Chapter 6.1-6.5 Bio Knowledge Check 4

Which statements are true of an inhibitor that binds the active site of an enzyme? Select all that apply. These inhibitors are a kind of allosteric regulator that decreases enzyme activity. These inhibitors are structurally similar to the normal substrate of an enzyme. Adding more substrate can reduce the effect of these inhibitors. These inhibitors compete with the substrate for the active site of the enzyme. These inhibitors increase the rate of enzyme activity.

These inhibitors are structurally similar to the normal substrate of an enzyme. Adding more substrate can reduce the effect of these inhibitors. These inhibitors compete with the substrate for the active site of the enzyme.

In cellular chemical pathways the product(s) of any particular reaction are often quickly consumed by the next reaction in the pathway. This would tend to keep the product concentration _____ and drive the reaction _____. high; in the forward direction low; in the forward direction low; in the reverse direction high; in the reverse direction

low; in the forward direction

Which of the choices are examples of living cells or organisms exhibiting kinetic energy? Select all that apply. muscles in a bird's wing contracting an earthworm burrowing through decaying leaf litter fats (triacylglycerides) being mobilized to provide cellular energy single‐celled algae swimming towards a light source energy from soft drink sugars being stored as triacylglycerides in fat cells

muscles in a bird's wing contracting an earthworm burrowing through decaying leaf litter single‐celled algae swimming towards a light source

Animals such as cats, worms, and butterflies are classified as: chemoautotrophs. chemoheterotrophs. photoheterotrophs. photoautotrophs.

chemoheterotrophs.

Imagine that a researcher tries to reduce the size of an enzyme by removing all the amino acids from the protein except those flanking, and constituting, the active site. Why wouldn't this work? All of these choices are correct. The removal of the amino acids may affect the ability of the enzyme to bind to substrates. Without the additional amino acids, the protein may not fold properly. The removal of the amino acids will likely affect the shape of the active site.

All of these choices are correct.

Which of the statements represent the laws of thermodynamics? Select all that apply. The amount of energy in the universe is constant. Enzymes lower the activation energy requirement of reactions. The energy available to do work decreases as energy is transformed from one form to another. Matter cycles in the biosphere, but energy flows. All cells arise from pre-existing cells.

The amount of energy in the universe is constant. The energy available to do work decreases as energy is transformed from one form to another.

Which of the statements are true? Select all that apply. The entropy of the products of a reaction is always greater than the entropy at the start of the reaction. The entropy at the start of a reaction is always greater than the entropy of the products. The amount of useable energy resulting from a reaction is always less than the total energy available at the start of the reaction. The energy for a reaction equals the sum of the energy in the product plus energy released as heat and disorder.

The amount of useable energy resulting from a reaction is always less than the total energy available at the start of the reaction. The energy for a reaction equals the sum of the energy in the product plus energy released as heat and disorder.

Of the choices, which can be a product of a catabolic reaction? an amino acid like tryptophan a motor protein like myosin a nucleic acid like RNA a complex carbohydrate like cellulose a lipid like cholesterol

an amino acid like tryptophan

In the metabolic pathway illustrated, the reactant (substrate A) is converted equally to one of two end products, E or G. Use the diagram of the pathway to answer the questions. Letters indicate the substrates and products, and numbers indicate the enzymes. In this pathway, the intermediate, C, is a substrate for both enzyme 3 and enzyme 5 and is converted with equal efficiency to D and F. If end product G inhibits enzyme 3, what would you expect to observe as the amount of G increases in the cell? an increase in the production of G an increase in the production of C an increase in the production of D an increase in the production of E an increase in the production of B

an increase in the production of G

A biologist working in a lab adds a compound to a solution that contains an enzyme and substrate. This particular compound binds reversibly to the enzyme at the active site. Once the compound is bound to the enzyme, the catalysis of substrate to product stops. Which of the statements is true of the compound? The effect of the compound cannot be overcome by adding more substrate. The compound is a catalyst for the reaction. The compound is an allosteric inhibitor. The compound is an allosteric activator. The effect of the compound can be overcome by adding more substrate.

b. The effect of the compound can be overcome by adding more substrate.

The synthesis of ATP from ADP and Pi is a(n) _____ reaction with ____ ΔG. reversible; zero endergonic; a positive endergonic; a negative exergonic; a negative exergonic; a positive

endergonic; a positive

Plant cells rely on energy obtained directly from the sun to carry out cellular processes and derive energy from sugars only as a backup on cloudy days. true false

false

Of the molecules, which has the greatest chemical potential energy? carbon dioxide alanine glucose sodium chloride water

glucose

Based on what you know of ATP's chemistry, which of the substances is most likely to have similar functions in energy‐management processes? steroids potassium ions (K+) lysine (amino acid) guanosine nucleotide triphosphate phospholipids

guanosine nucleotide triphosphate

In a metabolic pathway, a series of enzymatic reactions catalyzes the conversion of molecule A to molecule E. Several intermediate steps are involved in which the product of one reaction becomes the substrate for the next. The graph illustrates the changes of free energy that occur at each step in the pathway. Overall, this _____ based on the changes in free energy that take place as A is converted to E.pathway has four endergonic reactionsis an anabolic pathwaypathway has four exergonic reactionsis a catabolic pathway

is an anabolic pathway

Oak trees are categorized as: chemoautotrophs. chemoheterotrophs. photoautotrophs. photoheterotrophs.

photoautotrophs.

Organic molecules store _____ energy in their _____ bonds. kinetic; hydrogen potential; covalent kinetic; ionic potential; ionic kinetic; covalent

potential; covalent

Consult the figure to help you make your predictions. Consider an enzyme that has these three amino acids crucial to substrate binding at the active site: leucine, tryptophan, and alanine. What characteristics would you predict for this enzyme's substrate? relatively hydrophobic hydrophilic, with a positive charge hydrophilic, but without a charge hydrophilic, with a negative charge

relatively hydrophobic

Reactions in which there is a negative change in free energy (-ΔG) are: nonspontaneous and exergonic. spontaneous and endergonic. spontaneous and exergonic. nonspontaneous and endergonic.

spontaneous and exergonic.

Which of the examples are considered anabolism? Select all that apply. hydrolysis of glycogen (a glucose polymer) during physical activity synthesis of new DNA copies prior to cell division use of fat (triglyceride) stores as a cellular energy source a person losing weight on a calorie restriction diet fat cells growing bigger during times of ample nutrition

synthesis of new DNA copies prior to cell division fat cells growing bigger during times of ample nutrition