Cellular Respiration and Fermentation

These flashcards cover the key concepts of cellular respiration, including glycolysis, the Krebs cycle, the electron transport chain, and fermentation, based on the provided lecture notes.

What are the three main steps of cellular respiration?

The three steps are Glycolysis, Kreb’s Cycle, and the Electron Transport Chain.

According to the redox reaction of respiration, which molecule is oxidized and which is reduced?

Glucose ($C_6H_{12}O_6$) is oxidized into $6 CO_2$, and oxygen ($6 O_2$) is reduced into $6 H_2O$.

By what other name is Glycolysis known?

It is also known as the Embden- Myerhof pathway.

In Glycolysis, what is the 'net' and 'total' ATP production per molecule of glucose?

Glycolysis produces a total of $4$ ATP and uses $2$ ATP, resulting in a net gain of $2$ ATP.

Where does Glycolysis occur within the cell?

It occurs in the cytoplasm (cytoplasmic fluid).

What are two identified alternatives to Glycolysis?

The Pentose-phosphate pathway and the Entner-Doudoroff pathway.

What are the primary characteristics of the Pentose-phosphate pathway?

It uses $5$ carbon sugars, generates less energy than glycolysis, and produces metabolites for making nucleotides and amino acids.

What is the definition of substrate-level phosphorylation?

The enzymatic transfer of a phosphate from an organic substrate to ADP to form ATP.

What happens to pyruvic acid before it enters the Krebs Cycle?

Each pyruvic acid molecule is broken down to form $CO_2$ and a two-carbon acetyl group, which combines with coenzyme A to become Acetyl CoA.

According to the ATP Ledger for two pyruvates (one glucose), what is the total NADH and FADH2 production in the Krebs Cycle?

The Krebs Cycle produces $8$ NADH and $2$ FADH2.

Where does the Krebs Cycle occur in eukaryotes?

It occurs in the Mitochondria.

How many ATP molecules are generated from one NADH and one FADH2 in the Electron Transport Chain?

Each NADH generates $3$ ATP and each FADH2 generates $2$ ATP.

What is oxidative phosphorylation?

The production of ATP using the transfer of electrons and the generation of a chemiosmotic gradient via the Electron Transport Chain.

What is the terminal electron acceptor in the aerobic Electron Transport Chain?

Oxygen.

What is the primary purpose of fermentation?

To regenerate $NAD^+$ from NADH so that glycolysis can continue to produce energy in the absence of oxygen.

What are the end products of ethanol fermentation in yeast?

Ethanol and carbon dioxide ($CO_2$).

What defines a facultative anaerobe?

An organism, such as yeast or E. coli, that can grow with oxygen (carrying out cell respiration) or without oxygen (carrying out fermentation).

What are Zymurgy and Enology?

Zymurgy is the science of beer brewing, and Enology is the science of wine making.

What are the differences between ale yeast and lager yeast regarding temperature and fermentation speed?

Ale yeast works at room temperature and ferments quickly; lager yeast works at cold temperatures ($30$ to $40$ degrees Fahrenheit) and ferments more slowly.

What historical name was given to yeast before it was scientifically recognized, based on its 'miraculous' ability to ferment beer?

It was called "godisgood."