4-1 introduction to dna

8/11/2019 4-1 Introduction to DNA

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List the various techniques used in DNA p

Describe the nature of DNA

Learning Objectives

Explain how DNA technology is usedin paternity and maternity testing

1

3

Summarize how DNA technologyhas facilitated police work

2

4


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DNA technology

Sex crimes Victim and perpetrator

Only perpetrator left alRape-murder

DNA technology Identify the perpetreven without witne


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Cell

DNA

Human body containsabout 60 trillion cells

60 000 000 000 000

Except red blood cells

Each cell has a nucleus


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In the nucleus

Genetic material

Weighs about 7 picograms

Chromosomes,

genes, DNA The Human Geno


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DNA

Cannotbe found directly at the crime scen

Blood, semen, saliva, skin cells,hair (sometimes) and body parts

Canfind biological materials that contain D


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Chromosome

different orga

In the nucleus

Humans

23 pairs of chromosomes


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Humans

23 pairs of chromosomes

22 pairs autosomal

2 sex determining chromosomes

Genetic inform

XY Male

XX Female


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Chromosomes

Different sizes & shapes

Chromoso


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Chromosomes

Staining withfluorescent dyes

Distinctive patterns of

bright & dark bands

ChromosoDifferent chromosomescontain different genes


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Pairs of chromosomes

Homologous

Same size

Contain same genetic structure

One from mother; one from father


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Genes

DNA material made up of codingand non-codingregions

Codingregions Genes

90 to 95% of DNon-codingregions

Junk DNA


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Genes

Number of genes in the genomevaries from species to species

Complex organisms More genes

Several 100s to 1000sBacteria

30 000Humans


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What are genes made of?

What is DNA made of?

Made of base pairs

A single gene

1000 to 10 000 base pairs


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Sugar

Ribose

2-deoxyribose

Ribose

2-deoxyribose


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2-deoxyribose A phosphate

of 2-deoxyrib

- H2O



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Phosphate ester Nucleotide

Base


Bases Attached to 2-deoxyribose


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Bases

4 bases

Heterocyclic

Nitrogen containing

Aromatic


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Bases

N

NNH

N

NH2

NH

NNH

N

O

NH2

N

NH

NH2

O

NH

NH

O

O

H3C

Adenine Guan

Cytosine Thym


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N

NN

N

NH2

O

O

O

NH

N

N

O

NH2N

O

O

O

N

NH2

ON

O

O

O

NH

O

O

H3C

N

OO

PO

O

P

P

O

O

O

O

O

PO

O

O

What is DNA?

4 nucleotides inpolymer chain

The phosphate

links the sugars

A

G

C

T


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What is a double helix?

DNA

Stable under normal conditions

Twochains wound together

Held in place by hydrogen bon


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Hydrogen bonds

H

O

H

H

OH

Makes water a liquid

Bases in DNA hydrogen bond together


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Complementary base pairing

A and T

C and G

A

G

N

NN

N

N

OHH

H

N

NN

N

O

N

H

N

H

H

H



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Paris japoni

Human DNA

3 billion base pairs

150 billion base pairs

Paris japonica



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Sequence of base pairs

Write the code with A, T, C and G

The genetic code


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-C-C-T-G-A-G-G-A-G-

Code for one amino a3 nucleotides

The genetic code

Part of code for a prote

Proline Glutamate


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Part of the gene for hemoglobin

The genetic code

Different amino ac

-proline-glutamate-glutamate-

One wrong letter

Different protein


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-proline-valine-glutamate-

The genetic code

-proline-glutamate-glutamate-

-C-C-T-G-A-G-G-A-G-

-C-C-T-G-T-G-G-A-G-

Disease Sickle cell anemia

4-1 introduction to dna

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