Unit 2 Study guide- Energy, Metabolism, Cellular Respiration & Photosynthesis: Key Concepts and Processes

Energy

The capacity to do work.

Kinetic energy

Energy of motion.

Potential energy

Stored energy based on position.

Chemical energy

Energy stored in chemical bonds.

Exergonic reactions

Reactions that release energy.

Endergonic reactions

Reactions that require energy input.

Anabolic

Metabolic pathways that construct molecules.

Catabolic

Metabolic pathways that break down molecules.

Metabolism

All chemical reactions that occur within a living organism.

Activation energy

The minimum energy required to start a chemical reaction.

Enzyme

A protein that acts as a catalyst to speed up a reaction.

Substrate

The reactant on which an enzyme works.

Active site

The region on an enzyme where the substrate binds.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll.

Cellular respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

Aerobic

Processes that require oxygen.

Anaerobic

Processes that do not require oxygen.

Electron transport chain

A series of protein complexes that transfer electrons and pump protons to create a proton gradient.

Glycolysis

The metabolic pathway that converts glucose into pyruvate, yielding ATP.

Citric acid cycle

A series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetyl-CoA.

Oxidative phosphorylation

The process of ATP production in the mitochondria using the electron transport chain and chemiosmosis.

Chemiosmosis

The movement of ions across a selectively permeable membrane, down their electrochemical gradient.

ATP synthase

An enzyme that creates ATP from ADP and inorganic phosphate during chemiosmosis.

Fermentation

A metabolic process that converts sugar to acids, gases, or alcohol in the absence of oxygen.

Autotroph

Organisms that produce their own food from inorganic substances.

Heterotroph

Organisms that cannot synthesize their own food and rely on other sources of organic carbon.

Chlorophyll

The green pigment found in plants that is essential for photosynthesis.

Stomata

Small openings on the surface of leaves that allow gas exchange.

Thylakoid

Membrane-bound compartments inside chloroplasts that are the site of the light-dependent reactions of photosynthesis.

Stroma

The fluid-filled space surrounding the thylakoids in chloroplasts.

Granum

A stack of thylakoids within the chloroplast.

Pigment

A substance that absorbs light.

Electromagnetic spectrum

The range of all types of electromagnetic radiation.

Visible light

The portion of the electromagnetic spectrum that is visible to the human eye.

Light-dependent reactions

Reactions that convert light energy into chemical energy in the form of ATP and NADPH.

Carbon fixation

The process of converting inorganic CO2 into organic compounds by living organisms.

Photosystem

A protein and pigment complex that plays a key role in the light-dependent reactions of photosynthesis.

Calvin cycle

The set of chemical reactions that take place in chloroplasts during photosynthesis, where CO2 is converted into glucose.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Second Law of Thermodynamics

In any energy transfer, the total entropy (disorder) of a closed system will increase over time, indicating that energy transformations are not 100% efficient.

ATP Coupling

ATP (adenosine triphosphate) acts as an energy currency in cells, coupling exergonic reactions to drive endergonic processes, such as muscle contraction and active transport.

Enzyme Function

Biological catalysts that speed up reactions by lowering the activation energy required for the reaction to occur.

Competitive Inhibition

Inhibitors that bind to the active site of an enzyme, blocking substrate access.

Non-Competitive Inhibitors

Inhibitors that bind elsewhere, altering enzyme function without blocking the active site.

Where does Glycolysis occur?

Inside the cytoplasm.

Where does the Citric Acid Cycle occur?

Inside the Mitochondria

Where does Oxidative Phosphorylation occur?

Across the mitochondrial membrane.

What are the products of Glycolysis?

2 ATP, 2 NADH, and 2 pyruvate molecules are produced from one glucose molecule.

Pyruvate Transition Reaction

Converts pyruvate into Acetyl CoA, producing 2 NADH and releasing CO2.

Citric Acid Cycle Products

Each turn produces 3 NADH, 1 FADH2, 1 ATP, and releases 2 CO2.

What is the function of ATP Synthase?

Uses the proton gradient created by the electron transport chain to synthesize ATP from ADP and inorganic phosphate.

What are the different types of fermintation

Lactic Acid and alcoholic fermentation

Where does lactic acid fermentation occur?

In muscle cells

Where does Alcoholic Fermentation occur?

Occurs in yeast

Facultative Anaerobes

Can survive with or without oxygen

Obligate Anaerobes

Cannot survive in the presence of oxygen

Photosynthesis equation

6CO2 + 6H2O + light energy —> C6H12O6 + 6O2

Cellular Respiration Fomula

C6H12O6 + 6O2 —> 6CO2 + 6H2O + ATP

Where does Light-dependent reactions occur?

Inside the thylakoids

Where does the Calvin Cycle occur?

Inside the stroma

What is the global importance of photosynthesis?

Photosynthesis is crucial for life on Earth as it provides oxygen and organic compounds for heterotrophs.

What is the relationship between photosynthesis and cellular respiration?

The products of photosynthesis (glucose and oxygen) are the reactants for cellular respiration, illustrating a cyclical relationship.