Chapter 4- Energy & Enzymes

What is the best example of chemical work? What is the best example of chemical work? Lactate dehydrogenase reduces pyruvate to form lactate. Skeletal muscle contraction pulls on tendons and moves bones. H+ will diffuse across the inner mitochondrial membrane to provide the energy that powers the ATP synthase enzyme. The sodium-potassium pump exchanges 3 sodium ions for 2 potassium ions across the cell membrane.

In a system that includes a ball and a ramp, when would potential energy be greatest? In a system that includes a ball and a ramp, when would potential energy be greatest? When the ball is at its maximal velocity When the ball first begins to roll down the ramp When the ball was at rest at the top of the ramp When the ball comes to rest at the bottom of the ramp

Which of the following is the best example of the use of kinetic energy in a cell? Which of the following is the best example of the use of kinetic energy in a cell? ATP synthase using the diffusion of H+ across the inner mitochondrial membrane to power the phosphorylation of ADP to create ATP Enolase using a Mg2+ ion as a cofactor to catalyze the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP) in the second-to-last step of glycolysis Glucose is stored in liver and muscle cells as a polymer called glycogen. The sodium-potassium pump actively transporting Na+ and K+ across the cell membrane

In the hypothetical chemical reaction A+B → C+D, what is/are the reactant(s)?

What is the simplest way for a human cell to acquire the activation energy necessary for metabolic reactions? What is the simplest way for a human cell to acquire the activation energy necessary for metabolic reactions? Couple an exergonic reaction with an endergonic reaction. Increase the internal cellular temperature. Use the energy in sunlight to drive chemical reactions. Allow more water to flow across the cell membrane and use the kinetic energy to drive reactions.

An enzyme-catalyzed chemical reaction in which two substrates are joined using the energy of ATP is known as __________. An enzyme-catalyzed chemical reaction in which two substrates are joined using the energy of ATP is known as __________. addition ligation oxidation reduction

Enzymes __________. Enzymes __________. increase the rate of chemical reactions allow for chemical reactions to occur that would otherwise not be possible determine the direction of the chemical reaction (i.e., whether molecules are produced or broken down) are altered in structure as a result of chemical reactions

Which of the following best describes why vitamins are important in the human body? Which of the following best describes why vitamins are important in the human body? Vitamins are important because they are needed to activate the mitochondria for energy needs. Many vitamins are precursors of coenzymes, which are necessary for metabolic reactions. Vitamins can be converted to ATP (adenosine triphosphate--the energy molecule). Vitamins are a good source of nitrogen, which is needed for metabolic reactions.

Which organic molecule acts as a receptor and carrier for atoms or functional groups that are removed from substrates during a reaction? Which organic molecule acts as a receptor and carrier for atoms or functional groups that are removed from substrates during a reaction? a coenzyme an enzyme a vitamin a cofactor

Which of the following best describes the function of enzymes? Which of the following best describes the function of enzymes? Enzymes will turn into specific molecules, such as ATP, as needed by the body. Enzymes slow down chemical reactions to prevent them from proceeding too fast and causing problems. Enzymes lower the activation energy level of a chemical reaction, thus enabling the reaction to proceed. Most reactions are due to the addition of a phosphate ion (phosphorylation) to a molecule to create a reaction. The phosphate ions come from enzymes.

In a reaction, a molecule loses an electron. This is an example of which type of reaction? In a reaction, a molecule loses an electron. This is an example of which type of reaction? ligation oxidation hydrolysis reduction

A kinase moves which functional group or molecule? A kinase moves which functional group or molecule? Water Phosphate Amino groups Hydroxyl

When an enzyme's activity is destroyed by heat or a change in pH, the enzyme is said to be When an enzyme's activity is destroyed by heat or a change in pH, the enzyme is said to be broken. conjugated. tertiary. toxic. denatured.

An enzyme that transfers chemical groups among substrates is a An enzyme that transfers chemical groups among substrates is a ligase. transferase. hydrolase. kinase. lipase.

An allosteric modulator binds to An allosteric modulator binds to the surrounding tissue. the substrate. a region of the enzyme other than the active site. the active site. the product.

The active sites of enyzmes are:

When an enzyme is working as fast as it can because its active site is continually refilled with substrate, the condition is referred to as