Chapter 6&7 (Intro to Biology)

While standing at the top of the stairs, you have a potential energy of 40 Joules. If you walk all the way down the stairs, what would your potential energy be at the bottom of the stairs? A) 0 Joules B) 20 Joules C) 40 Joules D) 80 Joules

A) 0 Joules

Why is the energy generated from the catabolism of sugars and other macromolecules ultimately harnessed to generate ATP? A) ATP can be used by cells to drive endergonic reactions. B) ATP can be used to make RNA, which is an energy storage molecule in the cell. C) ATP synthesis is an exergonic reaction. D) ATP is required to generate the proton gradient in the intermembrane space of mitochondria.

A) ATP can be used by cells to drive endergonic reactions.

The Law of Thermodynamics that states that energy cannot be created or destroyed is the A) First Law of Thermodynamics B) Second Law of Thermodynamics C) Third Law of Thermodynamics D) Fourth Law of Thermodynamics

A) First Law of Thermodynamics

As electrons move along the electron transport chain, they lose potential energy. How is the energy that is released used by the cell? A) The energy is used to transport protons against their concentration gradient. B) The energy is used to pump electrons along the electron transport chain. C) The energy is converted directly into ATP. D) The energy is used to pump NAD+ into the cytoplasm so it can be used in glycolysis.

A) The energy is used to transport protons against their concentration gradient.

A particular chemical reaction is exergonic. What can you say about the relationship between the reactants and the products in this exergonic reaction? A) The reactants have more free energy than the products. B) The reactants are likely more disordered and the products are likely more ordered. C) The reactants cannot spontaneously react to generate the products. D) The reactants likely have lower enthalpy than the products.

A) The reactants have more free energy than the products.

Why do we have storage macromolecules, such as fats, in our bodies? A) We can break down these macromolecules to provide energy for the endergonic reactions in our bodies. B) Human cells can directly capture the energy of sunlight through photosynthesis and store it as macromolecules such as fats. C) Macromolecules, such as fats, are a convenient way to store kinetic energy. D) Breaking down macromolecules, such as fats, is an endergonic process.

A) We can break down these macromolecules to provide energy for the endergonic reactions in our bodies.

What molecule can oxidize NADH? A) acetaldehyde B) lactate C) ubiquinone D) glucose E) isocitrate

A) acetaldehyde

The energy needed to destabilize existing chemical bonds and start a chemical reaction is called A) activation energy. B) free energy. C) kinetic energy. D) potential energy.

A) activation energy.

When the substrate is bound to the enzyme, the shape of the enzyme may change slightly, leading to A) an induced fit. B) a great range of possible catalytic activities. C) a greater supply of activation energy. D) more permanent binding through intimate total contact. E) more possible products of the reaction.

A) an induced fit.

The term oxidation is derived from the name of the element oxygen. This is reasonable, because oxygen A) attracts electrons very strongly. B) can be oxidized by accepting electrons. C) contains more electrons than are needed. D) passes electrons to many other types of molecules.

A) attracts electrons very strongly.

Organisms that can manufacture their own chemical energy are called ________. A) autotrophs B) heterotrophs C) oligotrophs D) chemotrophs

A) autotrophs

In an experiment described in a chemistry lab book, the directions state that after mixing two chemicals (A and B) and waiting 5 minutes that A will be oxidized. This means that A) chemical A has lost electrons to chemical B. B) chemical A has gained electrons from chemical B. C) chemical A has gained energy in the form of heat from chemical B. D) chemical A has lost energy in the form of heat to chemical B. E) chemical A has reacted with oxygen.

A) chemical A has lost electrons to chemical B.

This process is common to all living cells. A) glycolysis B) alcohol fermentation C) the Krebs cycle D) electron transport chain reactions E) pyruvate oxidation

A) glycolysis

What aspect of cellular respiration occurs in the cytoplasm in eukaryotic cells? A) glycolysis B) pyruvate oxidation C) the Krebs cycle D) the electron transport chain E) ATP synthesis

A) glycolysis

RNA molecules that also act as enzymes are given the name A) ribozymes. B) cofactors. C) coenzymes. D) allosteric enzymes.

A) ribozymes.

The ultimate source of energy for humans comes from what source? A) the sun B) plants C) water D) air E) animals

A) the sun

What is the net number of ATP generated directly during glycolysis per molecule of glucose? A) 0 B) 2 C) 4 D) 6 E) 8

B) 2

What are the products of one turn of the Krebs cycle? A) 1 CO2, 2 NADH, 1 FADH2, 1 ATP B) 2 CO2, 3 NADH, 1 FADH2, 1 ATP C) 2 CO2, 6 NADH, 2 FADH2, 2 ATP D) 4 CO2, 6 NADH, 2 FADH2, 2 ATP E) 4 CO2, 12 NADH, 4 FADH2, 4 ATP

B) 2 CO2, 3 NADH, 1 FADH2, 1 ATP

In a chemical reaction, glyceraldehyde-3-phosphate + NAD+ yields 1,3-bisphosphoglycerate + NADH. In this reaction, what happened to NAD+? A) It was oxidized to form NADH B) It was reduced to form NADH C) It was activated to form NADH D) It served as an enzyme to catalyze the reaction, and at the end of the reaction formed NADH

B) It was reduced to form NADH

What is different about the way that NADH and FADH2 donate electrons to the electron transport chain? A) NADH is oxidized and FADH2 is reduced. B) NADH contributes its electrons to the first transmembrane complex in the electron transport chain and FADH2 contributes its electrons after the first transmembrane complex. C) More protons are transported into the intermembrane space of the mitochondria in response to one molecule of FADH2 as compared to the number of protons transported in response to one molecule of NADH. D) The electrons from NADH ultimately go on to reduce oxygen to generate water, whereas the electrons from FADH2 are used to reduce pyruvate to lactate.

B) NADH contributes its electrons to the first transmembrane complex in the electron transport chain and FADH2 contributes its electrons after the first transmembrane complex.

The Law of Thermodynamics that states that increases in entropy are favored is the A) First Law of Thermodynamics. B) Second Law of Thermodynamics. C) Third Law of Thermodynamics. D) Fourth Law of Thermodynamics.

B) Second Law of Thermodynamics.

What important metabolic intermediate does not cross the inner membrane of the mitochondria? A) ATP B) acetyl-CoA C) pyruvate D) oxygen

B) acetyl-CoA

The inorganic nonprotein components that participate in enzyme catalysis are known as A) coenzymes. B) cofactors. C) products. D) substrates. E) reactants.

B) cofactors.

The synthesis of sugar molecules through the process of photosynthesis requires energy absorbed from sunlight. Bearing this in mind, what kind of reaction is photosynthesis? A) exergonic B) endergonic C) catabolic D) feedback

B) endergonic

The amount of energy available to do work is called A) activation energy. B) free energy. C) kinetic energy. D) potential energy.

B) free energy.

During what step of glycolysis are two ATP molecules required? A) cleavage and rearrangement B) glucose priming C) oxidation D) pyruvate formation E) acetyl-CoA formation

B) glucose priming

Organisms that depend on the energy stored in chemical bonds by other organisms for their food energy are called ________. A) autotrophs B) heterotrophs C) oligotrophs D) chemotrophs

B) heterotrophs

Energy is defined as A) heat. B) the capacity to do work. C) change. D) movement.

B) the capacity to do work.

When substrate-level phosphorylation occurs, it means that A) NAD+ is converted into NADH. B) ATP is converted into ADP plus a phosphate group. C) ADP is converted into ATP by the addition of a phosphate group. D) NADH is converted into NAD+ plus a proton.

C) ADP is converted into ATP by the addition of a phosphate group.

How and where is ATP made in a eukaryotic cell? A) ATP is only made in the mitochondria in response to chemiosmosis. B) ATP is made in all compartments of the cell in response to endergonic reactions and is used to drive exergonic reactions in the cell. C) ATP can be made by direct phosphorylation of ADP in the cytoplasm, and by an enzyme complex that uses the energy from a proton gradient to drive ATP synthesis in the mitochondria. It can also be made in other locations in the cell, depending on the cell type. D) ATP can be made by an enzyme complex that uses the energy of protons moving down their concentration gradient from the mitochondrial matrix to the cytoplasm to make the ATP.

C) ATP can be made by direct phosphorylation of ADP in the cytoplasm, and by an enzyme complex that uses the energy from a proton gradient to drive ATP synthesis in the mitochondria. It can also be made in other locations in the cell, depending on the cell type.

What oxidizing agent is used to temporarily store high energy electrons harvested from glucose molecules in a series of gradual steps in the cytoplasm? A) FADH2 B) ADP C) NAD+ D) oxygen

C) NAD+

You eat a bowl of beans as part of your dinner. As you digest the beans, the proteins that are present get broken down to their component amino acids. As your body destroys the macromolecules that were present in the beans, is the energy present in those molecules destroyed? A) Yes. By breaking down these macromolecules, some of the energy they contained is destroyed. B) No. While the vast majority of the energy contained in these macromolecules is converted to heat, it is not actually destroyed. C) No. The energy contained within these macromolecules is converted into other forms of chemical energy and kinetic energy, though some is lost as heat. D) No. Breaking down molecules does not lead to the release of energy.

C) No. The energy contained within these macromolecules is converted into other forms of chemical energy and kinetic energy, though some is lost as heat.

The organic nonprotein components that aid in enzyme functioning are called A) reactants. B) cofactors. C) coenzymes. D) substrates. E) products.

C) coenzymes.

A molecule that closely resembles the shape of a substrate for an enzyme would most likely serve as a A) noncompetitive inhibitor. B) allosteric inhibitor. C) competitive inhibitor. D) allosteric activator.

C) competitive inhibitor.

In the reaction: C4H6O4 + FAD → C4H4O4 + FADH2, what type of reaction took place to remove the protons from C4H6O4? A) decarboxylation B) reduction C) dehydrogenation D) oxidation

C) dehydrogenation

Oxidation and reduction reactions are chemical processes that result in a gain or loss of A) atoms. B) neutrons. C) electrons. D) molecules. E) protons.

C) electrons.

While conducting an experiment, you realize that a competitive inhibitor was interfering with your reaction. How could you overcome this problem? A) add a noncompetitive inhibitor to the reaction B) add a cofactor to the reaction C) increase the concentration of the correct substrate in the reaction D) add an allosteric activator to the reaction

C) increase the concentration of the correct substrate in the reaction

In an enzyme-catalyzed reaction, the reactant is called the A) coenzyme. B) catalyst. C) substrate. D) product.

C) substrate.

All of the reactions of cellular respiration that occur after glycolysis take place in what part of the eukaryotic cell? A) the chloroplast B) the nucleus C) the mitochondria D) the plasma membrane E) the cytoplasm

C) the mitochondria

What happens to the oxygen that is used in cellular respiration? A) It is converted to carbon dioxide. B) It is used to make glucose. C) It is used to make Krebs cycle intermediates. D) It is reduced to form water. E) It is converted to acetyl-CoA.

D) It is reduced to form water.

What is the oxidized form of the most common electron carrier that is needed for both glycolysis and the Krebs cycle? A) ATP B) FAD C) pyruvate D) NAD+ E) acetyl-CoA

D) NAD+

In animals that take in oxygen from their environment, glucose is broken down into carbon dioxide and water in a process called A) anaerobic respiration B) organic compound respiration C) glucose respiration D) aerobic respiration

D) aerobic respiration

A drug binds to the active site of an enzyme. If it is bound to the active site of the enzyme, it prevents substrate binding. This drug would be considered a A) noncompetitive inhibitor. B) allosteric inhibitor. C) allosteric activator. D) competitive inhibitor.

D) competitive inhibitor.

A calorie is the commonly used unit of chemical energy. It is also the unit of A) light. B) magnetism. C) sound. D) heat. E) radioactivity.

D) heat.

Where does pyruvate oxidation occur in eukaryotic cells? A) in the cytoplasm B) in the nucleus C) in the Golgi body D) in the mitochondria E) in the plasma membrane

D) in the mitochondria

The energy released in the mitochondrial electron transport chain is used to transport protons where? A) into the mitochondrial matrix B) into the cytoplasm C) into the endoplasmic reticulum D) into the intermembrane space of the mitochondria E) into the nucleus

D) into the intermembrane space of the mitochondria

When an atom or molecule gains one or more electrons, it is said to be A) energized. B) oxidized. C) polarized. D) reduced.

D) reduced.

What is an end-product of glycolysis? A) oxaloacetate B) NAD+ C) alcohol D) ADP E) pyruvate

E) pyruvate