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BIOCHEMISTRY
Read chapters 4 and 5 in Campbell.
Key Terms:
hydrocarbon
isomer
functional group
monosaccharide
amino group
disaccharide
condensation reaction (dehydration synthesis)
hydrolysis
polysaccharide
starch
glycogen
cellulose
polymer
fatty acid
saturated fat
unsaturated fat
phospholipid
amino acid
peptide bond
polypeptide
disulfide bond
primary structure
alpha helix
secondary structure
fibrous proteins
keratins
pleated sheet
tertiary structure
quaternary structure
denatured proteins
nucleic acids
DNA
adenine
guanine
cytosine
thymine
RNA
free energy (_G)
First Law of Thermodynamics
Second Law of Thermodynamics
exergonic
endergonic
Answer the following questions:
1.
Name and diagram the functional groups listed in Table 4.1.(pg 64). Indicate whether each group is
charged, polar, or nonpolar, and whether it is hydrophilic or hydrophobic.
2.
Describe the structure of a typical monosaccharide such as glucose. Write out a condensation reaction
(dehydration synthesis) between the two given glucose molecules, and explain what is meant by hydrolysis.
3.
Draw a diagram which shows the similarities and the differences between alpha and beta linkages in
carbohydrate molecules. Explain why the glucose molecules in starch can be used directly for food by
animals whereas those in cellulose cannot.
4.
Draw a lipid molecule (triglyceride). Point out the carboxyl, or acid, group and the hydrocarbon chains.
Explain the difference between a saturated fatty acid and an unsaturated fatty acid. For butter and corn oil,
indicate whether each is considered a saturated or an unsaturated fat. Using a diagram, explain how three
fatty acids can react with glycerol to make a fat.
5.
Draw a phosopholipid molecule, point out the polar and nonpolar portions of a phospholipid molecule.
Specify which end of the molecule would be soluble in water.
6.
Draw an amino acid, point out the carbonyl, and the carboxyl group, the amino group, and the R groups
that are attached to it. Be able to tell whether the R group is charged or polar, and therefore hydrophilic, or
nonpolar and hydrophobic.
7.
Diagram and describe a condensation (dehydration synthesis) reaction between two amino acids and circle
the resulting peptide bond. Explain how a polypeptide chain is formed and how it is broken down by
hydrolysis.
8.
Discuss the various levels of protein structure - primary, secondary, tertiary, and quaternary. Specify the
level(s) of structure shown by fibrous proteins, such as hair, and the levels shown by globular proteins.
Explain why proteins are so sensitive to changes in temperature and pH.
9.
Diagram a simple stretch of DNA (see pg 291). Point out an individual nucleotide and the five-carbon
sugar, the phosphate group, and the nitrogen-containing base of which it is made; a base from a nucleotide
on one chain bonded to a base on the opposite side; the sugar-phosphate uprights; and the hydrogen
bonds between bases.
10. List 3 examples of each of the four main classes of biologically important organic molecules
(carbohydrates, lipids, proteins and nucleic acids) and the building-block units of which they are composed.