Principles of Biology - Biology 101
Fall Qtr
Lake Tahoe Community College
Instructor: Sue Kloss
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Chapter 5: Organic Molecules
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Molecules of life
4 types: carbs, lipids, proteins, nucleic acids. Some are small; many organic molecules are huge. For example, proteins
may consist of thousands of covalently bonded atoms.
I. Macromolecules are polymers
A. polymers consist of monomers
B. Synthesis and breakdown of polymers
1. dehydration synthesis,
2. enzymes in the process
3. Hydrolysis
C. Diversity of polymers
II. Carbohydrates
A. Sugars
1. monosaccharides, disaccharides
2. Carbonyl group C=O and multiple hydroxyls OH
3. sugars = aldose or ketoses
4. arrangements of parts around skeleton differs
5. simple sugars - fuel for cellular work
B. Polysaccharides
1. storage polysaccharides
2. structural polysaccharides
3. glycosidic linkages
III. Lipids
A. Fats
1. glycerol
2. fatty acid
3. ester linkages
B. Phospholipids
1. negatively charged phosphate group
2. head is hydrophilic, tail is hydrophobic
3. cell membranes
C. Steroids
1. functional groups vary
2. cholesterol
IV. Proteins
A. functions
B. polypeptides
1. amino acid monomers (You do not need to write/memorize all monomers)
2. amino acid polymers
3. peptide bond formation
C. protein conformation and structure
1. 4 levels of structure
2. change in primary structure causes function change
3. conformation
a. denaturation
4. protein folding
V. Nucleic acids
A. roles of nucleic acids
1. DNA
2. RNA
3. DNA -->RNA-->protein = basic model for turning a gene into a protein
B. Structure of nucleic acids
1. nucleotide monomers
a. components
b. purines and pyrimidines
c. ribose and deoxyribose
d. carbon atoms in sugar have ' (prime) to distinguish from C in base
2. nucleotide polymers
a. sugar phosphate backbone
b. phosphodiester linkages
c. each backbone has a 5' end and a 3' end
d. Adenine bonds with thymine; Guanine bonds with cytosine
e. one strand can serve as a template for the other in DNA synthesis
C. DNA double helix and RNA structure
1. double helix
2. antiparallel
3. DNA base pairing rules – complementary
4. types of RNA
5. RNA complementary bases
D. DNA and proteins help measure evolution
Ch. 5 Objectives
1. List the four major classes of macromolecules.
2. Distinguish between monomers and polymers.
3. Draw diagrams to illustrate condensation and hydrolysis reactions.
4. Distinguish between monosaccharides, disaccharides, and polysaccharides.
5. Describe the formation of a glycosidic linkage, and distinguish between the glycosidic linkages found in
starch and cellulose. Explain why the difference is biologically important, and how herbivores may digest
cellulose.
6. Describe the building-block molecules, structure, and biological importance of fats, phospholipids, and
steroids, and identify an ester linkage and describe how it is formed.
7. Distinguish between saturated, unsaturated and trans fats.
8. Distinguish between the principal energy storage molecules of plants and animals.
9. Distinguish between a protein and a polypeptide, and list/describe 8 protein functions.
10. Explain how a peptide bond forms between two amino acids.
11. List and describe the four major components of an amino acid. Explain how amino acids may be
grouped according to the physical and chemical properties of the R group.
12. Explain what determines protein conformation and why it is important.
13. Explain how the primary structure of a protein is determined.
14. Name two types of secondary protein structure. Explain the role of hydrogen bonds in maintaining
secondary structure.
15. Explain how weak interactions and disulfide bridges contribute to tertiary protein structure.
16. List four conditions under which proteins may be denatured.
17. List the major components of a nucleotide, and describe how these monomers are linked to form a
nucleic acid.
18. Distinguish between:
a. pyrimidine and purine
b. nucleotide and nucleoside
c. ribose and deoxyribose
d. 5’ end and 3’ end of a nucleotide
19. Briefly describe the three-dimensional structure of DNA.