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47 terms

microbiology chapter 2

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isotopes
atoms with different numbers of neutrons in their nuclei
ionic bond
an attraction between ions of opposite charge that holds them together to form a stable molecule
covalent bond
a chemical bond formed by two atoms sharing one or more pairs of electrons
hydrogen bond
bond in which a hydrogen atoms is covalently bonded to one oxygen or nitrogen atom is attracted to another oxygen or nitrogen atom
chemical reactions
involve making or breaking bonds between atoms
endergonic reaction
reactions that absorb more energy than they release
exergonic
reaction that releases more energy than it absorbs
synthesis reaction
when two or more atoms, ions, or molecules combine to form new and larger molecules
anabolism
synthesis reactions in living organisms
decomposition reaction
reaction when bonds are broken
catabolism
decomposition reactions in living organisms
inorganic compounds
small and simple, lack carbon, ionic bonds (oxygen, carbon dioxide, salts, acids and bases)
organic compounds
contain carbon and hydrogen, complex, covalent bonds, macromolecules
water
polar molecule; capable of forming four hydrogen bonds with nearby water molecules; excellent solvent; reactant or product in many chemical reactions, splitting and rejoining or hydrogen and hydroxide ions; excellent temperature buffer
acid
a substance that dissociates into one or more hydrogen ions and one or more negative ions (anions), hydrogen donor
base
dissociates into one or more positive ions (cations) plus one or more negatively charged hydroxide ions
salt
a substance that dissociates in water into cations and anions
functional groups
specific groups of atoms that are most commonly involved in chemical reactions and are responsible for most of the characteristic chemical properties and many of the physical properties of a particular organic compound
hydroxyl group
alcohols, hydrophilic, --OH
amino group
function as bases because they readily accept hydrogen ions
sulfhydryl group
helps stabilize the intricate structure of many proteins
carboxyl group
a source of hydrogen ions, molecules containing it have acidic properties
R
can be used to stand for the remainder of the molecule
dehydration synthesis or condensation reaction
hydrogen atom and hydroxyl group combine to produce water
carbohydrates
sugars and starches; functions: building block of DNA, cell walls, synthesis of amino acids and fats in cell membranes, food reserves, to fuel cell activities with a ready source of energy; made of CHO
isomers
two molecules with the same chemical formula but different structures and properties
hydrolysis
water is added and comlex molecules break down
polysaccharides
tens or hundreds of monosaccharides joined through dehydration synthesis; include: glycogen, cellulose, dextran, chitin, starch; broken down by amylase
lipids
nonpolar; insoluble in water; function in energy storage and provide the structure of membranes and some cell walls
simple lipids
fats or triglycerides; contain an glycerol and fatty acids; primary function is formation of plasma membranes that enclose cells
ester linkage
bond formed when glycerol attaches to fatty acid and water is removed
saturated
fatty acid that has no double bonds
unsaturated
fatty acids that hae double bonds; create kinks in the chian, which keep the chains apart from one another
complex lipids
contain elements such as phosphorus, nitrogen, and sulfer in addition to CHO
phospholipids
made up of glycerol, two fatty acids, and a phosphate group bonded to one of several organic groups; have polar heads and nonpolar tails; mycobacterium cell walls rich in complex lipids
steroids
four interconnected carbon rings; with and --OH group is called a sterol; sterols separate fatth acid chains
proteins
organic molecules that contain CHON, some also contain sulfur; 50% of cell's dry weight; functions: enzymes, transporter, bacteriocins, toxins, contraction and movement, structures, hormones, and antibodies
amino acids
building blocks of proteins; contain carboxyl group and one amino group;
stereoisomers
configurations of amino acids; designated by D and L; most are L; glucose occurs as D-glucose
peptide bonds
bonds between amino acids; dehydration synthesis
levels of protein structure
primary, secondary, tertiary and quaternary
denaturation
proteins unravel and lose characteristic shape and function
conjugated proteins
combinations of amino acids with other organic or inorganic components
deoxyribonucleic acid
the substance of which genes are made; made of sugar and phosphate backbone (double helix) and nitrogenous bases; A and G are purines, C and T/U are pyrimidines; G+C = 3 H bonds; A + T = 2 H bonds
ribonucleic acid
single helix; same as DNA except uracil instead of thymine; mRNA, rRNAand tRNA
nucleotides
adenine, cytosine, guanine, thymine and uracil
adenosine triphosphate
the principal energy carrying molecule of all cells and indespensable to the life of the cell; can be stored in every cell, where its potential energy is not released until needed; and adenosine unit (adenine and ribose) and three phosphate groups