Photosynthesis, Energy, and Enzymes: Key Concepts for Biology

A plant uses sunlight to convert carbon dioxide and water into sugar. What type of energy is being used?

Solar energy

During photosynthesis, CO₂ and H₂O are combined using energy. What is produced?

Carbohydrates (glucose)

A student labels CO₂ and H₂O as "low-energy molecules." Why?

They contain little stored energy

Energy captured from sunlight is stored in what form in plants?

Carbohydrates

A scientist notes that energy lost as heat cannot be reused by the system. What concept explains this?

Law of entropy

Which statement best describes the law of entropy?

Disorder increases during energy transfer

A molecule of glucose is considered "organized." What does this mean?

It has low entropy and stored energy

Hydrogen ions move across a membrane from one side to another to help make ATP. What process is this related to?

Chemiosmosis

In a chemical reaction, the starting materials are called what?

Reactants

The final substances formed in a reaction are called what?

Products

A reaction releases usable energy that a cell can perform work with. What is this energy called?

Free energy

A reaction releases energy as it proceeds. What type of reaction is this?

Exergonic

A reaction requires energy input to occur, such as building glucose. What type is this?

Endergonic

A cell uses ATP to power a reaction that would not happen on its own. This is an example of:

Coupled reaction

What happens in a coupled reaction?

Energy from one reaction powers another

ATP is broken down into ADP + P to release energy. What type of reaction is this?

Hydrolysis

What is ATP made of (its basic unit)?

Nucleotide

ATP can help power cellular work by doing what?

Transferring a phosphate group

ATP is mainly used for which two functions in cells?

Energizing reactions & changing shape of molecules

Food provides what type of energy for the body?

Chemical (potential) energy

A reaction that does NOT occur on its own and requires energy is:

Endergonic (nonspontaneous)

What is the role of enzymes in chemical reactions?

Speed up reactions

Some RNA molecules can act like enzymes. What are they called?

Ribozymes

A series of chemical reactions that starts with a reactant and ends with a final product is called:

Metabolic pathway

In enzyme-controlled reactions, the molecules enzymes act on are called:

Substrates

A substance enters an enzyme and is changed into a new substance. What was the original substance?

Substrate

After a reaction occurs, substrates are converted into:

Products

An enzyme slightly changes shape to better fit a substrate. What is this called?

Induced fit model

If molecules spread out randomly in a system, what increases?

Entropy

A plant builds glucose from smaller molecules using energy. What type of reaction is this?

Endergonic