Water and Biological Macromolecules

Comprehensive vocabulary flashcards covering key concepts of water properties, carbohydrates, lipids, proteins, and nucleic acids from Biology 1003 Unit 2.

Oxygenic Photosynthesis

The photosynthetic process performed by cyanobacteria, algae, and plants that uses carbon dioxide, water, and light energy to produce glucose, oxygen, and water ($6CO_2 + 12H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2 + 6H_2O$).

Anoxygenic Photosynthesis

Photosynthesis performed by organisms such as purple sulfur bacteria that uses light energy and an electron donor other than water (such as $H_2S$ or $H_2$) without producing free oxygen ($CO_2 + 2H_2A + \text{light energy} \rightarrow [CH_2O] + 2A + H_2O$).

Extracellular Fluid (ECF)

The portion of total body water (~33%) located outside cells, divided into interstitial fluid, intravascular fluid (blood plasma and lymph), and transcellular fluid.

Intracellular Fluid (ICF)

The portion of total body water (~67%) located inside cells, consisting primarily of cytosol (~80% of cytoplasm) and nucleoplasm.

Hydrophilic

Descriptive of polar or charged molecules that interact favorably with and readily dissolve in water via dipole-dipole attractions or hydrogen bonding.

Hydrophobic

Descriptive of non-polar molecules (such as dietary fats, steroid hormones, and fat-soluble vitamins) that repel water and cannot dissolve in it.

Anabolism

Metabolic processes that construct complex, large molecules from simple, small ones, requiring energy and enzyme catalysis (frequently involving dehydration synthesis).

Catabolism

Metabolic processes that break down complex, large molecules into simple, small ones, releasing energy and using enzyme catalysis (frequently involving hydrolysis).

Dehydration Synthesis

Anabolic chemical reaction where two molecules are covalently bonded together accompanied by the removal and formation of a water molecule.

Hydrolysis

Catabolic chemical reaction in which a covalent bond in a macromolecule is cleaved by the addition of a water molecule.

Monosaccharides

Simple single-sugar carbohydrate monomers with the general formula $C_n(H_2O)_n$, including glucose, fructose, galactose, ribose, and deoxyribose.

Disaccharides

Carbohydrates composed of two monosaccharide units covalently linked by a glycosidic bond, such as sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).

Polysaccharides

Complex carbohydrates formed by long chains of monosaccharide units linked by glycosidic bonds, including cellulose, starch, and glycogen.

Cellulose

A structural polysaccharide forming plant cell walls composed of linear chains of glucose joined by indigestible $\beta 1\text{-}4$ glycosidic bonds.

Glycogen

The short-term animal energy storage polysaccharide composed of branched glucose chains, stored primarily in skeletal muscle (~75%) and the liver (~25%).

Glycolysis

The metabolic oxidation of glucose to pyruvate occurring in all cells.

Glycogenesis

The metabolic conversion of glucose into stored glycogen occurring in the liver and skeletal muscle.

Glycogenolysis

The metabolic breakdown of stored glycogen into glucose occurring in the liver and skeletal muscle.

Gluconeogenesis

The metabolic creation of glucose from non-carbohydrate precursors occurring in the liver.

Saturated Fatty Acid

A fatty acid with only single carbon-carbon bonds, allowing straight hydrocarbon chains to pack closely together and remain solid at room temperature.

Cis-Unsaturated Fatty Acid

An unsaturated fatty acid where hydrogen atoms at a C=C double bond are on the same side, creating a kink in the chain that keeps it liquid at room temperature.

Trans-Unsaturated Fatty Acid

An unsaturated fatty acid where hydrogen atoms at a C=C double bond are on opposite sides, maintaining a linear structure and increasing risk of heart disease.

Essential Fatty Acids

Fatty acids that cannot be synthesized by the human body and must be acquired through diet: Alpha-linolenic acid (omega-3) and Linoleic acid (omega-6).

Eicosanoids

A class of rapid lipid chemical messengers derived from arachidonic acid (omega-6 pathway), including prostaglandins, thromboxanes, and leukotrienes.

Cholesterol

A steroid lipid synthesized in the liver featuring four carbon rings and a hydrocarbon tail, essential for cell membrane fluidity, steroid hormone synthesis, bile salts, and lipoprotein transport.

Triglycerides

Energy-storage lipids composed of one glycerol molecule covalently bonded to three fatty acids, yielding $9\,\text{cal/g}$ of energy and comprising ~98% of body fat.

Lipogenesis

The metabolic process in the liver where excess calories from any macronutrient are converted into triglycerides once glycogen stores are full.

Lipolysis

The breakdown of triglycerides into glycerol and three fatty acids occurring in adipocytes, liver, or muscle cells.

Phospholipids

Amphipathic membrane lipids consisting of glycerol, two fatty acids, a phosphate group, and a polar R group, forming the structural lipid bilayer of cells.

Amphipathic

Descriptive of a molecule (such as a phospholipid) that contains both a hydrophilic (polar) region and a hydrophobic (non-polar) region.

Amino Acids

Organic monomers consisting of a central carbon, an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group) that defines their chemical properties.

Peptide Bond

The covalent amide bond ($\text{CONH}$) linking two amino acids together formed between the carboxyl group of one amino acid and the amino group of another via dehydration synthesis.

Essential Amino Acids

The 9 amino acids that cannot be synthesized by the human body in sufficient amounts and must be supplied by the diet.

Primary Structure

The specific linear sequence of amino acids in a single peptide or polypeptide chain.

Secondary Structure

Localized spatial folding patterns within a single polypeptide chain, such as $\alpha$-helices and $\beta$-pleated sheets, stabilized by hydrogen bonds.

Tertiary Structure

The overall three-dimensional folded conformation of a single polypeptide chain.

Quaternary Structure

The overall three-dimensional arrangement resulting from the combination of two or more polypeptide subunits into a functional protein complex.

Denaturation

The process in which a protein loses its secondary, tertiary, or quaternary three-dimensional structure due to changes in pH or temperature, rendering it non-functional while leaving its primary structure intact.

Albumin

The most abundant plasma protein synthesized by the liver that plays a major role in maintaining blood osmotic pressure.

Nucleotides

Monomers of nucleic acids composed of a 5-carbon sugar (ribose or deoxyribose), a 5' phosphate group, and a 1' nitrogenous base.

Phosphodiester Bond

The covalent bond linking nucleotides together in a nucleic acid chain between the 3' OH group of one sugar and the 5' phosphate group of the adjacent sugar.

Central Dogma of Biology

The framework describing the flow of genetic information: DNA replication, transcription of DNA into RNA, and translation of RNA into protein.

Complementary Base Pairing

The specific hydrogen bonding between nitrogenous bases in DNA, where cytosine pairs with guanine via 3 hydrogen bonds and adenine pairs with thymine via 2 hydrogen bonds.