VIRUSES lesson 4: Bacteriophages

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I decided to divide this lesson into (a) and (b), like I did with lesson 2.  Part (a) will introduce you to bacteriophages, as well as the infection process in general (the lytic and lysogenic cycles).   Part (b) will be a short biography of Felix d’Herelle, discover of phages, and some info about “phage therapy” where they are used to treat antibiotic-resistant bacterial infection.

The part(a) video [above] runs 55 minutes, with an optional intermission at the 25 minute mark)

LESSON 4(a)

Download and print this template page before you begin watching the video for part (a):

Virus lesson 4(a) template page

You might also want to print this info page for part (a).  It gives a written description of what we learn in this lesson.

Virus lesson 4(a) info page

If you need to see the final drawing, here is the one I did on camera:

Virus lesson 4(a) final sample

 

ACTIVITY IDEAS for part (a):

Activity 4.1:  Make a model of the T4 phage

Copy this pattern page onto card stock.  You will also need 3 chenille stems for the tail fibers.  (If you want to add whiskers, you can cut thin strips of paper and glue them on.)

Phage virus cut and assemble

 

LESSON 4(b):  A short biography of Felix d’Herelle

(runs about 27 minutes)   (Contains lots of bonus science facts!)

 

Instead of a template page for this video,  I have a word puzzle that you fill in as you watch. 

Print out this puzzle page and fill in the answers to the questions.  All the answers are given as you watch the video.  (Feel free to keep your finger on the pause button if you need time to write the answers.)  Then, when you have all the answers, you can use them to figure out the secret website address where I have posted an incredibly silly video of a phage talent show. 

Word puzzle for lesson 4b

 

Here are the phage characters you will see in the silly video.  (Don’t ruin your nice phage model!  Make a second if you want a silly one!)

 

 

 

 

 

 

 

 

 

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ACTIVITY IDEAS for part (b):

Activity 4.2:  Do a “Black Box” experiment

Sometimes scientists work with things that can’t see or touch or sense directly in any way.  They feel like they are working in the dark, so to speak, trying to figure out ways to get information without direct observation.  (D’Herelle couldn’t actually observe the phages.  He was blindly guessing as to what this mysterious bacteria killer might be.)  The “Black Box” experiment is a classic experiment, and you’ll find different versions of it online.  I typed up my own version using materials that you will be able to find around the house.  You can make this activity as easy or difficult as you want to.  You will probably be able to add your own ideas, also, and make it as difficult as you need it to be.

Black box experiment

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SUPPLEMENTAL VIDEOS for part (a):

 

Oh yeah, everyone’s favorite biology series… the Amoeba Sisters!  What a fun way to review the lytic and lysogenic cycles!

 

Here is how phages might look if you could shrink down to their size:

 

This video doesn’t have any sound.  It is intended to be a reference for professional scientists so they can see every single part of a T4 phage.  Each protein is labeled with a number.  How does it go together like this automatically?  When two proteins snap together, the act of snapping together makes a small change in the shape of the molecules which results in the creation of a new binding site for the next protein to latch onto.  When the correct protein floats by, it will be attracted to that binding site and snap in automatically.  (The shapes are very specific so only the correct protein will fit into the binding site.)  And then that new protein will create a new binding site for the next protein.  And so on.  It’s a continuous chain reaction of opening up binding sites for the next protein that is needed.  (NOTE:  Watch for that protein motor I talked about in the lesson video– you’ll see it stuffing DNA into the capsid!)

 

 

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SUPPLEMENTAL VIDEOS for part (b):

 

A short tribute to Felix d’Herelle, with some of his grandchildren being interviewed.

 

This man was saved by “phage therapy.”  It’s a happily-ever-after story and a great advertisement for getting our health care system more interesting in pursuing phage therapy on a large scale.  (See if you can spot Felix d’Herelle in the antique historical picture they show when the talk about phage therapy being used in the country of Georgia.  There he is in the picture!  He’s the one who brought the tech to several countries, including Georgia.)

 

 

Ready to take the quiz?  (Not required)

(If the online quiz isn’t working, try turning off your ad blocker.  I’ve heard that can fix the problem.)

If you need a printed copy of the quiz, here is a PDF you can download and print.  The PDF gives you both the quiz and the answer key.

Virology quiz lesson 4

 

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