomic mass units used in chemistry (one-twelfth the weight of an atom of 12C) |
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| Buffers |
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| substances that maintain a specific pH, does not necessarily maintain a neutral pH, but rather whatever pH is required for that environment, most biological buffers consist of a weak acid and a weak base |
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| Organic Compound |
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| - compounds related to or having a carbon basis: carbohydrates, lipids, proteins, and nucleic acids |
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| Polymer |
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| a substance formed by combining smaller molecules into larger ones |
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| Monomers |
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| -a simple organic molecule that can join in long chains with other molecules to form a more complex molecule |
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| Functional Groups |
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| points where further chemical reactions can occur if facilitated by a specific enzyme because these reactions will not occur spontaneously |
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| Enzyme |
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| a protein that facilitates a specific chemical reaction |
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| Carbohydrates |
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| organic compounds composed of carbon, hydrogen, and oxygen atoms that build sugars and starches; the ratio of hydrogen to oxygen is always 2:1 |
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| Monosaccharide |
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| simple sugars (ie: glucose), building blocks for polysaccharides |
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| Photosynthesis |
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| A biochemical process in which light energy is converted to chemical energy, which is then used for carbohydrate synthesis |
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| Disaccharides |
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| composed of two monosaccharides held together by a covalent bond (ie: Sucrose (table sugar) which is constructed from a glucose and fructose molecule through dehydration synthesis reaction, Maltose- composed of two glucose monomers, occurs in barley, and fermented by yeasts, which can produce beer, Lactose (milk sugar) composed of monosaccharides glucose and galactose |
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| Polysaccharides |
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| complex carbohydrates formed by joining together hundreds of thousands of simple monomers, covalent bonds link them together (ie: starch and glycogen, cellulose) |
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| Lipids |
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| nonpolar organic compound composed of carbon, hydrogen, and oxygen, (ie: triglycerides, phospholipids); hydrophobic -consist of a 3-carbon glycerol molecule and up to 3 long-chain fatty acids, each fatty acid is a long nonpolar hydrocarbon chain containing b/w 16-18 carbon atoms, bonding occurs through dehydration synthesis reaction between hydroxyl and carboxyl functional groups |
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| Saturated |
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| referring to a water-insoluble compound that cannot incorporate any additional hydrogen atoms |
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| Unsaturated |
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| Referring to a water-soluble compound that can incorporate additional hydrogen atoms |
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| Phospholipids |
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| A water-insoluble compound containing glycerol, two fatty acids, and a phosphate head group, forms part of the membrane in all cells |
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| Sterols |
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| An organic solid containing several carbon rings with side chains (ie: Cholesterol) |
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| Nucleic Acids |
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| a high-molecular-weight molecule consisting of nucleotide chains that convey genetic information and are found in all living cells and viruses |
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| Deoxyribonucleic Acid (DNA) |
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| the genetic material of all cells and many viruses |
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| Ribonucleic acid (RNA) |
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| the nucleic acid involved in protein synthesis and gene control, also the genetic information in some viruses |
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| Nucleotides |
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| a component of a nucleic acid consisting of a carbohydrate molecule, a phosphate group, and nitrogenous base |
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| nitrogenous bases |
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| any of five nitrogen-containing compounds found in nucleic acids, including adenine, guanine, cytosine, thymine, and uracil |
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| RNA nitrogenous bases |
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| adenine, guanine, and cytosine are present but uracil (U) replaces thymine (T) |
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| DNA nitrogenous bases |
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| purine bases are Adenine (A) and guanine (G), while pyramidine bases are cytosine (C) and thymine (T); |
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| Polynucleotide |
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| a chain of linked nucleotides |
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| James Watson, Francis Crick, Rosalind Franklin, Maurice Wilkins |
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| 1953 published papers describing how a complete DNA molecule consists of 2 polynucleotide strands opposed to each other in a ladder-like arrangement -Guanine and Cytosine line up opposite one another, and thymine and adenine opposite each other, they are held together by hydrogen bonds, |
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| DNA Double Helix |
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| the structure of DNA, in which two complementary strands are connected by hydrogen bonds b/w complementary nitrogenous bases and wound in opposing spirals |
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| Genes |
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| a segment of a DNA molecule that provides the biochemical information for a polypeptide or for a functioning RNA molecule |
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| Chromosomes |
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| A DNA molecule containing the hereditary information in the form of genes |
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| RNA |
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| single stranded polynucleotides, intermediaries, involved in carrying gene information or as structural molecules needed to construct proteins -in viruses, it is the genetic information playing roles in regulating gene activity, |
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| Adenosine Triphosphate (ATP) |
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| a molecule in cells that provides most of the energy for metabolism |
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| Proteins |
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| a chain or chains of linked amino acids used as a structural material or enzyme in living cells |
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| Amino Acids |
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| an organic acid containing one or more amino groups; the monomers that build proteins in all living cells -center of each is a carbon atom attached to 2 functional groups: an amino group (-NH2) and a carboxyl group (-COOH) and is linked to them by dehydration synthesis reactions |
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| R Group |
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| the side chain on an amino acid that helps determine the final shape and function of a protein |
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| Polypeptide |
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| a chain of linked amino acids |
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| Peptide Bond |
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| A linkage between the amino group on one amino acids and the carboxyl group on another amino acids |
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| Nitrogen Fixation |
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| the chemical process by which microorganisms convert nitrogen gas (N2) to nitrogen-containing substances in soil and living organisms, then reconverted to the gas |
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| Primary Structure |
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| the sequence of amino acids is in a polypeptide |
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| Alpha Helix |
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| the spiral structure of a polypeptide consisting of amino acids stabilized by hydrogen bonds |
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| Secondary Structure |
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| the region of a polypeptide folded into an alpha helix or pleated sheet |
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| Pleated Sheet |
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| the zig-zag secondary structure of a polypeptide in a flat plane |
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| Tertiary Structure |
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| the folding of a polypeptide back on itself |
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| Disulfid Bridges |
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| A covalent bond b/w sulfur-containing R groups in amino acids |
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| Denaturation |
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| a process caused by heat or pH in which proteins lose their function due to changes in their 3D structure |
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| Quaternary Structure |
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| the association of two or more polypeptides in a protein |
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| Atoms |
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| made of a nucleus containing protons and neutrons surrounded by a negatively charged cloud of electrons |
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| Hydrogen Bonding |
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| the electrostatic attraction between a partially positive hydrogen atom that is covalently bonded to a partially negatively polar molecule |
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| Hydroxyl |
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| -OH -O-H |
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| Carboxyl |
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| -COOH O ll -C-OH |
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| Carbonyl |
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| -CO- O ll -C- |
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| Amino |
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| -NH2 H l -N-H |
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| Sulfhydryl |
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| -SH -S-H |
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| Phosphate |
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| -H2PO4 OH l -O-P=O l OH |
