bio

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

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?

Add more of the proteins to the plasma membrane and measure the rate of the particle movement.

An investigator wants to understand whether a newly found membrane protein is involved in membrane transport of a certain particle. Which investigation will help determine whether the new membrane protein is a channel protein involved in membrane transport?

The ability to form a covalent bond with both its NH2 group and its COOH group

As shown in Figure 1, an amino acid must have which of the following properties in order to be incorporated into a polypeptide?

Na+ transport out of the cell requires ATP hydrolysis.

The manner in which several different ions and molecules move through a cell membrane is shown in the diagram above. For each ion or molecule, the relative concentration on each side of the membrane is indicated. Which of the following accurately describes one of the movements taking place?

Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.

The molecular structures of linoleic acid and palmitic acid, two naturally occurring substances, are shown in the figure.Based on the molecular structures shown in the figure, which molecule is likely to be solid at room temperature?

By simple diffusion

Aldosterone (a steroid hormone) is a small, nonpolar, hydrophobic molecule that enters a target cell by moving across the plasma membrane, down a concentration gradient. Based on the information presented, how does aldosterone most likely enter target cells?

The water molecules in ice are farther apart than those in liquid water, so the ice floats, maintaining the warmer, denser water at the lake bottom.

As shown in the diagram, when environmental temperatures drop below freezing, a layer of ice typically forms on the surface of bodies of freshwater such as lakes and rivers. Which of the following best describes how the structure of ice benefits the organisms that live in the water below?

hydrogen bonds between molecules at the surface of the water provide surface tension, which allows the water surface to deform but not break under the insect.

Figure 1 is a diagram of water molecules at the air-water interface at the surface of a pond. Based on Figure 1, which of the following best describes how the properties of water at an air-water interface enable an insect to walk on the water's surface?

The formation of a covalent peptide bond in a dehydration synthesis reaction

Figure 1 represents a common process that occurs in organisms. Which of the following is an accurate description of the process shown in Figure 1 ?

Passage of a solute against its concentration gradient

If ATP breakdown (hydrolysis) is inhibited, which of the following types of movement across cell membranes is also inhibited?

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

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?

Repeat the process with other salt concentrations.

Intravenous (IV) therapy is used for fluid replacement in instances of dehydration in humans and other animals. One type of IV fluid is essentially a saltwater solution. To determine the best concentration for therapy in people, a team of students is researching the effects of solutions of different salt concentrations on red blood cells. The following observations were made from three different red blood cell samples viewed under a microscope.The team wants to extend the research project. What should the team of students do next to obtain data that are more conclusive?

The organelle has a double membrane.

Researchers claimed that a particular organelle originated from a free-living prokaryotic cell that was engulfed by a larger cell, as shown in Figure 1.

The Na+concentration inside the cell will increase.

Some membrane proteins help maintain the concentrations of ions inside a cell by transporting the ions across the cell's plasma membrane. Other membrane proteins form pores in the plasma membrane through which the ions can diffuse. A model showing the influence of membrane proteins on the movement of sodium (Na+) and potassium (K+) ions across a plasma membrane is presented in Figure 1. Based on the model presented in Figure 1, which of the following changes will most likely result from a depletion of available ATP stores inside the cell?

Sodium ions cannot move across the cell membrane when membrane protein activity is blocked.

The cell membrane is selectively permeable due to its structure. Thus, the internal environment of the cell is distinct from the external environment of the cell. One biologist hypothesizes that small nonpolar molecules readily pass through the membrane. Another biologist alternatively hypothesizes that these types of molecules require channel and transport proteins that are embedded in the membrane in order to move across the membrane.Which of the following data would best refute this alternative hypothesis?

osmosis

The following question refer to the graph below, which illustrates the percent change in the mass of pieces of plant tissue placed in solutions of different sucrose molarities. Water enters and leaves the plant cells primarily by

Both molecules contain nucleotides that form base pairs with other nucleotides, which allows each molecule to act as a template in the synthesis of other nucleic acid molecules.

Which of the following best describes a structural similarity between the two molecules shown in Figure 1 that is relevant to their function?

H+ ions will stop moving through the protein.

Which of the following best predicts the effect of not having ATP available to supply energy to this process?

It increases the surface area available for ATP production, which results in faster cell growth.

Which of the following conclusions about increasing the number of folds in the inner mitochondrial membrane is best supported by the results of the experiment?

Monomers are joined by a covalent bond, and a water molecule is produced.

Which of the following is common feature of the illustrated reactions showing the linking of monomers to form macromolecules?

Hydrogen bonds between the oxygen atom of one water molecule and a hydrogen atom of another water molecule

Which of the following is responsible for the cohesive property of water?

Mitochondria are surrounded by a double membrane.

Which of the following observations best supports the claim that mitochondria evolved from once-free-living prokaryotic cells by the process of endocytosis?

Rabbits eat plants and break down plant molecules to obtain carbon and other atoms that they rearrange into new carbon-containing molecules.

Which of the following statements best describes how organisms such as rabbits obtain the carbon necessary for building biological molecules?

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

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

It will show the color change that occurs in the absence of enzyme activity.

Which of the following statements best justifies the inclusion of test tube V as a control in the experiment?

The transport of glucose molecules against a concentration gradient

Which of the following transport mechanisms will be affected most directly by a temporary shortage of ATP molecules inside the cell?