The Art of Explanation

Hi all,

On Friday, we looked at unpacking, a strategy to maximize the depth of explanation in a short response.  This works best when you see the command term explain on your IB exams.  The goal is to give a lot of depth at the molecular and cellular level about what's going on.  To use this strategy on a short answer:

1. Identify key concepts the question is asking about.
2. Unpack those concepts by brainstorming everything we learned in connection with them.
3. Draw a model of what's happening at the cellular or molecular level.
4. Repack your explanation into a few concise, deep sentences explaining the phenomenon.

For example, in the prompt "Explain the necessity of enzymes in digestion"

I would "unpack" the terms enzyme (biological catalyst, lowers activation energy, speeds up reactions, breaks down bigger molecules into smaller molecules, acts on a substrate, examples are amylase, pepsin, lipase) and digestion (break down of big molecules like polysaccharides, polypeptides, and fatty acids into smaller molecules, absorption into blood stream, smaller molecules diffuse into cells, where they can be respired).  I can use this information to now answer the question in greater depth.

For homework:

"Repack" the examples we looked at in class, writing your deep explanations.  This will go in as a take home quiz grade, so do a good, thorough job.  If you are missing the sheet, the questions are:

1. Explain, with an example, the necessity of enzymes in digestion.
2. Explain the effect of pH on enzyme activity.
3. Explain why the rate of glucose uptake by facilitated diffusion (on the DBQ) levels off after an external concentration of 450.
4. Explain the importance of the tertiary structure of proteins to membrane ion channels.

Below is the graph for #3 for those who may need it.  Thanks to Kai Ni for pointing this out!

On Monday, we're moving onto our next topic: cell respiration (whoo!)

Best,

Mr. Hill

Dee Bee Cue

Today we took a practice data based question, or DBQ.  These are by far the toughest IB questions!  But you all did quite well.  We came up with the following strategies for attacking a DBQ:

• Read the paragraph; circle the most important information.  
• Draw the situation to show what's going on if you're a visual person.
• The graph: check the key, label on each axis, title, and units.
• Read the graph with a ruler - and be precise.
• Draw on your knowledge from math to predict and calculate - you have the tools in your head.

Thanks to Genesis, Shaq, and Brian for recording that.

For homework

Complete the take-home DBQ, which will be put in as a 6 points quiz grade.  If you need the DBQ, you can download it here:

Take Home Enzyme DBQ (6 points) 

To complete it successfully, you will need to teach yourself about competitive inhibition.  Look it up in your text, google, or use this web animation:

Enzymes Inhibition Tutorial

Incidentally, you can also introduce inhibitors using the enzyme simulation we used in class (I posted this  two days ago for the curious.)

Best,

Mr. Hill

Take home quiz!

NOTE: PLEASE COMPLETE THE BRIEF POLL AT THE RIGHT.  


Today we reviewed the exam and went over strategies for constructed response questions.  Some pointers:

1. The number of points indicates how many "informational nuggets" you need to dish out.  [total 8 marks] means you need to provide at least 8 distinct pieces of information to get full credit.
   
2. You don't lose points for incorrect or irrelevant information - so it's better to hedge your bets and put as much information down as you reasonably can.
3. You have freedom to construct your response how you want - bullet points, a chart, a table, a diagram, or narrative prose can all be excellent ways to respond depending on the question and your strengths.
4. If you have the time, be elegant - because especially high-quality responses can earn you up to two extra "bonus points" that pull up your overall score or compensate for a lack of information.
   

A take-home quiz is the consummate gift to you: a chance to recoup or maximize your quiz grade and a chance to practice the art of the constructed response - all with ample time at your disposal so that you may put the maximum of effort into your endeavors.  If you don't get at least a 100%, it will be because of your laziness, not your intelligence or test taking skill.

So, your assignment for Tuesday is:

On unlined, white paper, hand write a constructed response to the following prompt:


     1.  Explain the various methods cells use to transport materials across membranes. (Total 8 marks)


You might look back at the lecture notes for cell transport (posted online), your class notes, and the textbook for resources.

Also, please remember that your DCP write-up for our osmosis lab is due Wednesday.  Late papers will not be accepted.

Thanks!

Practice identifying cell parts in micrographs

Boston University has an excellent catalog of electron micrographs that highlight the different cell parts.  This is great practice for you in identifying cell parts.  The site can be found here:

BU Histology Catalog

If you scroll down to where it says "know the structure, function, and location of:", it lists different organelles.  If you click on the arrow next to each organelle, it will take you to an annotated micrograph pointing out the organelle.  

Note that this resource comes from the BU medical school.  I hope that gives you an idea of the caliber of the IB program - we need doctoral program resources to tackle it!  This is good.


[Note - if you are looking for the pre-lab homework for lab#1, scroll down to the post for Friday, Oct 2]

Cell drawings for assessment statements

There was a question on the parking lot about what your cell diagrams should look like for assessment statements.  I found an exemplar to give you an idea:

Unlike the electron micrographs, you cannot simply cut and paste this in your notebook.  Rather, you should be able to draw and label a diagram of a generalized cell like this on the spot, from memory.  You may very well see a question on your exams that instructs you to do this.