3 What does DNA do? STORES AND PASSES ON GENETIC INFORMATION FROM ONE GENERATION TO ANOTHER. Scientists Hershey and Chase confirmed that DNA carries genetic information.
4 Where can we find DNA? 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 found in the cell s nucleus in the form of chromosomes.
5 DNA Structure DNA is too small to see, but under a microscope it looks like a twisted up ladder! Watson and Crick=scientists who are responsible for the idea that DNA forms a threedimensional double helix. Also stated that the strands are complimentary to each other, they fit together and are opposite of each other.
6 DNA Structure Composed of four types of nucleotides. Each nucleotide has three parts: Phosphate A phosphate group Deoxyribose sugar Nitrogen-containing base Only 4 types of nucleotides in DNA because there are 4 nitrogen bases Adenine, Thymine, Guanine, Cytosine. Deoxyribose sugar Nitrogenous Base
7 DNA Structure NITROGEN BASES: Held together by hydrogen bonds SUGARS, PHOSPHATES
8 Nitrogen Bases ADENINE = A GUANINE = G CYTOSINE = C THYMINE = T THEY ARE REPRESENTED BY THEIR CAPITAL LETTER.
9 Nitrogen Bases Single ring always pairs up with a double ring.
10 Chargaff's Base Pairing Rules Chargaff found that all organisms' DNA is made of Adenine, Thymine, Cytosine and Guanine. The only difference is the amount of each base in the organism. In each organism, the amount of adenine approximately equals thymine and the amount of cytosine roughly equals the amount of guanine.
11 Chargaff's Base Pairing Rules ADENINE PAIRS WITH THYMINE A-T GUANINE PAIRS WITH CYTOSINE C-G THIS IS THE ONLY WAY BASES PAIR UP TO FORM DNA!
12 Base Pairing Rules Example of a genetic code that maybe found in your body: AATGCTACATGTCAC TTACGATGTACAGTG
13 Base Pairing Rules Using the base pairing rules, pair up the nitrogen bases with the correct base: TATCCCGATGCGGTT
14 8.3 DNA Replication
15 What is DNA replication? DNA replication copies the genetic information of a cell.
16 WHEN does DNA replication happen? DNA is replicated during the synthesis stage of the cell cycle.
17 A single strand of DNA serves as a template for a new strand. Using a template ensures that the order of the bases is correct and DNA can be successfully replicated over and over again. Original DNA strand Template Template New Strand New Strand
18 Chargaff's base pairing rules apply during DNA replication. Adenine pairs with Thymine Cytosine pairs with Guanine
19 The DNA molecule replicates inside a cell nucleus so that each new cell receives a copy of the genetic material contained in the original parent cell. Parent 2 Daughter Cells
20 The result of replication is...two new strands of DNA!
21 How does DNA replication happen? Step 1: An enzyme called helicase, unzips the DNA molecule which breaks the hydrogen bonds that hold the base pairs together. When the bonds break and the bases separate, the template for the new DNA molecule is created.
22 How does DNA replication happen? Step 2: Free-floating nucleotides connect, one by one, with the bases on the template strands. DNA polymerases help the bases find their correct base pair, A's with T's and C's with G's, and binds them together.
23 How does DNA replication happen? End Result: Two new DNA molecules, each made up of one strand of the original DNA molecule along with a newly formed matching strand. DNA replication is called semiconservative because DNA molecule is made of one old strand and one complimentary new strand. Each new molecule is identical to the original molecule of DNA.