AP Biology Fall 2023

Hydrophobic substances such as vegetable oil are

• 1.  nonpolar substances that repel water molecules.

• 1.  nonpolar substances that have an attraction for water molecules.

• 1.  polar substances that repel water molecules.

• 1.  polar substances that have an affinity for water.

• 1.  charged molecules that hydrogen-bond with water molecules.

2. A biologist wants to use a radioactive isotope of nitrogen to radiolabel certain molecules in a culture of cells she is growing.  If the biologist uses 15N, which of the following groups of macromolecules will be labeled in the culture of cells?

• 1. Nucleic acids and proteins 

• 1. Phospholipids 

• 1. Nucleic acids

• 1.   Proteins

3. Which of the following is true of the molecule shown in the Figure above? 

• 1. It is an unsaturated fatty acid. 

• 1. Molecules of this type are usually liquid at room temperature

•   Molecules of this type cause the membrane to be more solid

7. The diagram above illustrates a dipeptide, is an example of

• removing a water known as dehydration synthesis

• adding water known as hydrolysis

• photosynthesis

• photolysis

7. Upon chemical analysis, a particular polypeptide was found to contain 144 amino acids. How many peptide bonds are present in this protein?

• 1. 143

• 1. 144

• 1. 146

• 1. 145

A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. Which of the following observations provides the best evidence to support the claim?

• 1. Elysia chlorotica will die if not exposed to light.

• 1. Elysia chlorotica grows when exposed to light in the absence of other food sources.

• 1. Elysia chlorotica grows faster when exposed to light than when placed in the dark.

Which of the following statements best helps explain the reaction specificity of an enzyme?

3. The concentration of the enzyme inside living cells is greater than the concentration of substrate.

• 1. The free energy of the reactants is greater than the free energy of the products.

• 1. The equilibrium constant of the reaction is much greater than 1.

• 2. The shape and charge of the substrates are compatible with the active site of the enzyme.

 Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?

• 1. The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH

• 1. The light-dependent reactions occur only during the day; the light-independent reactions occur during the night.

• 1. The light-dependent reactions occur in the cytoplasm; the light-independent reactions occur in chloroplasts

 Which of the following statements is a correct distinction between autotrophs and heterotrophs? 

• 1. Autotrophs, but not heterotrophs, can nourish themselves beginning with CO2 and other nutrients that are inorganic.

• 1. Only heterotrophs have mitochondria.

• 1. Cellular respiration is unique to heterotrophs.

 Succinate Dehydrogenase is an enzyme that catalyzes the oxidation of Succinic Acid.  If Malonic Acid is added to the mixture, the rate of reaction is reduced.  An increase in succinic acid will increase the rate of reaction again.  For this system, which term best describes Malonic Acid? 

• 1. Substrate

• 1. End product

• 1. Competitive Inhibitor

• 1. Non-competitive inhibitor