Chapter5

Nutrition

The process by which organisms obtain and utilize nutrients for growth and metabolism.

Macronutrients

Essential elements required in large amounts, including carbon (C), oxygen (O), nitrogen (N), hydrogen (H), phosphorus (P), sulfur (S), potassium (K), magnesium (Mg), calcium (Ca), and sodium (Na).

Micronutrients

Trace elements required in small amounts, such as iron (Fe) and other metals, which play crucial roles in cellular functions.

Culture media

Nutrient mixtures used to grow microorganisms in laboratory settings, classified into liquid and solid media.

Complex media

Culture media containing digests of chemically undefined substances, such as yeast and meat extracts.

Defined media

Culture media with a precise chemical composition known.

Bioenergetics

The study of energy flow and transformation in biological systems, particularly in relation to free energy (G).

Enzymes

Biological catalysts, typically proteins, that increase the rate of chemical reactions without being consumed.

Active site

The specific region of an enzyme where substrate binding occurs, facilitating catalysis.

Redox reaction

A chemical reaction involving the transfer of electrons between two species, consisting of oxidation and reduction processes.

Electron carrier

Molecules that transport electrons during redox reactions, including coenzymes like NAD+ and NADH.

ATP (Adenosine triphosphate)

The primary energy currency of the cell, used to store and transfer energy.

Glycolysis

A metabolic pathway that converts glucose into pyruvate, producing ATP and NADH, and is a common pathway for fermentation and respiration.

Fermentation

A metabolic process that converts sugars to acids, gases, or alcohol in the absence of oxygen, primarily through substrate-level phosphorylation.

Respiration

A metabolic process that involves the oxidation of substrates and the production of ATP, utilizing an electron transport chain and a terminal electron acceptor.

Proton motive force

The electrochemical gradient generated by the movement of protons across a membrane, driving ATP synthesis.

Tricarboxylic acid (TCA) cycle

Also known as the Krebs cycle or citric acid cycle, it is a key metabolic pathway that generates energy through the oxidation of acetyl-CoA.

Anabolism

The metabolic process that builds complex molecules from simpler ones, including the biosynthesis of sugars, amino acids, and fatty acids.

Gluconeogenesis

The metabolic pathway that synthesizes glucose from non-carbohydrate precursors, primarily occurring in the liver.

redox tower

Definition: A visual representation of the relative strength of oxidizing and reducing agents. It ranks substances based on their ability to gain or lose electrons. The higher a substance is on the tower, the stronger it is as an oxidizer, while those lower down are stronger reducers. It helps predict the direction of electron flow in redox reactions.

the top of the redox tower

Definition: This position in the redox tower indicates a strong tendency to gain electrons and undergo reduction. Substances here are powerful oxidizing agents, capable of driving reactions by accepting electrons from other species. They have high standard reduction potentials and are often found in biological and industrial processes. Examples include fluorine and oxygen.

bottom of the redox tower

Definition: This position in the redox tower indicates a strong reducing agent, meaning it readily donates electrons. Compounds here have a high tendency to lose electrons and are often involved in processes like oxidation. These substances are less stable and more reactive, often leading to the release of energy when they participate in redox reactions.

Catabolism

Definition:This process involves the breakdown of complex molecules into simpler ones, releasing energy in the form of ATP. It plays a crucial role in metabolism, providing the necessary energy for cellular functions. Common examples include the digestion of food and the breakdown of glucose during cellular respiration.

Nucliec acid

Definition: Biopolymers essential for all known forms of life, composed of nucleotide monomers. They store and transmit genetic information, guiding the synthesis of proteins. The two main types are DNA, which carries the genetic blueprint, and RNA, which plays various roles in translating that information into proteins.