BIOLOGY 20 PHOTOSYNTHESIS AND RESPIRATION

Cellular Respiration

The process by which cells release energy stored in organic compounds.

ATP

A high-energy molecule that provides energy for cellular metabolism and various processes such as active transport and muscle contraction.

Aerobic Respiration

A type of cellular respiration that requires oxygen to produce ATP.

Anaerobic Respiration

A type of cellular respiration that occurs without oxygen, producing less ATP than aerobic respiration.

Glycolysis

The first step of cellular respiration where glucose is split into two pyruvate molecules.

Krebs Cycle

A series of reactions in cellular respiration that produces ATP and high-energy molecules through the oxidation of acetyl-CoA.

Electron Transport Chain

A series of proteins in the inner mitochondrial membrane that transfer electrons and generate ATP through oxidative phosphorylation.

Fermentation

An anaerobic process that allows for the recycling of NAD+ in the absence of oxygen to continue glycolysis.

NADH

A reduced form of nicotinamide adenine dinucleotide, it acts as an electron carrier in cellular respiration.

FADH2

A reduced form of flavin adenine dinucleotide, it also serves as an electron carrier in the electron transport chain.

Mitochondria

Organelles responsible for producing ATP through cellular respiration.

Pyruvate

A 3-carbon molecule produced from the breakdown of glucose in glycolysis.

ATP Synthase

An enzyme that produces ATP from ADP and inorganic phosphate during oxidative phosphorylation.

Active Transport

The process of moving substances in or out of a cell against their concentration gradient, using ATP.

Acetyl-CoA

A two-carbon molecule that enters the Krebs Cycle; formed from pyruvate after glycolysis.

Lactic Acid Fermentation

A process by which glucose is converted into lactic acid and ATP when oxygen is scarce, occurring in muscle cells.

Alcohol Fermentation

A process by which glucose is converted into ethanol and carbon dioxide, occurring mostly in yeast.

Chemiosmosis

The movement of ions across a selectively permeable membrane, driving the production of ATP.

Second Law of Thermodynamics

Energy cannot be created or destroyed, only transformed; in cellular respiration, some energy is lost as heat.

Organelles

Specialized structures within a cell that perform specific functions; mitochondria are the organelles of cellular respiration.

Purpose of Photosynthesis

Convert solar energy into glucose which can then be used by the cells to form ATP which is the main fuel for cells to do their metabolic activities.

Side Product of Photosynthesis (that we need for function)

Oxygen.

Adenosine Triphosphate (ATP)

Supply molecule for cellular functions of all cells.

ATP Energy Source

Provides an immediate source of energy for cellular processes.

ATP Formation

Formed by addition of phosphate.

Nicotinamide Dinucleotide Phosphate (NADPH)

During photosynthesis, NADP+ accepts electrons to form NADPH.

NADPH Function

NADPH is an electron carrier, thus becomes NADP+ again.

High Energy Bonds in ATP

A molecule containing three high-energy phosphate bonds that act as the primary energy-transferring molecule in living organisms.

ATP Formation Process

Formed when a phosphate group is added to a molecule of adenosine diphosphate (ADP).

Adenosine Diphosphate (ADP)

A molecule containing two high-energy phosphate bonds.

ADP Formation

May be formed by breaking one of the phosphate bonds in ATP.

Light Dependent Reactions

Energy from the sun is captured in energy-carrying molecules.

Location of Light Dependent Reactions

Must take place in thylakoid membranes.

Light Independent Reactions

The energy from the light reactions is used to convert atmospheric carbon dioxide into organic compounds.

Location of Light Independent Reactions

Does not have to take place in the light.

Synthesis in Photosynthesis

Makes glucose in the stroma.

Photosynthesis Equation

H2O + CO2 + light → O2 + C6H12O6.

Photosynthesis Reactants

Uses ATP and NADPH.

Photon Interaction

This reaction begins with the light striking a chlorophyll and splitting it apart.

Water Splitting Reaction

H2O → 2H+ + 2e- + ½ O2.

Thylakoid Function

The thylakoid is where the light reactions occur.

Photosystems

The electrons get excited on two photosystems.

Photosystem Location

The photosystems are highly organized clusters on the thylakoid membrane.

Photosynthesis

The process that converts light energy into chemical energy.

Light Reactions

The first stage of photosynthesis occurring in the thylakoid membrane.

Synthesis

The process of making glucose in the chloroplast.

ATP and NADPH

Energy carriers used in the synthesis phase of photosynthesis.

Photosystem

Clusters of pigments that capture light energy.

Electrons

Negatively charged particles present in all atoms.

Thylakoid Membrane

The membrane where light reactions occur.

Photon

A particle of light that initiates the light-dependent reactions.

Electron Transport Chain

The part of the photosystem that accepts and moves electrons.

Electron Transport Chain (ETC)

The pathway where excited electrons are passed down.

Clusters of Chlorophyll

Structures that capture energy from photons.

Light-Dependent Reactions

Reactions that capture solar energy and convert it into chemical energy.

Excited Electrons

Electrons that have absorbed energy and are transferred through the photosystems.

H+ Flow

The movement of hydrogen ions that creates ATP.

Dark Reaction

Another name for the Calvin Cycle, where glucose is synthesized.

Solar Energy

Energy from the sun that is captured during photosynthesis.

Chemical Energy

Energy stored in the bonds of chemical compounds, produced during photosynthesis.

Glucose

A simple sugar produced during photosynthesis.

Light

The form of energy that initiates the process of photosynthesis.

Photon of Light

Before it strikes, the electron in the chlorophyll molecule has a low amount of energy.

Photon Conversion

The photon has now been converted to chemical energy.

Plastoquinone (PQ)

The primary electron acceptor in PSII.

PQH2 Travel

PQH2 travels from PSII to PSI.

Protons Drop-off

The protons are dropped off in the thylakoid interior, where they accumulate.

Source of Interior H+

Other interior H+ come from the splitting of water molecules.

PQ Recycling

PQ goes back to the photosystem to transport electrons.

Electron Transport Chain (ETC)

The electron is removed from the photosystem and transferred from one molecular complex to another, releasing energy.

Electron Replacement

Electrons that are removed from the photosystem must be replaced.

Photolysis

A chemical reaction in which water molecules are split by light.

Photolysis Location

Photolysis occurs in the thylakoid membrane.

Water Splitting Reaction

2 H2O + energy → 4 H+ + O2 + 4 e-.

NADPH Function

NADPH2 is a high-energy molecule used to power the Calvin Cycle.

ATP Synthase Complex

A specialized protein embedded in the thylakoid membrane.

H+ Gradient

As more electrons are carried through the ETC, more H+ ions are pulled into the lumen, creating an electrochemical gradient.

Chemiosmosis

The process of making ATP using the energy from an H+ ion gradient.

Calvin Cycle

The next phase of photosynthesis where ATP and NADPH are utilized.

Oxygen

Released into the atmosphere as a byproduct of photosynthesis.

Carbon Fixation

Formation of high-energy compounds from CO2.

Light-Independent Reaction

The process that forms glucose from the products of light-dependent reactions.

Chloroplast

The organelle where the Calvin Cycle occurs.

1 Carbon

Amount of carbon created for every turn of the Calvin Cycle.

Calvin Cycle

Takes three turns to make one glucose molecule.