BIOLOGY 2.3
EMILY KINZLER
, NUCLEOTIDES
bio mols HOW DNA ORGANISED IN CELLS
!
phosphate esters of pentose sugars eukaryotes:
nitrogenous base linked to c1 of sugar residue majority of dna content in nucleus
phosphate linked to c5/c3 of sugar residue by cov bonds formed by condensation each large mol of dna tightly wound around histone proteins into chromosomes
reactions each chromosome = 1 mol of dna
form monomers of nucleic acids (DNA/RNA) loop of dna without histone proteins inside mitochondria + chloroplasts
in RNA nucleotide for pentose sugar is ribose prokaryotes:
in DNA nucleotide pentose sugar is deoxyribose dna in loop in cytoplasm
become phosphorylated nucleotides when contain more than 1 phosphate group not wound round histone proteins (naked)
(e.g. ADP + ATP) viruses:
ATP - adenosine triphosphate, energy rich end product of energy releasing loop of naked dna
biochemical pathways, used to drive energy requiring metabolic processes
nucleotides help regulate metabolic pathways e.g. by ATP/ADP/AMP
nucleotides can be a component of coenzymes
adenine nucleotides are a component of coenzyme NADP (nicotinamide adenine
dinucleotide phosphate), used in photosynth
adenine nucleotides also component of coenz NAD (nicotinamide adenine
ANTIPARALLEL SUGAR - PHOSPHATE BACKBONES
dinucleotide), used in resp antiparallel polynucleotide strands formed by sugar phosphate backbone
adenine nucleotides also in FAD + coenz a the 5 carbon end of mol us where the phosphate is attached to the 5th carbon atom of the deoxyribose sugar
the 3 carbon end is where the phosphate group is attached to the 3rd carbon atom of deoxyribose sugar
rungs of ladder are complementary base pairs joined by h bonds
mol stable + integrity of info protected
DNA IS A NUCLEID ACID
found in nucleus of eukarytoes
in cytoplasm of prokaryotes
DNA - DEOXYRIBONUCLEIC ACID
a macromolecule
STRUCTURE OF DNA
"
polymer of nucleotides
dna mol has 2 polynucleotide strands
2 strands are antiparallel - run in opposite directions
each nucleotide has phosphate group, 5 carbon sugar (deoxyribose) +
nitrogenous base (adenine/guanine/thymine/cytosine)
cov bond between sugar residue + phosphate group in nucleotide =
phosphodiester bond
phosphodiester bond broken when polynucleotides break down + form when
polynucleotides synthesised
dna mols are long so can carry lots of genetic info (coded) IMPORTANCE OF HYDROGEN BONDS
2 antiparallel strands joined by h bonds between nitrogenous bases
adenine pairs w thymine w/ 2 h bonds
guanine pairs w cytosine w/ 3 h bonds
purine always pairs w pyrimidine, giving equal sized “rungs” on the ladder which can
then twist into the double helix, giving mol stability
PURINES + PYRIMIDINES h bonds allow mol to unzip for transcription + replication
purine - adenine/guanine (2 rings)
pyrimidine - thymine/cytosine (1 ring)
EMILY KINZLER
, NUCLEOTIDES
bio mols HOW DNA ORGANISED IN CELLS
!
phosphate esters of pentose sugars eukaryotes:
nitrogenous base linked to c1 of sugar residue majority of dna content in nucleus
phosphate linked to c5/c3 of sugar residue by cov bonds formed by condensation each large mol of dna tightly wound around histone proteins into chromosomes
reactions each chromosome = 1 mol of dna
form monomers of nucleic acids (DNA/RNA) loop of dna without histone proteins inside mitochondria + chloroplasts
in RNA nucleotide for pentose sugar is ribose prokaryotes:
in DNA nucleotide pentose sugar is deoxyribose dna in loop in cytoplasm
become phosphorylated nucleotides when contain more than 1 phosphate group not wound round histone proteins (naked)
(e.g. ADP + ATP) viruses:
ATP - adenosine triphosphate, energy rich end product of energy releasing loop of naked dna
biochemical pathways, used to drive energy requiring metabolic processes
nucleotides help regulate metabolic pathways e.g. by ATP/ADP/AMP
nucleotides can be a component of coenzymes
adenine nucleotides are a component of coenzyme NADP (nicotinamide adenine
dinucleotide phosphate), used in photosynth
adenine nucleotides also component of coenz NAD (nicotinamide adenine
ANTIPARALLEL SUGAR - PHOSPHATE BACKBONES
dinucleotide), used in resp antiparallel polynucleotide strands formed by sugar phosphate backbone
adenine nucleotides also in FAD + coenz a the 5 carbon end of mol us where the phosphate is attached to the 5th carbon atom of the deoxyribose sugar
the 3 carbon end is where the phosphate group is attached to the 3rd carbon atom of deoxyribose sugar
rungs of ladder are complementary base pairs joined by h bonds
mol stable + integrity of info protected
DNA IS A NUCLEID ACID
found in nucleus of eukarytoes
in cytoplasm of prokaryotes
DNA - DEOXYRIBONUCLEIC ACID
a macromolecule
STRUCTURE OF DNA
"
polymer of nucleotides
dna mol has 2 polynucleotide strands
2 strands are antiparallel - run in opposite directions
each nucleotide has phosphate group, 5 carbon sugar (deoxyribose) +
nitrogenous base (adenine/guanine/thymine/cytosine)
cov bond between sugar residue + phosphate group in nucleotide =
phosphodiester bond
phosphodiester bond broken when polynucleotides break down + form when
polynucleotides synthesised
dna mols are long so can carry lots of genetic info (coded) IMPORTANCE OF HYDROGEN BONDS
2 antiparallel strands joined by h bonds between nitrogenous bases
adenine pairs w thymine w/ 2 h bonds
guanine pairs w cytosine w/ 3 h bonds
purine always pairs w pyrimidine, giving equal sized “rungs” on the ladder which can
then twist into the double helix, giving mol stability
PURINES + PYRIMIDINES h bonds allow mol to unzip for transcription + replication
purine - adenine/guanine (2 rings)
pyrimidine - thymine/cytosine (1 ring)
