CHM 222 Biomolecules Review Questions - Answers

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CHM 222
Biomolecules Review Questions - Answers
1. The bond that links saccharides is called a(n) glycosidic linkage.
H
2. Draw maltose, name the individual saccharide units, and describe where they link.
3. The oxidized form of a reducing monosaccharide is called a(n) aldonic acid
4. There are two broad categories of lipids and carbohydrates known as
OH
OH
H
OH
OH
H
H
OH
H
OH
H
H
OH
O
HO
H
OH
OH
2 molecules of D-glucose linked alpha-1Æ 4
simple and complex.
The lipid at right is an example of this category. simple
OH
To which of the seven lipid subcategories that we discussed does it belong? steroid
Is it a chiral molecule? Yes. There are several chiral centers
5. What structural characteristics distinguish fatty acid from other carboxylic acids?
O
Even number of carbons. (mostly 12-20 C’s)
Cis C=C
6. Terpenes are built from isoprene which has 5 carbons.
7. What are the two essential fatty acids? Linoleic acid and linolenic acid What does essential indicate? Our bodies cannot
produce enough so we must get them in our diet. What part of the two fatty acids does our body have trouble
producing? The C=C at omega-3 and omega-6
8. Which category of lipid is most important for cell membranes? Phospholipids – phosphoglycerides and sphingomyelins
9. What are the two types of plant starch? Amylose and amylopectin How are their structures similar and different?
Both have many D-glucoses linked alpha-1Æ4. Amylopectin also has some alpha-1Æ6 branch points.
10. Which of the following are macromolecules? proteins, lipids, carbohydrates
11. A tetrapeptide contains 4 amino acids.
12. The amino acid at right is in its D configuration.
13. An ion having both a positive and negative charge is a zwitterion.
-
CO 2
+
H
NH3
CH3
14. To which of the four classes of amino acid does cysteine belong? polar
15. Draw the structure of a generic dipeptide using H3N+-CHR-CO2-. What type of bond
links the amino acids? Draw an arrow to this bond.
16. What are the four levels of protein structure? Primary, secondary, tertiary, quaternary
O
H3N CH C NH CH CO2
R
R
+
peptide bond
What level is given for this tripeptide? alanine–lysine–aspartic acid primary
17. What is denaturation of protein? see notes What can cause this to happen? Temperature change, pH change,
agitation,heavy metals Is it permanent? sometimes
18. What is the net charge on cysteine, pI=5.1, when the pH=6.3? negative
Which way will it move during electrophoresis? Toward the positive electrode
19. The site on the enzyme where reaction occurs is known as the active site.
20. DNA is sometimes made from RNA by retro viruses. This process is called reverse transcription.
21. Nucleic acids are synthesized from their 5′ end to their 3′ end.
22. Two main categories of nucleic acids. (full names)
Deoxyribonucleic acid ribonucleic acid
Name the three subcategories of one of the nucleic acids above. Be sure that you know the purpose of each.
O
Transfer-RNA messenger-RNA ribosomal-RNA
N
HN
23. What are the building blocks of nucleosides? Sugar and base
NH
H2N
N
24. Give the name and type of base shown at right. Guanine, Purine
25. What is the anticodon for the codon UUC? For what amino acid does this code?
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