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Ch. 3 Notes – Carbon Compounds in Cells
I.
Carbon compounds
A. Organic chemistry is the study of all compounds that contain bonds
between carbon atoms
B. Chemistry of carbon – because of its 4 valence e- , carbon will form 4
strong polar covalent bonds in a wide variety of ways
C. Macromolecules
1. polymers: made of 100s-1000s of smaller molecules through
polymerization
2. monomers: smaller units that make up polymers
D. Four groups of organic compounds:
1. carbohydrates
2. lipids
polymers
3. proteins/polypeptide
4. nucleic acids
II.
CARBOHYDRATES: polymers that contain C, H, O (in a 1:2:1 ratio)
A. Monosaccharides – single sugar monomer; simplest carb (ex. C6H12O6):
1. Glucose ring structure:
O
or
2. made by plants during photosynthesis
B. Disaccharides – 2 monosaccharides bonded together through
dehydration synthesis
(ex. Glucose + glucose = maltose)
O
C. Polysaccharides- many monosaccs. condensed together forming a polymer
1. Starch – stores energy in plants
2. Cellulose- fibers making up plant cell walls; gives strength and
flexibility
3. Glycogen- stored energy in muscles and liver
D. Importance of Carbohydrates:
1. Monosaccharides- used by the mitochondria (small organelle in the cell) to
provide energy
2. Di- and polysaccharides- used by organisms to store energy for later use;
cellulose gives structure to plants
III.
LIPIDS: polymers (fats) made of C H O in no particular ratio
A. Used to store energy, makes biological membranes, waterproof coverings, and
steroids
B. Two monomers – glycerol and fatty acid chains (f.a.c.)
1. Saturated fatty acids - f.a.c contain only single bonds between C
2. Unsaturated fatty acids - f.a.c contain 1+ double bonds between
carbons
C. Triglycerides – oils, lard, and body fat supply a rich energy source;
H
O
H–C –O—C—C—C—C…
glycerol
fatty acid chains
H–C–O—C—C—C—C…
H–C–O—C—C—C=C…
H
D. Phospholipids- made of glycerol and 2 f.a.c; builds cell membranes
E. Sterols- cholesterol is a precursors to animal steroid hormones
F. Waxes – substance that repels water and may protect and lubricate
G. Importance of lipids- alternate energy source other than monosaccharides;
fats are lighter than polysacc. and take up less space
IV.
PROTEINS: polymers made of C H O N (sometimes S)
A. Structure: amino acids monomers linked by polypeptide bonds
1. Amino group (-NH2)
2. Carboxyl group (-COOH)
3. One of 20 various “R” groups
B. Peptide bonds- bonds between a C and N that link amino acids
C. Polypeptide chain - many amino acids linked together
D. Importance of proteins:
1. structural proteins build all living organisms
2. enzymes act as catalysts making metabolic reactions proceed faster
3. transport proteins move substances across the cell membrane
4. regulatory proteins signal for change in cell activities