Nucleic AcidsNucleic AcidsDNA vs. RNADNA vs. RNA

Chapter 12-3Chapter 12-3

Nucleic AcidsNucleic Acids There are 2 types of nucleic acids.There are 2 types of nucleic acids.

DNA DNA RNARNA

All living organisms have both DNA All living organisms have both DNA and RNA.and RNA.

Nucleic acids are made of Nucleic acids are made of nucleotides.nucleotides.

They carry genetic information.They carry genetic information.

DNA vs. RNA DNA vs. RNA DNADNA

Deoxyribonucleic Deoxyribonucleic acidacid

Double-strandedDouble-stranded Sugar = deoxyriboseSugar = deoxyribose Nucleotide Bases:Nucleotide Bases:

AdenineAdenine ThymineThymine GuanineGuanine CytosineCytosine

RNARNA Ribonucleic acidRibonucleic acid Single-strandedSingle-stranded Sugar = riboseSugar = ribose Nucleotide Bases:Nucleotide Bases:

AdenineAdenine UracilUracil GuanineGuanine CytosineCytosine

DNADNA

DNA Nitrogen BasesDNA Nitrogen Bases G bonds to G bonds to

CC A bonds to A bonds to

TT

G and A are G and A are purinespurines

C and T are C and T are pyrimidinespyrimidines

DNA Nucleotide StructureDNA Nucleotide Structure

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DNADNADouble HelixDouble Helix2 strands 2 strands wrapped around wrapped around each othereach otherStrands are Strands are twisted because twisted because of the bonding of the bonding of pyrimidines of pyrimidines to purinesto purines

DNADNADouble HelixDouble Helix

Strands Strands are are oriented in oriented in opposite opposite directions directions

3’ to 5’ OR 3’ to 5’ OR 5’ to 3’ 5’ to 3’

Function of DNAFunction of DNA DNA can be copied, but that does NOT DNA can be copied, but that does NOT

explain how a explain how a genegene works. works. DNA contains coded DNA contains coded

instructions for making instructions for making proteins.proteins.

The first step of making proteins is The first step of making proteins is decoding the genetic messagesdecoding the genetic messages by by copyingcopying the nucleotide sequence from the nucleotide sequence from DNA into RNA.DNA into RNA.

RNARNA

RNA Nucleotide StructureRNA Nucleotide Structure

Ribose

RNARNASingle HelixSingle Helix1 twisted strand1 twisted strand3 Types3 Types

mRNA — mRNA — Messenger RNAMessenger RNA

tRNA — tRNA — Transfer RNATransfer RNA

rRNA — rRNA — Ribosomal RNARibosomal RNA

Functions of RNAFunctions of RNA In most cells RNA molecules have In most cells RNA molecules have

just one job — just one job — protein synthesisprotein synthesis.. All 3 types of RNA are involved in All 3 types of RNA are involved in

protein synthesis.protein synthesis. Amino acids are the building blocks Amino acids are the building blocks

of proteins.of proteins. The assembly of amino acids is The assembly of amino acids is

controlled by RNA.controlled by RNA.

mRNAmRNA Messenger RNA serve Messenger RNA serve

as messengers from as messengers from DNA to the rest of the DNA to the rest of the cell. cell.

They They carrycarry copies of copies of the the instructionsinstructions found found on genes. on genes.

tRNAtRNA tRNA takes the tRNA takes the

messages from mRNA messages from mRNA and and decodesdecodes them them for the ribosome. for the ribosome.

During the During the construction of a construction of a protein, transfer RNA protein, transfer RNA transferstransfers each each amino acid to the amino acid to the ribosome.ribosome.

rRNArRNA Proteins are assembled on Proteins are assembled on

ribosomes.ribosomes. RibosomesRibosomes are made up of are made up of

ribosomal RNAribosomal RNA.. Ribosomal RNA helps Ribosomal RNA helps buildbuild

the actual protein. the actual protein. rRNA puts together the amino rRNA puts together the amino

acid messages carried by acid messages carried by mRNA and decoded by tRNA.mRNA and decoded by tRNA.

DNA vs. RNA DNA vs. RNA Venn DiagramVenn Diagram

DNA RNABoth