Unit 3 AOS 2 - Chapter 6

Cellular Respiration

the process by which cells create usable energy in the form of ATP from a series of biochemical reactions, involving the breakdown of glucose

Glucose

a simple 6-carbon sugar molecule with the formula

C6H12O6

ATP

adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes

Aerobic cellular respiration

cellular respiration that occurs in the presence of oxygen. Involves three stages, during which glucose and O2 are converted into ATP, CO2, and water

Anaeroboic fermentation

a metabolic pathway that occurs in the absence of oxygen. Involves glycolysis, followed by further reactions that convert pyruvate into lactic acid in animals, or ethanol and CO2 in yeast

Glycolysis

the first stage of aerobic cellular respiration in which glucose is converted to two pyruvate molecules

Krebs Cycle

the second stage of aerobic cellular respiration, where multiple reactions occur to create ATP, NADH, FADH2, and the waste product CO2.

Electron Transport Chain

the third stage of aerobic cellular respiration, in which a series of protein complexes embedded in the inner membrane of a mitochondrion harness the stored energy in NADH and FADH2 to generate large amounts of ATP

Mitochondrion

a double-membrane-bound organelle that is the site of the second and third stages of aerobic cellular respiration

Cytosol

the aqueous fluid that surrounds a cell's organelles inside the plasma membrane

Mitochondrial Matrix

the space inside the inner membrane of a mitochondrion. The site of the Krebs cycle.

Crista

the folds of the inner membrane of a mitochondrion. The site of the electron transport chain

Pyruvate

a three-carbon molecule that can be formed from the breakdown of glucose via glycolysis

NAD

a coenzyme that acts as a proton (H+)and electron carrier in cellular respiration. NAD can cycle between its NAD+ and NADH forms, depending on the reaction it takes part in

FAD

a coenzyme that acts as a proton (H+) and electron carrier in cellular respiration. FAD can cycle between its FAD and FADH2 forms, depending on the reaction it takes part in

Coenzyme A (CoA)

a large organic non- protein molecule that plays a key role in the modification of pyruvate to allow it to enter the Krebs cycle.

Acetyl-CoA

the product of the link reaction where pyruvate is conjugated to coenzyme A, creating the primary input into the Krebs cycle

ATP Synthase

an enzyme in the inner mitochondrial membrane that uses the concentration gradient of H+ to synthesise ATP from ADP and Pi

Catalyse

to increase the rate of a reaction

Yeast

unicellular eukaryotic organisms from the kingdom Fungi

Lactic Acid fermentation

the process of anaerobic fermentation in animals, where pyruvate produced via glycolysis is converted to lactic acid

Lactic Acid

a 3-carbon molecule that is the product of anaerobic fermentation in animals.

Ethanol

a 2-carbon alcohol molecule that is produced along with carbon dioxide during anaerobic fermentation in yeast, bacteria, and plants

Ethanol fermentation

the process of anaerobic fermentation in yeasts, where pyruvate produced via glycolysis is converted to ethanol and carbon dioxide.

pH

a scale used to measure the acidity or basicity of an aqueous solution

Saturation point

the point at which a substance(e.g. an enzyme) cannot receive more of another substance (e.g. a substrate)

Enzyme inhibitor

a molecule that binds to and prevents an enzyme from functioning

Competitive Inhibitor

a molecule that hinders an enzyme by blocking the active site and preventing the substrate from binding

Non-competitive Inhibitor

a molecule that hinders an enzyme by binding to an allosteric site and changing the shape of the active site to prevent the substrate from binding

Allosteric Site

a region on an enzyme that is not the active site

End-product inhibition

a form of inhibition where the final product in a series of reactions inhibits an enzyme in an earlier reaction in the sequence

Fossil fuel

fuel that formed over tens of millions of years from the remains of dead organic material. Fossil fuels are considered non- renewable

Non-renewable

refers to a resource that is replenished at a slower rate than it is being used, meaning that it will eventually run out

Biofuel

fuel created from organic material known as biomass

Biomass

organic material, including plants, animal by-products, and biological waste material. Biomass can be sourced from many industries,

including farming, forestry, and food manufacturing

Renewable

refers to a resource that can typically be replenished at the same (or faster) rate than it is being used, meaning it is unlikely to run out

Carbon Neutral

a state in which there is no net release of carbon dioxide into the atmosphere, meaning that there is a balance between the amount of CO2 that is emitted during combustion of a fuel and how much was originally absorbed during the formation process of that fuel

Fermentation

the anaerobic

chemical breakdown of high- energy organic molecules, typically via the action of enzymes. For many plants, fermentation involves the conversion of glucose to ethanol and carbon dioxide

Bioethanol

a type of biofuel that is produced via the anaerobic fermentation of plants such as sugarcane or corn

Hydrolysis

a chemical reaction in which water is used to break down the chemical bonds of a substance

Food vs Fuel debate

a central concern of large-scale biofuel manufacturing that questions the validity of using arable farmland to produce fuel, rather than food

First generation biofuels

biofuels produced from edible food crops such as corn or sugarcane.These compete directly with agricultural land

Second generation biofuels

biofuels produced from non-edible crops such as agricultural and forestry residues and municipal waste.These typically compete less with agricultural land