The Chemistry of Organic Molecules Chapters 4 & 5
1. Main elements found in living things are: CHON
2. What are organic chemicals? contain carbon bound to hydrogen
3. List the four classes of organic compounds. carbohydrates, lipids, proteins, nucleic acids
4. Which atoms does carbon almost always share electrons with? CHON
5. Explain how carbon’s need for four electrons contributes to the diversity seen in carbon-based molecules.
It is compatible with many different elements. It’s 4 valence electrons make it versatile
6. Why are carbon chains so common? Because carbon can bond to carbon
7. How do double bonds contribute to the shape of a molecule? Cause kinks.
8. Complete this table summarizing the characteristics of the most biologically significant functional groups:
Group
Structure
Compound
Significance
Carbonyl
Aldehyde and ketones
found in sugars
methyl
CH3
Methyl cytidine
found hormones, DNA, gene expression
amino
NH2
Amine as in tryptophan
forms proteins
phosphat
e
Hydroxyl
PO4
phospholipids, DNA
-OH
Alcohols
Polar, acidic; present in nucleotides,
phospholipids
polar so can for H bonds with water.
sulfhydryl
R-SH
Cysteine
forms cross linkages between Sulfurs
carboxyl
cooh
Carboxylic acid as in acetic acid
acidic and polar
9. What is an isomer and how can they be biologically significant? same formula different arrangement.
Shape determines function.
10. Discuss the association between polymers and monomers. Polymers are made up of bonded monomers.
11. Complete this table summarizing the macromolecules.
Category
Example
Carbohydrates
sucrose, glucose
nucleic acids
DNA, RNA
proteins
hemoglobin
lipids
phospholipids
Subunit(s)
monosaccharide
nucleotides
Amino Acid
phosphate group, 2 fatty acids
12. Explain the difference between hydrolysis and synthesis (condensation) reactions. Hydrolysis breaks apart
molecules by adding water. Synthesis connects molecules by taking out water.
13. Which monosaccharide is the major source of cellular fuel for all living things? glucose
14. 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.
15. Why are lipids insoluble in water? Lipids have large hydrocarbon regions which are hydrophobic
16. Complete this table summarizing the types of lipids:
Type
Function(s)
Organism use
Steroids
Hormones
chemical signals
Fats
phospholipids
Long-term energy storage and
insulation in animals
molecular component of cell
membranes
Waxes
hydrophobic, antibiotic
Energy storage, cushioning
organs, insulation
barrier between the inside of a
cell and the outside
environment
ear wax
Long term compact storage
food for seedlings
Oils
17. Explain the difference between a saturated and unsaturated fatty acid. Unsaturated have some double
carbon bonds.
18. List some of the many functions of proteins. transport, hormones, receptors, defense, etc.
19. How do amino acids differ? R group
20. What is a peptide bond? covalent bond between two amino acids
21. Discuss the connection between the term peptide and polypeptide. peptide is the monomer of a protein
which is also called a poly peptide.
22. Why is a protein’ shape so important? determines function.
23. Match the level of protein structure to it’s description and example:
Primary
Folding resulting in a three-dimensional
Fibrous proteins, such as keratin.
shape.
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.
24. What happens when a protein denatures? unfolds
25. Explain the biological significance of chaperone proteins. assists protein folding
26. Discuss the effect of prions, both chemically and systematically. causes proteins to fold incorrectly. Causes
diseases like Mad Cow.
27. Explain how DNA and RNA work together to build a protein.
28. What is ATP used for? Energy storage
29. Label this diagram showing the structure of a nucleotide:
30. Explain the difference between purines and pyrimidines.
Purines – six membered ring fused to a five membered ring. Adenine and Guanine form a triple bond.
Pyramidine – six membered fring. Cytosine, Thymine, Uracil – form double bond.
31. What is complementary base pairing? A bond to T, C to G
32. Why is ATP a high-energy molecule? Energy stored in chemical bonds between phosphates.