AP BIO MIDTERM Review

During a science experiment, Jackson, Evelyn, and Samuel observed a water molecule. They noticed that there was an unequal sharing of electrons in the water molecule. What is this property of water called?

• polarity

• Cohesion

• Adhesion

• Capillary action

A chemical binds to a protein composed of a single polypeptide chain and prevents the formation of an alpha helix that is typically formed in the absence of the chemical. Which of the following best describes the effect the chemical has on the structure of the protein?

• The primary structure held together by covalent bonds is affected.

• The secondary structure held together by hydrogen bonds is affected.

• The secondary, tertiary, and quaternary structures are affected.

• All levels of protein structure are effected.

1. Determine the median for the following values: 12, 8, 16, 22, 17, 12, 16, 20

A researcher proposes a model of an enzyme-catalyzed reaction in which a reactant is converted to a product. The model is based on the idea that the reactant passes through a transition state within the enzyme-substrate complex before the reactant is converted to the product.

Which of the following statements best helps explain how the enzyme speeds up the reaction?

• The enzyme's active site binds to and stabilizes the reactant, which decreases the free-energy change of the reaction.

• The enzyme's active site binds to and stabilizes the transition state, which decreases the activation energy of the reaction.

• The enzyme's active site binds to and stabilizes the product, which increases the amount of energy released by the reaction.

• The enzyme's active site binds to and stabilizes both the reactant and the product at the same time, which increases the reaction's equilibrium constant.

Orlando and Daniela were discussing a type of chemical reaction in their AP Biology class. They were talking about those reactions where the products have less energy than the reactants. What type of reactions were they discussing?

• Endergonic reactions

• Exergonic reactions

• Catalytic reactions

• Combustion reactions

Membrane-bound organelles have been an important component in the evolution of complex multicellular organisms. Which of the following best summarizes an advantage of eukaryotic cells having internal membranes?

• Eukaryotic cells are able to reproduce faster because of the presence of organelles.

• Some organelles, such as mitochondria and chloroplasts, are similar to prokaryotic cells in structure.

• Organelles isolate specific reactions, increasing metabolic efficiency.

• Compartmentalization leads to a higher mutation rate in DNA, which leads to more new species.

Which of the following accurately describes a model of active transport?

• A membrane channel protein facilitates the movement of molecules from an area of high concentration on the outside of the cell to an area of lower concentration on the inside.

• A cell in a hypotonic solution swells as water moves into it.

• A membrane protein binds a specific molecule outside of the cell and moves the molecule into the cell where there is already a high concentration of the molecule compared with the outside.

• A membrane protein binds a specific molecule on the inside of the cell and moves the molecule to an area of lower concentration on the outside of the cell.

Intravenous (IV) solutions administered to patients are normally isotonic. Which of the following is most likely if an IV of distilled water is administered to a patient?

• The cells that are exposed to hypotonic solutions will shrink as a result of salt moving into the blood.

• The liver will secrete additional bile salts into the blood to raise the tonicity of the administered fluid.

• The cells that are exposed to hyptonic solutions will expand as water moves osmotically into the cells from the blood

• The patient's respiration rate will slow to compensate for the higher levels of circulating blood.

A researcher designs an experiment to investigate the effect of environmental temperature on the function of an enzyme. For each trial included in the experiment, the researcher will add the enzyme and its substrate to an aqueous buffer solution and then measure the amount of product formed over 20 minutes.

Which of the following must remain the same for all trials of this experiment?

• The initial concentration of the substrate.

• The final concentration of the product.

• The three-dimensional structure of the enzyme.

• The temperature of the aqueous buffer solution.

The synthesis of protein or carbohydrate polymers always produces which of the following as a byproduct?

• ATP

• Oxygen

• Carbon dioxide

• Water