Nucleic Acids DNA vs. RNA

Chapter 12-3

Nucleic Acids

There are 2 types of nucleic acids.

DNA

RNA

All living organisms have both DNA and RNA.

Nucleic acids are made of nucleotides.

They carry genetic information.

DNA vs. RNA DNA

Deoxyribonucleic acid

Double-stranded

Sugar = deoxyribose

Nucleotide Bases:

Adenine

Thymine

Guanine

Cytosine

RNA

Ribonucleic acid

Single-stranded

Sugar = ribose

Nucleotide Bases:

Adenine

Uracil

Guanine

Cytosine

DNA

DNA Nitrogen Bases

G bonds to C

A bonds to T

G and A are purines

C and T are pyrimidines

DNA Nucleotide Structure

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DNA Double Helix

2 strands wrapped around each other

Strands are twisted because of the bonding of pyrimidines to purines

DNA

Double Helix

Strands are oriented in opposite directions

3’ to 5’ OR 5’ to 3’

Function of DNA

DNA can be copied, but that does NOT explain how a gene works.

DNA contains coded instructions for making proteins.

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

RNA

RNA Nucleotide Structure

Ribose

RNA Single Helix

1 twisted strand

3 Types

mRNA — Messenger RNA

tRNA — Transfer RNA

rRNA — Ribosomal RNA

Functions of RNA

In most cells RNA molecules have just one job — protein synthesis.

All 3 types of RNA are involved in protein synthesis.

Amino acids are the building blocks of proteins.

The assembly of amino acids is controlled by RNA.

mRNA

Messenger RNA serve as messengers from DNA to the rest of the cell.

They carry copies of the instructions found on genes.

tRNA tRNA takes the

messages from mRNA and decodes them for the ribosome.

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

rRNA Proteins are assembled on

ribosomes.

Ribosomes are made up of ribosomal RNA.

Ribosomal RNA helps build the actual protein.

rRNA puts together the amino acid messages carried by mRNA and decoded by tRNA.

DNA vs. RNA Venn Diagram

DNA RNA Both