Chapter 2 - The Chemical Composition of Cells-1

Phytoremediation

The use of hyperaccumulator plants to remove heavy metals from contaminated soils.

Hyperaccumulator plants

Species that can absorb and accumulate high levels of heavy metals from soils.

Phytomining

Utilizing hyperaccumulator plants to grow and harvest for the recovery of commercially valuable metals from metal-rich sites.

Proton

A subatomic particle with a positive electric charge and small mass.

Neutron

A subatomic particle that is uncharged and has a mass approximately equal to that of a proton.

Electron

A subatomic particle with a negative charge and an extremely small mass.

Ions

Atoms that tend to gain or lose electrons, resulting in a charge.

Chemical bond

An attraction between atoms that allows them to combine chemically.

Ionic bond

An electrostatic attraction between oppositely charged ions.

Covalent bond

A chemical bond involving one or more shared pairs of electrons.

Hydrogen bond

An attraction between a slightly positive hydrogen atom in one molecule and a slightly negative atom (usually oxygen) in another molecule.

Cohesion

The tendency of molecules to form hydrogen bonds with one another.

Adhesion

The tendency of water molecules to form hydrogen bonds with other substances with ionic or polar regions.

pH scale

A measure of the relative concentrations of H+ and OH- in a solution.

Acids

Compounds that dissociate in water to form hydrogen ions (H+).

Bases

Compounds that dissociate in water to yield negatively charged hydroxide ions (OH-).

Carbohydrates

Organic compounds containing carbon, hydrogen, and oxygen, typically in a 1C:2H:1O ratio, important for energy and structure.

Monosaccharides

Simple sugars that are the building blocks of carbohydrates.

Disaccharides

Carbohydrates formed by two monosaccharide units.

Polysaccharides

Carbohydrates composed of many monosaccharide units.

Lipids

Organic compounds that are insoluble in water but soluble in fat solvents, important for energy storage and cell membranes.

Proteins

Large, complex organic compounds made up of amino acids, performing various functions in the body.

Nucleic acids

Complex organic molecules that control cell life processes; includes DNA and RNA.

DNA

Deoxyribonucleic acid, which transmits information from one generation to the next.

RNA

Ribonucleic acid, which is involved in protein synthesis.

Amino acids

The building blocks of proteins, joined together by peptide bonds.

ATP

Adenosine triphosphate, a modified nucleotide compound important in energy transfers in biological systems.

Enzymes

Organic catalysts produced within organisms that accelerate specific chemical reactions.

Activation energy

The energy required to initiate a chemical reaction.

First Law of Thermodynamics

Energy cannot be created or destroyed; it can only be transformed from one form to another.

Second Law of Thermodynamics

Every transfer of energy increases the entropy (disorder) of the universe.

Entropy

A measure of disorder or randomness in a system.

Primary metabolites

Compounds directly involved in the growth and development of a plant.

Secondary metabolites

Organic compounds produced in other metabolic pathways, not directly involved in growth or reproduction.

Alkaloids

Naturally occurring chemical compounds primarily containing basic nitrogen atoms, often with pharmacological effects.

Terpenoids

Secondary metabolites indicative of ecological responses, often involved in plant defense.

Phenolics

Compounds produced in response to ecological pressures; involved in plant defense and traditional medicine.

Molecular structure

The arrangement of atoms in a substance, determining its properties and functions.

Peptide bonds

Covalent bonds formed between amino acids in a protein.

Hydrophobic effect

The tendency of non-polar substances to aggregate in aqueous solution, minimizing their exposure to water.

Biological catalyst

A substance that accelerates a chemical reaction in a biological context.

Cohesion and adhesion

Physical properties of water that are critical for transport in biological systems.

Chemical composition

The types and arrangements of atoms within a molecule.

Plant defense mechanisms

Various strategies employed by plants to protect themselves from herbivores and pathogens.