Deck 4: Chemical Building Blocks

Question 1

An atom of the element with the atomic number of 11 (which can form an ion) always contains 11 _____.

A) neutrons
B) nuclei
C) electrons
D) protons

Answer 1

D

Question 2

In the figure below, a negative ion is surrounded by water molecules.
The water molecules are oriented as shown above because the slightly _____________ in the water molecule is (are) attracted to the ion.

A) negative hydrogen atoms
B) positive hydrogen atoms
C) negative oxygen atom
D) positive oxygen atom

Answer 2

B

Question 3

Which of the following combinations of atoms would form ionic bonds?

A) H+ and O
B) Na+ and K+
C) Na+ and Cl-
D) PO4- and I2-

Answer 3

C

Question 4

The outer electron shell of a nitrogen atom can hold up to eight electrons, but contains only five. As a result, nitrogen can form ______ covalent bonds.

A) 0
B) 1
C) 3
D) 8

Question 5

In the equation 3H₂ + N₂ ® 2NH₃, how many molecules of hydrogen gas (H₂) are present?

A) 2
B) 3
C) 6
D) 12

Question 6

The strongest possible chemical link between two atoms is a(n)

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

Question 7

Ionic bonds

A) result from the sharing of electrons between atoms.
B) form only between polar molecules.
C) form between atoms that develop opposite charges.
D) are due to protons repelling each other.

Question 8

Individual water molecules are pulled toward each other by _______ bonds.

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

Question 9

The figure below shows two hydrogen atoms.
How many covalent bonds will form between these two atoms?

A) 1
B) 2
C) 3
D) None, these atoms would form an ionic bond.

Question 10

Oil and water do not mix together well because

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

Question 11

The smallest unit of a chemical element that still has the properties of that element is a(n)

A) amino acid.
B) molecule.
C) atom.
D) bond.

Question 12

Electrons are found

A) in the nucleus of an atom.
B) only in complex molecules.
C) in a shell that surrounds the atom's nucleus.
D) in both the nucleus and inner shell of an atom.

Question 13

An acid is a polar substance that dissolves in water and

A) becomes nonpolar.
B) leaves behind an OH- ion.
C) accepts hydrogen ions.
D) loses hydrogen ions.

Question 14

A solution with a pH of 3 is

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

Question 15

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 16

A proton has _______ charge.

A) no
B) a neutral
C) a negative
D) a positive

Question 17

Of the following which indicates the most basic pH?

A) 3
B) 7
C) 8
D) 10

Question 18

Radioisotopes are useful in scientific research and medicine because they

A) have a different number of protons than other isotopes of the same element.
B) give off high-energy radiation that can be detected by film and specialized scanning machines.
C) have the same atomic mass as other isotopes of the same element.
D) all of the above

Question 19

How many hydrogen atoms are in a molecule of C₈H₁₀N₄O₂?

A) 8
B) 10
C) 24
D) 20

Question 20

In the chemical reaction , _____ are considered reactants.

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

Question 21

In organic compounds, carbon atoms are bound to each other by

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

Question 22

You purchase a laundry product that claims to use natural enzymes to remove stains from clothing. After spilling grape juice on your favorite shirt, you apply the product and wash your shirt (following the directions, of course). When you pull the shirt out of the washer, the stain is still there! Which of the following might explain why the stain remover did not work?

A) The stain remover and the grape juice are both hydrophilic, so the enzymes could not interact with the stain.
B) The pH of the water in your house is too basic or acidic for the enzymes to work properly.
C) Before you got home from the store, you stopped at the mall and left your stain remover in the trunk of your car on a hot day, denaturing the enzymes.
D) Both B and C are possible explanations.

Question 23

ATP is a universal fuel for living organisms. The energy that ATP molecules deliver in chemical reactions is stored in

A) covalent bonds between the molecule's phosphate groups.
B) covalent bonds between the molecule's sugar and phosphate group.
C) hydrogen bonds between the bases of two of these molecules.
D) ionic bonds between the molecule's sugar and base.

Question 24

Which of the following levels of protein structure involves more than one chain of amino acids?

A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure

Question 25

An oil is a lipid that is _______ at room temperature.

A) liquid
B) saturated
C) supersaturated
D) solid

Question 26

One function of nucleotides is energy transfer. Carbohydrates can be used to store energy. These related processes are important because

A) if we could not store and transfer energy, we would have to match our energy input (eating) exactly to our energy requirements, even when sleeping.
B) there are not enough kinds of amino acids for proteins to be used as energy storage molecules.
C) energy transfer and storage are processes that are unique to humans, and therefore are used to determine the classification of people.
D) energy transfer is how we take the energy we gather from photosynthesis and transfer it into water molecules for later use when we need energy.

Question 27

Cholesterol is commonly found in the cell membranes of warm-blooded animals because

A) excess dietary cholesterol is stored in cell membranes.
B) cholesterol is involved in the muscle contractions needed to move an animal around its environment.
C) it prevents the cell membrane from becoming too runny at body temperature.
D) warm-blooded animals tend to consume large amounts of cholesterol-rich foods.

Question 28

A scientists finds a chemical that changes to bright red in the presence of organic compounds containing nitrogen and phosphorus. To test this chemical, you prepare a set of test tubes each containing a purified sample of one of the following organic compounds. You then add the chemical to each tube. Which test tube will always turn bright red?

A) the tube containing nucleic acids
B) the tube containing proteins
C) the tube containing carbohydrates
D) the tube containing phospholipids

Question 29

In water, phospholipids arrange themselves such that

A) their fatty acid head groups are facing the water.
B) their hydrophobic tails are kept away from the water.
C) saturated fatty acids face the water while unsaturated fatty acids are separated from the water.
D) the charged atoms on their fatty acid chains can interact directly with the water molecules.

Question 30

The carbon dioxide you breath out is carried to the lungs in the blood. Carbon dioxide, when dissolved in a liquid, is an acid. How does the body prevent your blood from becoming too acidic on the way to your lungs?

A) Buffers in the blood release OH- ions to make the blood more basic.
B) Buffers in the blood accept H+ ions to make the blood less acidic.
C) Buffers in the blood release H+ to make the blood more basic.
D) Buffers in the blood accept OH- to make the blood less acidic.

Question 31

A molecule composed of amino acids is

A) a nucleotide.
B) a lipid.
C) a carbohydrate.
D) a protein.

Question 32

A molecule with the general formula CH₂O is a(n)

A) protein.
B) carbohydrate.
C) amino acid.
D) nucleic acid.

Question 33

The sugar glucose has an important role

A) in the formation of proteins.
B) in short-term energy storage.
C) in the formation of membranes.
D) as a building block of nucleotides.

Question 34

Pure water has a pH of 7. The inside of a cell is also about pH 7. This might be so because

A) buffers work best when the pH is close to 7.
B) humans are largely made up of water by weight.
C) most of the chemical reactions that occur in humans can proceed optimally at pH 7.
D) ionic bonds cannot form at pH 7.

Question 35

You add a watery solution to another solution and find that the pH drops from 8 to 3. You have added a(n)

A) buffer.
B) acid.
C) phospholipid.
D) base.

Question 36

Which of the following is not a role of fatty acids in living organisms?

A) energy storage
B) storage of genetic information
C) membrane construction
D) building blocks of fats

Question 37

When phospholipids are added to water, they arrange themselves so that

A) their hydrophobic tails are on the inside of a lipid droplet.
B) their hydrophilic tails are on the outside of a lipid droplet.
C) their hydrophobic heads are facing the water.
D) both A and C

Question 38

When you place a piece of red meat on a hot barbeque, it slowly changes from soft to firm. Meat is primarily made of proteins. Which of the following might account for the change in meat texture during cooking?

A) The heat causes the cells in the meat to produce more protein.
B) The heat causes the chemical bonds to form between the proteins and nucleic acids in the meat.
C) The heat from the barbeque converts proteins into lipids.
D) The addition of heat causes proteins to lose their three-dimensional shape and link together.

Question 39

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 DNA.

Question 40

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 41

The process of partial hydrogenation turns liquid plant lipids into semi-solid lipids by

A) adding antioxidants that prevent lipid oxidation.
B) creating hydrocarbon chains that are more kinked than those in natural fats.
C) substituting nitrogen for carbon in fatty acid chains.
D) removing double bonds from the fatty acid chains of plant lipids.

Question 42

________ ________ are a type of organic compound that plays roles in both heredity and the energy delivery in cells.

Question 43

The uncharged component in the core of atoms is a(n) ____________.

Question 44

A _______ is a compound that maintains the pH of a solution by taking up or releasing hydrogen ions.

Question 45

_______ molecules are nonpolar molecules that are repelled by water.

Question 46

This figure shows the chemical structure and space-filling models for stearic acid and oleic acid.
Although the fatty acids stearic acid and oleic acid have the same number of carbon atoms, they have different three-dimensional structures. Oleic acid has a slight bend in the middle. As a result,

A) a pure sample of oleic acid would be more liquid than a pure sample of stearic acid.
B) stearic acid would be considered an unsaturated fatty acid.
C) you would be more likely to find stearic acid in the form of an oil than in the form of a fat.
D) oleic acid would be considered a saturated fatty acid.

Question 47

The monomers linked together in DNA are called ____________.

Question 48

Lipids with a four-ring structure are called __________.

Question 49

Oxygen has six electrons in its outer shell that can hold up to eight electrons. As a result, oxygen can form up to _____ covalent bonds.

Question 50

The monomers in proteins are ________.

Question 51

_________ are types of proteins that speed up the rate of chemical reactions in the cell.

Question 52

Most living organisms consist of more than 70 percent _______ by weight.

Question 53

The predominant atom in living systems is _______.

Question 54

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

Question 55

The sum of an atom's protons and neutrons is its ________ _______.

Question 56

A group of monomers bonded together form a _______.

Question 57

An atom that becomes charged due to the gain or loss of an electron is called an _______.

Question 58

We use soap to clean ourselves better than we could with water alone. Soaps contain phospholipids which 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 water.
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 59

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

Question 60

Most lipids contain one or more _____ _____, long, hydrophobic hydrocarbon chains.

Question 61

Nucleic acids contain phosphorus but not sulfur.

Question 62

Chemical reactions rearrange atoms but do not create or destroy them.

Question 63

Proteins provide most of the energy for life processes.

Question 64

A solution with a pH of 7 is neither acidic nor basic.

Question 65

This figure shows the chemical structure and space-filling models for stearic acid and oleic acid.

The reason oleic acid is slightly bent (as compared to stearic acid) is that it contains a _____ ______ between two of its carbon atoms.

Question 66

_____ are the most hydrophobic of the four classes of organic compounds because they are made of hydrocarbon chains that repel water.

Question 67

An atom is in its most stable state when all its electron shells are filled to capacity.

Question 68

Steroids and proteins are lipids.

Question 69

A monosaccharide is made up of several sugar molecules strung together.

Question 70

The primary structure of a protein consists of its amino acid sequence.

Question 71

The number of electrons surrounding an atom's core never changes.

Question 72

Nonpolar molecules are highly charged.

Question 73

Phospholipids are found in cell membranes.

Question 74

Covalent bonds contain ions.

Question 75

Describe how the chemical makeup of a carbohydrate differs from that of a nucleic acid.

Question 76

The atoms in water molecules are held together by hydrogen bonds.

Question 77

All the isotopes of a particular element have the same number of protons.