D.N.A. Replication

Last Time Origin of Life - The three experiments - Electric Shock v Panspermia theories of origin DNA Structure - Deoxyribose sugar + Phosphate Group (Backbone) - Nitrogenous bases; C-G, A-T

Objective How DNA makes copies of itself via Replication! And a very quick quiz to make sure you’ve been paying attention

Why Does DNA Replicate? Each time a cell divides, the two resulting daughter cells must contain exactly the same genetic information, or DNA, as the parent cell…

DNA Replication …The process of copying DNA in a cell is known as “Replication” Figure 10.5 in Text The first step of DNA replication is the separation of the Nucleotide chains

Seperation The point at which the 2 DNA strands separate is known as the replication fork The chains are separated by an enzyme known as DNA Helicase Break H-bonds between the complementary base pairs, causing chains of DNA to separate Helicase

Replicating Next, enzymes known as DNA polymerase bind to the separate chains of DNA. DNA polymerase moves along the separated strands, it begins adding complementary nucleotides from the surrounding medium Nucleotides are joined to the new chains by covalent bonds between the P group and Deoxyribose sugars

Replication When replication is completed, two new exact copies of the original DNA are produced, and the cell is ready to undergo cell division!

Accuracy + Repair DNA replication is a very accurate procedure Approx. 1 error per every 10,000 nucleotides However, a change in the nucleotide sequence, called a mutation, can have serious effects in new cells More on this later However, there are repair enzymes working hard to make sure that these errors can be fixed

Journal Quiz!! Put Everything Away, only journals and writing utensil allowed on your desk

1. Write the complementary base-pairs to this sequence A T C A T G G T A C 2. What is the name of the enzyme that “unzips” the DNA double helix during replication? 3. What are the three parts of a nucleotide? (Hint: P, D, N) 4. What does D.N.A. stand for? 5. The theory that living organisms come from other living organisms is known as __________________

1. Write the complementary base-pairs to this sequence A T C A T G G T A C T A G T A C C A T G 2. What is the name of the enzyme that “unzips” the DNA double helix during replication? DNA Helicase 3. What are the three parts of a nucleotide? (Hint: P, D, N) Phosphate Group, Deoxyribose (5 Carbon Sugar), Nitrogenous base (Nitrogen containing base) 4. What does D.N.A. stand for? Deoxyribose Nucleic Acid 5. The theory that living organisms come from other living organisms is known as Biogenesis

Review Work on your Chapter 10.1 Review to the bell