DNA

The fingerprint that’s inside your body!!!!!! DNA The fingerprint that’s inside your body!!!!!!

You can tell people apart by their fingerprints because everyone’s are a little bit different… DNA is like a fingerprint because everyone’s is a little different!

Fun DNA Facts! DNA is too small to see, but under a microscope it looks like a twisted up ladder! DNA stands for: D: Deoxyribose N: Nucleic A: Acid Every living thing has DNA. That means that you have something in common with a zebra, a tree, a mushroom and a beetle!!!!

DNA is packed tightly in the cell Learning Target: Describe the structure of a DNA molecule chromosome DNA double helix Supercoils histones

DNA is made up of steps and rails like a ladder. This is a rail/side This is a step/rung Green can only go with Red Purple can only go with Yellow

organic polymer made up of repeating nucleotides DNA Structure: organic polymer made up of repeating nucleotides Nucleotide H bonds Sugar-phosphate backbone Nitrogen Bases A T C G

Building blocks of DNA: Nucleotides

The sugar = Deoxyribose Shape = pentose The phosphate

The nitrogenous bases Purines

How are the pyrimidines different from the purines? The nitrogenous bases Pyrimidines How are the pyrimidines different from the purines?

Purines =(2 Carbon rings) Pyrimidines = (1 Carbon ring) A G C T

Four different Nucleotides BASIC STRUCTURE

DNA is a polymer formed by base pairing: Base pairing rule A pairs with T C pairs with G

PRACTICE BASE PAIRING __________________________________ A G T C C G T T A G T T C A G G C A A T C A

The Double Helix The overall shape of DNA is described as a double helix (a twisted ladder). What forces holds the two strands together? Covalent Bonds Hydrogen bonds

Who Discovered the DNA Structure? Watson and Crick – 1953 Model was a rope ladder that had been given a twist = double helix http://www.immediart.com/catalog/images/big_images/SPL_E_H400040-Watson_and_Crick_with_their_DNA_model-SPL.jpg

Where have we seen DNA being replicated? Cell cycle MITOSIS AND MEIOSIS

DNA Replication 1. DNA “unzips” Enzymes (helicases) break H bonds b/w nitrogen bases Forming a replication fork (where the 2 strands separate) 2. Free DNA nucleotides pair up along the nitrogen bases DNA polymerases (enzymes) make sure that the bases pair correctly 3. Bonds form Covalent bonds form b/w sugars and phosphates Hydrogen bonds form b/w nitrogen bases for both molecules

DNA Replication Result: 2 new exact copies of original DNA molecule/ happens b/4 mitosis See page 316 in book and animations

DNA Replication ANIMATION ANIMATION DETAILED

How are DNA and RNA similar? DNA is composed of nucleotides and RNA is composed of nucleotides

How are DNA and RNA different?

How are DNA and RNA different? Nucleotides = deoxyribose sugar Double helix structure Stays inside nucleus RNA… Nuleotides = ribose sugar Single-strand structure Located both inside and outside of nucleus Uracil instead of thymine (U instead of T)

Enzymes involved in DNA replication Helicase – opens the double helix to allow for replication DNA polymerase – reads the original DNA strand and lays down complementary bases Ligase - glues the newly formed DNA together

DNA replication practice You are DNA polymerase. Helicase has opened the DNA strand – read each side and produce the complementary copies. __________________________________ A G G T A A C C G G T T A C G A T T A T T C C A T T G G C C A A T G C T A A T A

PRACTICE BASE PAIRING RULES AGAIN __________________________________ A G T C C G T T A G T T C A G G C A A T C A

Protein Synthesis= transcription and translation DNA contains all the information for your traits – the genes These genes are blueprints and need to remain safe – kept inside the nucleus Copies can be made though – a messenger