Nucleic Acid Structure DNA and RNA

Where are Nucleic Acids located? In the nucleus DNA stays RNA can leave Nucleus

DNA and RNA Structure DNA RNA Double Helix Nucleotide Strands Basic Building Block of DNA Composed of Sugar (Deoxyribose) Phosphate group Base (A, T, G or C) Single Strand Nucleotide strands Basic Building Blocks of RNA Composed of Sugar (Ribose) Phosphate group Base (A, U, G, or C

Create the appropriate nucleotides.

DNA and RNA Backbone Alternating sugar and phosphates

What are the bases? Purines Pyrimidines

Place your nucleotides in two piles: purines and pyrimidines. Which nucleotide are we missing? Why?

Which bases join together? DNA RNA A with T Purine with pyrimidine G with C How are they joined? Hydrogen Bonds These strands are complements! Allowing for DNA replication to take place. Remember  Single Strand RNA pairs with DNA A (DNA) with U (RNA) T (DNA) with A (RNA) G (DNA) with C (RNA) C (DNA) with G (RNA) How are they joined? Hydrogen Bonds

Line Up 5’ to 3’ Antiparallel

Create your DNA strand.

DNA Replication Why?

DNA Characteristics Double Helix Antiparallel? Base pairs? Antiparallel? 5’-3’ 3’-5’ Replication is semi-conservative?

Begin replication on your strand. What has to happen first?

DNA Replication Step 1 Double Helix needs to be unwound and unzipped Creates a replication bubble / fork DNA Helicase What is that? Creates a leading and lagging strand Leading – replication occurs continuously Lagging – occurs in fragments called Okazaki fragments

DNA Replication Step 2 Step 3 Step 4 How does replication know where to begin? RNA Primase Lays down a primer RNA – ribonucleic acid (both oxygens, uracil instead of thymine, single strand) Step 3 DNA Polymerase Lays down complementary base pairs 5’  3’ The replicated strand always starts from the phosphate end and replicates towards the sugar end. Continues until done Step 4 DNA Polymerase changes the RNA Primer to DNA

DNA Replication Step 5 What are we left with? Ligase comes in and fills the Okazaki fragment gaps. What are we left with? Why do we call it semi-conservative again?

Your Turn Create a flow chart of DNA Replication Start from the very beginning. Your sequence is 5’-TGCACGAATG-3’ Create a Double Helix using that sequence You have a template to trace from the picture handout I gave you When you unwind make sure you show the structure of each nucleotide Use the template from the picture handout I gave you. Make sure you show everything in detail of what is going on. Make sure you have an explanation of what is going on under each picture. Be neat and detailed. Due Tomorrow.