Metabolic Pathways

Question 1

Oxidation

Answer 1

Strips an electron from an atom in a compound

Question 2

Reduction

Answer 2

The addition of an electron to a compound

Question 3

ATP

Answer 3

(Adenosine triphosphate) small molecule that is used to power reactions in the cell

Question 4

Substrate-level phosphorylation

Answer 4

A phosphate group is transferred from a pathway intermediate straight to ADP

Question 5

Electron Transport Chain

Answer 5

Group of proteins in the inner membrane of the mitochondrion

Question 6

Oxidative phosphorylation

Answer 6

Energy released in ETC captured as proton gradient, which powers production of ATP by membrane protein (ATP synthase)

Question 7

Aerobic respiration

Answer 7

Oxygen requiring process

Question 8

Anaerobic respiration

Answer 8

Non-oxygen requiring process

Question 9

Oxidized

Answer 9

One of the reacting molecules loses electrons

Question 10

Reduced

Answer 10

Another reacting molecule gains electrons

Question 11

Reducing agent

Answer 11

Atom or molecule that donates electrons

Question 12

Oxidizing agent

Answer 12

Atom or molecule that accepts electrons

Question 13

When is a carbon-containing molecule likely reduced?

Answer 13

If it gains hydrogen atoms or loses oxygen atoms

Question 14

When is a carbon-containing molecule likely oxidized?

Answer 14

If it loses hydrogen atoms or gains oxygen atoms

Question 15

Oxidation as defined by a Biologist

Answer 15

Losing hydrogen atoms

Question 16

Reduction as defined by a Biologist

Answer 16

Gaining hydrogen atoms

Question 17

Spontaneous reactions

Answer 17

Redox reactions that move electrons or electron density from a less to a more electronegative atom, and release energy

Question 18

Non-spontaneous reactions

Answer 18

move the system from a lower to a higher energy state and require energy

Question 19

What are the two ways glucose is oxidized in a gradual way?

Answer 19

1) electrons are stripped off of glucose in pairs during cellular respiration, rather than at the same time. Electrons are then transferred to electron carriers

2) electron carriers deposit electrons in ETC, electrons are passed in energy-releasing steps so that energy is captured in the form of an electrochemical gradient

Question 20

Why is the transfer of electrons important in cellular respiration?

Answer 20

Most energy stored in atoms and used to fuel cell functions is in the form of high-energy electrons. This allow cells to transfer and use energy in increments.

Question 21

Electron carriers

Answer 21

Small organic molecules that readily cycle between oxidized and reduced forms and are used to transport electrons during metabolic reactions.

Question 22

NAD+

Answer 22

(nicotinamide adenine dinucleotide) the primary electron carrier during cellular respiration that accepts 2 electrons and 1 hydrogen ion to become NADH

Question 23

FAD

Answer 23

(flavin adenine dinucleotide) an electron carrier that only participates in 1-2 reactions during cellular respiration and accepts 2 electrons and 2 hydrogen ions to become FADH2

Question 24

Coenzyme

Answer 24

Organic molecules that serve as helpers during enzyme-catalyzed reactions, and they receive electrons and protons as part of these reactions

Question 25

Dehydrogenases

Answer 25

Enzymes which remove one or more hydrogen atoms from their substances

Question 26

Explain what it means that the ETC is energetically “downhill”

Answer 26

Energy is released at each step. Each member of ETC is more electronegative than the one before it, and less electronegative than the one after it.

NADH deposits electrons at the beginning of the ETC and is least electronegative. Oxygen receives electrons at the end of the ETC and is most electronegative.