Science Elluminate Session

Wednesday February 20th, 2008

Science 9 Agenda

Deadlines and RemindersReviewQuestion Time

Science 9 - Deadlines & Reminders

This week: complete sections 1.3 and 1.4Week of February 25th: write module test or hand in projectWeek of March 3rd: complete section 2.1See the Grade 9 calendar for deadlines.OUR GOAL -- BE DONE BY JUNE 6th!!!

Science 9 -- Cell Review

Cell Parts and FunctionsPlant Cells vs. Animal CellsNucleus: procaryotic vs eukaryoticDNA, Genes, and Chromosomes

Science 9 - Making Proteins

DNA --> mRNA --> protein

DNA: made of nucleotides, double stranded, in nucleusmRNA: made of nucleotides, single stranded, in cytoplasmprotein: made of amino acids, made by ribosomes in cytoplasm

Use codon chart (pg 33) to determine what amino acid is coded by the mRNA.

Bottom Line: DNA is the genetic code; it determines what we are, who we are and what we are made of.

Science 9 - Cell Division

Cell Cycle:Cells spend most of their time growing.Before cells divide, all of the information in the DNA must be copied; this process is called mitosis.When the cell actually divides, this is called cytokinesis (cyto = cell)

Science 9 - Phases of the Cell CycleSimple mnemonic: I Put My Alligator Through College

I = Interphase -- the longest part of the cell cycle, cell growth and repair, organelles are duplicatedP = Prophase -- 1st stage of mitosisnuclear envelope dissolves, chromosomes condense and become visible, centrioles start moving to the poles, spindle fibres become visible and attach to chromosomesM = Metaphase -- 2nd stage of mitosisX-shaped chromosomes line up along the centre of the cellA = Anaphase -- 3rd stage of mitosischromosomes are pulled to opposite ends of the cellT = Telophase -- 4th stage of mitosisnuclear membrane forms around the two new nuclei, spindle disappear, chromosomes unwind and are no longer visible.C = Cytokinesis -- cell divides in half (animal cell pinches, plant cell, cell plate forms)

Science 9 -- Meiosis

Mitosis is a form of asexual reproduction where there is a single parent producing 2 identical offspring (cells).

Sexual Reproduction requires 2 parents and results in offspring that are not identical.

Sexual Reproduction involves sperm and eggs (ova). What would happen to the number of chromosomes if sperm and eggs were produced by mitosis?

Meiosis is the form of cell division used to produce eggs and sperm.

Science 9 - Question Time