Posted in P6 SBI3U Biology

6 SBI3U Cracking The Code of Life

The following documentary explores The Human Genome Project, which was the massive study done to sequence all of the DNA in the human genome – all a 3 billion base-pairs of one set of chromosomes.  Sometimes, like in Tay-Sachs, one mutation of one base-pair out of three billion can have devastating effects:

Tay-Sachs Case Study:  11:58-26:30

Taylor is a young woman now who is likely concerned if she is a carrier for Tay-Sachs or not.  Carriers are those who carry the gene for a trait but express the other trait.  In this case, H represents the working HEXA gene on chromosome 15, h represents the mutated non-functional HEXA gene on chromosome 15.  So if an individual has Tay-Sachs like Hayden and Camryn did, they had the hh combination.  Since Taylor does not have Tay-Sachs, she can’t be hh.  She could be HH or Hh (carrier).  What is the probability that she is a carrier?  To answer this question we have to go back to her conception event and look at the possibilities:

Capture 2018-10-18 01_55_15

If you were Taylor, you have some options now that you know it’s a 67% chance that you are a carrier for Tay-Sachs:
a) Choose to get yourself tested for this an many other genes, along with your ancestry for the low price of $249 plus tax.
b) Choose to not get tested and take your chances.
What are the risks and/or benefits to either choice?

Posted in P4 SNC2D Science

4 SNC2D Chemistry Test 2 Tuesday October 23


  • Law of Conservation of Mass
  • State symbols
  • Chemical Equations
  • Reaction Types
  • Acids, Bases & Indicators


  • multiple choice
  • equations problem solving like our practice quiz

Practice Questions

  1. For each skeleton equation below:
    a) Identify the reaction type: synthesis, decomposition, combustion, single displacement, double displacement, neutralization.  Note, if they fit into two categories then include both.
    b) Balance the equation
    c) Write the word equation above the skeleton equation.
    d) Above the word equation, identify the kind of particles each substance is made of.  Choose from: atoms, ions or molecules.
    practice rxs
  2. For each of the following:
    a) Identify the reaction type.
    b) Write the word equation.
    c) Write the balanced chemical equation with state symbols.

    i) A piece of nickel is placed into a solution of silver nitrate. A chemical reaction occurs and the mixture is filtered.  Silver metal remains caught in the filter while the solution of nickel (II) nitrate passes through into the flask below.

    ii) A sample of mercury (II) nitrate crystals are heated.  Nitrogen dioxide and oxygen gasses are formed and pure liquid mercury is left behind.

    iii) Crystals of tetraphosphorous decoxide are dropped into pure water.  They react to form a solution of phosphoric acid.

    iv) A solution of barium hydroxide is mixed with a solution of iron (III) sulfate.  The mixture is filtered.  Barium sulfate is insoluble so crystals of it are trapped in the filter while the solution of iron (III) hydroxide passes into the flask below.

    v) Methane is burned in oxygen from a Bunsen burner.  It’s a perfect combustion resulting in the production of carbon dioxide gas and water vapour.

    vi) A solution of aluminum hydroxide is mixed with sulfuric acid.  Heat is produced resulting in new water molecules floating around in the solution of aluminum sulfate.

    vii) Iron (II) chloride crystals are reacted with chlorine gas which turns them into crystals of iron (III) chloride.