Question 1

The uncharged component in the core of an atom is a(n)________.

Accepted Answer

The answer of The uncharged component in the core of...

Question 2

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 is prepared,with each tube containing a purified sample of one of the following organic compounds.The chemical is then added to each tube.The test tube containing ________ will always turn bright red.

Accepted Answer

Nucleic acids contain both nitrogen and phosphorus, which are necessary for DNA and RNA synthesis. Therefore, the chemical will always turn bright red in the presence of nucleic acids. Proteins also contain nitrogen, but not all proteins contain phosphorus, so this choice is not as specific. Carbohydrates and phospholipids do not contain nitrogen or phosphorus, so they would not react with the chemical.

Question 3

Which statement below is consistent with the facts that one function of nucleotides is energy transfer and that carbohydrates can be used to store energy?

Accepted Answer

Nucleotides are involved in energy transfer, and carbohydrates can be used to store energy. Choice A is the only statement that connects both ideas and is consistent with the facts presented in the question.

Question 4

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

Accepted Answer

Fatty acids do not store genetic information. They play important roles in energy storage, membrane construction, and building blocks for fats.

Question 5

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

Accepted Answer

The energy that ATP molecules deliver in chemical reactions is stored in covalent bonds between the molecule's phosphate groups. When the ATP molecule is hydrolyzed, the phosphate bond is broken, releasing the energy stored in the bond. This energy can then be used for cellular work.

Question 6

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

Accepted Answer

Phospholipids arrange themselves with their hydrophobic tails on the inside, away from water, and their hydrophilic heads facing the water, forming structures like micelles or bilayers.

Question 7

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

Accepted Answer

The answer of An atom that becomes charged due to...

Question 8

Both trans fats and saturated fats have been linked to comparable groups of undesirable health complications.What do the two types of molecules share in common that may account for the similarity in their health impacts?

Accepted Answer

The answer of Both trans fats and saturated fats have...

Question 9

The process of partial hydrogenation turns liquid plant lipids into semisolid lipids by

Accepted Answer

The process of partial hydrogenation involves removing double bonds from the fatty acid chains of liquid plant lipids and adding hydrogen atoms in their place, making them more saturated and solid at room temperature. This also leads to the formation of trans fats, which are known to have negative health effects.

Question 10

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?

Accepted Answer

Enzymes are proteins that can be denatured or destroyed by high temperatures. Leaving the stain remover in the hot trunk of a car could denature the enzymes, making them ineffective at removing the stain.

Question 11

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

Accepted Answer

Oils are liquid at room temperature because they are primarily composed of unsaturated fatty acids that have a lower melting point than saturated fatty acids. This is in contrast to solid fats, such as butter or lard, which are primarily composed of saturated fatty acids and are solid at room temperature.

Question 12

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 texture during cooking?

Accepted Answer

The addition of heat causes proteins to denature which means the protein structure changes, causing them to lose their natural shape and link together, resulting in a firmer texture. This is the reason why meat becomes firm during cooking. A and C are incorrect because heat does not cause the cells to produce more protein or convert proteins into lipids. B is incorrect because there are no nucleic acids in meat that can form chemical bonds with proteins during cooking.

Question 13

Nucleotides

Accepted Answer

Nucleotides are the building blocks of nucleic acids, which include DNA and RNA. They are composed of a nitrogenous base, a sugar molecule, and a phosphate group.

Question 14

The following figure shows the structural and space-filling models for stearic acid and oleic acid.  Although the two fatty acids have the same number of carbon atoms,they have different three-dimensional configurations; oleic acid has a slight bend near the middle.The result is that

Accepted Answer

The slight bend in oleic acid creates a kink in its molecule, preventing it from packing tightly and forming a solid state at room temperature. Therefore, a pure sample of oleic acid would be more liquid than a pure sample of stearic acid.

Question 15

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?

Accepted Answer

Phospholipids have two distinct ends, a polar head and a nonpolar tail. The polar head interacts with water, while the nonpolar tail is attracted to oily dirt. Therefore, the phospholipid tail attaches to the oily dirt, while the polar head interacts with the rinse water and carries the dirt (and soap) away with it. This is how soaps work to clean better than water alone.

Question 16

Which of the following is NOT a function of cholesterol?

Accepted Answer

Cholesterol is a necessary component in the cell membranes of animals, not plants. Plant cell membranes contain phytosterols instead.

Question 17

In water,phospholipids arrange themselves such that

Accepted Answer

Phospholipids are amphipathic molecules, meaning they have both hydrophobic and hydrophilic regions. In water, the hydrophobic tails of the phospholipids arrange themselves away from the water, forming a bilayer with the hydrophilic head groups facing the water. This creates a stable structure that is essential for biological membranes. A and C are incorrect because it is the hydrophobic tails, not the head groups or specific types of fatty acids, that are kept away from the water. D is incorrect because while phospholipids do have charged groups, these groups interact with water indirectly through hydrogen bonding.

Question 18

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

Accepted Answer

The answer of The sum of an atom's protons and...

Question 19

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

Accepted Answer

The answer of Oxygen has six electrons in its outer...

Question 20

Which of the following is NOT a method used to tenderize meat?

Accepted Answer

Marinades with high pH do not tenderize meat; instead, acidic marinades (low pH) like lemon juice, vinegar, or wine are used for tenderizing.

Quiz 2: The Chemistry of Life