Cellular Respiration and Fermentation

Flashcards covering essential vocabulary terms related to cellular respiration and fermentation from Campbell Biology.

Cellular Respiration

The process that encompasses both aerobic and anaerobic respiration but is often used to refer specifically to aerobic respiration.

Aerobic Respiration

A form of respiration that consumes organic molecules and oxygen to yield ATP.

Anaerobic Respiration

A form of respiration similar to aerobic respiration but with final electron acceptors other than oxygen.

Glycolysis

The splitting of glucose into two pyruvate molecules; occurs in the cytoplasm and can occur without oxygen.

Oxidative Phosphorylation

The stage of cellular respiration that generates the most ATP, including electron transport and chemiosmosis.

Fermentation

A metabolic process that regenerates NAD+ from NADH, allowing glycolysis to continue in the absence of oxygen.

NAD+

A coenzyme that serves as an electron acceptor in cellular respiration, functioning as an oxidizing agent.

Electron Transport Chain (ETC)

A series of protein complexes in the inner mitochondrial membrane that transfer electrons from NADH and FADH2 to oxygen.

Chemiosmosis

The use of a hydrogen ion gradient to drive ATP synthesis.

Substrate-level Phosphorylation

The direct transfer of a phosphate group to ADP to form ATP during glycolysis and the citric acid cycle.

Catabolic Pathways

Metabolic pathways that yield energy by oxidizing organic fuels.

Pyruvate Oxidation

The conversion of pyruvate into acetyl CoA as it enters the mitochondrion.

Beta Oxidation

The metabolic process that breaks down fatty acids to yield acetyl CoA.

Obligate Anaerobes

Organisms that cannot survive in the presence of oxygen.

Facultative Anaerobes

Organisms that can survive with or without oxygen, utilizing fermentation or cellular respiration.

Proton-Motive Force

The concentration gradient of hydrogen ions (H+) across a membrane that drives ATP synthesis.

Redox Reactions

Chemical reactions that involve the transfer of electrons, including oxidation (loss of electrons) and reduction (gain of electrons).

Stages of Cellular Respiration

1. Glycolysis

2. Krebs Cycle (Citric acid cycle)

3. Electron Transport Chain

Glycolysis

• in cytoplasm of cell

• Glucose broken down by ATP, NAD+, and various enzymes

Steps of Glycolysis

1. 2 ATP and enzymes begin to break down glucose

   1. 1 Phosphate from ATP added to glucose

   2. Makes 2 PGAL - three carbons + phosphate

2. Enzymes add another P to each PGAL

   1. Turns into another intermediate molecule

3. NADH created and enters the mitochondria

   1. NAD+ + a H+ ion stripped off from the intermediate molecules

   2. Creates 2 NADH

4. 4 ATP created

   1. 4 ADPs strip off the total 4 Ps from the 2 intermediate molecules to makes ATP

5. Two pyruvates (3C) left over

Pyruvate pathways

• Aerobic pathway

  • Krebs Cycle

  • ETC

• Anaerobic pathway

  • Fermentation

Krebs Cycle (Citric Acid Cycle) Steps

1. Pyruvate broken into acetic acid

   1. NAD+ H+ from Pyruvate to create NADH

   2. CO2 waste generated

2. Coenzyme-A (CoA) bonds to acetic acid

   1. Creates Acetyl-CoA (intermediate molecule)

3. Citric acid is formed when Acetyl-CoA bonds with a 4C molecule from the previous Krebs cycle

   1. Citric acid (6C)

4. Citric acid (6C) broken into 5C molecule

   1. NAD+ removes H+ to make NADH

   2. CO2 waste released

5. 5C broken into 4C molecule

   1. NAD+ removes H+ ion to make NADH

   2. ADP + P bond to make ATP

   3. CO2 waste (C from 5C)

6. Enzyme rearrange the 4C molecule

   1. NADH and FAD2 created by stripping of H+ ions from intermediate molecule

   2. Acetyl-CoA bonds to 4C molecule to recreate citric acid

   3. Process repeats

Krebs Cycle Location

• in mitochondrial matrix

• Creates

  • 8 NADH

  • 2 FADH2

  • 6 CO2

  • 2 ATP

ETC Location

inner mitochondrial matrix

Steps of ETC

1. NADH and FADH2 deliver H+ ions and electrons (e-)

2. Electrons activate protein channels to pump H+ ions out of the matrix

3. H+ ions activate ATP Synthase

   1. H+ ions diffuse through ATP Synthase back into matrix

   2. ADP + P bond to create ATP

   3. Up to 34 ATPs created

4. Water waste created when O, H+, e- bond together