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Biochem
Exam 1 Prep
65
Other
Not Applicable
09/25/2006

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Term
what is biochemistry?
Definition
the study of the chemistry of biological molecules
Term
most biological molecules are composed of which elements?
Definition
C, H, N, O
Term
name the major components of a prokaryotic cell
Definition
cell wall, cell membrane, nucleoid, ribosomes, storage granules, cytosol, and flagella
Term
name the major components in a eukaryotic cell
Definition
extracellular matrix, cell membrane, nucleus, cytoskeleton, golgi apparatus, endoplasmic reticulum, lysosomes, peroxisomes, mitochondria
Term
what is the purpose of cell wall in plant cells
Definition
to withstand water pressure
Term
what makes water so special
Definition
structure: gives overall dipole moment; polar so it can H bond
Term
what are the effects of water's polarity?
Definition
cohesiveness due to H bonding, dipole moment influences intermolecular interactions (ie enzyme mechanisms, protein folding)
Term
equation for pH
Definition
pH = -log[H+]
Term
how do cells and organisms maintain pH?
Definition
by buffers such as phosphate, histidine, and bicarbonate
Term
why are strong acids/bases really bad buffers?
Definition
they dissociate completely in solution
Term
what is the typical buffer in living cells?
Definition
phosphate, because it has three protons tha can dissociate
Term
what is the henderson-has equation
Definition
pH = pka + log(A-/HA)
Term
how to make a buffer
Definition
1.choose buffer system w/pka close to pH
2. Use H-H to calc ration of Ha to A-
3. solve for HA in terms of A-
4. Solve for A-
Term
In the titration curve, what does
a) pka indicate
b) isoelectric point
Definition
a) proton deprotonated 50/50
b) completely deprotonated, or overall neutral charge
Term
is the lowest/highest pka proton deprotonated first?
Definition
the lowest pka
Term
are lipids soluble in nonpolar or polar solvents?
Definition
nonpolar
Term
how many carbons typically in fatty acid?
Definition
14-18 (even #)
Term
what is the structure of a TAG
Definition
three fatty acid chains esterified to a glycerol
Term
are TAGs a good source of E? why/why not?
Definition
yes, because righ source of reduced C's
Term
what is the most common lipid in biological membranes
Definition
glycerophospholipids
Term
what is the structure of glycerophospholipids?
Definition
2 fatty acids chains and one phosphate group
Term
what is phosphatidic acid?
Definition
the simplest glycerophospholipid; parent for the generation of others
Term
in a glycerophospholipids, what is usually attached to C(1) and C(2)?
Definition
C(1): saturated fatty acid
C(2): unsaturated fatty acid
Term
strucutre of terpenes?
Definition
two or more isoprenes linked together
Term
is cholesterol in plants?
Definition
no
Term
why is cholesterol important?
Definition
it plays a huge role in animal cells and its an important component in lipid membranes
Term
how does a steroid work?
Definition
it goes right through the cell membrane and to the nucleus where it binds to DNA
Term
when do micelles form?
Definition
when the conc of lipids is above the CMC
Term
what are integral membrane proteins
Definition
polypeptide chain extends through the membrane; nonpolar aa's are in the membrane
Term
what are peripheral membrane proteins
Definition
polypeptide doesn't extend through the membrane; interacts with the surface of the membrane; hooks onto lipids and anchors it well
Term
lateral assymetry
Definition
along the membrane there are clusters:
1. lipid clustering
2. protein clusters
3. membrane rafts; cell puts everything it needs in one place (rich in proteins)
Term
transverse Asymmetry
Definition
more charged lipids are on one side
Term
are carbohydrates soluble in water?
Definition
yes
Term
what are the bonds called b/w carbohyrates?
Definition
glycosidic bonds
Term
An aldose with at least ___ carbons is chiral
Definition
three
Term
a ketose with at least ___ carbons is chiral
Definition
four
Term
can yeasts break down a beta linkage?
Definition
no; only bacteria can
Term
name some storage polysaccharides
Definition
1. starch: mix of amylose and amylopectin
2. glycogen: basically it is amylopectin
3. dextran: all linkages are branched
Term
name some structural polysaccharides
Definition
1. chitin: hooked by beta links
2. cellulose: H bonding is important
Term
what is the enzyme in saliva
Definition
alpha-amylose
Term
what is a nucleoside?
Definition
nitrogenous base bound to sugar
Term
what is a nucleotide?
Definition
phosphate bound to nucleoside
Term
what is more soluble, nitrogenous base or nucleoside?
Definition
nucleoside, because it is bonded to a sugar
Term
what is the 5' end?
what is the 3' end?
Definition
5': phosphate on the end
3': sugar on the end
Term
what is zwitterionic
Definition
equal pos/neg charges
Term
is the formation of peptide bond favorable or not?
Definition
energetically unfavorable
Term
at pH 7, does an acidic aa have a positive or negative net charge?
Definition
negative charge
Term
what is the 1 structure of proteins?
Definition
the linear sequence of aa's
Term
what is the 2 structure of proteins
Definition
folding of aa polymer into helices and sheets
Term
what is the 3 structure of proteins
Definition
complete folding of aa chain in 3D space
Term
what is the 4 structure of protein
Definition
interaction of multiple folded aa chains in 3D space
Term
what are the helix formers?
Definition
Ala, Glu, Phe, His, Ile, Leu, Met, Gln, Arg, Trp, Tyr
Term
what are the helix breakers?
Definition
Pro, Asn, Ser
Term
do beta turns promote the formation of anti-parallel sheets?
Definition
yes
Term
what does "alpha 2" refer to?
Definition
an oligomer homodimer
Term
what does "alpha beta" refer to?
Definition
oligomer heterodimer
Term
what does "alpha two beta two" refer to?
Definition
oligomer heterotetramer
Term
what is gel filtration chromatography based on?
Definition
molecular size; the larger molecules travel fasther bc the small beads get stuck in the beads' caves
Term
what is ion exchange chromatography based on?
Definition
charged proteins bind to beads and travel slower than the uncharged proteins
Term
what is affinity chromatography based on?
Definition
proteins bind to beads with specific reagent bound to them, and they are eluted by changing the pH or ionic strength
Term
Hydrophobic Chromatography
Definition
the greater amount of hydrophobicity, the stronger it sticks to the column
Term
what is electrophoresis
Definition
separates molecules based on migration in electric field (run from neg to pos)
Term
native PAGE electrophoresis
Definition
based on the amount of charge affected by molecular size; small protein passes through faster
Term
SDS PAGE electrophoresis
Definition
smaller proteins run faster because of SDS binding; based on molecular size
Term
Isoelectric focusing electrophoresis
Definition
proteins migrate based on charge; move until it hits another molecule with the same charge
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