Saturday, December 3, 2011


In November, our Biology classes covered material on how cells obtain, store and release energy. During that time, there were several groups of notes of various sizes for students to access.

First, this Power Point (previously given) contains an outline of photosynthesis, relating it to the 'Great Circle' of chemical reactions that all living things participate it (autotrophs and heterotrophs!), reactions which recycle the raw materials that life requires. Much of this material is covered in the first two sections of Chapter 8 in the Dragonfly Book.

The Power Point for Photosynthesis, Part I, is available here.

Photosynthesis, Part II provides much more detail about the light reactions, photosystems, the proton pumps that use the enzyme ATP synthase, the electron transport chains that help power those pumps. There is less detail about the 'dark reactions' of the Calvin cycle and other material which is not explicitly part of the state standards. This is covered in Section 8.3 of the Dragonfly Book.

You can download Photosynthesis, Part II here.

A third Power Point is somewhat brief, but has many helpful animations that help describe and explain the structure and function of ATP (adenosine triphosphate), the main energy-carrying molecule used by living things.

The fourth and final Power Point in this unit contains information about cellular respiration, including glycolysis (which takes place in the cytoplasm) and the Krebs Cycle (which takes place in the matrix of the mitochondria). The electrons produced in the Krebs Cycle move through the inner membrane, or cristae, of the mitochondria. The motion of these negatively-charged particles attracts protons (H+), and eventually a high concentration of protons within the membrane is available to drive 'proton pumps' that power an enzyme, ATP synthase, leading to the production of more ATP:

You can download the Power Point for Cellular Respiration here.


SATURDAY SCHOOL was held on Dec. 3rd, in Room N-63, between 8:45 and 11:30. Students who attended received a packet of illustrations to color and label based on materials from chapters 7-9 (cell membrane, transport, animal and plant cells, photosynthesis) as well as a diagram on DNA.

Students also received (in advance) the Final Project for the fall semester, a handout called "A Twist of Fate" based on an article that appeared in TIME magazine to celebrate the 50th anniversary of the discovery of DNA's structure. The original article can be viewed on-line here; the text has been modified to emphasize vocabulary development and will challenge students to analyze a test case of science as actually practiced by real men and women.

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