March 30, 2015 Period 2 • Cell Reproduction Unit 2 Quiz – Mitosis Study Guide will be updated and available online by this evening. • Cell Reproduction Unit 2 Quiz – Mitosis is scheduled for Thursday, 4/2/15, but it will be on the fourth marking period. • Yes, you will be able to see your Quiz 1 from Friday, but I will be collecting it back until Wednesday. Happy Monday! • • • • • • Two sets of DNA Mitosis Chromatin Chromosomes Segregation is occurring Creating Proteins and structures necessary for segregation and cytokinesis. If these were the answers, what were the questions? Two sets of DNA How many sets of DNA are needed for cell division to occur? What genetic material is present after the S Phase of the cell cycle? Mitosis Which phase within the cell cycle includes the distribution of the chromosomes (the genetic material)? Chromatin What is a complex of DNA and proteins called? Possible Questions Chromosomes What is the genetic material within a cell called? How do we refer to DNA when it is occurring in pairs? Segregation is occurring What is happening during the first phase of cell division? Creating proteins and structures necessary for segregation and cytokinesis What is happening during the GAP 2 phase of the cell cycle? Possible Questions • During S phase? • What does DNA look like? • How does the cell ensure that the two copies of each chromosome stay together? • Distinguish between chromatin, chromosome, chromatids. Which ones are visible under the microscope? What Happens Before Mitosis? • During S phase? The DNA is being replicated so that at the end of the S Phase there are two complete sets of DNA • What does DNA look like? DNA is long, thin, thread-like DNA and contains associated proteins. • How does the cell ensure that the two copies of each chromosome stay together? During prophase of Mitosis the chromatin super coils and wraps around proteins called histones and becomes chromosomes. A protein disk called a centromere attaches the DNA and its exact copy together forming chromosome. • Distinguish between chromatin, chromosome, chromatids. Which ones are visible under the microscope? Chromatin is long, thin, thread-like DNA that is invisible under a light microscope. Chromosome is super coiled DNA wrapped around histones. When the DNA and its exact copy are super-coiled, the centromere attaches them together. Each half of the chromosome is now called a chromatid. Chromosomes and chromatids are both visible under light microscope. What happens before Mitosis?