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1. Label the components that make up the DNA.

2. Draw a box surrounding one nucleotide of the double helix and label this.

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All life on earth uses a chemical called DNA to carry its genetic code or blueprint. In this lesson we be examining the structure of this unique molecule.

By the way, can you make out what this is?

We study DNA for many reasons, e.g.,

its central importance to all life on Earth/ identifies organisms,

HowStuffWorks Videos "Solved: DNA Analysis"

medical benefits such as cures for diseases or risks for genetic diseases

http://www.redorbit.com/news/video/science/5/dna_testing_for_everyone/25395/index.html

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How is DNA similar to the Morse Code or any other secret codes?

How can we tell if organisms are related to each other and how organisms change over time?

D=Deoxyribo N=Nucleic A=Acid

Deoxyribonucleic Acid

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WHAT IS DNA?WHAT IS DNA? DNA DNA is often

called the blueprint of life..

In simple terms, DNA contains the instructions for making proteins within the cell.

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CHROMOSOMES AND DNA?CHROMOSOMES AND DNA?

Our genes are on our chromosomes.

Chromosomes are made up of a chemical called DNA.

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DNA is a very long polymer.

The basic shape is like a twisted ladder or zipper.

This is called a double helix.

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THE DOUBLE HELIX THE DOUBLE HELIX MOLECULEMOLECULE The DNA

double helix has two strands twisted together.

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DNA DOUBLE HELIXDNA DOUBLE HELIX

NitrogenousNitrogenousBase (A,T,G or C)Base (A,T,G or C)

““Steps of ladder”Steps of ladder”

““Rails of ladder”Rails of ladder”

Phosphate &Phosphate &Sugar BackboneSugar Backbone

WHAT MAKES UP WHAT MAKES UP THE STRAND THE STRAND (RAILS) OF DNA?(RAILS) OF DNA?

The backbone of the molecule is alternating phosphates and deoxyribose sugar

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phosphate

deoxyribose

bases

Cytosine C Thymine T

Adenine A Guanine G

THESE MAKE UP THE STEPS OF THE

LADDER!!!13

DNA has four different bases:

DNA is made up of repeating units called nucleotides

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nucleotide

WHAT MAKES UP THE DNA WHAT MAKES UP THE DNA NUCLEOTIDES?NUCLEOTIDES?

OO=P-O O

1.1. Phosphate Phosphate GroupGroup

N3.3. Nitrogenous base Nitrogenous base (A, G, C, or T)(A, G, C, or T)

CH2

O

C1C4

C3 C2

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2. 2. SugarSugar(deoxyribose)(deoxyribose)

A. Phosphate group

B. Deoxyribose sugar

C. Nitrogen base

A.

B.

C.

CHARGAFF’S RULE:CHARGAFF’S RULE:

DNA has specific pairing between DNA has specific pairing between the the nitrogen bases:nitrogen bases:

AdenineAdenine must pair with ThymineThymine

GuanineGuanine must pair with CytosineCytosine

Their amounts in a given DNA molecule will be about the sameabout the same.

G CT A

BASE-PAIRINGSBASE-PAIRINGS

CG

H-bonds

T A

TWO STRANDED DNATWO STRANDED DNA Remember, DNA has

two strands that fit together something like a zipper.

DNA was made of DNA was made of 22 long stands of long stands of nucleotides nucleotides arranged in a arranged in a specific way called specific way called the the “Complementary “Complementary Rule”Rule”

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GENETIC DIVERSITY…GENETIC DIVERSITY…

Different Different arrangements of arrangements of NUCLEOTIDESNUCLEOTIDES in a in a nucleic acid (DNA) nucleic acid (DNA) provides the key provides the key to to DIVERSITYDIVERSITY among living among living organisms.organisms.

THE CODE OF LIFE…THE CODE OF LIFE… The “code” of the chromosome is the The “code” of the chromosome is the

SPECIFIC ORDERSPECIFIC ORDER that bases occur. that bases occur.

A T C G T A T G C G G…A T C G T A T G C G G…

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1. Which of the following bases pairs with adenine in DNA?

a. Thymineb. Guaninec. Adenined. Cytosine

2. If the template of a strand of DNA is 5' AGATGCATC 3’ ,the complementary strand will be —

F 3' TCTACGTAG 5'G 5' CTACGTAGA 3'H 3' AGATGCATC 5'J 5' AGACGTCTA 3'

F Amount of adenineG Number of sugarsH Sequence of

nitrogen basesJ Strength of

hydrogen bonds

A. orders of nucleotidesB. types of sugar moleculesC. sized phosphate groupsD. types of nitrogenous bases

F. DNA provides the shape and structure of the nucleus.

G. DNA packages materials for transport through the nucleus.

H. DNA carries materials into and out of the nucleus.

J. DNA contains the blueprint for producing the whole organism.

Create a paper model of the double helix paying close

attention to the components that make up the nucleotides!