Monday, April 28, 2008

Intro to Genetics

This week in Life Science, we will begin our unit on Genetics - the study of inheritance.

We will start off the unit by learning about cell division. Sound familiar?? If you recall, we first learned about cell division way back in the Bacteria and Viruses Unit when we discussed how bacteria reproduce through a process called binary fission. Cell division occurs in all living things, from uni to multicellular. Cell division enables unicellular organisms (like bacteria and protists) to reproduce, while helping multicellular organisms (like humans) to grow, develop and repair themselves.

Before a cell divides, it must first make sure that each daughter cell will be identical to itself - it does this by making a duplicate copy of its genetic material, DNA. DNA (short for deoxyribonucleic acid) is a chemical that contains all the information needed for an organism's growth and functioning. It is comprised of two strands of molecules that twist around one another, like a twisted ladder. The two strands are connected in the center by chemical rungs. We call this structure a double helix.

DNA is located within the nuclei of eukaryotic cells. Most of the time, DNA looks like loose strands. However, before the cell divides, DNA wraps itself around proteins and forms structures called chromosomes. The chromosome is made of two identical structures called chromatids that are held together in the middle by a centromere. Humans have 46 chromosomes in each of their non-reproductive cells - a number that is consistent throughout the human species. Other species have different chromosomal numbers - fruit flies have 8 chromosomes, dogs have 78 and cats have 38.

Additionally, the DNA is very well wrapped around the chromosome's protein core - if you stretch out a single strand of DNA, it measures approximately 2 meters! Even cooler - some sources state that if you line up all of the DNA in all of the cells in your body end-to-end, it can reach from Earth to the Sun and back - 70 times!

All of this is very important for the development of any organism - unicellular organisms reproduce by cell division and therefore need to ensure that their offspring have the same genetic information as themselves. Cell division is very important to you, as a multicellular organism, as well. Each one of us started out as a single fertilized egg cell. Through cell division after cell division, we became multicellular. Cell division enables you to grow - the bigger you get, the more cells you have, to the point where an adult human can have about 100 trillion cells! From one to 100 trillion....amazing!

This week, we will also be sitting for state testing in Language Arts and Math. There is no science component for the 7th grade (though there is one in 8th grade). Testing will take place in the morning, and the afternoons will have an altered schedule so that every class meets at least twice during the week. The schedule is as follows:

  • Tuesday: testing until 11:28, periods 3, 4, 5, 6
  • Wednesday: testing until 11:48, periods 3, 4, 2, 1
  • Thursday: testing until 10:48, periods 3, 4, 5, 6
  • Friday: testing until 10:48, periods 3, 4, 2, 1
In science class during testing days, we will be viewing the movie Gattaca as a tie into our genetics unit. It is a great movie with a strong science theme - what could be better?

During the test week, don't forget to stick to these basic guidelines:

  1. Get plenty of rest the night before (be in bed way before 10pm!).
  2. Eat a nourishing breakfast the morning of the test.
  3. Arrive to school on time!
  4. Read the directions carefully, paying close attention to what the question is asking you to do.
  5. Stay relaxed and do the best that you can.
Good luck with this week's testing!

Friday, April 18, 2008

Spring Break!!

Yes, we made it! Hackensack Middle School is officially on Spring Break for one whole week!

I hope that everyone takes the time off to relax, play, sleep late and mentally prepare for the week of NJ ASK testing coming up.

I hope that some of you will be visiting locations outside of Bergen County - if you do, make sure to send me a postcard and make me totally jealous! The furthest I'll be traveling is to Paramus, though I wish that I were laying in that hammock on a powdery soft beach somewhere in the Caribbean. Maybe on the next vacation.......

Have a great Spring Break! When we return, we'll begin our Genetics unit!

See you in 10 days!

Sunday, April 13, 2008

So Busy!

I apologize to all of my students for neglecting to update this blog!!! : (

As you all know, I have been ridiculously busy working on projects for Graduate School (which I am looking forward to using with you kids - you can check out my Charles Darwin project and my U.S. Oil Spills project online.....let me know what you think!) as well as putting together the website for your Unit Project, which is due very soon. You can access the Human Disease Project website here, as well as on

Along with the excitement of looking forward to spring break, this week will be a busy one for the 7th grade Life Science students! This week, we will be:
  • Reviewing for the Human Body Systems Unit Test
  • Taking the Human Body Systems Unit Test
  • Preparing our notebooks for collection on Tuesday
  • Presenting completed Human Disease Project work

I am truly looking forward to seeing each student's presentation on the disease that he/she chose! Just remember, PowerPoint presentations will be presented off my laptop, so the best way to avoid any last-minute problems is to email me the presentations ahead of time ( . One hard copy (paper) of the presentation must be submitted, as well.

Because of the response that they received in class, I included the link to the Optical Illusions used in the Nervous System lesson on Wednesday in the "Favorite Links" section to the right. You can also access it directly by going to My favorite is #8, showing where your blind spot is!

Good luck with your project's finishing touches, review for Tuesday's test on the 10 body systems that we studied, and have a great weekend!

Spring Break, here we come..

Saturday, April 12, 2008

Fear Factor Projects

It took me a while, but here they are....the icky, scary, gooey and delicious Fear Factor projects that our 7th graders created out of food (mostly candy!) to anatomically resemble arthropods. Congratulations to Bryan, Jonathan and Scott on being crowned the reigning champions of Fear Factor Day! (I hope that your crowns lasted the day!)