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
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