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02/12 02 Chemistry of Life Online Quiz Questions

Use this free practice quiz with 20 questions to review 02/12 02 Chemistry of Life, test your knowledge, and prepare for your next test or exam.

20 questions
01
Choose one
1 point

Why can carbon form the structural framework of many complex biological molecules?

  1. A

    Carbon normally forms one covalent bond.

  2. B

    Carbon normally forms two covalent bonds.

  3. C

    Carbon normally forms three covalent bonds.

  4. D

    Carbon normally forms four covalent bonds.

02
Choose one
1 point

A nonpolar group is placed in an aqueous solution. Which outcome best illustrates the hydrophobic effect?

  1. A

    They form strong ionic bonds with water.

  2. B

    They become permanently charged in water.

  3. C

    They cluster together to reduce their exposure to water.

  4. D

    They form hydrogen bonds more readily with water than polar molecules do.

03
Choose one
1 point

Compared with a solution at pH 5, what is true of a solution at pH 3?

  1. A

    The pH 3 solution has 100 times more hydrogen ions.

  2. B

    The pH 3 solution has 2 times more hydrogen ions.

  3. C

    The pH 3 solution has 10 times more hydrogen ions.

  4. D

    The two solutions have the same hydrogen-ion concentration.

04
Choose one
1 point

A researcher identifies repeated alpha helices and beta sheets within one polypeptide. Which level of protein structure is being described?

  1. A

    The amino-acid sequence of the polypeptide

  2. B

    Local alpha helices and beta sheets

  3. C

    The association of multiple polypeptide subunits

  4. D

    The complete three-dimensional shape of several interacting proteins

05
Choose all
1 point

Select all statements that are explained by hydrogen bonding among water molecules.

  1. A

    Water has a high heat of vaporization.

  2. B

    Ice is less dense than liquid water.

  3. C

    Water has no attraction between its molecules.

  4. D

    Ice contains no hydrogen bonds.

06
Choose all
1 point

Select all statements that correctly match a biological macromolecule class with a function described in the material.

  1. A

    Carbohydrates can provide immediate energy.

  2. B

    Lipids can form membrane bilayers.

  3. C

    Nucleic acids primarily waterproof body surfaces.

  4. D

    Proteins can act as enzymes.

07
True or false
1 point

True or false: Denaturation can impair a protein's function because changes in its shape alter the molecular surfaces used for binding or catalysis.

  1. A

    True

  2. B

    False

08
True or false
1 point

True or false: A buffer completely prevents the pH of a solution from changing, regardless of how much acid or base is added.

  1. A

    True

  2. B

    False

09
Written response
1 point

What term describes a molecule that has both hydrophilic and hydrophobic regions?

10
Written response
1 point

How many times greater is the hydrogen-ion concentration of a solution at pH 3 than that of a solution at pH 5? Enter the numerical ratio.

11
Fill in the blank
1 point

In , two smaller molecules are joined by a covalent bond while a molecule of is removed.

12
Fill in the blank
1 point

Complete the DNA base-pairing rules: adenine pairs with , and cytosine pairs with .

13
Open ended
1 point

Design an investigation to determine how pH affects the activity of an enzyme. Identify the independent and dependent variables, describe at least three controlled conditions, explain how activity should be measured, and predict why activity may decrease at pH values far from the optimum.

14
True or false
1 point

True or false: Evaporation of water can cool a surface because water requires substantial energy to change from liquid to vapor.

  1. A

    True

  2. B

    False

15
Choose one
1 point

Why does sodium chloride dissolve readily in water?

  1. A

    Sodium chloride is nonpolar and mixes with water through temporary electron shifts.

  2. B

    Water's partial charges surround and stabilize the separated sodium and chloride ions.

  3. C

    Water converts sodium chloride directly into covalent molecules.

  4. D

    The hydrophobic effect pulls the sodium and chloride ions into solution.

16
Choose one
1 point

A digestive enzyme adds water to split a large biological molecule into smaller molecules. Which process is occurring?

  1. A

    Two monomers join while water is removed.

  2. B

    A molecule loses electrons and another molecule gains them.

  3. C

    Water is added to break a covalent bond in a larger molecule.

  4. D

    A catalyst lowers the activation energy without being consumed.

17
Choose one
1 point

A buffer contains a weak acid and its conjugate base. What happens first when a small amount of acid is added to the buffer?

  1. A

    The conjugate base binds the added hydrogen ions.

  2. B

    The weak acid releases additional hydrogen ions.

  3. C

    The buffer permanently removes all hydrogen ions from the solution.

  4. D

    The buffer changes into a strong acid that cannot dissociate.

18
Choose one
1 point

Which experimental design best tests how pH affects the activity of an enzyme?

  1. A

    Use a different enzyme concentration at every pH and compare the final products.

  2. B

    Change both pH and temperature so the enzyme experiences realistic conditions.

  3. C

    Measure activity only at the pH where the enzyme is expected to work best.

  4. D

    Keep temperature, enzyme concentration, and substrate concentration constant while varying pH.

19
Written response
1 point

A solution has a hydrogen-ion concentration of 1 × 10⁻⁴ M. What is its pH?

20
Written response
1 point

What scientific term describes a molecule that has both hydrophilic and hydrophobic regions, such as a phospholipid?