GOOD Morning!

Classroom Expectations! The Big 3: Respectful Responsible Reliable No hats, No phones, raise hands

Classroom Procedures Your Name Your Name Your Name Your Name Your Name I do not accept “I Dont Know”, either take a guess or explain what you do know about the question

Chromosomes and DNA Replication Vocabulary, Notes, and Review

Cross out Thursday’s Mind Moo-ver Monday 1/11: Draw and label the 3 parts of a Nucleotide

Vocabulary Histone: Globular protein molecule around which DNA is tightly coiled in chromatin. Histone are positively charged DNA is negatively charged; phosphate groups give it a negative charge

Sentence DNA is tightly wrapped around proteins called ___________ in order form __________ in the nucleus.

Vocabulary Chromatin: Granular material visible within the nucleus; consists of DNA tightly coiled around proteins.

Sentence In the cell’s __________, DNA is wound around _________ to create ___________ in order to store DNA efficiently DNA wraps around the histone proteins to form nucleosomes; these in turn couple to become the chromatin fiber. 1. DNA 2. DNA wrapped around histone octamers to form nucleosomes 3. Nucleosomes compacted into a chromatin fiber

Replication: Copying process by which a cell duplicates its DNA. Vocabulary Replication: Copying process by which a cell duplicates its DNA. Semi-conservative: contains 1 parent strand and 1 new daughter strand

DNA is _________ in a process called _______________. Sentance DNA is _________ in a process called _______________.

Vocabulary DNA Polymerase: Enzyme that “proofreads” new DNA strands, helping to ensure that each molecule is a perfect copy of the original DNA. template strand is at the bottom, and consists of the bases A, C, C, T, G, A, C, G, and G (from left to right). A DNA polymerase is copying this template strand to form a complementary strand. So far the complementary bases T, G, G, A, and C have been added to the growing DNA chain.

Sentence In order to make sure that DNA is copied perfectly, an __________ called DNA ____________ is in charge of “_____________” new DNA strands.

NOTES Duplicating DNA Replication: the process used for copying a cell’s DNA before the cell divides A DNA molecule separates into two strands, then produces two new complementary strands using base pairing DNA replication is semiconservative because one original strand is used as a template to form a complementary strand and both become the new DNA double-helix

Notes Key items before understanding Replication: DNA is antiparallel DNA strands run opposite of eachother DNA can only be replicated 5’-3’ when replicated it will be going in opposite directions

Notes How Replication Occurs 1. An enzyme, called DNA polymerase, carries out DNA replication and “proof- reads” new strands for errors a. They “unzip” a molecule of DNA, breaking the hydrogen bonds, and strands unwind, serving as a template for complementary bases to attach Two identical DNA molecules are produced

NOTES steps: Helicase unwinds DNA forming a “replication fork” RNA Primer adds a complementary template strand to get started Leading strand: DNA Polymerase reads the template strand (3’-5’) and adds new complimentary nucleotides (5’-3’) Lagging Strand: (other strand), RNA Primer is added and new nucleotides are added (5’-3’) moving away from the replication fork, called Okazaki fragments RNA Primase adds the RNA primer leading strand is continous

Notes Steps (continued) DNA Ligase joins the Okazaki Fragments Helicase rewinds the different strands

Review How is DNA replicated? How is DNA “packaged” in the cell nucleus? What is the role of DNA Polymerase in DNA replication? How is DNA “packaged” in the cell nucleus? ¤ DNA molecule is wrapped around histone proteins, forming nucleosomes which then coil to form chromatin fibers and super coil to form chromosomes. How is DNA replicated? ¤ The DNA molecule separates into two strands, which each serve as a template for new, complementary strands to be made, following the rules of base pairing. What is the role of DNA Polymerase in DNA replication? ¤ It polymerizes individual nucleotides to produce DNA. In addition, it “proofreads” new strands to catch mistakes.