INTRODUCTION

This section can be intimidating, especially if you have not had much chemistry background. Do not rush through this. Take your time and only do a little bit at a time.

If you have studied nutrition, you know there are many different chemicals that our body needs to function properly, from carbohydrates to Vitamin C to calcium. Then there are even more molecules that the body makes for itself. It is easier to take all this in if we have patterns to look for.

Fortunately, most (but not all) of the molecules in living cells fall into four categories – carbohydrates, fats, proteins and nucleic acids. If you have spent any time looking at nutrition labels you are probably already familiar with 3 of these. The last one – nucleic acids – you would know if it is put differently and that is DNA. The “NA” in DNA stands for nucleic acid.

So there you have it, just 4 molecule types. Again, there are more than four types of molecules in the body, but these 4 carbon-based, or organic, molecules are the ones that come up the most. So we will start to look at examples of molecules from each of these 4 categories – carbohydrates, fats, proteins and nucleic acids – and learn the roles each play in the body. And since you will be looking at them frequently during biology classes, you should learn what they look like as well.

LAB - Biomolecule Scavenger Hunt

The lab for this topic is a scavenger hunt where you will take pictures of food items that are rich in each biomolecule type. I estimate this will take you 20 minutes if you have a well-stocked kitchen. If you live in a dorm or your cupboards are bare, it may required a trip to a grocery store. You have to take the pictures yourself - no downloading images. You must remember to place your PPI beside the food item before the photo is taken.

READINGS

Read the following:
- Most biomolecules are made of repeating subunits called monomers, which are linked together to form polymers. Polymers can be broken down again into monomers.
- Even the way biomolecules are linked and unlinked is similar.
  - Dehydration synthesis is how monomers are linked together. It requires the removal of 2 hydrogens and one oxygen (water) to do so, thus dehydration.
  - Hydrolysis is how polymers are broken apart. After breaking, the octet rule must be satisfied so 2 hydrogens and one oxygen (water) are brought in to share electrons.
Read Openstax 2.3 “Biological molecules” (other texts may cover this in chemistry sections)
- This section will work a little differently than others. There are many facts presented in the chapter and it is not useful to try to absorb them all at once, so we will take it one section at a time.

BASIC QUESTIONS

Organic molecules contain ________________ and hydrogen.
Molecules in living beings, biomolecules, are carbon-based. What other major atoms, besides carbon are usually present?
What are the four major types of biomolecules in living beings?
Look at the two monomers below. These are both glucose molecules. The two monomers will be linked after dehydration synthesis. The hydrogens and oxygens to be removed have been circled. Draw the two molecules joined together. They will be linked by a C-O-C bond. Make sure other bonding rules are followed (carbon has 4 bonds, oxygen two, etc.). Feel free to use skeleton formulas if you find it easier.)
Now try hydrolysis on this small protein polymer. Break the molecules where indicated and redraw them to the right as two separate molecules. Use the 2 hydrogens and 1 oxygen to stabilize the resulting molecules.

dipeptide split rxn.jpg

LECTURES

See the powerpoint lecture from Openstax.

Panoptos could be added.

APPLICATION QUESTIONS

Classify chemical reactions as dehydration synthesis or hydrolysis. Example, making glycogen from glucose in the liver is dehydration synthesis. What about...

storing fat
building muscle
burning fat
breaking glycogen into glucose
digestion of starch