Chromosomes and DNA Replication DNA Deoxyribonucleic Acid O

Chromosomes and DNA Replication DNA = Deoxyribonucleic Acid

O. Looking at DNA from a strawberry. J. What was the best thing you did over your break? Reminders: Registration forms due: 12/6 to me. 12/6 is Final Exam Performance event 12/4 Quiz – no notes allowed Can no longer access Holt online – I will update you as soon as we know more

Understand the structure, function, and replication of DNA. J. Which scientist(s) determined the following from the experiment that they conducted. a. The transformation factor determined phenotypes b. Complementary base pairing rule c. DNA and not protein is the genetic material, used radioactively labeled sulfur and phosphorus for this d. Used enzymes and the transformation experiment to determine DNA was the genetic material

O. Understanding the role models play in understanding DNA structure. J. What type of organic molecule is DNA? What are the building blocks of DNA? What are the 3 components of the building blocks? What would it mean if phosphorus was replaced with arsenic? http: //www. cnn. com/2010/US/12/02/nasa. extr aterrestrial. life/index. html? iref=allsearch

O. Using models to understand the structure, function, and replication of DNA. J. Please take out your strawberry extraction lab and complete the post-lab questions.

O. By the end of the hour I will understand DNA replication and the roles of the enzymes involved. J. Describe what an enzyme is and what type of role they play in DNA replication.

• • • DNA stands for Deoxyribonucleic Acid It is a nucleic acid Found in the nucleus of eukaryotic cells, nucleoid region of prokaryotic cells • Role – DNA are the instructions for all of the traits in an organism. ex. Hair color, pigments is a leaf, enzymes that control digestion

Central Dogma DNA is made up of genes, which code for proteins.

DNA Structure • DNA is a long, double stranded molecule made up of smaller units called nucleotides

Nucleotide: building block or monomer for the nucleic acid

Nucleotide • Each Nucleotide has three parts – 1. a phosphate group – 2. a 5 carbon sugar called deoxyribose – 3. a nitrogen base: • Adenine • Guanine • Cytosine • thymine

Chromosomes and DNA • DNA is found in the nucleus organized into chromosomes

Eukaryotic chromosomes • Eukaryotic chromosomes contain both DNA and proteins • The proteins are called histones

Practice • DNA is a double stranded helix. If there was a string of bases that had the nucleotides sequence… ACCCTAGGAAATC What would the complementary strand be?

Duplicating DNA 1. DNA molecule is separated by the Helicase enzyme. • DNA Replication 2. DNA polymerase adds new nucleotides to the chain. Each strand of the double helix of DNA serves as a DNA Replication template, or model for the new strand. a. Adenine pairs with Thymine b. Guanine pairs with Cytosine

3. Ligase synthesizes Okazaki fragments. 4. The end: 2 new DNA strands are formed **DNA replication is semi-conservative.

Duplicating DNA • The DNA molecule separates into two strands. • Each strand acts as a template or model for the new strand • The bases pair complementarily

Enzymes Needed for Replication • Helicases – separate the DNA • DNA polymerases – add complementary nucleotides on to original strands and can repair the DNA if bases are joined incorrectly • DNA ligase – joins Okazaki fragments • Single-strand binding protein – holds DNA strands stable during replication • Primase – lays down and RNA primer to begin replication on the lagging strand