Chapter 1 - Molecules and Fundamentals of Biology Flashcards
Organic molecules contain what elements?
carbon, hydrogen, nitrogen, oxygen
Starch is a ____ polysaccharide in ____
storage; plants
Linear plant starch is called ____ and contains ____ bonds
amylose; alpha-1,4 glycosidic bonds
___ is a critical storage polysaccharide found in humans
glycogen
___ is the branched form of plant starch and forms ____ bonds
amylopectin; alpha 1,4 and alpha-1,6 glycosidic bonds
glycogen is mainly stores in:
liver and muscle cells
structural polysaccharide found in plant cell walls:
cellulose
cellulose contains what kind of bonds? what kind of structure results?
beta-1,4 bonds; linear strands that pack together in parallel, adjacent strands held together by H bonding
True or false: humans can digest cellulose
false: cannot digest cellulose, it passes through our digestive tracts as fiber
chitin is a _____ polysaccharide found in ____ cell walls and _____
structural; fungi cell walls; exoskeleton of insects
what kind of bonds does chitin have?
Beta-1,4 glycosidic bonds; however is a polymer of N-acetylglucosamine
True or false: chitin is a polymer of glucose molecules
false: made of N-acetylglucosamine molecules
proteome
all the proteins expressed in a cell under one set of conditions
at physiological pH, amino group in an amino acid is ____ and the carboxyl group is ____
protonated; deprotonated
unique enzymes called ____ ____ help peptide bond formation
peptidyl transferases (belong to broader class of enzymes called aminoacyl transferases)
primary structure
specific order of a peptide which is determined by DNA genes
secondary structure
folds that occur in polypeptide chain due to intermolecular interactions between atoms of the polypeptide backbone (not R group atoms)
two of the most common secondary protein structures
alpha helices; beta-pleated sheets
tertiary structure
3D structure of larger polypeptide chains which occurs due to R-group interactions
what R-group interactions can occur in tertiary structure?
- ionic bonding
- hydrogen bonding
- dipole-dipole interactions
- London dispersion forces
- hydrophobic interactions
- disulfide bonds between cysteines
True or false: tertiary structure interactions are usually not covalent
true; disulfide bonds are an exception to this
quaternary structure1
refers to large proteins that have multiple subunits which come together by the same general interactions used in creating tertiary structure
protein denaturation can occur by:
excess temperature, chemicals, pH changes, radiation
True or false: denatured proteins cannot fold back into their functional shapes
false: some can, which tells us that all of the information necessary for the folding of those proteins is contained directly within the amino acid sequence.
enzymes are:
globular (usually) protein catalysts that speed up specific forward and reverse reactions by lowering their activation energies
enzymes change the energy of:
the transition state
enzymes catalyze reactions by:
binding to reactant molecules called substrates
active site
location on enzymes where the substrate binds to
Because most enzymes are proteins, amino acids give the active site unique properties and ____ ___
substrate specificity
specificity constant
measures how efficient an enzyme is in converting substrate to product (high specificity constant means high efficiency)
true or false: some enzymes are not proteins
true: one example is ribozymes (RNA molecule capable of acting as enzyme)
cofactor
non-protein molecules that assist enzymes in the reactions they manipulate
coenzymes
organic cofactors (usually include things like vitamins)
inorganic cofactors
tend to be metal ions like Fe2+ or Mg2+