Lecture 13: Cellular Respiration 2 & Fermentation

Cellular Respiration

A metabolic process that converts food into energy in the form of ATP.

ATP

A molecule that carries energy within cells, enabling various biochemical processes.

Oxidative Phosphorylation

The process where ATP is formed as a result of the transfer of electrons from NADH and FADH2 to molecular oxygen.

Fermentation

A metabolic process that allows organisms to produce ATP without oxygen, by converting glucose to either lactic acid or ethanol and CO2.

Pyruvate

A three-carbon molecule that is produced from glycolysis and can be oxidized to enter the Krebs cycle.

Glycolysis

The first step in cellular respiration that breaks down glucose into two molecules of pyruvate, producing a small amount of ATP.

Acetyl CoA

A two-carbon molecule formed from pyruvate that enters the Krebs cycle.

Krebs Cycle

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

Electron Transport Chain

A series of complexes in the inner mitochondrial membrane that transfers electrons to oxygen, resulting in the pumping of protons and generation of ATP.

Chemiosmosis

The movement of protons across a membrane, driving the synthesis of ATP.

NADH

An electron carrier that stores energy used to produce ATP in cellular respiration.

FADH2

An electron carrier that also contributes to the production of ATP during cellular respiration.

Substrate-Level Phosphorylation

A method of producing ATP by directly transferring a phosphate group to ADP from a donor molecule.

Electrochemical Gradient

A difference in charge and concentration of ions across a membrane that drives the movement of protons.

Proton Motive Force

The force generated by the electrochemical gradient of protons, driving the conversion of ADP to ATP.

Lactic Acid Fermentation

A type of fermentation that converts pyruvate into lactic acid, regenerating NAD+.

Alcoholic Fermentation

A type of fermentation that converts pyruvate into ethanol and carbon dioxide, regenerating NAD+.

Facultative Anaerobes

Organisms that can switch between aerobic respiration and fermentation depending on the presence of oxygen.

Obligate Anaerobes

Organisms that are poisoned by oxygen and rely solely on anaerobic processes like fermentation.

Gluconeogenesis

The metabolic process that creates glucose from non-carbohydrate precursors.

ATP Synthase

An enzyme that catalyzes the formation of ATP from ADP and inorganic phosphate, utilizing the proton gradient.

Cristae

The folds of the inner mitochondrial membrane where the electron transport chain is located.

Coenzyme A (CoA)

A cofactor that plays a crucial role in the synthesis and oxidation of fatty acids and the Krebs cycle.

Reactive Oxygen Species (ROS)

Chemically reactive molecules containing oxygen that can lead to cellular damage.

Citric Acid Cycle

Also known as the Krebs cycle; the series of reactions that produce electron carriers and ATP from acetyl CoA.

Metabolic Pathways

Series of enzymatic reactions that convert substrates into products, crucial for cellular processes.

Oxidation

The process of losing electrons, which often accompanies a loss of energy.

Reduction

The process of gaining electrons, often associated with an increase of energy in molecules.

Energy Investment Phase

The initial phase of glycolysis where ATP is consumed to phosphorylate glucose.

Energetic Payout

The phase of cellular respiration where ATP is produced, mainly through oxidative phosphorylation.

Carbon Dioxide (CO2)

A waste product of cellular respiration produced during the Krebs cycle.

Water (H2O)

A byproduct of aerobic respiration formed when electrons are transferred to oxygen.

Bacterial Anaerobes

Bacteria that thrive in the absence of oxygen, using fermentation for energy.

Liver

An organ that processes lactate, converting it back into glucose when oxygen is available.

Lactate

The end product of lactic acid fermentation, which can be converted back into pyruvate.

Aerobic Respiration

Cellular respiration that requires oxygen to produce ATP.

NAD+

An electron carrier that accepts electrons and becomes reduced to NADH during glycolysis.

Hydrocarbon Bonds

Chemical bonds made up of hydrogen and carbon, which contain a high amount of energy.

Dietary Fats

Nutritional components that provide a higher energy yield compared to carbohydrates.

Primary Metabolites

Substances produced during the central metabolic pathways that are necessary for cellular functions.

Energy Currency

Refers to ATP, which is used to power cellular processes.

Homeostasis

The state of steady internal conditions maintained by living organisms.

Photosynthesis

The process by which plants and some microbes convert light energy into chemical energy.

Heterotrophs

Organisms that consume organic compounds to obtain energy, as they cannot produce their own food.

Microbiome

The collection of microorganisms living in a particular environment, especially within the human body.

Nitrogen Fixation

The process by which certain bacteria convert atmospheric nitrogen into a form usable by living organisms.

Synchronous Metabolism

The metabolic coordination between various biochemical pathways occurring in cells.

Lipid Metabolism

Processes that manage the intake, storage, degradation, and synthesis of lipids.

Pentose Phosphate Pathway

A metabolic pathway parallel to glycolysis that generates NADPH and ribose-5-phosphate.

Enzyme Kinetics

The study of the rates of enzyme-catalyzed reactions.

Feedback Inhibition

A regulatory mechanism where the end product inhibits its own production by blocking an enzyme.

Allosteric Regulation

The regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site.

Hydrolysis

The chemical breakdown of a compound due to reaction with water.

Functional Groups

Specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

Amino Acids

Organic compounds that combine to form proteins, containing carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.

Polymerization

The process of combining small molecules (monomers) to form larger molecules (polymers).

Glycogen

A storage polysaccharide composed of glucose, found primarily in the liver and muscles.

Fatty Acids

Long hydrocarbon chains that are components of lipids and are important for energy storage.

Transcription

The process by which the information in a gene is encoded into messenger RNA.

Translation

The process by which ribosomes synthesize proteins using the information provided by messenger RNA.

Chromatin

The complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells.

Mitochondrial Matrix

The gel-like substance within the inner membrane of the mitochondria where the Krebs cycle occurs.

Mitochondrial Evolution

The endosymbiotic theory suggesting that mitochondria originated from free-living bacteria.

Photorespiration

A process where plants consume oxygen and release carbon dioxide in the light, seemingly counterproductive to photosynthesis.

Calvin Cycle

A set of chemical reactions that take place in the chloroplasts of photosynthetic organisms, converting carbon dioxide into glucose.

Plastoquinone

An electron carrier in photosynthesis, similar in function to coenzyme Q in cellular respiration.

Histones

Proteins that help package and order DNA into structural units called nucleosomes.

Eukaryotes

Organisms whose cells contain a nucleus enclosed within membranes.

Prokaryotes

Single-celled organisms that lack a membrane-bound nucleus.

Biosynthesis

The process by which living organisms produce complex compounds from simple precursors.

Chloroplast

The organelle in plant cells where photosynthesis occurs.

Respiratory Surface

The area through which gas exchange occurs in organisms.

Metabolic Flexibility

The ability of an organism to adjust its metabolism based on nutrient availability.

Obligate Aerobes

Organisms that require oxygen for survival as they rely on aerobic respiration.

Cytoplasm

The jelly-like substance within a cell that holds organelles and is the site of many metabolic processes.

Steroid Hormones

Hormones derived from cholesterol that play key roles in various physiological processes.

Bioenergetics

The study of the energy flow through living systems.

Energy Metabolism

The process of converting food into usable energy by cells.

Antioxidants

Molecules that inhibit oxidation and protect cells from the damage caused by reactive oxygen species.

Fermentation Products

Substances produced from fermentation, including ethanol, lactic acid, and carbon dioxide.

Anaerobic Glycolysis

The conversion of glucose into energy without the use of oxygen, yielding lactic acid or ethanol.

Redox Reactions

Chemical reactions involving the transfer of electrons, involving reduction and oxidation.

Flavin Adenine Dinucleotide (FAD)

A coenzyme involved in several enzymatic reactions in metabolism, serving as an electron carrier.

Hydrogen Ion Concentration

The amount of hydrogen ions present in a solution, influencing pH and chemical reactions.

Energy Yield

The amount of energy produced from a metabolic process, often measured as ATP.

Fermentation Pathways

Metabolic routes that enable the regeneration of NAD+ under anaerobic conditions.

Bacterial Fermentation

The metabolic process where bacteria convert sugars into energy, producing alcohol or acids.

Microbial Fermentation

Fermentation processes carried out by microorganisms for the production of various products.

Nutritional Biochemistry

The study of how nutrients are metabolized and utilized by the body.

Physiological Response

The body’s biological reaction to various stimuli, including exercise and dietary changes.

Energy Transfer

The process of moving energy from one form to another in biological systems.

Entropy

The measure of disorder or randomness in a system, often related to energy distribution.

Synthesis Pathways

Metabolic routes involved in the formation of complex molecules from simpler substances.

Electron Carriers

Molecules that transport electrons during cellular respiration.

Nutritional Requirements

The essential nutrients that an organism needs for growth, metabolism, and maintenance.

Enzymatic Activity

The rate at which an enzyme converts substrate into product under specific conditions.

Chemical Energy

Energy stored in the bonds of chemical compounds, which is released during reactions.