AP Biology - Cellular Energetics and Enzymes

This set of flashcards covers key concepts related to cellular energetics and enzymes, focusing on metabolism, enzyme function, and regulation.

What is metabolism?

The sum total of all chemical reactions occurring in a biological system at a given time.

What type of reactions link simple molecules to form complex ones?

Anabolic reactions.

What do anabolic reactions require?

Energy inputs (endergonic or endothermic).

What do catabolic reactions do?

Break complex molecules into simpler ones and release energy (exergonic or exothermic).

How are anabolic and catabolic reactions related?

They are often linked in metabolic pathways.

What is activation energy?

The input of energy needed to initiate a reaction.

How do enzymes affect activation energy?

Enzymes lower the activation energy needed for reactions to occur.

What is a substrate?

The reactant that enzymes act upon and bind to at active sites.

What is feedback inhibition?

A regulatory mechanism whereby the final product of a metabolic pathway acts as an inhibitor of the first enzyme, shutting down the pathway.

What are competitive and noncompetitive inhibitors?

Competitive inhibitors block the active site; noncompetitive inhibitors bind to an allosteric site, altering the enzyme's function.

What factors affect enzyme activity?

Temperature, pH, enzyme concentration, and the presence of activators or inhibitors.

What can happen to enzymes when the temperature is too high?

They can denature, losing their functionality.

What does it mean for an enzyme to be saturated?

It means that all enzyme molecules are bound to substrate molecules, and the reaction rate levels off.

What is the turnover rate for enzymes?

The maximum reaction rate, which indicates the efficiency of an enzyme in converting substrate to product.

Why is constant energy input required for life?

To maintain order, as metabolism creates more disorder than order is stored.

What are the two types of metabolic pathways mentioned?

Cellular respiration and photosynthetic pathways.

What role do allosteric enzymes play in metabolism?

They can regulate the activity of metabolic pathways at critical points.

What are ribozymes?

RNA molecules that act as catalysts, similar to proteins.

What is the optimum pH range for most enzymes?

Most enzymes have a specific optimal pH for activity.