Cellular Energetics and Metabolism

A comprehensive set of flashcards covering essential vocabulary and concepts in Cellular Energetics and Metabolism.

Metabolism

The sum of all chemical reactions within a cell.

Metabolic pathway

A series of reactions that are linked with each other within a cell, beginning with a specific molecule and ending with a product.

Catabolic pathways

Pathways that break down complex molecules to release energy.

Anabolic pathways

Pathways that use energy to build complex molecules from simpler ones.

Energy

The ability of a cell to cause change.

Kinetic energy

The energy of motion.

Potential energy

Energy possessed by an object due to its location or structure.

Chemical energy

Potential energy stored within bonds released through a chemical reaction.

Phosphorylation

The process when a molecule gives up a phosphate group and attaches it to another molecule.

Energy coupling

The use of exergonic processes to drive endergonic processes.

Endergonic reactions

Reactions in which free energy is absorbed.

Exergonic reactions

Reactions in which free energy is released.

Entropy

A measure of molecular disorder.

Free energy

Energy that can do work when temperature and pressure are uniform.

ADP

Adenosine diphosphate; the product of ATP hydrolysis, containing two phosphate groups.

Catalyst

A chemical agent that speeds up a reaction without being consumed.

Enzyme

A macromolecule that acts as a catalyst, mostly proteins.

Activation energy

The energy required to start a reaction.

Substrate

The substance an enzyme acts on or catalyzes a reaction.

Active site

The part of an enzyme where a substrate binds.

Denaturation

The process where high temperatures destroy an enzyme’s shape.

Heat

A type of energy transferred between two objects due to temperature difference.

Phosphorylated Intermediate

A molecule with a phosphate group bonded to it, making it very reactive.

Inhibitors

Chemicals that harm enzyme activity, can be competitive or non-competitive.

Competitive inhibitors

Inhibitors that bind to the active site of an enzyme.

Non-competitive inhibitors

Inhibitors that bind to sites other than the active site on an enzyme.

Allosteric regulation

When a regulatory molecule binds to an allosteric site.

Allosteric site

A non-active site on an enzyme.

Feedback inhibition

When a metabolic pathway is halted by an inhibitory chemical binding to an intermediate enzyme.

Cooperation

When several cycles work together.

Cofactors

Compounds bound to proteins required for activity.

Laws of thermodynamics

Principles governing the conservation and transformation of energy.

Principle of conservation of energy

Energy in the universe is constant; cannot be created or destroyed.

ATP

Adenosine triphosphate; a molecule consisting of ribose, adenine, and three phosphate groups.

Chemical change

The process which lowers the free energy state of a molecule.

Renewable resource

Resources that can be regenerated, such as ATP.

Photosynthesis

The process of creating glucose from carbon dioxide and water using light energy.

Autotroph

An organism that creates its own food.

Heterotroph

An organism that consumes other organisms for food.

Chloroplast

An organelle in plant cells responsible for photosynthesis.

Mesophyll

Tissue on the interior of a leaf where photosynthesis occurs.

Stomata

Pores in leaves allowing gas exchange.

Stroma

Cytoplasm-like liquid within a chloroplast for reactions.

Thylakoid

Stacked structures in chloroplasts assisting in light conversion to chemical energy.

Chlorophyll

A pigment that catalyzes photosynthesis.

Light reactions

Photosynthetic reactions dependent on light energy.

NADP+/NADPH

Electron carrier molecules involved in photosynthesis.

Photophosphorylation

Using light energy to phosphorylate ADP into ATP.

Carbon fixation

Converting inorganic carbon into organic compounds.

Wavelength

The length or width of a wave of light.

Electromagnetic spectrum

The range of all types of electromagnetic radiation.

Visible light

The part of the electromagnetic spectrum visible to humans.

Photon

A singular particle of light.

Spectrophotometer

A device used to measure light absorption.

Absorption Spectrum

The range of a pigment's ability to absorb light wavelengths.

Chlorophyll A

A pigment involved in the light reactions of photosynthesis.

Photosystem

A light-capturing unit in chloroplast thylakoids.

Reaction Center

A complex of proteins at the core of a photosystem.

Photosystem II

The site where electrons first get excited.

Photosystem I

The destination for electrons from Photosystem II.

Linear electron flow

The use of absorbed photon energy to oxidize water in PSII.

Cyclic electron flow

Production of ATP without NADPH synthesis.

G3P/PGAL

A 3-carbon sugar produced during photosynthesis.

Rubisco

An enzyme facilitating carbon fixation in photosynthesis.

Reduction

When molecules gain electrons, represented by RIG (reduction is gain).

Oxidation

When molecules lose electrons, represented by OIL (oxidation is loss).

Regeneration

The process of remaking in metabolic reactions.

Calvin Cycle

Light-independent reactions responsible for carbon fixation and sugar production.

Cellular respiration

A catabolic process used to break down glucose.

Glycolysis

The initial phase of cellular respiration where glucose is broken down.

Pyruvate oxidation

The conversion of pyruvate into acetyl-CoA.

Krebs cycle

Also known as the citric acid cycle; generates electron carriers.

Oxidative phosphorylation

The final stage of cellular respiration that produces ATP.

NADH

An electron carrier produced during metabolic processes.

FADH2

An electron carrier similar to NADH, produced during the Krebs cycle.

30-40 ATP

The amount of ATP produced during oxidative phosphorylation.

Hydrogen ions

Ions pumped during the electron transport chain, creating a gradient.

Hydrolysis of ATP

The breakdown of ATP releasing energy.

PGA

3-phosphoglycerate, a 3-carbon intermediate in the Calvin cycle.

Light-dependent reactions

The phase of photosynthesis requiring light.

Light-independent reactions

Reactions of photosynthesis not dependent on light.

Photosynthetic pigment

Compounds in plants that absorb light for photosynthesis.

Electron transport chain

A series of proteins transferring electrons releasing energy.

ATP Synthase

An enzyme that synthesizes ATP using a proton gradient.

Photolysis

The process of breaking down water using light energy.

Chemiosmosis

The process of using a proton gradient to generate ATP.

Plant cell

A cell containing chloroplasts for photosynthesis.

Electron carrier

Molecules that transport electrons during cellular respiration.

Glucose

A simple sugar that is an important energy source in living organisms.

Reduction phase of Calvin Cycle

Phase where ATP and NADPH are used to convert PGA to G3P.

ATP hydrolysis

The reaction where ATP is broken down to release energy.

Energy investment phase

The initial stage of glycolysis requiring energy input.

Oxaloacetate

A 4-carbon molecule that combines with acetyl-CoA in the Krebs cycle.

Intermembrane space

The space between the inner and outer membranes of a chloroplast.

Interconnectedness of Photosynthesis and Cellular Respiration

Two vital biological processes that are complementary, where the products of one often serve as the reactants for the other.

Relationship of Photosynthesis products to Cellular Respiration

Glucose (C6H{12}O6) and oxygen (O2) produced by photosynthesis are the primary reactants needed for cellular respiration.

Relationship of Cellular Respiration products to Photosynthesis

Carbon dioxide (CO2) and water (H2O) released by cellular respiration are the main reactants required for photosynthesis.

Energy transformation between Photosynthesis and Cellular Respiration

Photosynthesis captures light energy and converts it into chemical energy stored in glucose, which cellular respiration then releases as ATP.

Organelles involved in the Photosynthesis-Respiration cycle

Photosynthesis occurs in chloroplasts, while cellular respiration primarily occurs in mitochondria, forming an essential energy loop.

Overall chemical equation for Photosynthesis

6CO2 + 6H2O + \text{Light Energy} \rightarrow C6H{12}O6 + 6O2