BIO 121 Exam 1 Glycosidic Bonds

process of translation

gene is transcribed to pre-mRNA premRNA is processed to mature mRNA exits nucleus translated on ribosomes

aglycone

group attached to carbohydrate that is not another saccharide

resonance in amide groups

has 3 resonance forms

ribosome

have 2 subunits are where the mRNA is translated contains rRNA and ribosomal proteins

# of amino acids

50-100 is a polypeptide over 100 is a protein

sites on ribosome

A site and P site A = aminoacyl binding site P = peptidyl binding site

difference between alpha and beta glycosidic bonds

based on relative stereochemistry of anomeric position alpha has axial orientation beta has equatorial orientation

metasable

bonds that will break in presence of water

glycoside hydrolases

break glycosidic bonds. act on either alpha or beta

polypeptide

chains of aa held by peptide bonds (backbone of PNA)

speed of folding

conformational folding is faster than cis trans isomerization

peptide bond/link

covalent bond between 2 molecules carboxyl reacts with amine group create an "amide" or amino acid

glycosidic bond

covalent bond that joins carbohydrate with other molecule (amino group or other nitrogen-containing group) from between hemiacetal group of saccharide and hydroxyl group of another compound

ethyl glucoside

ethanol and glucose with an alpha glycosidic bond

glucuornidation

joining substance to glucuronic acid to increase solubility

mRNA components

leader, reading frame, and trailer sequence

peptidyl prolyl isomerases

naturally occurring enzymes that catalyze cis and trans isomerization of X Pro peptide bonds

O-glycosidic bond

oxygen links glycoside to aglycone or sugar

C-glycosol

oxygen replaced by carbon. more resistant to hydrolysis

reactivity of peptide bond

peptide bond is unreactive react by attack of electronegative atom on carbonyl carbon, breaking double bond, and forming tetrahedral intermediate

isomers of amide group

planar because of partial double bond cis or trans isomer equal in energy trans form is in most peptide bonds dihedral is 0 for cis isomer and 180 for trans isomer

tRNA

recognize codons bring amino acids to ribosome encoded by tRNA genes all similar in shape and size have CCA at 3 prime end to which amino acid attaches have anticodon on other end

adenosine

sugar ribose and adenine bonded by N-glycosidic bond (bonded to Nitrogen) glycosylamines

S-glycosidic bond

thioglycosides oxygen in glycosidic bond is replaced with sulfur

sugar nucleotides

when monosaccharides are joined by a glycosidic bond to the phosphate group of a nucleotide to be activated