BIo 151 chapter 4

nucleic acid

polymer of nucleotide monomer

3 components

phosphate groups

five-carbon sugar

nitrogenous nase

RNA

Ribonucleotides are monomers of RNA

has ribose as its sugar

has an OH group bonded to its 2 carbon

DNA

Deoxyribonucleotides are monomers of DNA

sugar as doexyribose (doexy = no oxygen)

has H instead of 2 carbon

nitrogenous bases

purines- adenine, guanine

pyrimidines - cytosine, uracil, thymine

condesation reaction

nucleic acid poplymerixe with phospdiester linkage

phosodiester linkage

occurs between phosphate group of 5 carbon of 1 nucletide and OH group on the 3 carbon of another

forms sugar-phosphte backbone

one end 5 phosphate

one end 3 hydroxyl group

nucleic acid polymerization

take place in cells by use of enzymes

potential energy ids raised by 2 additional phosphate groups

creates nucleoside triphosphates “activated nucleotides”

reaction is spontaneous

DNA strands antiparrel

tertiary structure of DNA

3-dimensional

DNA wraps around DNA-binary proteins called hitones

DNA wound tightly or loosely twist to form supercoils

DNA replictaion

strands are seperated by breaking H bonds

free deoxyribonnucleoptides form H binds with complemenatry bases on orginal strand of DNA

complementary base

pairing allows each strand to be copied eactly producing 2 identical daughter molecules

DNA double helix

very stable

base stacking critical for polynucleotide strand stablilty

primary structure of RNA

single stranded most of the time

4 types of nirtegens bases and phosphate backbones

how RNA differs from DNA

contains ribose

contains uracil instead of thymine

2OH more reactive

less stable

RNA seconday structure

results from complementray bases

RNA strands fold over

antiparrel

bases on one part of RNA strand fold over and H bonds with bases on other part of the base

RNA teriary structure

fold into more complex shapes

more diverse in shape, size, and reactivity than DNA

RNA versatrility

folds into complex 3-dimensional shapes

structure flexabilty allows it to perforom many tasks

interminate DNA and proteins, mRNA transmits info

regulate production of mRNA and DNA

capable of catalyzing reactions

ribozymes

RNA catlyxes reactions

3-dimensional vital to catlytic activity

has active sites like protiens

RNA could repicate inself

abilty to catlyze pohophinister boinds