lab quiz 8 pt 1

What is metabolism?

All the chemical reactions that occur in a living organism.

Define catabolism.

Breaking down reactions that release energy from organic molecules.

Define anabolism.

Building up reactions that require energy to create larger molecules.

What are enzymes?

Proteins that catalyze (speed up) reactions.

What are endoenzymes?

Enzymes that function inside the cell.

What are exoenzymes?

Enzymes released from the cell to speed up reactions outside the cell.

What is the purpose of the OF test?

To determine whether an organism uses oxidative or fermentative pathways for catabolism.

What does a yellow tube indicate in the OF test?

Acid production due to carbohydrate fermentation.

What does a blue tube indicate in the OF test?

A basic pH, indicating no fermentation has occurred.

What is the role of phenol red in fermentation tubes?

It acts as a pH indicator, turning yellow in acidic conditions.

What is the significance of a Durham tube in fermentation tests?

It traps gas produced during fermentation, indicating gas formation.

What happens to the pH of the media if fermentation occurs?

The pH drops to 6.8 or less, turning the media yellow due to acid production.

What is the cellular respiration formula?

C6H12O6 + O2 → CO2 + H2O + ATP + heat.

What are monosaccharides?

Simple sugars that have between 3 to 7 carbons.

What are oligosaccharides?

Carbohydrates composed of 2 to 20 monosaccharides.

What are polysaccharides?

Carbohydrates composed of 20 or more monosaccharides.

What is starch hydrolysis?

The breakdown of starch into simple sugars by exoenzymes like amylase.

What reagent is used to detect starch?

Iodine, which turns blue-black in the presence of starch.

What indicates a positive result for an exoenzyme in starch hydrolysis?

A clear area around the bacterial growth after iodine is added, indicating starch breakdown.

What does the MRVP test stand for?

Methyl Red and Voges-Proskauer tests for acid and neutral product production.

What does a red color after adding methyl red indicate?

The organism produces acid, with a pH < 4.4.

What does a yellow color in the MRVP test indicate?

Neutral products are produced, indicating a pH above 6.

What does a red color in the VP test indicate?

The presence of the neutral product acetoin.

What is the significance of incubating fermentation tubes for 24 hours?

To ensure that bacteria ferment carbohydrates before they switch to protein metabolism.

What is the result of prolonged incubation of fermentation tubes?

The media may turn pink/red due to protein metabolism, indicating a basic pH.

What is the role of bromthymol blue in OF media?

It indicates pH changes, turning yellow in acidic conditions and blue in basic conditions.

What does it mean if both tubes in the OF test turn yellow?

The organism is a fermenter, producing acid in both aerobic and anaerobic conditions.

What does it mean if only the open tube in the OF test turns yellow?

The organism is an oxidizer, producing acid only in the presence of oxygen.