Download Introduction to Biology Week 3

Introduction to Biology W eek 3
The Chemistry of life
Introduction
Last week you learned about the atom, different types of chemical bond between atom giving rise
to molecules, water (a special type of covalent bond) and pH or hydrogen ion concentration of a solution.
This week we will explore four classes macromolecules found in living systems: carbohydrates, lipids,
proteins, and nucleic acids. By definition organic compounds are carbon based. These carbon compounds
share similar reactive properties. For instances, starting with a simple mono-saccharide produced through
the process of photosynthesis plants produce various different types of polysaccharide. Potatoes tubers
contain starch, a polysaccharide. Other forms of polysaccharide make up cellulose or wood products.
W hen complex nitrogen bases are covalently bond with a sugar-phosphate molecule nucleic acid form. The
common central theme to chapter 3 is the condensation/hydrolysis reactions: water removed through the
formation of covalent bonds and water added across these very same bonds to reduce polysaccharides to
their simpler forms.
Course outcome:
Describe structure and function of the four main biological macromolecules
Learning goals:
After studying this week’s material you should:
1. Know what kinds of molecules are organic
2. Know how organic molecules differ from each other
3. Be able to describe how these molecules combine to form large organic
macromolecules
4. Describe how these molecules are split apart by living things.
5. Know what roles these molecules play in living organisms.
Assignments:
These will be found in the W eek 3 Folder
1. Read Chapter 3, Organic Chemistry.
2. Visit the following URL:
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookCHEM2.html
Read and study the material here over looking the pKa section. This material is important. This page will
provide additional diagrams of biological molecules and information about them. The page takes a long
time to load since there are many diagrams and graphics here. Be patient. There is good information to
augment material in your text and the diagrams and models of molecules can be very helpful.
W riting for week 3:
Prepare written responses to the following questions. This assignment will be lieu of a
reading/writing assignment and will count 10 points. These questions are to be answered on your own
using whatever resources you wish such as your text, W eb sites, lectures and so forth. Your responses will
be graded for clarity and content. Be sure to spell correctly, use complete sentences and correct grammar.
Also, your answers should be in your own words.
1. Describe how organic molecules combine to form larger macromolecules and how
macromolecules are split apart to form smaller units. Be sure to discuss the types of chemical
reactions involved, the scientific terms used for all relevant components, and provide clear
definitions or explanations for these terms.
2. Describe the four major types of biological macromolecules of a living system while explaining
their functions. Your descriptions should include molecular structural component giving rise to
hydrophilic or phobic nature.
3. For the chemistry of life lab you discussed the various type of protein configuration. Explain
the molecular interaction that leads to these various configurations. Use hemoglobin (human red
blood) as an example while discussing what can occur if one amino acid is substituted for another
amino acid during the synthesis of the protein. (Hint: look up sickle-cell anemia).
4. Organic acids include such molecules as fatty acids and amino acids. Discuss both the
similarities between organic acids and inorganic acids, and the differences between
these two groups of acids.
Before Tuesday 12:00 PM Mid
5. Our text book show a description of a condensation reaction between two glucose
molecules, mono-saccharides, resulting in maltose, a dis-saccharide. Examination of the
glucose molecule reveals five possible position on the hexose molecule that contain
hydroxyl molecules, -OH, groups. Discuss whether the other four hydroxyl sites can
react to form differing combinations of di-saccharides.
Before W ednesday 12:00 PM Mid night.
6. Phospholipids, by far constitute the major macro-molecule of a membrane. Chapter
three of the text introduces us to phospholipids while chapter four describes a few unique
biochemical properties of these phospholipids. Discuss the unique biochemical
properties of the phospholipid examining its head and tail components and where would
expect to find phospholipds?