Deck 3: Chemistry of Life

Question 1

Atoms in a single molecule of methane,CH₄,share electrons.Methane is formed by ________ bonds joining ________ atoms.

A) hydrogen; 2
B) covalent; 5
C) ionic; 5
D) ionic; 2

Answer 1

B

Question 2

Individual water molecules orient toward each other because of the ________ bonds that form between them.

A) covalent
B) peptide
C) hydrogen
D) ionic

Answer 2

C

Question 3

Sodium chloride (table salt)is formed when positively charged sodium ions and negatively charged chloride ions are chemically attracted to each other.This attraction is best described as a(n)

A) hydrogen bond.
B) ionic bond.
C) covalent bond.
D) solution.

Answer 3

B

Question 4

In the chemical reaction that forms hydrogen peroxide (H₂O₂),hydrogen and oxygen share electrons,creating ________ bonds between the two atoms.

A) covalent
B) peptide
C) hydrogen
D) ionic

Question 5

Which of the following is likely to participate in ionic bonding?

A) Li⁺
B) H₂O
C) He
D) C₆H₁₂O₆

Question 6

Nitrogen has seven protons,seven neutrons,and seven electrons.What is the atomic mass of nitrogen?

A) 0
B) 7
C) 14
D) 21

Question 7

If iodide ions (I⁻)were dissolved in water,they would be attracted to

A) A only.
B) B only.
C) C only.
D) A and C.

Question 8

Which of the labeled areas of the water molecule pictured below possesses a partial negative charge?

A) A only
B) B only
C) C only
D) A and C

Question 9

Hydrogen and oxygen atoms are held together within an individual water molecule by ________ bonds.

A) hydrogen
B) peptide
C) polar covalent
D) ionic

Question 10

When calcium (Ca⁺)and chloride (Cl⁻)interact with one another,they bond using ________ bonds.

A) hydrogen
B) peptide
C) covalent
D) ionic

Question 11

The subatomic particles that possess a single negative charge and surround the nucleus are the

A) isotopes.
B) protons.
C) neutrons.
D) electrons.

Question 12

Which of the images shown below illustrates both hydrogen bonds and covalent bonds?

A)
B)
C)
D)

Question 13

The subatomic particles that possess a single negative charge,surround the nucleus,and are lost or gained by atoms called ions are the

A) isotopes.
B) protons.
C) neutrons.
D) electrons.

Question 14

The chemical reaction that represents photosynthesis is 6 H₂O ⁺ 6 CO₂ → C₆H₁₂O₆ ⁺ 6 O₂.What are the reactants?

A) H₂O and CO₂
B) C₆H₁₂O₆ and CO₂
C) H₂O and O₂
D) C₆H₁₂O₆ and CO₂

Question 15

Which of the following is correct about hydrogen bonds?

A) Individually, hydrogen bonds are very strong.
B) They form between neighboring oxygen atoms.
C) They do not involve binding with a hydrogen atom.
D) They form due to partial positive and partial negative charges on atoms.

Question 16

The bonds connecting the atoms in the molecule below are ________ bonds

A) polar, hydrogen
B) polar, covalent
C) nonpolar, ionic
D) nonpolar, covalent

Question 17

Neighboring water molecules are held together with hydrogen bonds because

A) partially negatively charged oxygen atoms and partially positively charged hydrogen atoms on separate water molecules are attracted to one another.
B) the hydrogen and oxygen atoms within a single water molecule share electrons equally.
C) the oxygen and hydrogen atoms that participate in hydrogen bonding are sharing electrons within a single valence shell.
D) ionic interactions repel water molecules from hydrophobic oils that may be present in a solution.

Question 18

O₂,also termed atmospheric oxygen,is formed by a covalent bond between two oxygen atoms.This type of bond involves oxygen atoms

A) releasing protons.
B) releasing electrons.
C) sharing protons.
D) sharing electrons.

Question 19

Ionic bonds ________,whereas covalent bonds ________.

A) form between the same two elements; form between different elements
B) hold together compounds that do not dissolve in water; hold together molecules that dissolve in water
C) hold together oppositely charged atoms; hold together atoms that share electrons
D) consist of atoms with partial charges; consist of atoms with full positive and negative charges

Question 20

Ice floats on water because

A) the crystal structure of ice is more regular than that seen in liquid water.
B) the distance between water molecules in ice is greater than in liquid water.
C) the cool temperature of ice reduces the extent of molecular motion relative to liquid water.
D) when ice forms, the hydrogen bond in the water molecule becomes nonpolar; ice behaves like oil.

Question 21

The pH scale measures the

A) amount of water in a solution.
B) likelihood that a solution will evaporate.
C) concentration of hydrogen ions in a solution.
D) number of atoms found within a molecule.

Question 22

Of the following values,which indicates the MOST basic pH?

A) 5
B) 7
C) 8
D) 10

Question 23

Which of the following solutions has the highest concentration of free H⁺ ions?

A) pH 1
B) pH 4
C) pH 7
D) pH 14

Question 24

A solution with a pH of 3 is

A) acidic.
B) basic.
C) nonpolar.
D) neutral.

Question 25

In making her morning tea,Dorothy drops a sugar cube into the hot water.She stirs the mixture but no longer sees the sugar cube at the bottom of her mug.In this scenario,the sugar is

A) nonpolar.
B) the solvent.
C) an acid.
D) a solute.

Question 26

The most acidic solution in the figure shown below is

A) stomach acid.
B) lemons.
C) oven cleaner.
D) pure water.

Question 27

When ammonia (NH₃)is dissolved in a solution,it accepts hydrogen ions from its surroundings.Ammonia is therefore a(n)

A) base.
B) isotope.
C) salt.
D) acid.

Question 28

When sodium chloride (Na⁺Cl⁻)is dissolved in water,the sodium ion is

A) attracted to the hydrogen atoms of water molecules.
B) repelled by the oxygen atoms of water molecules.
C) attracted to other sodium ions that are being dissolved.
D) attracted to the oxygen atoms of water molecules.

Question 29

A solution with a pH of 4 is ________ acidic than a solution with a pH of 5.The solution with the pH of 4 has a ________ concentration of hydrogen ions than the solution with a pH of 5.

A) more; higher
B) more; lower
C) less; higher
D) less; lower

Question 30

Oil and water do not mix well because

A) water is polar and oil is nonpolar.
B) only identical molecules of the same chemical can easily mix.
C) water has hydrogen bonds and oil is polar.
D) water and oil are covalently bonded.

Question 31

You are given an unknown substance and asked to determine whether it is polar or nonpolar.The easiest way to do this would be to

A) determine whether the compound is held together by hydrogen bonds.
B) determine the number of electrons in the compound's outer shell.
C) mix the compound with an ionic substance to see whether its bonds can withstand the pressure.
D) determine whether the compound dissolves in water.

Question 32

Carbon atoms are bound to each other by ________ bonds.

A) ionic
B) polar
C) hydrogen
D) covalent

Question 33

In making her morning tea,Dorothy drops a sugar cube into some hot water.She stirs the mixture but no longer sees the sugar cube at the bottom of her mug.Based on her observation of sugar dissolving in hot water,she can properly conclude that the sugar is

A) hydrophobic.
B) nonpolar.
C) hydrophilic.
D) inert.

Question 34

Based on the figure shown below,which of the following has a lower concentration of hydrogen ions?

A) milk
B) oranges
C) antacids
D) baking soda

Question 35

A carwash attendant offers to treat Martin's windshield with a protective agent.This substance coats the glass,causing beads of water to easily roll off during a rain shower.Which of the following must be correct about the protective agent?

A) It resists temperature changes well.
B) It must be an acid.
C) It is a polar substance.
D) It must be hydrophobic.

Question 36

The highest concentration of free hydrogen ions is found in

A) household ammonia.
B) lemons.
C) human blood.
D) stomach acid.

Question 37

An acid is a polar substance that dissolves in water and

A) becomes nonpolar.
B) leaves behind an OH⁻ ion.
C) accepts hydrogen ions from the solution.
D) donates hydrogen ions to the solution.

Question 38

After adding a small amount of Solution A to Solution B,the pH of Solution B declines from 8 to 3.Solution A must contain

A) a salt.
B) a base.
C) water only.
D) an acid.

Question 39

In living systems,a critical component of many reactions is

A) carbon dioxide.
B) calcium.
C) water.
D) hydrogen sulfide.

Question 40

The most basic solution in the figure shown below is

A) seawater.
B) borax.
C) baking soda.
D) tomatoes.

Question 41

A disaccharide consists of two

A) sugars.
B) hydrocarbons.
C) fatty acids.
D) amino acids.

Question 42

Macromolecules are typically formed by repetitively adding small monomers together.Which macromolecule is properly matched with the appropriate monomer?

A) polypeptide-amino acid
B) nucleic acid-amino acid
C) polysaccharide-nucleotide
D) triglyceride-cholesterol

Question 43

Which of the following statements is true of proteins,carbohydrates,and nucleic acids?

A) All three are used to store genetic information.
B) None of these macromolecules mixes well with water.
C) Each of these molecules is built from a common set of monomers.
D) All of these molecules are primarily used as energy-storage molecules.

Question 44

The central element found in organic molecules is

A) calcium.
B) carbon.
C) silicon.
D) sodium.

Question 45

A scientist observed a chemical that changes to bright red in the presence of organic compounds containing nitrogen and phosphorus.To test this chemical,a set of test tubes each containing a purified sample of one of the following organic compounds is prepared.The chemical is then added to each tube.The test tube containing ________ will always turn bright red.

A) nucleic acids
B) proteins
C) carbohydrates
D) phospholipids

Question 46

Carbon's prominence in living systems can be explained by the fact that

A) it forms weak reversible bonds.
B) it bonds with up to three other atoms.
C) carbon-based molecules can form long chains and rings.
D) it does not form small molecules.

Question 47

Carbon is an example of a(n)

A) compound.
B) macromolecule.
C) element.
D) amino acid.

Question 48

Astronauts returning from outer space studied samples taken from their lunar landing.They found that one of their samples was coated with organic compounds.Which of the following statements must be correct about their samples?

A) The compounds must be covered with ammonia (NH₃) and water vapor.
B) The samples must lack water, but contain DNA.
C) The samples must contain carbon atoms.
D) The specimen must lack water, pesticides, and added hormones.

Question 49

Which of the following is the largest in size?

A) glucose
B) protein
C) carbon atom
D) nucleotide

Question 50

Which of the following are composed of the same monomers?

A) proteins and DNA
B) RNA and cellulose
C) starch and cellulose
D) cholesterol and sucrose

Question 51

Which of the following pieces of evidence would best demonstrate that a bacterium found on an asteroid originated in outer space?

A) the presence of volcanic ash on the outside of the bacterial cell
B) the absence of common gases found in Earth's atmosphere
C) the presence of right-handed amino acids in the bacterium's proteins
D) the absence of hydrogen bonds between water molecules in the bacterial cell

Question 52

Which of the following could be built solely from glucose molecules?

A) fatty acids
B) DNA
C) oils
D) starch

Question 53

We use soap to clean ourselves better than we could with water alone.Soaps contain phospholipids that are responsible for the cleansing action.Which of the following statements is the MOST likely explanation for how soaps work?

A) Phospholipids are ions and therefore mix with both the water and oily dirt.
B) Phospholipids are completely hydrophilic, and therefore oily dirt takes the place of the phospholipid molecules that would be dissolved in the rinse.
C) The phospholipid tail attaches to the oily dirt while the phospholipid head interacts with the rinse water and carries the dirt (and soap) away with it.
D) The nonpolar fatty acid chains that make up the heads of the phospholipid are hydrophilic, and thus are repelled by the water.

Question 54

A researcher in a laboratory tests a food item and identifies protein in it.The food item must also contain

A) glucose.
B) lipids.
C) amino acids.
D) nucleotides.

Question 55

The genetic material found in all living things is made of building blocks called

A) nucleotides.
B) monosaccharides.
C) phospholipids.
D) steroids.

Question 56

One of the symptoms of kidney disease is the presence of proteins in a patient's urine.To quickly test for kidney disease using a urine sample,a doctor might add a chemical that causes a color change when

A) nitrogen, but not oxygen, is present.
B) nitrogen, but not phosphorus, is present.
C) only oxygen and hydrogen are present.
D) only carbon and hydrogen are present.

Question 57

Laura's supervisor provides her with lipids,carbohydrates,proteins,and nucleic acids and asks her to determine their chemical components.Which of the following elements would she NOT expect to find in these items?

A) phosphorus
B) iron
C) hydrogen
D) nitrogen

Question 58

Nucleotides

A) are the building blocks of proteins.
B) are involved in every chemical reaction in the cell.
C) form physical structures such as hair.
D) are the building blocks of nucleic acids.

Question 59

Monomers that can be commonly made from components in Earth's atmosphere are

A) nucleotides.
B) amino acids.
C) triglycerides.
D) monosaccharides.

Question 60

Which of the following is an organic compound?

A) water (H₂O)
B) methane (CH₄)
C) ammonia (NH₃)
D) carbon dioxide (CO₂)

Question 61

The weak electrical attractions that form between two water molecules are called ________ bonds.

Question 62

During a study session,a Biology classmate holds up a bottle of water and mentions that there are both hydrogen bonds and covalent bonds found within the liquid.Explain your classmate's statement by describing the types of bonds that are found within your bottle of water.

Question 63

The element ________ makes up the chemical backbone of most molecules on planet Earth.

Question 64

Nonpolar molecules that are repelled by water are known as ________ molecules.

Question 65

Nitrogen has an atomic number of 7 and an atomic mass number of 14.Using the image provided below,diagram the location and number of protons,neutrons,and electrons in nitrogen.

Question 66

Molecules with an uneven distribution of charge are described as ________.

Question 67

The biomolecules that are copied and transmitted from parents to offspring are ________.

Question 68

The pH value of pure water is 7.0.When Ralph measures the pH of rainwater in his neighborhood,he finds the pH value is 6.0.Which of these solutions has a higher concentration of hydrogen ions? What is the difference in the hydrogen ion concentration?

Question 69

A solution with a higher free H⁺ ion concentration is more ________ than a solution with a lower free H⁺ ion concentration.

Question 70

Gina makes vinaigrette dressing with olive oil and vinegar and then shakes the jar vigorously.For a few minutes it appears as if the oil and vinegar have mixed.Then,she notices the two liquids separating from each other.Describe why these two liquids do not stay together even after vigorous mixing.

Question 71

The number that represents neutrality on the pH scale is ________.

Question 72

After giving a baby a bath,a parent applies baby oil to their child's skin.How does the baby oil help the baby's skin to retain moisture throughout the day? Explain the chemical basis of water retention in this example.

Question 73

An atom that becomes charged due to the gain or loss of an electron is called a(n)________.

Question 74

Antibodies are an important class of human proteins that function in immune defense.If scientists fragmented antibodies under laboratory conditions,what chemical building blocks would they recover?

A) monosaccharides
B) phospholipids
C) amino acids
D) nitrogenous bases

Question 75

The bonds within an individual water molecule and between separate water molecules explain the special properties of water.Describe the type of bond within individual water molecules and the type of bond between separate water molecules.Then,list two unique properties of water.

Question 76

Lithium,with an atomic number of 3,has a tendency to lose electrons when it chemically bonds to another atom.What type of chemical bonds does lithium usually form with other atoms? Explain how you determined your answer.

Question 77

The positively charged subatomic particle is located in the ________.

Question 78

A solution with a pH of 9 is more ________ than a solution with a pH of 7.

Question 79

The class of macromolecules that do not form true polymers are the ________.

Question 80

How many different amino acids are used to build proteins?

A) 90
B) 20
C) 19
D) 4