Chapter 1-7: Introduction, NAD, Enzymes, Cofactors, and Glycolysis

Flashcards covering key vocabulary from lecture notes on metabolism, redox reactions, enzymes, cofactors, and the process of glycolysis.

Anabolic

Taking smaller building blocks and putting them together to make bigger chemicals; building things.

Catabolic

Taking complicated, bigger chemicals and digesting them, making them smaller, simpler ones; tearing apart.

Redox Reactions

Short for reduction-oxidation reactions, which always happen together.

Oxidation (original definition)

The process of increasing the amount of oxygen (e.g., when iron rusts).

Reduction (original definition)

The process of reducing the amount of oxygen, taking oxygen away.

Oxidation (electron definition)

The loss of electrons.

Reduction (electron definition)

The gain of electrons; refers to the reduction of the charge by gaining electrons.

Electron Transport Chain

The destination where electrons are taken by electron carriers; a major site of ATP synthesis.

NAD

A molecule that acts as an electron taxi cab; built from niacin (a B vitamin).

NAD+

The oxidized (empty) form of NAD, which has lost electrons.

NADH

The reduced (loaded) form of NAD+ after it gains two electrons and a hydrogen atom (with one electron).

Electron Carrier

Molecules (like NADH) that carry electrons from one place to another, such as to the electron transport chain.

Enzymes

Proteins that help out (catalyze) chemical reactions by lowering their activation energy.

Substrate

A chemical that an enzyme reacts with.

Active Site

The specific place on an enzyme where the chemical reaction (activity) occurs.

Product

The substance formed as a result of a chemical reaction, after reactants are changed.

Activation Energy

The energy cost that must be paid to initiate a reaction; the energy to activate the reaction.

Catalyzes (a reaction)

To speed up a chemical reaction by lowering its activation energy, effectively providing a 'discount' for the reaction to occur.

Cofactor

A non-protein substance that cooperates with an enzyme to facilitate a reaction (e.g., magnesium, iron, zinc, potassium are mineral cofactors).

Coenzyme

An organic cofactor (e.g., vitamins like NAD from niacin).

Vitamins

Organic cofactors that are essential for enzymes to function properly.

Minerals

Inorganic substances (like zinc, magnesium, calcium, potassium) that can act as cofactors but are not organic vitamins.

Cellular Respiration

The process of breaking down glucose with oxygen to produce ATP, typically involving glycolysis, the Krebs cycle, and the electron transport chain.

Fermentation

The process of breaking down glucose without oxygen.

Glycolysis

The initial 10-step enzymatic pathway for the breakdown of glucose, serving as the starting point for both respiration and fermentation.

Glyco-

A prefix meaning sugar.

-lysis

A suffix meaning breakdown.

Enzymatic Pathway

A series of steps in a biological process where each individual step is facilitated by an enzyme.

Investment Phase (Glycolysis)

The first phase of glycolysis (steps 1-3) where the cell spends two ATP molecules to phosphorylate glucose.

Phosphorylate

To add a phosphate group to a molecule.

Lysis Phase (Glycolysis)

The phase of glycolysis where the weakened bond in the phosphorylated glucose is broken, yielding two molecules of G3P.

G3P

Glyceraldehyde-3-phosphate, a 3-carbon sugar produced during the lysis phase of glycolysis.

Payoff Phase (Glycolysis)

The phase of glycolysis where NADH and a net gain of ATP (2 ATP) are produced.

Net Gain of ATP (Glycolysis)

The profit of ATP produced during glycolysis (2 ATP), calculated by subtracting the 2 ATP invested from the 4 ATP produced.

Pyruvate

A 3-carbon sugar that is the final product of glycolysis; two pyruvate molecules are produced from one glucose molecule.