Biology Fundamentals: Properties of Life, Chemistry, and Macromolecules

A set of vocabulary flashcards covering basic principles of life, foundational biology theories, organic chemistry, carbohydrates, polysaccharides, and protein structural levels based on the lecture notes.

Properties of Life

The shared characteristics of living organisms, including keeping order/information, responding to environmental changes/stimuli, reproduction, capacity to adapt, regulation/homeostasis, growth and development, and energy processing.

Fundamental Nutritional Needs of Life

The two basic requirements for living organisms: energy (stored and converted into ATP) and molecules to serve as building blocks for macromolecules.

Three Pillars of Modern Biology

The foundational theories of modern biology: 1) Cell theory, 2) Evolution from natural selection, and 3) Theory of inheritance (chromosome theory).

Hypothesis

A tentative explanation about an observed phenomenon that can often be wrong.

Scientific Law

A mathematical description of a natural phenomenon that can be proven wrong, though not often.

Scientific Theory

An explanation for phenomena seen in nature that is supported by a wide body of evidence and can be proven wrong, though not often.

Elemental Composition Table

A table comparing abundances of major elements: Oxygen (Life 65%, Atmosphere 21%, Earth 46%), Carbon (Life 18%, Atmosphere trace, Earth trace), Hydrogen (Life 10%, Atmosphere trace, Earth 0.1%), and Nitrogen (Life 3%, Atmosphere 78%, Earth trace).

Autotrophs

Organisms that acquire carbon directly from inorganic $CO_2$.

Heterotrophs

Organisms that acquire carbon by consuming organic molecules.

Organic Molecules

Molecules that include at least one carbon atom, usually containing C-H and C-C bonds, with common elements including H, O, N, and S.

Four Major Classes of Biological Macromolecules

The primary groups of large organic molecules found in living organisms: Carbohydrates, Proteins, Nucleic acids, and Lipids.

Condensation Reaction (Dehydration Reaction)

A polymerization reaction where a monomer is added to a chain and a water molecule is released (monomer in, water out).

Hydrolysis Reaction (Hydration Reaction)

A chemical reaction that breaks down polymers by removing a monomer through the addition of water (monomer out, water in).

Stereoisomers

Isomers that have at least one asymmetric carbon and share the same bonding arrangement but differ in their 3-D spatial arrangement (e.g., glucose and galactose).

Structural Isomers

Isomers that have the same chemical formula but different bonding arrangements (e.g., galactose and fructose).

Monosaccharides

Simple sugar monomers with formulas approximating $(CH_2O)_n$ that serve as building blocks for disaccharides and polysaccharides or as energy sources.

Triose

A 3-carbon monosaccharide, such as glyceraldehyde.

Pentose

A 5-carbon monosaccharide, such as ribose.

Hexose

A 6-carbon monosaccharide, such as glucose.

Glycosidic Linkage

A covalent bond formed between two monosaccharides via a condensation reaction, requiring enzymes and energy input.

Anabolic Reaction

An endergonic reaction that requires energy input and an enzyme to build complex molecules.

Catabolic Reaction

An exergonic reaction that releases energy, such as hydrolysis.

Amylose

An unbranched, linear plant starch composed solely of alpha-glucose units joined by C1-C4 glycosidic linkages, forming a compact helical shape.

Amylopectin

A plant starch composed of alpha-glucose units with C1-C4 linkages and C1-C6 branch points every ~30 glucose residues.

Glycogen

A highly branched, relatively soluble polysaccharide used for short-term glucose storage in animals, consisting of alpha 1-4 chains with alpha 1-6 branch points every 8–12 glucose residues.

Cellulose

The most abundant structural carbohydrate on Earth, consisting of linear chains of beta-glucose subunits joined by beta 1,4 glycosidic linkages that form strong, insoluble microfibrils in plant cell walls.

Chitin

A structural amino-sugar polysaccharide made of N-acetylglucosamine (NAG) monomers that stiffens fungal cell walls and exoskeletons of arthropods.

Peptidoglycan

A structural polysaccharide in bacterial cell walls composed of alternating NAG and NAM monomers, with short peptide chains on NAM cross-linking adjacent strands.

Amino Acid Structure

A monomer consisting of a central alpha carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R-group).

Ionization of Amino Acids

At pH 7 in water, the amino group gains a proton to acquire a positive charge and the carboxyl group loses a proton to acquire a negative charge, aiding solubility and buffering capacity.

N-terminus

The end of a peptide or polypeptide chain that features a free amino group, conventionally written on the left.

C-terminus

The end of a peptide or polypeptide chain that features a free carboxyl group, where new amino acids are added during protein synthesis.

Oligopeptide

A medium-sized chain consisting of 3 to 50 amino acids linked by peptide bonds.

Protein Primary Structure

The linear sequence of amino acids in a polypeptide chain, determined by DNA/RNA code.

Protein Secondary Structure

Recurring structural arrangements formed by hydrogen bonding within the polypeptide backbone between amino group hydrogen atoms and nearby carboxyl group oxygen atoms.

Alpha-helix

A type of protein secondary structure formed when hydrogen bonding occurs between backbone amino acid residues 4 places apart.

Beta-pleated Sheet

A protein secondary structure where adjacent parallel or anti-parallel beta-strands are held together by hydrogen bonds, with R-groups oriented perpendicular to the sheet plane.

Protein Tertiary Structure

The overall 3D conformation of a single polypeptide chain driven by interactions between R-groups (side chains).

Protein Quaternary Structure

The overall 3D structure resulting from the combination of two or more individual polypeptide subunits.