General Biology: Chapters 1 to 4 Comprehensive Review

Comprehensive vocabulary flashcard set covering foundational principles of life, chemical basis of biology, cell anatomy, transport mechanisms, bioenergetics, and cellular respiration.

Science

The process of using observations and experiments to draw evidence-based conclusions.

Order

The presence of highly ordered structures, which is one of the seven required characteristics that must be present for something to be considered alive.

Evolutionary Adaptation

The accumulation of favorable traits in a population over time, occurring because individuals with traits best suited to their environments achieve greater reproductive success and pass those traits to offspring.

Homeostasis

The ability of an organism to control and maintain its internal environment within limits that sustain life.

Cell

The fundamental unit of life and the lowest organizational level of structure capable of performing all seven characteristics of life.

Population

All the individuals of a single species living within a specific area.

Community

All the organisms occupying a single ecosystem, composed of more than one population.

Ecosystem

All the living organisms in a particular area together with the physical, non-living components with which they interact.

Taxonomy

The scientific discipline that names species and classifies them into a system of broader groups based on similarities, often reflecting evolutionary history.

Domains of Life

The three high-level divisions of biodiversity: Bacteria (diverse and widespread prokaryotes), Archaea (prokaryotes living in extreme environments), and Eukarya (eukaryotes including protists, fungi, animals, and plants).

Inductive Reasoning

A scientific approach wherein general conclusions are drawn from a large number of specific observations.

Deductive Reasoning

A scientific method approach wherein a proposed explanation (hypothesis) is invented for an observation, and an experiment is designed to test it and generate results.

Scientific Theory

A broad, comprehensive explanation that represents a very strongly supported hypothesis backed by extensive experimental testing and a high degree of confidence.

The Central Dogma

The fundamental concept describing the basic flow of genetic information in a cell: DNA is transcribed into RNA, and RNA is translated into protein.

Natural Selection

The evolutionary mechanism proposed by Charles Darwin where the natural environment edits populations by favoring individuals with beneficial traits, leading to unequal reproductive success.

Matter

Anything that occupies physical space and has mass.

Atom

The smallest unit of matter that still retains the properties of a chemical element, consisting of subatomic protons, neutrons, and electrons.

Atomic Number

The number of protons in an atom's nucleus, which is unique to each chemical element.

Isotopes

Atoms of the same element that share the identical atomic number (number of protons) but have different numbers of neutrons, resulting in different mass numbers.

Valence Electrons

Electrons located in an atom's outermost shell that dictate its chemical reactivity, bonding behavior, and valence.

Ion

An atom that carries a net electrical charge due to having an unequal number of protons and electrons from gaining or losing valence electrons.

Ionic Bond

An electrical attraction between oppositely charged ions (cations and anions) formed when one atom transfers electrons to another.

Covalent Bond

A strong chemical bond formed when two atoms share one or more pairs of valence electrons.

Electronegativity

A measure of an atom's pulling power or attractiveness for shared electrons within a chemical bond.

Polar Covalent Bond

A covalent bond between atoms of differing electronegativity, leading to unequal electron sharing and resulting in partial negative ($\delta^-$) and partial positive ($\delta^+$) charges.

Hydrogen Bond

A weak intermolecular attraction (roughly $5\%$ the strength of a covalent bond) occurring between an area of partial charge on one molecule and an oppositely charged partial region on another molecule.

Chemical Reaction

A process that rearranges matter through the making and breaking of chemical bonds, converting starting substances (reactants) into final substances (products).

Cohesion

The tendency of molecules of the same type to stick together, which in water is mediated by hydrogen bonds and produces surface tension.

pH Scale

A negative logarithmic scale from 0 to 14 measuring hydrogen ion ($H^+$) concentration, where values below 7 indicate acidic solutions and values above 7 indicate basic solutions.

Buffer

A substance that minimizes fluctuations in $H^+$ concentration by accepting excess $H^+$ ions or donating $H^+$ when depleted, maintaining biological fluids like human blood within a narrow range ($7.36 - 7.44$).

Isomer

Compounds that possess identical molecular formulas but have different spatial or structural arrangements, giving them distinct biological properties.

Dehydration Reaction

A chemical reaction that links monomers together into polymers by removing a molecule of water ($H_2O$).

Hydrolysis

A chemical reaction that disassembles polymers into monomers through the addition of a water molecule ($H_2O$).

Monosaccharide

The simplest type of carbohydrate and the monomer building block of polysaccharides, having molecular formulas that are multiples of $(CH_2O)_n$.

Amino Acid

The monomer building block of proteins, consisting of a central carbon atom bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable R group (side chain).

Quaternary Protein Structure

The overall protein structure that results when two or more individual polypeptide chains (subunits) associate together into a single functional complex.

Denaturation

The process where changes in pH, salt concentration, or temperature cause a protein to lose its native 3-D fold and biological function without breaking the primary peptide bonds.

Unsaturated Fatty Acid

A fatty acid chain that possesses one or more double bonds ($C=C$), resulting in kinks that prevent tight packing and cause it to remain liquid at room temperature.

Phospholipid

An amphipathic lipid made of a hydrophilic glycerol and phosphate head attached to two hydrophobic fatty acid tails, forming the bilayer basis of cellular membranes.

Nucleoid

The non-membrane-enclosed region within a prokaryotic cell where its DNA/chromosome is situated in direct contact with the cytoplasm.

Eukaryotic Cell

A complex cell type characterized by possessing a membrane-bound nucleus housing its genome and numerous internal membrane-enclosed organelles.

Rough Endoplasmic Reticulum

A network of membranous sacs studded with ribosomes that synthesizes secretory proteins and phospholipids before pinching them off in transport vesicles.

Golgi Apparatus

An organelle consisting of flattened membranous sacs that receives, modifies, sorts, and packages cell products received from the endoplasmic reticulum for export or delivery.

Lysosome

A membrane-enclosed digestive sac of hydrolytic enzymes found in animal cells that maintains an internal pH of 5 to dismantle nutrients, cellular debris, and foreign material.

Mitochondria

Organelles in eukaryotic cells that conduct cellular respiration, harvesting chemical energy from fuel molecules to synthesize ATP.

Chloroplast

Energy-processing organelles found in plants and algae that conduct photosynthesis, converting solar energy into chemical energy stored in glucose.

Endosymbiont Theory

The widely accepted scientific theory stating that mitochondria and chloroplasts originated as small prokaryotes that took up residence inside larger host cells.

Membrane Fluidity

The degree of freedom and mobility of lipids and proteins within the plasma membrane, regulated by temperature, cholesterol, and the ratio of unsaturated to saturated fatty acids.

Transmembrane Protein

An integral membrane protein that completely spans across the phospholipid bilayer, possessing both internal hydrophobic regions and exterior hydrophilic regions.

Active Transport

The movement of ions or solutes across a membrane against their concentration gradient, requiring cellular energy (such as ATP) and specific transport proteins.

Osmosis

The passive transport and diffusion of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

First Law of Thermodynamics

The law of energy conservation stating that energy can be transferred and transformed from one form to another, but cannot be created or destroyed.

Entropy

A quantitative measure of disorder or randomness in a system; energy transformations are not $100\%$ efficient and inevitably increase the universe's entropy by releasing heat.

Catabolic Reaction

A metabolic pathway that breaks down complex molecules into simpler compounds, releasing stored chemical potential energy (exergonic).

Adenosine Triphosphate (ATP)

The primary energy-coupling molecule of the cell that drives endergonic cellular work when hydrolyzed into ADP and inorganic phosphate ($\text{P}$).

Cellular Respiration

The metabolic process by which cells break down glucose and other fuel molecules in the presence of oxygen to produce ATP, carbon dioxide, water, and heat: $C_6H_{12}O_6 + 6\,O_2 \rightarrow 6\,CO_2 + 6\,H_2O + \text{ATP} + \text{Heat}$.

Active Site

The specific pocket or groove on an enzyme that matches and binds the substrate to catalyze a chemical reaction.

Metabolic Pathway

A series of sequential chemical reactions within a cell that converts a starting molecule into an end product through intermediates, with each step catalyzed by a specific enzyme.

Oxidation

The chemical process in a redox reaction involving the loss of hydrogen atoms and electrons from a fuel molecule, such as the conversion of glucose into carbon dioxide.

Electron Transport Chain

A sequence of protein complexes within the inner mitochondrial membrane that transfers electrons from NADH and $FADH_2$ down an energy gradient to oxygen, using the released energy to pump protons ($H^+$).

Pyruvate Oxidation

The phase of cellular respiration within the mitochondrion where pyruvate is oxidized to Acetyl CoA, producing NADH and releasing carbon dioxide ($CO_2$).

Chemiosmosis

The process wherein the potential energy of a transmembrane proton ($H^+$) gradient drives ATP synthesis via the catalytic action of ATP synthase.

Fermentation

An anaerobic metabolic pathway that regenerates $NAD^+$ from NADH in the absence of oxygen, enabling glycolysis to continuously synthesize ATP.