genetics http://www.youtube.com/watch?v=B_PQ8qYtUL0

DNA Deoxyribonucleic acid Located in the nucleus Instructions for how to make proteins

Determined the shape/structure of DNA in 1953 Watson & Crick Determined the shape/structure of DNA in 1953

Rosalind Franklin X-ray Crystallography

Structure Scientists James Watson and Francis Crick developed a three dimensional model of DNA This model of DNA consisted of two strands which were wound around each other like a twisted ladder. This structure is known as a double helix

Every living thing has DNA. That means that you have something in common with a zebra, a tree, a mushroom and a beetle!!!!

Three critical things genes need to do: 1.) genes need to carry information from one generation to the next 2.) put that information to work by determining the heritable characteristics of organisms 3.) genes need to be easily copied

DNA is like a fingerprint because everyone’s is a little different! You can tell people apart by their fingerprints……… and their DNA! How would the police look at DNA to figure out who committed a crime?

PUT ON YOUR SCIENCE EYES!

Which statement reflects the correct relationship between the nucleus, the cell, chromosomes, and DNA? A. DNA is made of chromosomes that are contained inside the nucleus of a cell. C. DNA makes up the membrane surrounding a cell’s nucleus. B. A cell’s nucleus contains the chromosomes which are made of DNA. D. Chromosomes make up DNA that is contained outside the cell’s nucleus in the cytoplasm.

SO WHAT IS DNA? PLEASE COPY THIS CHART INTO YOUR NOTES NUCLEOTIDE 4 BASES DOUBLE HELIX

DNA stands for: D: Deoxyribose N: Nucleic A: Acid DNA is too small to see, but under a microscope it looks like a twisted up ladder!

What is DNA? DeoxyriboNucleic Acid A molecule of nucleic acids that carries genetic information. 2 strands twisted around each other called a “double helix” (twisted ladder) Each strand is made of linked nucleotides.

Made up of nucleotides – sugar phosphate nitrogen base Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

What is a Nucleotide? A subunit of DNA made of 3 parts: 5-carbon sugar (deoxyribose) phosphate group nitrogenous base (there are 4)

DRAW THIS NUCLEOTIDE

Structure of DNA Nucleotide Hydrogen bonds Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

The nucleotides are made up of: deoxyribose(sugar) phosphate group nitrogen bases-4 types 1. Adenine- A 2. Guanine-G 3. Cytosine- C 4. Thymine-T

WHAT ARE THE 4 BASES? Adenine Thymine Cytosine Guanine (A) (T) (C) (G) 5 WHAT ARE THE 4 BASES? Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

adenine deoxyribose PO4

What is the structure of DNA? The sides (backbone) are made of sugars and phosphates held together by a strong chemical bond. The rungs (steps) are paired nitrogenous bases held together by a weak hydrogen bond.

How are the Bases paired? Adenine pairs w/Thymine (A-T) Guanine always pairs w/Cytosine (G-C) This is called complementary pairing. They fit like puzzle pieces. Allows the DNA to be replicated (copied). G C A T

2-stranded DNA 9 PO4 PO4 PO4 PO4 PO4 PO4 PO4 PO4 PO4

14 THE DOUBLE HELIX bases sugar-phosphate chain

TIME TO MAKE A DNA MODEL!!!

Left Hand Assignment: DNA Structure Glue the DNA strand and use the following instructions to color the double helix. Write and answer the questions when you are finished DNA Structure Analysis The twisted ladder structure of DNA is called a ________________. The backbone of DNA is made up of _______________________. The ladder-like rungs of DNA are made up of _________________. Adenine always pairs up with __________. Cytosine always pairs up with _________________. A nucleotide is the basic building block of DNA. A nucleotide is made up of one ___________, one ________, and one___________. DNA Coloring Instructions Color the deoxyribose sugars green. Leave the phosphate groups white. Color the nitrogen base adenine orange. Color the nitrogen base thymine light blue. Color the nitrogen base cytosine red. Color the nitrogen base guanine yellow.