A1.2 Nucleic Acids

How structure of DNA dictates directionality

Pentose sugar linked to phosphate in another nucleotide, so everything in polymer faces the same way.

Directionality of replication

Both strands are used as templates

5’ to 3’ assembly of new strand in opposite direction of the other strand being assembled

Directionality of transcription

Only one strand is needed as RNA template

RNA production can move in the same direction as transcription

directionality of translation

Ribosome that carries out translation moves along RNA molecule towards 3’ end

Structure of nucleosome

core of each are 8 histone proteins

DNA is wound around proteins twice

Additional histone protein reinforces binding of DNA, packaging of chromosomes when a nucleus is prepping to divide.

Describe the bonding of the sugar phosphate backbone

Phosphate of one nucleotide is covalently bonded to another’s sugar

Base and phosphate are covalently bonded to the sugar

Contrast DNA and RNA

2 polymers of nucleotide vs 1

Double helix vs single strand

ACTG vs ATUG

Deoxyribose vs ribose

significance of codons in the genetic code?

Codon = group of 3 bases (64 total)

Codons specify one amino acid, 1 says it should stop, 3 says it should stop

Describe the bonding of the sugar phosphate backbone

Phosphate of one nucleotide is covalently bonded to another’s sugar

Base and phosphate are covalently bonded to the sugar

Contrast DNA and RNA

2 polymers of nucleotide vs 1

Double helix vs single strand

ACTG vs ATUG

Deoxyribose vs ribose

significance of codons in the genetic code?

Codon = group of 3 bases (64 total)

Codons specify one amino acid, 1 says it should stop, 3 says it should stop

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