Regents Biology 2006-2007

Nucleic acids: Information molecules

Regents Biology

Nucleic Acids Examples

u DNA § DeoxyriboNucleic

Acid

u RNA § RiboNucleic Acid

RNA

Regents Biology

DNA

Nucleic Acids § Function:

u genetic material § stores information

w genes w blueprint for building proteins

n  DNA → RNA → proteins § transfers information

w blueprint for new cells w blueprint for next generation

proteins

Regents Biology

A A

A

A

T C

G

C G

T G

C T

Genes (DNA) are needed

to run bodies every day… to make you and me… to make new cells…

to make babies!

Regents Biology

Nucleic acids

§ Building block = nucleotides

u  5 different nucleotides u  different nitrogen bases u  A, T, C, G, U

nucleotide – nucleotide – nucleotide – nucleotide

phosphate

sugar N base

Nitrogen bases I’m the

A,T,C,G or U part!

Regents Biology

Nucleotide chains § Nucleic acids

u nucleotides chained into a polymer § DNA

w double-sided w double helix w A, C, G, T

§ RNA w single-sided w A, C, G, U

phosphate

sugar N base

phosphate

sugar N base

phosphate

sugar N base

phosphate

sugar N base

strong bonds

RNA

Regents Biology

DNA § Double strand twists into a double helix

u weak hydrogen bonds between nitrogen bases join the 2 strands § A pairs with T w A :: T

§ C pairs with G w C :: G

u  the two strands can separate when our cells need to make copies of it

weak bonds

Regents Biology

Copying DNA § Replication

u copy DNA u 2 strands of DNA helix are

complementary §  they are matching §  have one, can build other §  have one, can rebuild the whole

Regents Biology

§ Copying DNA u pairing of the bases

allows each strand to serve as a pattern for a new strand

Newly copied strands of DNA

DNA replication

Regents Biology

Watson and Crick … and others… 1953 | 1962

Regents Biology

HELIXHELIX

Let’s build some DNA!