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AP BIOLOGY
Name:
Guided Reading:
Ch. 3 – The Chemistry of Organic Molecules
Answer the following questions as you read the chapter.
1. All organic molecules contain carbon. What is it about carbon that makes it such a fundamental building block?
2. Any organic molecule can be thought of as having a carbon-based core with specific groups of atoms with definite
chemical properties attached. These groups of atoms are known as _____________.
3. Complete this table summarizing the characteristics of the most biologically significant functional groups:
Group
Structure
Compound
Polar or
Found in many
Found in many
nonpolar
or all proteins
lipids
Hydroxyl
Carbonyl
Aldehyde
Amine as in tryptophan
Polar
phospholoipids
R-SH
Carboxyllic acid as in
acetic acid
4. What is an isomer and how can they be biologically significant?
5. Complete this table summarizing the macromolecules.
Category
Example
Carbohydrates
DNA, RNA
Subunit(s)
Amino Acid
6. Explain the difference between hydrolysis and synthesis reactions.
7. Which monosaccharide is the major source of cellular fuel for all living things?
8. How do plants transport sugar?
9. Match the polysaccharide to it’s structure and then to it’s function:
Cellulose
Long chain with a few branches
Forms the cell walls of bacteria.
Chitin
Long chain with many branches
Forms the cell walls of fungi, and
the exoskeletons of arthropods.
Glycogen
Long chain with no branches,
forming long fibers
Forms the cell walls of plant cells.
Peptidoglycan
Monomer has amino groups too.
The form in which animals store
glucose.
Starch
Monomer has amino acid chains.
The form in which plants store
glucose.
10. Why are lipids insoluble in water?
11. Complete this table summarizing the types of lipids:
Type
Function(s)
Steroids
Human Uses
Long-term energy storage and
insulation in animals
None (part of our cells)
Waxes
12. Discuss the benefit of using fat instead of glycogen for long-term energy storage.
13. List some of the many functions of proteins.
14. How do amino acids differ?
15. What is a peptide bond?
16. Discuss the connection between the term peptide and polypeptide.
17. Why is a protein’ shape so important?
18. Match the level of protein structure to it’s description and example:
Primary
Folding resulting in a three-dimensional
shape.
Fibrous proteins, such as keratin.
Secondary
Results when there are two or more
polypeptides in a protein.
Hemoglobin is an example.
Tertiary
The specific sequence of amino acids.
Globular proteins, such as enzymes.
Quaternary
The coils and folds of a polypeptide.
No example.
19. What happens when a protein denatures?
20. Explain how DNA and RNA work together to build a protein.
21. What is ATP used for?
22. Label this diagram showing the structure of a nucleotide: [p.50]
23. Explain the difference between purines and pyrimidines.
24. What is complementary base pairing?
25. Why is ATP a high-energy molecule?
26. Explain why the last phosphate bond of an ATP molecule is called a “high energy” bond.