Exam 2: Oxidation-Reduction Reactions

Question 1

Atomic nucleus

Answer 1

made of protons and neutrons

Question 2

Coenzyme

Answer 2

An organic molecule that binds to the active sites of certain enzymes to assist in the catalysis of a reaction. More specifically, coenzymes can function as intermediate carriers of electrons during these reactions or be transferred between enzymes as functional groups.

Question 3

Electron cloud

Answer 3

electrons present outside the nucleus, do not follow a regular trajectory, vary greatly in position and distance from the nucleus.

Question 4

Electron shells

Answer 4

regions surrounding the atomic nucleus containing a specific number of electrons. Commonly depicted as rings. Within each shell there are one or more orbitals.

Question 5

Energy Level

Answer 5

Fixed distances from the nucleus of an atom where electrons may be found

Question 6

Define and contrast anabolism and catabolism

Answer 6

Anabolism is when stored energy is used to synthesize or assemble complex molecules while catabolism is energy released and harvested during the breakdown of various molecules. The difference is catabolism is energy released while anabolism is energy used.

Question 7

Define and contrast ground state and excited state.

Answer 7

When electrons move further away from the nucleus to a more outer electron shell it has moved to an excited state from the ground state. The excited state is unstable and cannot be maintained for long. When the electron moves back down to the “ground state” it releases energy.

Question 8

Define and Contrast NAD+ and NADH

Answer 8

NAD+ Is the oxidized form, that is, a state in which it loses an electron. NADH is a reduced form of the molecule, which means that it gains the electron lost by NAD+

Question 9

Define and contrast oxidation and reduction

Answer 9

Oxidation is the loss of electrons while reduction is the addition of electrons which decreases the overall charge. Electron donor becomes oxidized and electron accepter becomes reduced.

Question 10

Define and contrast protons, electrons, and neutrons.

Answer 10

Proton is a subatomic particle with a positive electrical charge, neutron subatomic particle with no charge, and electron is an elementary particle that has a negative charge of electricity and travels around the nucleus (protons and neutrons) of an atom. They all make up an atom but differ in their charges and locations.

Question 11

What are the two main divisions of metabolism, and what is the relationship between these two main divisions? How are oxidation-reduction reactions related to these processes?

Answer 11

Catabolism and anabolism. Catabolic processes release energy and a fraction of this energy is harvested. Some of the harvested energy is used to fuel anabolic processes. Catabolism is coupled to anabolism. Redox reactions in which an organic molecule is oxidized are catabolic while redox reactions in which an organic molecule is reduced are anabolic.

Question 12

Is aerobic cellular respiration an anabolic or a catabolic process? How are oxidation-reduction reactions related to this process?

Answer 12

Catabolic process, glucose is oxidized and oxygen is reduced.

Question 13

List the three types of subatomic particles. Which have significant mass? Which possess an electrical charge?

Answer 13

Protons, neutrons, and electrons.

Question 14

In one or two sentences, describe the basic organization of these three types of subatomic particles in an atom.

Answer 14

Protons and neutrons are present in the atom’s nucleus. Electrons are present outside the atomic nucleus.

Question 15

Electron shells are commonly depicted by a series of concentric circles surrounding an atomic nucleus. What do each of these “rings” represent?

Answer 15

Represent the average distance of electrons from the nucleus and subsequently the amount of energy possessed by each electron. Does not represent trajectories of the electrons.

Question 16

Do all electrons in the first electron shell possess the same amount of energy as each other? Do these electrons in the first shell possess the same amount of energy as those second electron shell? Explain.

Answer 16

Yes, all electrons in the same shell have the same amount of energy. But each shell has a different amount of energy compared to one another.

Question 17

Relative to the atomic nucleus, is the position of the electrons in the first electron shell the same as the position of the electrons in the second shell?

Answer 17

no?

Question 18

Can an electron move from one energy level to another? Describe this process.

Answer 18

Electrons can move between orbitals of different shells. Electrons can be promoted from an inner shell to an outer shell increasing distance from the nucleus increasing its energy. Moved from “ground state” to “excited state”, only maintained for a short amount of time before dropping back down but energy is released.

Question 19

Why does the dark interior of a car feel so hot on a summer day? Explain this phenomenon in terms of energy and electrons.

Answer 19

light hits atoms in the upholstery and electrons are promoted to an “excited state”.As they drop back down to ground state they release heat.

Question 20

Define and contrast the terms oxidation and reduction. Explain.

Answer 20

Oxidation means loss of electrons while reduction means the addition of electrons. Electrons have a negative charge so when you add them you are reducing the overall charge.

Question 21

In what ways can a molecule be reduced?

Answer 21

Gaining a simple electron or gaining an electron that is part of a hydrogen atom.

Question 22

In what way can a molecule be oxidized?

Answer 22

Losing a simple electron or losing a hydrogen atom, or gaining an oxygen.

Question 23

Do oxidation and reduction reactions always occur simultaneously?

Answer 23

Yes

Question 24

What does LEO the lion say, and why is this relevant to this topic?

Answer 24

LEO the lion says GER=Losing electrons is oxidation, gaining electrons is reduction

Question 25

What is the energy distribution between oxidation molecules an reduction molecules?

Answer 25

Reduction molecules are high energy molecules.
Oxidized molecules possess much less energy.

Question 26

Consider the following reaction:
Ae- + B –> A + Be-
Which reactant is being oxidized?
Which reactant is being reduced?
Which reactant serves as the electron donor?
Which reactant serves as the electron acceptor?
Which is a higher energy molecule, Ae- or A?

Answer 26

Which reactant is being oxidized?
Ae-
Which reactant is being reduced?
B
Which reactant serves as the electron donor?
Ae-
Which reactant serves as the electron acceptor?
B
Which is a higher energy molecule, Ae- or A?
Ae-

Question 27

Does aerobic cellular respiration involve oxidation reactions, reduction reactions, or both? Explain.

Answer 27

Both, if one thing is reduced then the resulting product is oxidized

Question 28

How and why is H2O produced during aerobic cellular respiration?

Answer 28

Water is a byproduct of the reaction, oxygen accepts electrons and takes up protons to form water.

Question 29

In the burning of methane, what is being oxidized and what is being reduced?

Answer 29

Methane is being reduced and possesses much energy and CO2 is being oxidized, possessing little useful energy.

Question 30

What is the most reduced form of carbon? The most oxidized?

Answer 30

Most reduced is methane CH4 and most oxidized is CO2

Question 31

In the aerobic catabolism of glucose (aerobic cellular respiration), what is being oxidized and what is being reduced?

Answer 31

Glucose is being oxidized and oxygen is being reduced.

Question 32

Compare the energy inherent in a methane molecule to the energy inherent in a molecule of carbon dioxide. Which has more energy inherent in its chemical bonds?

Answer 32

Methane has more energy in its chemical bond then carbon dioxide.

Question 33

What is a coenzyme? From what types of nutrients are they produced?

Answer 33

Coenzymes are organic cofactors. Vitamins and organic essential nutrients.

Question 34

Describe the general function of coenzymes related to the oxidation of food molecules within a cell. How does this relate to catabolism and anabolism?

Answer 34

Reduced molecules are oxidized within cells, electrons are removed from these moves. These electrons can be added to a coenzyme.

Question 35

List the three coenzymes that function as electron carrier molecules, showing each in both its oxidized and its reduced form.

Answer 35

NAD+ reduced to NADH
NADP+ reduced to NADPH
FAD reduced to FADH2

Question 36

Of NAD’s two forms, which is high energy and which is lower energy?

Answer 36

NAD+ is oxidized from so low energy.

NADH is reduced form so high energy.

Question 37

In what ways is NADH like ATP? In what ways is it different?

Answer 37

Both have value but the value of NADH is greater than ATP. However ATP is easier for cells to use.

Question 38

Compare the cycling of coenzymes to the ATP cycle. How are they alike?

Question 39

Which of the following is the reduced form of falvin adenine dinucleotide (FAD)?

FAD+
FADH2
FADH
FAD-
FAD

Answer 39

FADH2

Question 40

During aerobic cellular respiration, __________ becomes reduced to form ________.

Glucose, Carbon dioxide
Water, oxygen
nitrogen, ammonia
oxygen, water
carbon dioxide, glucose

Answer 40

oxygen is reduced to form CO2 and water

Question 41

nWhich of the following subatomic particles lacks a charge and has a negligible mass?

Electrons, protons, or neutrons?

Answer 41

Neutrons

Question 42

The reaction for aerobic cellular respiration is “glucose + O2 → CO2 + H2O + energy” What is the electron acceptor?

glucose
H2O
O2
energy
CO2

Answer 42

H2O