Chemical Foundations of Life: Biogenic Elements, Water, Carbohydrates, Lipids, Proteins, and Nucleic Acids

Comprehensive vocabulary flashcards covering the chemical basis of life, including biogenic macro- and microelements, the biological properties of water, the structures and functions of carbohydrates, lipids, proteins, and nucleic acids (DNA/RNA).

Macroelements

Chemical elements that occur in organisms in large quantities, constituting $0.01\%$ or more of an organism's dry mass.

Biogenic Elements

The six essential macroelements that form the primary structural backbones of organic compounds in all organisms: carbon ($\text{C}$), hydrogen ($\text{H}$), oxygen ($\text{O}$), nitrogen ($\text{N}$), phosphorus ($\text{P}$), and sulfur ($\text{S}$).

Microelements

Trace chemical elements that make up less than $0.01\%$ of an organism's dry mass, including iron ($\text{Fe}$), copper ($\text{Cu}$), iodine ($\text{I}$), fluorine ($\text{F}$), and cobalt ($\text{Co}$).

Calcium ($\text{Ca}$)

A macroelement that builds bones, participates in blood clotting, and is required for the proper functioning of the nervous system and muscles.

Magnesium ($\text{Mg}$)

A macroelement that regulates enzymatic activity, conducts nerve impulses, and supports proper heart and muscle function; abundant in pumpkin seeds, wheat bran, bananas, and cocoa.

Chlorine ($\text{Cl}$)

A macroelement essential for maintaining water balance, producing hydrochloric acid ($\text{HCl}$) in the stomach, and sustaining acid-base balance in blood and lymph.

Iron ($\text{Fe}$)

A microelement that forms a core component of hemoglobin for oxygen transport in blood and activates immune system cells during infections.

Copper ($\text{Cu}$)

A microelement that functions in enzymes responsible for cellular energy production, the synthesis of the skin pigment melanin, and the formation of collagen and elastin.

Iodine ($\text{I}$)

A microelement essential for the synthesis of thyroid hormones and assisting the body in eliminating cells that could cause cancer development.

Fluorine ($\text{F}$)

A microelement possessing antibacterial and anti-caries properties that is required for the proper formation and hardening of dental enamel.

Cobalt ($\text{Co}$)

A microelement that is an essential structural component of vitamin $\text{B}_{12}$, supports the nervous and circulatory systems, and helps inhibit cancer development.

Polarity of Water

The molecular asymmetry of water featuring a partial negative charge at the oxygen atom and partial positive charges at the hydrogen atoms, enabling the formation of hydrogen bonds between molecules.

High Specific Heat of Water

The physical property where water requires significant heat energy to change its temperature, buffering organisms against sudden ambient temperature shifts and stabilizing body temperature.

High Heat of Vaporization of Water

The property requiring substantial energy input to convert liquid water into water vapor, allowing organisms to thermoregulate and cool down through the evaporation of sweat.

Temperature-Dependent Density of Water

The physical phenomenon where water attains its highest density at $4^\circ\text{C}$, causing cooler water and ice to stay at the surface, creating an insulating thermal layer that protects aquatic life in winter.

Surface Tension of Water

The cohesive force forming an elastic-like membrane at the water-air interface, which allows lightweight organisms such as water striders to rest and move across the water's surface.

Monosaccharides

Simple carbohydrates characterized by a carbon backbone containing $3$ to $10$ carbon atoms; they taste sweet, dissolve readily in water, and can alternate between chain and ring configurations.

Glucose

A primary six-carbon monosaccharide ($\text{C}_6\text{H}_{12}\text{O}_6$) that provides cellular energy through mitochondrial respiration and serves as the structural monomer for many disaccharides and polysaccharides.

O-Glycosidic Bond

The covalent linkage formed between monosaccharide units via an oxygen atom connecting carbon atoms from different sugar molecules with the elimination of a water molecule.

Maltose

A disaccharide composed of two glucose molecules linked together; it is produced during starch degradation and utilized as a sweetener and in brewing beer.

Lactose

A disaccharide composed of one glucose unit and one galactose unit, functioning as an energy source found naturally in mammalian milk.

Sucrose

A disaccharide formed from glucose and fructose that serves as the primary sugar transport form in plants and is extracted from sugar cane or sugar beet for sweetening.

Starch

A plant storage polysaccharide consisting of polymerized glucose subunits, abundantly accumulated in potato tubers and cereal grains.

Glycogen

A highly branched polysaccharide composed of glucose residues that acts as the reserve carbohydrate in animals and fungi, stored primarily in the liver and skeletal muscle cells.

Cellulose

An unbranched polysaccharide made of glucose monomers that forms plant cell walls; it cannot be digested by humans and constitutes dietary fiber.

Chitin

A tough structural polysaccharide composed of modified nitrogen-containing sugar units that forms the cell walls of fungi and the external exoskeletons of arthropods.

Lipids

A diverse class of hydrophobic organic compounds composed of carbon, hydrogen, and oxygen (and sometimes nitrogen or phosphorus) that are insoluble in water but soluble in organic solvents.

True Fats (Triglycerides)

Simple lipids composed of glycerol connected to fatty acids via ester bonds, serving as a high-energy storage material and a subcutaneous thermal insulation layer in mammals.

Saturated Fatty Acids

Fatty acids containing exclusively single carbon-carbon bonds, typically giving lipids a solid state at room temperature, which is characteristic of animal fats.

Unsaturated Fatty Acids

Fatty acids containing at least one carbon-carbon double bond, imparting a liquid consistency at room temperature, which is predominant in plant oils.

Waxes

Simple lipids composed of fatty acids linked to an alcohol other than glycerol, forming insoluble protective coatings on bird feathers, plant leaves, and honeybee comb structures.

Phospholipids

Compound lipids composed of glycerol, fatty acids, and a phosphoric(V) acid residue, featuring a hydrophilic head and hydrophobic tails that assemble into biological membranes.

Glycolipids

Compound lipids containing carbohydrate components bound to a lipid core that function as membrane structural elements and cell-surface antigens, such as blood group determinants.

Cholesterol

An isoprenoid steroid lipid that stiffens and seals animal cell membranes, acts as a precursor for vitamin $\text{D}_3$ and hormones like testosterone, and can form vascular plaques leading to heart attacks if present in excess.

Sudan III Test

A biological diagnostic staining method used to confirm the presence of lipids in plant material, such as crushed sunflower seeds, by producing a characteristic red/orange coloration.

Amino Acid

The monomeric subunit of proteins consisting of a central carbon atom bonded to an amino group ($-\text{NH}_2$), a carboxyl group ($-\text{COOH}$), a hydrogen atom, and an interchangeable variable side chain ($\text{R}$).

Peptide Bond

The covalent linkage formed between the carboxyl group of one amino acid and the amino group of another amino acid, releasing one molecule of water ($\text{H}_2\text{O}$).

Simple Proteins

Proteins composed entirely of amino acid chains without non-protein components, including histones, keratins, albumins, and globulins.

Conjugated Proteins

Complex proteins consisting of amino acid polypeptide chains joined to a non-protein prosthetic group, such as the heme group in hemoglobin and myoglobin.

Histones

Simple structural proteins situated in the cell nucleus that act as structural spools around which double-stranded DNA threads are wound.

Pepsin

An enzymatic protein produced in the gastric mucosa of the stomach that catalyzes the chemical breakdown of dietary proteins.

Hemoglobin

A conjugated transport protein in erythrocytes containing iron that carries oxygen ($\text{O}_2$) and carbon dioxide ($\text{CO}_2$) throughout the bloodstream.

Fibrinogen

A protective blood protein that plays an indispensable role in blood coagulation, forming clots that prevent fatal blood loss.

Protein Salting Out

A reversible process wherein light metal salts (such as $\text{NaCl}$) dehydrate colloidal protein molecules, causing them to aggregate into a precipitate without disrupting their native structural integrity.

Protein Denaturation

The irreversible disruption of a protein's spatial tertiary/secondary architecture through breaking non-covalent bonds (preserving peptide bonds), triggered by heat above $40^\circ\text{C}$, UV or X-rays, pressure, concentrated acids, bases, heavy metals, or alcohols.

Prions

Pathological proteins with abnormal conformations that degrade nervous system tissue into a sponge-like texture, transmitting fatal diseases such as kuru through cannibalism.

Nucleotide

The monomeric unit of nucleic acids, consisting of a five-carbon sugar (ribose or deoxyribose), a nitrogenous base, and a phosphate group from phosphoric(V) acid.

Phosphodiester Bond

The covalent link connecting the pentose sugar of one nucleotide to the phosphoric(V) acid group of the adjoining nucleotide in a nucleic acid strand.

Deoxyribonucleic Acid (DNA)

A double-stranded antiparallel nucleic acid formed of deoxyribonucleotides (with bases A, T, C, G) that stores and transmits hereditary information.

Rule of Base Complementarity

The strict chemical pairing in DNA where adenine binds exclusively to thymine via $2$ hydrogen bonds ($\text{A}=\text{T}$) and cytosine binds to guanine via $3$ hydrogen bonds ($\text{C}\equiv\text{G}$).

DNA Replication

The template-guided duplication of genetic material before cell division where uncoiled DNA strands direct the assembly of complementary nucleotides to yield two identical daughter DNA molecules.

Ribonucleic Acid (RNA)

A predominantly single-stranded nucleic acid containing ribose and the nitrogenous base uracil ($\text{U}$) instead of thymine, primarily dedicated to translating genetic directives into proteins.

Messenger RNA (mRNA)

The ribonucleic acid variety that transcribes genetic structural information from nuclear DNA and carries it to the ribosomes for protein synthesis.

Transfer RNA (tRNA)

The specific ribonucleic acid molecules that transport individual amino acids to ribosomes during translation.

Ribosomal RNA (rRNA)

The structural and catalytic RNA constituent that builds ribosomes and participates directly in binding amino acids together into polypeptide chains.

Adenosine Triphosphate (ATP)

A free cellular nucleotide composed of adenine, ribose, and three phosphate groups that acts as the universal chemical energy transporter in cells.

Dinucleotide Electron Carriers

Dinucleotide cofactors, notably $\text{NAD}^+$ and FAD, that capture and shuttle electrons during metabolic reactions such as aerobic cellular respiration.