chapter 3- sec 1 what is dna? life science. dna what does dna stand for? deoxyribonucleic acid !!!...

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Chapter 3- Sec 1 What is DNA? Life Science

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Page 1: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

Chapter 3- Sec 1What is DNA?

Life Science

Page 2: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

DNA

What does DNA stand for? Deoxyribonucleic Acid !!! De/oxy/ribo/nucleic Acid

Deoxyribonucleic Acid, or DNA, is a code that contains information that an organism needs to grow and function.

Page 3: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

Discovering DNA In 1952, Rosalind Franklin discovered

that DNA is two chains of molecules in a spiral form.– Used X-Rays

Page 4: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

In 1953, James Watson and Francis Crick created an accurate model of DNA.– Model was similar to a ladder

The structure of DNA is similar to a twisted ladder.

Thieves?

Watson

Crick

Page 5: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

The structure of DNA is a similar to a twisted ladder

(double helix)…

Page 6: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

DNA Structure The structure of the “Ladder”…

The sides of the ladder are made up of Deoxyribose (sugar) and Phosphate.

The rungs (or steps) of the ladder are made up of nitrogen bases (ATCG).

Page 7: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

The steps of the ladder are made of pairs of smaller molecules called Nitrogen Bases.

These bases “fit together” in the combination:– Adenine fits with Thymine

– Cytosine fits with Guanine Connected by a Hydrogen bond

Page 8: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

A molecule of DNA is formed by millions of nucleotides joined together in a long chain

PO4

PO4

PO4

PO4

sugar-phosphate backbone

+ bases

Joined nucleotides 7

Page 9: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

What does ATCG stand for???

Page 10: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

DNA Replication When a cell divides, the DNA

“code” is copied (or duplicated) and passed to the new cells.

The DNA duplicates itself by unwinding and separating the bases forming 2 strands.

Page 11: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,
Page 13: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

DNA makes up chromosomes–Each chromosome is composed

of a long strand of DNA wrapped around.

Human Body cells have 46 chromosomes or 23 pairs.

<stop here>

Page 14: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,
Page 15: Chapter 3- Sec 1 What is DNA? Life Science. DNA  What does DNA stand for?  Deoxyribonucleic Acid !!!  De/oxy/ribo/nucleic Acid  Deoxyribonucleic Acid,

How many chromosomes are in other living things?

Toucan – 104

Goldfish – 94

Dogs – 78 chromosomes

Horse- 64

Banana- 22 chromosomes

Jack Jumper Ant- only 2 chromosomes!