All about DNA Structure Building Blocks and Replication

All about DNA Structure, Building Blocks, and Replication

DNA Structure-Review • • REVIEW! • Which type of organic molecule is DNA? • NUCLEIC ACID!! • DNA stands for DEOXYRIBONUCLEIC ACID Building Blocks of Nucleic Acids = • NUCLEOTIDES • Or subunits

DNA Structure- Nucleotides • Each nucleotide is made of 3 parts: 1. Sugar (Deoxyribose) 2. Phosphate 3. 1 of 4 Nitrogenous Bases: • • A = adenine T = thymine C = cytosine G = guanine 4. So which part of a nucleotide changes? ? • THE NITROGEN BASE!!!!! 5. So how many different nucleotides are there for DNA? • Four (4)

Label a nucleotide!

DNA Shape and Form • • DNA IS DOUBLE STRANDED STRANDS TWIST TO FORM DOUBLE- HELIX NITROGEN BASES BIND TOGETHER TO MAKE TWO STRANDS • A always binds with T • C always binds with G ****THIS IS CALLED THE BASE-PAIR RULE!**** Now, on your notesheet, fill in the COMPLEMENTARY strand using the BASE-PAIR rule!

Answer to Notesheet Practice

DNA Structure • • Let’s Practice Again! One strand of DNA has the sequence you see. What is the complimentary strand’s sequence? ? ? G-----C T -----A A -----T C-----G G-----C C-----G T -----A

Replication: The Video Clip • http: //www. youtube. com/watch#!v=z 685 FFqmrpo&feature=related

DNA Replication (Copying) • CLICK HERE FOR DEMO When does DNA need to be copied? ? • BEFORE any CELL DIVISION! • • DNA acts as a PATTERN or TEMPLATE to make copies of itself! Steps of DNA Replication: • First, two (2) strands are “unzipped” by enzymes • Second, other enzymes bring new subunits (nucleotides) to these separated strands • Each strand acts as a template to build a new DNA molecule • Third, you end up with 2 NEW identical double helices CLICK HERE FOR DEMO #2

DNA Replication Diagram Parent Strands New complimentary strands Free Floating Nucleotides

Replication Practice- Step 1 “Unzip” G-----C T -----A A -----T C-----G G-----C C-----G T -----A Enzymes UNZIP G G T A C G C C T C C A T G C G G A

Replication Practice- Step 2 Add Subunits using Base-Pair Rule G ----C T ----A A ----T C ----G G ----C C ----G T ----A G---- C T---- A A---- T C---- G G---- C C---- G T---- A

THE DNA RAP!!!! • http: //www. youtube. com/watch#!v=d 1 U Pf 7 l. Xe. O 8&feature=related