DNA Deoxyribonucleic Acid The Blueprint of Life I. DNA Structure & Function.

DNA Deoxyribonucleic Acid

“The Blueprint of Life”

I. DNA Structure & Function

A. What is DNA?

1. Organic molecule

2. Nucleic acid

B.Where is it

located?1. Nucleus2. Chromosomes

DNA

Chromosomes in Nucleus

C. Structure of DNA

1.Nucleotidesa. Phosphoric Acidb. Deoxyribose sugarc. Nitrogenous bases:

Adenine-ThymineGuanine-Cytosine

2. Ladder Shape 3. Double strand, helix

twist

Ladder Shape (Sides & Rungs)

Sides:Phosphoric AcidSugarPhosphoric Acid

Rungs:A-TT-AG-CC-G

SugarAcidSugarAcidSugar

T-AG-CC-GA-T

Watson & Crick’s Double helix:

D. What is DNA’s Function?

Hereditary InstructionsChemical code for every trait“Blueprint” for making Proteins

Chromosome DNA Code:

Genes =Segments of DNA Code for a trait

HairColor

EyeColor

DNA Chromosome Code:

Triplets=

Sets of 3 NucleotidesCode for

Trait

Acid AcidSugar-T-A-SugarAcid AcidSugar-G-C-SugarAcid AcidSugar-C-G-Sugar

DNA Chromosome Code:Like Morse Code: Hair =

*** *- ** *-*Or DNA

A-T

A-T

G-C

C-G

T-A

C-G

DNA ReplicationChromosomes doubleMitosisLate Interphase2n to 4n

2N

2N

E. Steps for DNA Replication:

1. DNA untwists2. DNA unzips3. Corresponding base pairs

Line upIn sets of 3

nucleotides (triplets)Or “codons”

4. DNA reforms 5. 2 strands twist into helix Identical

Strand

RNA Ribonucleic Acid“DNA messenger & taxi”

II. RNA Structure & Function

A. What is RNA?1.Organic

Molecule2.Nucleic Acid3.mRNA= messenger tRNA= transfer

B. Where is RNA located?

1.mRNA in nucleus & cytoplasm

2.tRNA only in cytoplasm

mRNA

mRNA

tRNA

B. What is RNA’s structure?

AcidSugar-BaseAcidSugar-BaseAcidSugar-BaseAcidSugar-Base

1.Nucleotides=a. Phosphoric Acidb. Ribose sugarc. Nitrogenous

Bases: Adenine-UracilGuanine-Cytocine

2. Single Strand3. No Twisted helix

Comparison of RNA & DNA:

AcidSugar-BaseAcidSugar-BaseAcidSugar-BaseAcidSugar-Base

Acid Acid

Sugar-Base-Sugar

Acid Acid

Sugar-Base-Sugar

Acid Acid

Sugar-Base-Sugar

Acid Acid

RNA DNA Ladder

Deoxy-riboseRibose

Uracil Thymine

D. What are RNA’s functions:

1.mRNA=Copies the DNA codeDeliveries message to RibosomeProtein Factories

Why not send the original DNA code out?

DNA might be damaged!mRNA components are reusedTo copy more messages

Original DNA

mRNA copy

RNA function cont.2. tRNA:

in cytoplasmPicks up an amino acid“Taxis” the aa to the Ribosome protein factories

tRNA

Aminoacid

III. Protein Synthesis

Assembling Proteins from the DNA Instructions

A. Transcription:

1.mRNA is copied off of DNA

2. In nucleus3.Steps:

DNA untwistsDNA unzipsRNA codons line up

Transcription:mRNA has:Ribose sugarUracil instead of thymine basesNuclear membrane allows it to leave!DNA Code

mRNAA

T

C

G

U

A

G

C

Transcription in The nucleus

mRNA copyDNA

B. Translation =Conversion of the message (mRNA Code)Into a proteinBy the ribosome factories

B.Translation

1.mRNA arrives at the Ribosome

2.tRNA picks up an amino acid

3.tRNA delivers the aa to the ribosome

4.aa are assembled into polypeptide proteins

U A G C

GC

U

A

mRNA code

tRNA taxi

• tRNA delivers

amino acid

2. Peptide bond forms

3. tRNA leaves ribosome

4. PolypeptideChain of aminoacids grows

Summary:

DNA Replication:Make duplicate DNAIn nucleusCopy the chromosomesFor Mitosis

Protein Synthesis:

1.Transcrition:Make mRNAFrom DNA

2.Translation:Make proteinOff mRNA codeUsing amino acids