The Structure and Function of Macromolecules Flashcards
polymer
a long molecule consisting of many similar or identical building blocks linked by covalent bonds
monomers
small molecules; repeating units that serve as the building blocks of a polymer
condensation reaction / dehydration reaction
monomers are connected by a reaciton in which two molecules are covalently bonded to each other through loss of a water molecule
hydrolysis
monomers being broken by addition of water molecules; break with water; reverse of the dehydration reaction
carbohydrates
include sugars and the polymers of sugars; monosaccharides, disacchaarides, polysaccharides
classifying sugars
depending on the location of the carbonyl group (=C=O) -end: aldoses; middle: ketoses; size of the carbon skeleton: usually three to seven carbs long
glycosidic linkage
covalent bond formel between two monosaccharides by a dehydration reaction
glycogen
polysaccride; vertebrates store it mainly in liver and muscle cells
cellulose
polysaccharide; major component of the tough walls that enclose plant cells
alpha and beta glucose ring structures
differ in the placement of the hydroxyl group attached to the number 1 carbon
starch 1-4 linkage of alpha glucose monomers
cellulose: 1-4 linkage of beta glucose monomers
fat
Fat is constructed from two kinds of smaller molecules: glycerol and fatty acids. Glycerol is an alcohol with three carbons, each bearing a hydroxyl group. A fatty acid has a long carbon skeleton, usually 16 to 18 carbon atoms in length. At one end of the fatty acid is a carboxyl group. function: energy storage, cushions, isolation
phospholipid
Two fatty acids attached to glycerol.The third hydroxyl group of glycerol is joined to a phosphate group, which has a negative electrical charge. Additional small molecules, usually charged or polar, can be linked to the phosphate group to form a variety of phospholipids. hydrophilic heads, hydrophobic tails
steroids
lipids characterized by a caron skeleton consisting of four rings
cholesterol
steroid, is a common component of animal cell membranes and is also the precursor from which other steroids are synthesized
proteins
speed up chemical reactions, structual support, storage, transport, cellular communication, movement, defense against foreign substances
enzymes
regulate metabolism by acting as catalysts, chemical agents that selectively speed up chemical reactions in the cell without being consumed by the reaction
enzymatic proteins
selective acceleration of chemical reactions
structual proteins
support
storage proteins
storage of amino acids
transport proteins
transport other substances
hormonal proteins
coordination of an organism’s activities
receptor proteins
response of cell to chemical stimuli
contractile and motor proteins
movement
defense proteins
protection against disease
polypeptides
polymers constructed from the same set of 20 amino acids. a protein consists of one or more polypeptides
amino acid
At the center of the amino acid is an asymmetric carbon atom called the alpha carbon. It’s four different partners are an amino group, a carboxyl group, a hydrogen group and a variable group symbolized by R.
peptide bond
covalent bond; When two amino acids are positioned so that the carboxyl group of one is adjacent to the amino group of the other, an enzyme can cause them to join by catalyzing a dehydration reaction, with the removal of a water molecule. amino end = N- terminus; carboxyl end = C- terminus; polypeptide backbone
Frederick Sanger
pioneer in determining the amino acid sequence in proteins; approach: using protein- digesting enzymes and other catalysts that break polypeptides at specific places rather than completely hydrolyzing the chains to amino acids.
primary structure
unique sequence of amino acids of a protein
secondary structure
coils and folds (result of hydrogen bonds between the repeating constitutes of the polypeptide backbone) alpha helix: delicate coil held together by hydrogen bonding between every fourth amino acid; beta pleated sheet: two or more regions of the polypeptide chain lying side by side are connected by hydrogen bonds between parts of the two parallel polypeptide
tertiary structure
overall shape of a polypeptide resulting from interactions between the side chains (R groups) of the various amino acids; hydrophobic interactions: As a polypeptide fold into its functional conformation, amino acids with hydrophobic side chains usually end up in clusters at the core of the protein, out of contact with water. (exclude nonpolar substances). disulfide bridges: form where two cysteine monomers, amino acids with sulfhydryl groups (-SH) on their side chains, are brought close together by the folding of the protein.
quaternary structure
the overall protein structure that results from the aggregation of these polypeptide subunits
denaturation
If the pH, salt concentration, temperature, or other aspects of its environment are altered, the protein may unravel and lose its native conformation, a change called denaturation. It returns to its functional shape when the denaturating agent is removed.
chaperonins (also called chaperone proteins)
protein molecules that assist the proper folding of other proteins, keep the new polypeptide segregated from bad influences PROCESS two proteins: one protein is a hollow cylinder, the othe is a cap that can fit on either end. 1.) an unfolded polypeptide enters the cylinder from one end 2.) the cap attaches, causing the cylinder to change shape in such a way that it creates a hydrophilic environment for the folding of the polypeptide 3.) cap comes off, and the prperly folded protein is released
X-ray crystallography
an important method used to determine a protein’s 3D -structure. an X-ray beam through the crystallized protein; the diffracted X-ray expose photographic film, producing a pattern of spots known as X-ray diffraction pattern; examine amino acid sequence and 3D computer model
nucleotide
3parts: nitrogenbase, pentose, phosphate group; without phosphate group it’s called a nucleoside
pyrimide
nitrogen base, has a six-membered ring of carbon and nitrogen atoms, examples: cytosine, thymine, uracil
purines
nitrogen bases; larger, with a six-membered ring fused to a five- membered ring, examples: adenine, guanine
Watson and Francis Crick
proposed the double helix as a three dimensional structure of the DNA in 1953
antiparallel
an arrangement, where two sugar-phosphate backbones run in opposite 5’ -> 3’ directions from each other
