General Biology Review: Scientific Method, Chemistry of Life, Macromolecules, and Cell Structure

Vocabulary practice flashcards covering fundamental introductory biology concepts, including scientific inquiry, macromolecule structures and functions, basic chemistry, biological themes, and cell structure.

Deductive Reasoning

A systematic thought process that begins with supplied information or premises and draws specific conclusions based on that information.

Inductive Reasoning

A systematic thought process that begins with specific observations and draws a general conclusion or principle.

Hypothesis

A tentative explanation for observations or phenomena that is reasonably consistent with well-established facts, testable, repeatable by independent observers, and falsifiable.

Scientific Theory

An explanation of an aspect of the natural world and universe that can be repeatedly tested and corroborated with extensive evidence.

Scientific Law

A principle that predicts what will happen under certain conditions in the natural world.

Independent Variable

The specific experimental factor or condition that is changed or manipulated by the experimenter.

Dependent Variable

The responding variable or outcome that is measured to determine the effect of the independent variable.

Null Hypothesis ($H_0$)

A statistical hypothesis that assumes there is no difference or effect between two groups or treatments being tested.

Paradigm Shift

A fundamental change in the set of assumptions or concepts that constitute scientists' way of thinking about reality to accommodate new knowledge.

Isomers

Compounds with the exact same molecular formula but different chemical structures and properties, such as glucose and fructose ($C_6H_{12}O_6$).

Functional Group

A shape-specific combination of bonded atoms that reacts consistently regardless of the organic carbon skeleton to which it is attached.

Dehydration Synthesis

A reaction where monomers link together to form a polymer through the removal of an $-OH$ group from one molecule and an $H^+$ ion from another.

Hydrolysis

A chemical degradation reaction where a polymer is broken down into monomers by the addition of a water molecule ($H_2O$).

Monosaccharides

Simple carbohydrates consisting of a single sugar unit, including pentoses such as ribose and hexoses such as glucose and fructose.

Disaccharides

Sugars composed of two monosaccharides linked by a glycosidic bond, such as maltose, lactose, and sucrose.

Polysaccharides

Macromolecules consisting of repeating units of simple sugars, functioning in energy storage (starch, glycogen) or structural support (cellulose, chitin).

Peptide Bond

A covalent carbon-to-nitrogen bond linking the amino group of one amino acid to the carboxyl group of another in a polypeptide chain.

Protein Primary Structure

The linear sequence of amino acids in a polypeptide chain.

Protein Secondary Structure

The local folding of a polypeptide chain into regular patterns like $\text{α-helices}$ or $\text{β-pleated sheets}$ held together by hydrogen bonds.

Protein Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain determined by interactions among amino acid side chains (R groups).

Protein Quaternary Structure

The overall protein structure resulting from the assembly and interactions of two or more individual polypeptide chains.

Protein Denaturation

The process in which a protein loses its functional three-dimensional shape and becomes disordered due to heat, extreme pH changes, or chemicals.

Purines

Double-ring nitrogenous bases present in nucleic acids, specifically adenine (A) and guanine (G).

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, including cytosine (C), thymine (T) in DNA, and uracil (U) in RNA.

Adenosine Triphosphate (ATP)

A nucleotide derivative containing adenine, ribose, and three phosphate groups that serves as the primary energy transfer molecule in cells.

Triacylglycerol

The main form of reserve fuel storage in living organisms, consisting of a glycerol molecule ester-linked to three fatty acids.

Saturated Fatty Acids

Fatty acid chains containing the maximum possible number of hydrogen atoms and no double carbon-to-carbon bonds; typically solid at room temperature.

Unsaturated Fatty Acids

Fatty acid chains containing one or more double carbon-to-carbon ($C=C$) bonds; typically liquid at room temperature.

Phospholipid

An amphipathic lipid consisting of a hydrophilic glycerol-phosphate head and two hydrophobic fatty acid tails, forming the structural foundation of cell membranes.

Steroids

Complex lipid molecules structured around four fused carbon rings (three six-carbon rings and one five-carbon ring), such as cholesterol, estradiol, and testosterone.

Proton

A subatomic particle located in the atomic nucleus carrying a charge of $+1$ and a mass of $1\text{ Dalton}$ ($1\text{ amu}$).

Neutron

An electrically neutral subatomic particle in the atomic nucleus with a mass of $1\text{ Dalton}$ ($1\text{ amu}$).

Electron

A negatively charged subatomic particle orbiting the nucleus with a charge of $-1$ and a relative mass of $$.

Isotope

Atoms of the same element that contain identical numbers of protons but different numbers of neutrons, resulting in distinct atomic masses.

Valence Electrons

Electrons located in the outermost energy shell of an atom that determine its chemical reactivity and bonding capacity.

Ionic Bond

A chemical linkage formed between metals and nonmetals through the transfer of electrons, creating positively and negatively charged ions.

Electronegativity

A measure of an atom's affinity for pulling shared electrons toward itself in a chemical bond, with oxygen, nitrogen, and fluorine having high values.

Hydrogen Bond

A weak electrostatic bond formed between a partially positive hydrogen atom covalently bonded to an electronegative atom (such as O or N) and another electronegative atom.

Acid

A substance that dissociates in aqueous solution to yield hydrogen ions ($H^+$), increasing solution acidity and lowering pH below $7$.

Base

A substance that accepts protons or releases hydroxide ions ($OH^-$) in solution, raising pH above $7$.

Buffer

A chemical system that minimizes changes in pH when acids or bases are added, serving to maintain homeostasis in biological fluids.

Homeostasis

The maintenance of an appropriate, balanced internal environment through coordinated physiological and metabolic regulation.

Systematics

The scientific study of the diversity of organisms and their evolutionary relationships.

Taxonomy

A branch of systematics concerned with the formal naming, description, and classification of living organisms.

Emergent Properties

Novel characteristics that appear at a given biological level of organization that were not present in the simpler lower levels.

Autotrophs

Organisms that synthesize organic molecules from inorganic materials, typically using sunlight energy via photosynthesis.

Heterotrophs

Organisms that obtain energy and organic nutrients by consuming producers or other organisms.

LUCA

Acronym for Last Universal Common Ancestor, the ancient ancestor common to all cellular life on Earth.

Cell Theory

The foundational principle stating that all organisms consist of one or more cells, the cell is the basic functional unit of life, and all cells arise from pre-existing cells.

Surface Area-to-Volume Ratio

The mathematical relationship between a cell's outer membrane area and its internal volume; a higher ratio facilitates faster exchange of nutrients and wastes.

Prokaryotic Cell

A simple unicellular organism belonging to Domain Bacteria or Archaea, typically smaller than $5\,μm$, lacking a nucleus or membrane-bound organelles.

Eukaryotic Cell

A complex cell containing a distinct membrane-bound nucleus housing DNA and various specialized membrane-bound organelles.

Peptidoglycan

A complex polymer composed of sugars and amino acids that forms the cell wall in Domain Bacteria.

Pseudomurein

A structural cell wall component characteristic of certain organisms in Domain Archaea.

Chitin

A tough structural polysaccharide forming the cell walls of fungi and the exoskeletons of arthropods, crustaceans, and insects.

Chloroplast

A double-membrane organelle found in plants and algae that captures light energy to convert carbon dioxide and water into carbohydrates.

Mitochondrion

An organelle in eukaryotic cells that carries out cellular respiration, breaking down carbohydrates to produce ATP.