ATP, Metabolism, and Enzymes - Practice Flashcards

A set of Q&A flashcards covering ATP structure and cycling, energy types, metabolism, catabolism vs anabolism, activation energy, and enzymes/denaturation.

What does ATP stand for and what is its primary role in cells?

Adenosine triphosphate; an energy-carrying molecule that stores and provides energy for cell functions.

In the ATP/ADP cycle, which reaction releases energy: ATP hydrolysis or ATP synthesis?

ATP hydrolysis (ATP -> ADP + Pi) releases energy; ATP synthesis (ADP + Pi -> ATP) requires energy (endothermic).

Which macromolecule is most commonly broken down to supply ATP first?

Carbohydrates are most commonly broken down first to supply ATP.

Which macromolecule is typically used for energy after carbohydrates, with proteins being least likely?

Lipids (fats) are used for energy after carbohydrates; proteins are least likely to be used for energy.

What are the components of ATP?

Adenine base, ribose sugar, and three phosphate groups.

What is metabolism?

All chemical reactions occurring within a cell; they provide energy and build key molecules.

What is catabolism?

Catabolic reactions break down larger molecules into simpler ones and release energy (exergonic).

What is anabolism?

Anabolic reactions build larger molecules from smaller ones and require energy (endergonic).

What is Activation Energy?

The amount of energy required to start a chemical reaction.

What are Reactants and Products in a chemical reaction?

Reactants (substrates) are the substances that react; products are the substances formed.

Is photosynthesis endothermic or exothermic, and why?

Endothermic; energy from light is absorbed to store as chemical energy in sugars.

Is cellular respiration endothermic or exothermic, and why?

Exothermic; chemical energy in sugar is released during respiration.

What is an enzyme?

A protein that speeds up biochemical reactions by lowering activation energy and is not consumed in the reaction.

Where does a substrate bind in an enzyme, and what is the complex called?

The substrate binds to the enzyme's active site, forming an enzyme–substrate complex.

What is denaturation of an enzyme?

Loss of enzyme shape and activity due to environmental changes like extreme temperature or pH.

Can a denatured enzyme always be renatured?

Some enzymes can be renatured to their original shape, but not always.

What is the role of enzymes in metabolism?

Enzymes speed up metabolic reactions and regulate life's processes by lowering activation energy.

What is the difference between exothermic and endothermic reactions?

Exothermic releases energy; endothermic absorbs energy.

What is the enzyme–substrate complex?

A temporary complex formed when an enzyme binds to its substrate at the active site to facilitate a reaction.

What happens to energy during bond breaking and forming in chemical reactions?

Breaking bonds generally requires energy (endothermic); forming bonds releases energy (exothermic).