General Biology: Life, Chemistry, Cells, Tissues, and the Cardiovascular System

Comprehensive vocabulary flashcards covering the scientific method, the chemical basis of life, cellular structure and transport, histology and organ systems, and cardiovascular anatomy and physiology.

Homeostasis

The maintenance of a distinct internal environment within set parameters that differs from outside conditions.

Adaptive Evolution

The evolutionary process caused by natural selection that results in traits that increase survival or reproduction in a particular context.

Inductive Reasoning

A form of scientific reasoning that involves making broad generalizations based on specific observations or recorded data.

Deductive Reasoning

A logical process in which general principles are applied to make predictions about specific observations, such as testing a hypothesis through an experiment.

Scientific Hypothesis

A testable and logical statement or proposed explanation regarding a phenomenon that makes specific predictions about the world.

Scientific Theory

A comprehensive body of work based on numerous combined hypotheses, much broader in scope, and supported by extensive empirical evidence.

Isotopes

Atoms of the same element that share identical numbers of protons but contain differing numbers of neutrons.

Ionic Bond

A chemical bond formed when one atom strips electrons from another, creating oppositely charged ions that attract electrostatically.

Covalent Bond

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

Hydrogen Bond

A weak, temporary electromagnetic attraction formed between the partially negative oxygen of one water molecule and the partially positive hydrogen of another.

Heat Capacity

The quantity of energy required to raise the temperature of a substance, representing the amount of thermal energy stored within it.

Amino Acid

The fundamental monomer of proteins, characterized by a central carbon bonded to a hydrogen atom, an amino group ($\text{H}_2\text{N}$), an acidic carboxyl group ($\text{COOH}$), and a variable $R$ group.

ATP (Adenosine Triphosphate)

A universal cellular energy currency nucleotide that releases energy when a phosphate is cleaved to yield ADP and absorbs energy when re-forming from ADP.

Cell Theory

A fundamental biological concept establishing that the cell is the smallest unit capable of life processes, all organisms consist of one or more cells, and all cells arise only from preexisting cells.

Surface Area-to-Volume Ratio

A physical constraint on cell size wherein volume expands faster than surface area as size increases, decreasing the rate of exchange relative to metabolic demand.

Phospholipid

A membrane lipid comprising a polar hydrophilic head and two nonpolar hydrophobic tails that spontaneously self-assembles into a bilayer in aqueous solutions.

Endosymbiont Theory

The evolutionary model explaining that eukaryotic organelles like mitochondria and chloroplasts originated as free-living bacteria that entered mutualistic relationships inside ancestral eukaryotic cells.

Fluid Mosaic Model

The structural model depicting the plasma membrane as a semi-fluid phospholipid bilayer containing proteins and lipids that are free to shift and drift dynamically.

Osmosis

The net diffusion of water across a membrane from a region of lower solute concentration (hypotonic) into a region of higher solute concentration (hypertonic).

Active Transport

The transport of substances across a biological membrane against their concentration gradient via membrane proteins, powered by energy expenditure (usually ATP).

Phagocytosis

A form of endocytic bulk transport where a cell engulfs large, solid particles or entire pathogens within membrane-bound vesicles.

Connective Tissue

A primary tissue category that binds and supports body parts, composed of specialized cells, ground substance, and protein fibers, and categorized into fibrous, supportive, and fluid types.

Fibroblasts

Widely spaced, specialized cells within fibrous connective tissue responsible for producing protein fibers and extracellular matrix components.

Compact Bone

A dense, rigid supportive connective tissue forming long bone shafts, organized into hard concentric matrix rings with living cells situated inside lacunae.

Epithelial Tissue

A basic tissue type consisting of tightly joined cells anchored to a basement membrane that covers body surfaces, lines hollow cavities, and forms glands.

Negative Feedback Loop

A primary homeostatic mechanism in which a stimulus detecting a deviation prompts a response that reverses the original change to return conditions toward a set point.

Effector

A component in a negative feedback system that receives commands from a control center and executes physiological modifications to counteract an internal deviation.

Keratin

A stiff, waterproof structural protein synthesized by epidermal cells as they migrate toward the outer surface of the skin.

Single Circulation

A low-energy circulatory pattern found in fish where blood passes through the heart once per circuit, traveling from the heart through gill capillaries, systemic capillaries, and back.

Double Circulation

A circulatory pathway present in amphibians, reptiles, birds, and mammals where blood is pumped twice—once to gas-exchange tissues and once to systemic body tissues.

Capillaries

Extremely narrow, convoluted microscopic vessels that serve as the principal sites of gas ($\text{O}_2$ and $\text{CO}_2$), nutrient, and waste exchange between blood and interstitial fluid.

Systole

The highest blood pressure measured against arterial walls during the cardiac cycle, occurring immediately upon contraction of the heart ventricles.

Diastole

The lowest hydrostatic pressure recorded in arterial walls during the cardiac cycle, occurring when the heart ventricles relax between beats.

Hemoglobin

An iron-containing protein packed inside erythrocytes that reversibly binds oxygen at high concentrations and releases it in depleted peripheral tissues.

Bicarbonate ($\text{HCO}_3^-$)

The primary dissolved chemical form by which carbon dioxide is transported through blood plasma, produced via the reaction $\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 \rightleftharpoons \text{H}^+ + \text{HCO}_3^-$.

Platelets

Cell fragments produced from bone marrow megakaryoblasts that aggregate at wound sites and secrete prothrombin activator to facilitate blood clotting.