Synthesis

Today, we examined synthesis reactions - the process by which the cell makes larger molecules.  This can be used to store food for later, as in the case of synthesizing a polysaccharide like starch or glucose; or, the cell can use synthesis to build functional or structural molecules - for example, synthesizing an enzyme or membrane protein from amino acids, or synthesizing a phospholipid from fatty acid tails, glycerol, and a phosphate.  With synthesis, the cell can build whatever it needs from the raw materials taken in from digestion.  Ian B. made a really good connection to digestion today, pointing out that we humans eat big polymers, break them down into monomers so they are small enough to cross the cell membrane into the cell, and then the cell uses synthesis to reconstruct the polymers inside it.  Pretty cool!

Homework
1) On looseleaf, write a response to the prompt we discussed in class: Explain the role of enzymes, activation energy, and ATP in the synthesis of a disaccharide from two monosaccharides [6].  

2) Your post-interim assignment is due Monday.

Best,
Mr. Hill

Carbs and Lipids

Today, we talked about how the molecular structure of carbs and lipids is related to their properties.  We talked about carbs, looking at the example of the monosaccharide (or simple sugar) glucose:

And we looked at a triglyceride, a molecule of fat composed of glycerol and three fatty acids:

You should be able to discuss the molecule in relationship to their polarity, energy capacity, and readiness to break down via respiration.

Homework

Read textbook pages 138-141 about monosaccharides, disaccharides, and polysaccharides, and answer the following questions in your journal:

1. Name two examples of each of the following: (a)monosaccharide, (b)disaccharide,  (c)polysaccharide
2. What's the difference between a monosaccharide, disaccharide, and polysaccharide?
3. Draw a picture of a condensation (dehydration synthesis) reaction between two monosaccharides to make a disaccharide.  Label the atoms that are removed and the new bond that is formed.
4. When you eat a candy bar, some of the glucose you take in is respired immediately, and some is synthesized into larger chain molecules (polysaccharides).  Why would your cells bother to synthesize a polysaccharide?

NOTE!!  I am missing the "Art of Explanation" unpacking take home quiz from last Friday for the following students:

IAN
JAFAR
GENESIS
BRIAN

If you have this, please hand it in tomorrow otherwise it's a zero!