DZI Biology and Health Education flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Central Dogma

The flow of genetic information from DNA to messenger RNA by transcription, then to protein by translation at ribosomes; retroviruses reverse this with reverse transcriptase.

Osmosis

Net movement of water across a semipermeable membrane toward the side with higher solute concentration; cells shrink in hypertonic solutions and swell in hypotonic ones.

Mitochondrial ATP Synthesis

Oxidative phosphorylation uses the electron transport chain to pump protons, creating a gradient that drives ATP synthase; aerobic respiration yields about 30 to 32 ATP per glucose.

Enzyme Kinetics (Michaelis-Menten)

Reaction rate equals Vmax times substrate concentration divided by Km plus substrate concentration; Km is the substrate level at which the reaction runs at half maximal velocity.

Hardy-Weinberg Equilibrium

A null model in which allele and genotype frequencies stay constant across generations absent mutation, migration, selection, genetic drift, and nonrandom mating.

Autosomal Recessive Inheritance

A trait appears only when both alleles are mutated; carrier parents are unaffected, the trait may skip generations, and each child has a 25 percent risk.

Genetic Drift

Random fluctuation of allele frequencies between generations, strongest in small populations; the founder effect and population bottlenecks are its two classic manifestations.

Natural Selection

Differential survival and reproduction of individuals carrying heritable trait variants, causing allele frequencies to shift toward variants that improve fitness in a given environment.

Cardiac Output

Volume of blood pumped by the heart per minute, calculated as heart rate multiplied by stroke volume; resting adult output averages roughly five liters per minute.

Negative Feedback

A homeostatic control loop in which a sensor detects deviation from a set point and an effector response reverses that deviation, stabilizing internal conditions.

Bohr Effect

A rightward shift in the hemoglobin oxygen dissociation curve caused by increased carbon dioxide, lower pH, or higher temperature, which releases oxygen to active tissues.

Nephron Filtration Sequence

Glomerular filtration produces filtrate, the proximal tubule reabsorbs most solutes and water, the loop of Henle concentrates urine, and ADH regulates collecting duct water reabsorption.

Chain of Infection

Six linked elements: pathogen, reservoir, exit portal, transmission mode, entry portal, and susceptible host; breaking any single link prevents transmission.

Herd Immunity Threshold

The proportion of a population that must be immune to interrupt transmission, approximated as 1 minus 1/R0; higher R0 requires higher coverage.

Gram Stain Principle

Gram-positive bacteria retain crystal violet and stain purple due to thick peptidoglycan; gram-negative bacteria lose it, stain pink, and possess an outer membrane.

Koch's Postulates

Criteria linking a microbe to a disease: present in all cases, isolable in culture, capable of causing disease when inoculated, and recoverable again from the infected host.

Energy Values of Macronutrients

Metabolizable energy per gram is about 4 kilocalories for carbohydrate, 4 for protein, 9 for fat, and 7 for alcohol.

Body Mass Index

Weight in kilograms divided by height in meters squared; values of 25 or above classify as overweight and 30 or above as obese in adults.

Essential Nutrients

Substances the body cannot synthesize in sufficient amounts, including nine amino acids, linoleic and alpha-linolenic fatty acids, vitamins, minerals, and water.

Marasmus versus Kwashiorkor

Marasmus is severe overall energy and protein deficiency causing wasting; kwashiorkor is protein deficiency with adequate energy, producing edema and an enlarged fatty liver.

Incidence versus Prevalence

Incidence counts new cases arising in a population at risk over a period; prevalence counts all existing cases at a time and roughly equals incidence times duration.

Relative Risk

Incidence of an outcome in the exposed group divided by incidence in the unexposed group; a value of one indicates no association and is used in cohort studies.

Sensitivity and Specificity

Sensitivity is the proportion of diseased people correctly identified as positive; specificity is the proportion of healthy people correctly identified as negative by a test.

Levels of Prevention

Primary prevents disease onset before it occurs, secondary detects disease early through screening, and tertiary reduces complications and disability after disease is established.

Health Belief Model

A behavior theory holding that perceived susceptibility, severity, benefits, and barriers, plus cues to action and self-efficacy, predict whether a person adopts a health behavior.

Transtheoretical Model

A stage model of behavior change: precontemplation, contemplation, preparation, action, maintenance, and termination, with interventions matched to each stage.

Self-Efficacy

Task-specific confidence in one's ability to perform a behavior successfully; built through mastery experiences, vicarious modeling, persuasion, and reduced emotional arousal.

Theory of Planned Behavior

Attitudes toward a behavior, subjective norms, and perceived behavioral control jointly shape intention, which is the strongest proximal predictor of actual behavior.

SMART Objectives

Program objectives stated as specific, measurable, achievable, relevant, and time-bound, allowing clear monitoring of whether planned activities and outcomes were achieved.

Formative versus Summative Evaluation

Formative evaluation occurs during program development to refine implementation; summative evaluation occurs after completion to judge whether intended outcomes were achieved.

Confidence Interval

A range of plausible values for a population parameter; a 95 percent interval arises from a method that captures the true value in 95 percent of repeated samples.

Number Needed to Treat

The number of patients who must receive an intervention for one additional favorable outcome, calculated as one divided by the absolute risk reduction.