Question 1

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

Accepted Answer

Marinades with a high pH (basic or alkaline solutions) are not typically used to tenderize meat. Tenderizing methods usually involve acidic components (like lemon juice, vinegar, or wine), physical methods (like pounding or grinding), or osmotic processes (like brining in salt water), which can break down proteins or alter the meat's structure to make it more tender. High pH substances would not have the same effect and are not commonly used for tenderizing meat.

Question 2

Nucleotides

Accepted Answer

Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Nucleic acids play a crucial role in the storage and transmission of genetic information. They also play a role in cellular signaling and energy transfer, but they are not involved in every chemical reaction in the cell or the formation of physical structures such as hair.

Question 3

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, such as DNA and RNA, contain nitrogen and phosphorus, which is what the chemical is reacting to in order to turn bright red. Proteins also contain nitrogen, but not all proteins contain phosphorus, so the reaction may not occur in all protein samples. Carbohydrates and phospholipids do not contain nitrogen or phosphorus, so the chemical will not react to those organic compounds.

Question 4

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

Accepted Answer

Phospholipids arrange themselves in water so that their hydrophobic tails are shielded from water, inside the lipid droplet, while their hydrophilic heads face the water.

Question 5

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

Both trans fats and saturated fats are linear in structure, which makes them more difficult to metabolize compared to unsaturated fats that have kinks in their chains due to double bonds. This linear structure contributes to their similar health risks.

Question 6

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, while carbohydrates are commonly used as energy storage molecules in living organisms. Option A states that humans need to store and transfer energy, and hence, it is consistent with the facts mentioned in the question. Option B talks about proteins, which are not specifically mentioned in the question. Option C is incorrect as energy transfer and storage are not unique to humans, but are common to all living organisms. Option D is incorrect as photosynthesis occurs in plants and not in humans.

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

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 9

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

Accepted Answer

Partial hydrogenation removes double bonds and adds hydrogen to the fatty acid chains of plant lipids, creating more saturated fatty acids and turning liquid plant lipids into semisolid ones.

Question 10

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

Accepted Answer

Fatty acids are not involved in the storage of genetic information. They play a role in energy storage, membrane construction, and are building blocks of fats.

Question 11

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 12

Which of the following is NOT a function of cholesterol?

Accepted Answer

Cholesterol is not a component of plant cell membranes; plants do not produce cholesterol. Cholesterol is primarily found in animal cells where it plays a crucial role in membrane structure, hormone production, and other functions.

Question 13

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 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 allows the molecules to pack less tightly, resulting in a more liquid consistency compared to stearic acid, which has a straight chain and packs more tightly, resulting in a solid consistency.

B) Stearic acid is actually a saturated fatty acid, meaning all of its carbon-carbon bonds are single bonds and saturated with hydrogen atoms.
C) Stearic acid is commonly found in the form of a solid fat, such as in animal fats and cocoa butter.
D) Oleic acid is actually classified as a monounsaturated fatty acid, meaning it has one carbon-carbon double bond.

Question 15

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

The enzymes in the stain remover may have been denatured or damaged if left in a hot temperature, reducing their ability to remove the stain. A and D are not relevant as the hydrophilic/hydrophobic nature of the stain and remover do not necessarily inhibit their interaction with enzymes. B is also not relevant as the pH of water in a house is typically neutral and should not affect the enzymatic activity of the stain remover.

Question 16

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

Accepted Answer

Oils are liquid at room temperature because they have a lower melting point and higher unsaturation compared to solid fats.

Question 17

In water,phospholipids arrange themselves such that

Accepted Answer

Phospholipids are amphipathic molecules, meaning they have both hydrophilic and hydrophobic regions. In water, phospholipids arrange themselves in a bilayer with their hydrophilic head groups facing outwards towards the water and their hydrophobic tails kept away from the water, facing towards each other in the center of the bilayer. This arrangement is known as the phospholipid bilayer, which is a fundamental component of cell membranes.

Question 18

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

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.

Question 19

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

Accepted Answer

The energy stored in ATP molecules is stored in the covalent bonds between the phosphate groups. When these bonds are broken, energy is released, which can be used by the cell for various processes such as muscle contraction, protein synthesis, and active transport.

Question 20

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

When heat is applied to meat, the proteins in the meat denature (unravel) and then link together. This causes the meat to become firmer as it cooks. Therefore, choice D, "The addition of heat causes proteins to denature and link together," is the best answer.

Quiz 2: The Chemistry of Life