Question 1

How does the interaction between water and hydrophobic molecules help to organize biological systems?

Accepted Answer

Because water molecules prefer...

Question 2

Rank the elements carbon, phosphorus, calcium, and iodine in order of decreasing number of energy shells/levels.

Accepted Answer

I<font face="symbol"></font>CaF...

Question 3

Humans are often referred to as "carbon-based" life forms. Given that humans breathe oxygen, shouldn't humans be referred to as "oxygen-based" life forms?

Accepted Answer

A)  Yes, because oxygen is the most abundant element in human cells, not carbon.
B)  Yes, because humans inhale oxygen.
C)  No, because carbon is the most abundant element in human cells, not oxygen.
D)  No, because humans exhale carbon dioxide.
E)  No, because oxygen is not an organic molecule.

Question 4

Consider two carbon atoms, one represented as 14C and the other as 12C. Which of the following statements is TRUE regarding these two atoms?

Accepted Answer

A)  These carbon atoms have the same number of protons.
B)  These carbon atoms have the same number of neutrons.
C)  These carbon atoms have different numbers of electrons.
D)  These carbon atoms have different numbers of protons.

Question 5

Calculate the number of different polypeptides, each 10 amino acids long, that can be made if you start with just 5 different kinds of amino acids.

Accepted Answer

Any of the 5 amino acids could...

Question 6

If an atom has three electrons, how many occupied orbitals will the atom have, and how many electrons will be in each?

Accepted Answer

The atom will have two orbital...

Question 7

Which of the following ranks the elements carbon, sodium, calcium, and iodine in order of decreasing abundance in living organisms?

Accepted Answer

A)  CaCaI
B)  ICaNaC
C)  ICCaNa
D)  CCaNaI

Question 8

List the five most abundant elements found in living organisms. For each of the following, indicate the biologically important molecules in which they are MOST important.

Accepted Answer

carbon - all macromoleculeshyd...

Question 9

A man heats water in a teakettle while drinking a glass of water at room temperature. The water molecules in the teakettle are moving _____ the water molecules in the glass.

Accepted Answer

A)  faster than
B)  slower than
C)  at the same speed as

Question 10

Imagine you are looking at a bottle of salad dressing containing oil, vinegar, and water. You notice that the oil sits on "top" of the other liquids. This is due, in part, to the fact that:

Accepted Answer

A)  water is hydrophobic.
B)  oil is hydrophilic.
C)  vinegar is hydrophobic.
D)  oil is hydrophobic.
E)  water is hydrophobic and oil is hydrophilic.

Question 11

Which one of the following statements about a carbon-carbon double bond is CORRECT?

Accepted Answer

A)  Each of the two carbons is capable of bonding to three other atoms.
B)  The double bond allows free rotation of the molecule at the bond position.
C)  The double bond is longer than a corresponding carbon-carbon single bond.
D)  Double bonds are often found in cyclical structures.
E)  None of the other answer options is correct.

Question 12

You have an aqueous solution with a pH of 8.0. You add sodium chloride to a concentration of 1 gram per 100 milliliters. What happens to the pH?

Accepted Answer

A)  It goes up.
B)  It goes down.
C)  It stays the same.
D)  It depends on the temperature.

Question 13

Which of the following was required for early life to form on Earth?

Accepted Answer

A)  low oxygen conditions, which allowed for the formation of amino acids
B)  clay, which allowed for the formation of nucleic acids
C)  phosphates, which allowed for the formation of nucleotides
D)  the presence of hydrogen, which allowed for the formation of amino acids
E)  All of these choices are correct.

Question 14

Which one of the following statements about pH is INCORRECT?

Accepted Answer

A)  An acidic solution has a higher concentration of protons than of hydroxide ions.
B)  Physiological pH is defined as the pH of pure water, 7.0.
C)  Some cellular compartments have different pH values than others.
D)  The pH of a solution can range from 0 to 14.
E)  A solution of pH 5 has a proton concentration 100 times greater than a solution of pH 7.

Question 15

Water is able to dissolve many compounds as a result of which of the following?

Accepted Answer

A)  the fact that water molecules are polar
B)  the fact that water molecules are nonpolar
C)  the fact that the hydrogen atoms in water molecules have a slight negative charge
D)  the fact that most nonwater molecules are hydrophobic
E)  the fact that water molecules are polar, and that the hydrogen atoms in water molecules have a slight negative charge

Question 16

Certain meteorites have been examined and found to carry samples of which one of the following?

Accepted Answer

A)  lipids
B)  amino acids
C)  polypeptides
D)  lipids and amino acids
E)  lipids, amino acids, and polypeptides

Question 17

As water is heated, the temperature rises before any hydrogen bonds between water molecules are broken.

Accepted Answer

A) True 
 B)False

Question 18

Which of the following molecules is classified as an organic molecule?

Accepted Answer

A)  NH3 (ammonia) 
B)  H2O (water) 
C)  NaCl (sodium chloride or salt) 
D)  O2 (oxygen gas) 
E)  None of the other answer options is correct.

Question 19

The ability of atoms to attract electrons is referred to as:

Accepted Answer

A)  van der Waals attraction.
B)  potential energy.
C)  hydrophobicity.
D)  cohesion.
E)  electronegativity.

Question 20

How many hydrogen atoms are present in a hydrocarbon chain of eight carbon atoms with three double bonds and the rest single bonds?

Accepted Answer

A)  10
B)  12
C)  14
D)  16

Exam 2: The Molecules of Life

Imagine you are looking at a bottle of salad dressing containing oil, vinegar, and water. You notice that the oil sits on "top" of the other liquids. This is due, in part, to the fact that:

Correct AnswerverifiedShow Answer

Which of the following molecules is classified as an organic molecule?

Correct AnswerverifiedShow Answer

The ability of atoms to attract electrons is referred to as:

Correct AnswerverifiedShow Answer

Rank the elements carbon, phosphorus, calcium, and iodine in order of decreasing number of energy shells/levels.

Correct AnswerverifiedICaF...View AnswerShow Answer

Consider two carbon atoms, one represented as 14C and the other as 12C. Which of the following statements is TRUE regarding these two atoms?

Correct AnswerverifiedShow Answer

Calculate the number of different polypeptides, each 10 amino acids long, that can be made if you start with just 5 different kinds of amino acids.

Correct AnswerverifiedAny of the 5 amino acids could...View AnswerShow Answer

You have an aqueous solution with a pH of 8.0. You add sodium chloride to a concentration of 1 gram per 100 milliliters. What happens to the pH?

Correct AnswerverifiedShow Answer

List the five most abundant elements found in living organisms. For each of the following, indicate the biologically important molecules in which they are MOST important.

Correct Answerverifiedcarbon - all macromoleculeshyd...View AnswerShow Answer

If an atom has three electrons, how many occupied orbitals will the atom have, and how many electrons will be in each?

Correct AnswerverifiedThe atom will have two orbital...View AnswerShow Answer

Which one of the following statements about a carbon-carbon double bond is CORRECT?

Correct AnswerverifiedShow Answer

Which of the following ranks the elements carbon, sodium, calcium, and iodine in order of decreasing abundance in living organisms?

Correct AnswerverifiedShow Answer

How does the interaction between water and hydrophobic molecules help to organize biological systems?

Correct AnswerverifiedBecause water molecules prefer...View AnswerShow Answer

Humans are often referred to as "carbon-based" life forms. Given that humans breathe oxygen, shouldn't humans be referred to as "oxygen-based" life forms?

Correct AnswerverifiedShow Answer

How many hydrogen atoms are present in a hydrocarbon chain of eight carbon atoms with three double bonds and the rest single bonds?

Correct AnswerverifiedShow Answer

As water is heated, the temperature rises before any hydrogen bonds between water molecules are broken.

Correct AnswerverifiedShow Answer

Water is able to dissolve many compounds as a result of which of the following?

Correct AnswerverifiedShow Answer

Certain meteorites have been examined and found to carry samples of which one of the following?

Correct AnswerverifiedShow Answer

A man heats water in a teakettle while drinking a glass of water at room temperature. The water molecules in the teakettle are moving _____ the water molecules in the glass.

Correct AnswerverifiedShow Answer

Which of the following was required for early life to form on Earth?

Correct AnswerverifiedShow Answer

Which one of the following statements about pH is INCORRECT?

Correct AnswerverifiedShow Answer

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ICaF...
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Consider two carbon atoms, one represented as ¹⁴C and the other as ¹²C. Which of the following statements is TRUE regarding these two atoms?

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Any of the 5 amino acids could...
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carbon - all macromoleculeshyd...
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The atom will have two orbital...
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Because water molecules prefer...
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