HUMAN BIOLOGY

40 Chapter 2

seLf-QUiz Answers in Appendix VI

1. The backbone of organic compounds forms when
   atoms are covalently bonded.


2. A carbon atom can form up to bonds with other
   atoms.
   a. four c. eight
   b. six d. sixteen


3. All of the following except are building blocks or
   energy sources in cells.
   a. fatty acids d. amino acids
   b. simple sugars e. nucleotides
   c. lipids


4. Which of the following is not a carbohydrate?
   a. glucose molecule c. margarine molecule
   b. simple sugar d. polysaccharide


5. , a class of proteins, make metabolic reactions
   proceed much faster than they would on their own.
   a. Nucleic acids c. Fatty acids
   b. Amino acids d. Enzymes


6. Examples of nucleic acids are.
   a. polysaccharides c. proteins
   b. DNA and RNA d. simple sugars


7. Which phrase best describes what a functional group does?
   a. assembles large organic compounds
   b. influences the behavior of organic compounds
   c. splits molecules into two or more parts
   d. speeds up metabolic reactions


8. In reactions, small molecules are linked by covalent
   bonds, and water can also form.
   a. hydrophilic c. condensation
   b. hydrolysis d. ionic


9. Match each type of molecule with its description.
   chain of amino acids a. carbohydrate
   energy carrier b. phospholipid
   glycerol, fatty acids, c. protein
   phosphate d. DNA
   chain of nucleotides e. ATP
   one or more sugar units


10. What kinds of bonds often control the shape (or tertiary
    form) of large molecules such as proteins?
    a. hydrogen d. inert
    b. ionic e. single
    c. covalent

CritiCaL thinKing

1. The pH of black coffee is 5, and that of milk of magnesia is
   10. Is the coffee twice as acidic as milk of magnesia?


2. Draw a shell model of an uncharged nitrogen atom. Hint:
   Nitrogen has seven protons.


3. A store clerk says that vitamin C from rose hips is
   healthier than synthetic vitamin C. Based on what you
   know of the structure of organic compounds, does this
   claim seem credible? Why or why not?


4. Use the Web to find three examples of acid rain damage
   and efforts to combat the problem. You might start with
   the U.S. Environmental Protection Agency’s acid rain
   home page.


5. Manufacturers make carbonated drinks by forcing
   pressurized carbon dioxide gas into flavored water.
   A chemical reaction between water molecules and
   some of the CO 2 molecules creates hydrogen ions (H^1 )
   and bicarbonate, which is a buffer. In your opinion, is
   this reaction likely to raise the pH of a soda above 7,
   or lower it? Give your reasoning.

Nuts of all types are good sources

of phytochemicals, among other

nutrients. Recently, several studies

indicated that eating a daily handful

of nuts as part of an overall healthy

lifestyle correlates with longer life.

Both studies followed many thousands of subjects for more

than 30 years. Some ate nuts regularly, others didn’t. Among

other findings, regular nut eaters had a 29 percent lower risk

of dying from heart disease and an 11 percent lower risk of

dying from cancer. More research may reveal the specific

substances in different types of nuts that may be associated

with these benefits.

your future

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