DZI Biology and Health Education key terms

A thin, flexible barrier made of a phospholipid bilayer with embedded proteins that surrounds every cell, controlling which substances enter and leave and helping cells communicate with their environment.

The net movement of particles from an area of higher concentration to an area of lower concentration, driven by random molecular motion, without requiring energy input from the cell.

The diffusion of water across a selectively permeable membrane from a region of lower solute concentration to a region of higher solute concentration, equalizing water potential on both sides.

The process of nuclear division in which one cell produces two genetically identical daughter cells, essential for growth, tissue repair, and asexual reproduction in multicellular organisms.

The semi-conservative process by which a DNA molecule is copied before cell division, producing two identical double helices, each containing one original and one newly synthesized strand.

The multi-step process by which information encoded in a gene is used to synthesize a functional product, usually a protein, involving transcription of DNA into RNA and translation of RNA into protein.

A specialized type of cell division that halves the chromosome number and produces four genetically varied gametes, creating genetic diversity through crossing over and independent assortment.

One of two or more alternative versions of a gene at a given locus on a chromosome, which may produce different observable traits and can be dominant or recessive.

The specific combination of alleles an individual carries for a particular gene or set of genes, which together with environmental influences determines the observable phenotype.

The observable physical or biochemical characteristics of an organism, resulting from the interaction between its genotype and environmental factors throughout development and life.

A permanent change in the nucleotide sequence of DNA, which may arise spontaneously or be induced by environmental agents and can alter gene function, sometimes causing disease.

The evolutionary mechanism whereby individuals with inherited traits that improve survival and reproduction in a given environment leave more offspring, gradually changing population characteristics over generations.

The ability of an organism to maintain relatively stable internal conditions, such as temperature, pH, and blood glucose, through coordinated physiological feedback mechanisms despite external changes.

A regulatory mechanism in which a change in a physiological variable triggers responses that counteract the original change, restoring the variable toward its set point and maintaining stability.

A specialized cell of the nervous system that receives, integrates, and transmits electrical and chemical signals, consisting of a cell body, dendrites, and an axon.

A chemical messenger released from the axon terminal of a neuron that crosses a synapse and binds to receptors on a target cell, either exciting or inhibiting its activity.

A chemical substance secreted by endocrine glands into the bloodstream that travels to target cells and regulates processes such as growth, metabolism, and reproduction.

Any microorganism or infectious agent, such as a bacterium, virus, fungus, or parasite, that can cause disease in a host organism by invading tissues or producing harmful substances.

The ability of bacteria to survive and grow in the presence of antibiotics that would normally kill them or inhibit their growth, often arising through mutation or acquisition of resistance genes.

Indirect protection of susceptible individuals in a population that occurs when a sufficiently high proportion of members are immune to an infectious disease, reducing transmission and outbreak risk.

The administration of a preparation that stimulates the immune system to develop protective immunity against a specific pathogen without causing the full disease, often using weakened or inactivated components.

A nutrient required by the body in relatively large amounts to provide energy and support growth and maintenance, comprising carbohydrates, proteins, and fats.

A vitamin or mineral needed by the body in small quantities for normal physiological function, such as vitamin C, iron, and iodine, but essential for health and disease prevention.

The amount of energy, expressed in calories per unit time, that a resting organism expends to maintain vital functions such as breathing, circulation, and cell production at complete rest.

A screening measure calculated as weight in kilograms divided by height in meters squared, used to classify underweight, normal weight, overweight, and obesity in populations and individuals.

The proportion of a population that has a particular disease or condition at a specific point in time or during a specified period, reflecting both new and existing cases.

The number of new cases of a disease or condition that develop in a population during a specified time period, often expressed as a rate per population at risk.

A characteristic, exposure, or behavior statistically associated with an increased probability of developing a disease or health condition, which may or may not be causally related.

A distortion of the true relationship between an exposure and an outcome caused by a third variable that is associated with both and is not accounted for in the study design or analysis.

A psychological framework proposing that health behavior is influenced by perceived susceptibility, perceived severity, perceived benefits, perceived barriers, cues to action, and self-efficacy.

An individual's belief in their own capacity to organize and execute the courses of action required to manage prospective situations and achieve desired outcomes.

A behavior change framework describing progress through stages-precontemplation, contemplation, preparation, action, maintenance, and termination-with tailored interventions appropriate to each stage.

The degree to which individuals can obtain, process, understand, and use basic health information and services to make informed health decisions and navigate health systems.

Preliminary data collection and analysis conducted before designing a health program to understand the target audience, context, needs, and barriers, so interventions can be tailored effectively.

An experimental study in which participants are randomly assigned to intervention or control groups to compare outcomes and reduce bias, providing strong evidence for causal effects.

A systematic error in study design, data collection, analysis, or reporting that produces results consistently different from the true value, threatening the validity of conclusions.

The ability of a screening or diagnostic test to correctly identify individuals who have the condition, calculated as true positives divided by the sum of true positives and false negatives.

The ability of a screening or diagnostic test to correctly identify individuals who do not have the condition, calculated as true negatives divided by the sum of true negatives and false positives.

The probability that a person with a positive test result truly has the condition, calculated as true positives divided by all positive results and influenced by disease prevalence.