Bio 121: Macromolecules, Functional Groups, and Protein Structure

Vocabulary practice flashcards covering fundamental characteristics of life, essential elements, functional group properties, disaccharide and polysaccharide structures, and protein structural hierarchy based on Bio 121 lecture notes.

Cell Theory

The fundamental theory stating that all living things are composed of cells.

Theory of Evolution by Natural Selection

The scientific theory that explains what causes biological diversity and where organisms come from.

Chromosome Theory of Inheritance

The scientific theory describing how hereditary information is passed from one generation to the next.

Fact (Scientific)

Simple, basic observations that have been confirmed many times and accepted as true, making them extremely unlikely to change.

Hypothesis

A tentative explanation about an observation that can be tested, though it is often wrong.

Scientific Law

A description (often mathematical) of a natural phenomenon that is not concerned with why or how, and can be proven wrong.

Scientific Theory

An explanation for a very general class of phenomena or observations that must be supported by a wide body of evidence and can be proven wrong.

Essential Elements for Life

About 25 of the 92 natural elements known to be essential for life, with Carbon, Nitrogen, Hydrogen, and Oxygen making up about 92% of living matter.

Functional Groups Overview Table

A summary table defining the structure and chemical properties of common functional groups including Hydroxyl, Methyl, Carbonyl, Carboxyl, Amino, Phosphate, and Sulfhydryl.

Hydroxyl Group

A polar functional group with the structure $R-OH$.

Methyl Group

A nonpolar functional group with the structure $R-CH_3$.

Carbonyl Group

A polar functional group with the structure $R-C(=O)-R'$.

Carboxyl Group

A charged, acidic functional group that ionizes in solution to release $H^+$ ions.

Amino Group

A charged, basic functional group that accepts $H^+$ from solution to form $NH_3^+$.

Phosphate Group

A charged, acidic functional group that ionizes to release $H^+$ ions into solution.

Sulfhydryl Group

A polar functional group with the structure $R-SH$.

Amylose

An unbranched plant starch polysaccharide with alpha glycosidic linkages exclusively between C1 and C4, forming a compact helical shape.

Amylopectin

A branched plant starch polysaccharide containing alpha C1-C4 linkages with C1-C6 branch points every ~30 glucose residues.

Glycogen

A highly branched animal storage polysaccharide featuring alpha 1-4 chains with alpha 1-6 branch points about every 8-12 glucose residues, stored mainly in the liver and muscles.

Cellulose

The most abundant structural polysaccharide on Earth, composed of linear beta-glucose subunits linked by beta-1,4 glycosidic linkages that form microfibrils.

Chitin

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

Peptidoglycan

A structural polysaccharide in bacterial cell walls made of alternating NAG and NAM monomers, where short peptide chains attached to NAM cross-link adjacent strands.

Amino Acid Ionization at pH 7

The process where an amino acid's amino group gains a positive charge ($NH_3^+$) and its carboxyl group loses a proton to take a negative charge, aiding solubility and buffering capability.

N-Terminus

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

C-Terminus

The carboxyl group end of a peptide chain, to which new amino acids are attached during polymerization.

Oxytocin

A nonapeptide, which is a peptide containing exactly nine amino acids.

Primary Structure

The unique sequence order of amino acids in a polypeptide chain from the N-terminus to the C-terminus.

Secondary Structure

Recurring local arrangements in a polypeptide chain, such as alpha-helices or beta-pleated sheets, stabilized by hydrogen bonding within the backbone.

Alpha-Helix

A protein secondary structure formed when hydrogen bonding occurs between backbone amino acid residues that are four positions apart.

Tertiary Structure

The overall three-dimensional shape of a polypeptide resulting from interactions between the R-groups (side chains).