Biochemistry Unit 3

Stereoisomers

Atoms are connected in the same order but differ in spatial arrangement

Enantiomers

Nonsuperimposable mirror images

Diastereoisomers

Isomers that are not mirror images

Epimers

Differ at one of several asymmetric carbon atoms

Anomers

Isomers that differ at a new asymmetric carbon atoms formed on ring closure

alpha anomers

C6 and Ca point in opposite directions

beta anomers

C6 and Ca point in the same direction

Aldoses

D-Glyceraldehyde, D-Ribose, D-Glucose, D-Mannose, D-Galactose

Beta-D-Glucopyranose

most stable carbohydrate, every group larger than an H is equatorial

D-Glyceraldehyde

D-Ribose

D-Glucose

D-Mannose

D-Galactose

Ketoses

Dihydroxyacetone, D-Fructose

Dihydroxyacetone

D-Fructose

alpha-D-Fructofuranose

cyclic form of fructose

Reducing sugars

need to have a hemiacetal, beta-D-Glucopyranose, Lactose, Maltose (not sucrose), can do mutorotation

Disaccharides

two cyclic carbohydrates connected by a glycosidic bond

Sucrose

Glucose + Fructose (not a reducing sugar)

Lactose

Galactose + Glucose (reducing sugar)

Maltose

Glucose + Glucose (reducing sugar)

Glycosidic Bond

Hemiacetal + Alcohol -H2O → Acetal

Cellulose

structural polysaccharide with beta-1,4 linkages

Amylose

unbranched polysaccharide, Starch or Glycogen

Amylopectin

branched polysaccharide, Starch or Glycogen

Starch

coil/ helical shaped homopolymer of glucose with alpha-1,4 linkages, branched every 20-30 residues

Glycogen

coil/ helical shaped homopolymer of glucose with alpha-1,4 linkages, branched every 5-10 residues

Glycoproteins

amino acid residue connected to sugar, connected to acetyl group

N-linked GlcNAc

O-Linked GalNAc

Mutorotation

interconversion of the alpha and beta anomeric forms using the open chain structure as an intermediate

Types of Lipids

free fatty acids, triglycerides, phospholipids, glycolipids, sterols

Fatty Acid

long chain carboxylic acids

omega-3 fatty acid

double bond is on the third carbon, starting on omega carbon atom

Fatty acid nomenclature X:Y (Delta^Z)

X is the number of the carbons, Y is the number of double bonds, Z are the carbon(s) where double bonds are located.

Fatty Acid double bonds are all

cis orientation

Triglyceride

Glycerol backbone with three fatty acid chains, long term storage molecule

Phospholipid

Alcohol bonded to phosphate group bonded to glycerol bond to two fatty acids

Sphingolipids

Sphingosine and Sphingomyelin

Sphingosine

Sphingomyelin

found in myelin sheaths

Glycolipid

Sugar unit bonded to sphingosine backbone that is bonded to a fatty acid unit

ABO blood group antigens are

glycolipids

Sterols

cholesterol

Micelle

membrane structure with triangular cross-sections

Phospholipid Bilayer

membrane structure with rectangular cross sections, 30 A long

Transmembrane Proteins

polar aa resides get buried and nonpolar aa residues are near surface of protein

Membrane Associate Protein

nonpolar aa residues are buried and polar aa residues are near surface, interact with polar heads, any anchors would be nonpolar

Anti-Parallel Beta-Sheet Barrel Transmembrane Protein

nonpolar aa residues on outside face and polar aa residues inside

Transmembrane alpha helix proteins must be at least … nonpolar aa long

20

Lateral Diffusion

phospholipids on the same layer flip, rapid

Transverse Diffusion

phospholipids on opp layers flip, very slow

At high temps the membrane is much more..

fluid

Saturated fatty acids

no double bonds, low fluidity, behave like a solid when stacked

Unsaturated Fatty Acids

cis double bonds create a kink in the chain, greater membrane fluidity, lower melting temp

Cholesterol

OH group in near polar head, makes cell membranes more fluid and permeable in low temps

Active Transport

ATP allows movement against a concentration gradient

Passive Transport

no ATP needed, simple and channel/facilitated diffusion

Sodium Potassium Pump

Active Transport, 3 Na+ ount and 2 K+ in, ATP is converted to ADP

Coupled Transport

one concentration gradient is used to power the formation of another using secondary transporters, only made possible by active transport setting up a gradient first

Antiporter

secondary transporter where molecules move in opp directions

Symporter

secondary transporter where molecules move in same direction 

Ion Channels

passive transport, holes in the membrane that allow ion movement 1000 x faster than pumps

Potassium Channel

K+ behaves like a lewis acids and uses solvation bonds to pull itself through the channel. Na+ is much smaller than K+ and cannot make the strong bonds needed to pull itself through the channel

Secondary Messengers

Cyclic AMP, phosphate group bonded to ribose bonded to adenine or guanine

7TM Receptors

where the ligand/primary messenger binds on the membrane

Inactive Trimeric G alpha Protein

Bonded to 7TM receptor, GDP, and G beta protein

Active Trimeric G alpha protein

bonded to GTP and adenylate cyclase

Adenylate Cyclase

allosteric enzyme that converts ATP to cAMP

cAMP

binds PKA, release the regulatory pieces from the catalytic pieces so that the catalytic subunits can phosphorylate other proteins

to reset G alpha protein add

H2O

Phosphodiesterase

with water breaks down cAMP into AMP

this type of lipid contains glycerol

phospholipid

cerebroside belongs to which type of lipid

glycolipid

Palmitate

16 carbon saturated fatty acid

Oleic Acid

18 carbon unsaturated fatty acid with double bond at C9

Arachidonic Acid

20 carbon unsaturated fatty acid with double bonds a C5,8,11, and 14

Stearate

18 carbon saturated fatty acid