BTEC Applied Human Biology - Unit 1 Fundamentals Revision Pack

Essential vocabulary flashcards covering fundamental biochemistry, cellular physiology, organ systems, pathology, immunology, and medical genetics for Unit 1 Fundamentals.

Carbohydrates

Biological molecules composed of monosaccharides (such as glucose) joined by glycosidic bonds to form disaccharides or polysaccharides; function in immediate energy provision, energy storage (glycogen in humans), and structural support.

Triglycerides

Lipid molecules formed from one glycerol and three fatty acids joined by ester bonds; act as a long-term energy store, thermal insulation, mechanical cushioning, and a metabolic source of water.

Glycoproteins

Proteins conjugated with carbohydrate chains that function in cell recognition, surface receptor binding, cellular signalling, and immune identity marking.

Collagen

A fibrous structural protein composed of three polypeptide chains coiled into a triple helix; provides high tensile strength in tendons, skin, ligaments, cartilage, and connective tissues.

Primary protein structure

The unique linear sequence of amino acids in a polypeptide chain, encoded directly by gene sequence, which governs higher levels of folding.

Secondary protein structure

The local conformational folding of a polypeptide chain into alpha helices or beta pleated sheets, stabilised by hydrogen bonds within the peptide backbone.

Tertiary protein structure

The overall three-dimensional conformation of a single polypeptide chain, maintained by interactions between amino acid side chains (R groups); this precise shape dictates biological function.

Quaternary protein structure

The structural arrangement formed by the assembly of two or more polypeptide subunits into a single functional protein complex (such as haemoglobin).

Diffusion

The passive net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient, requiring no ATP.

Osmosis

The net movement of water molecules across a partially permeable membrane from a region of higher water potential to a region of lower water potential.

Active transport

The energy-dependent movement of substances across a cell membrane against a concentration gradient, using carrier proteins or pumps and consuming ATP.

Endocytosis

The cellular uptake mechanism in which the plasma membrane invaginates to enclose extracellular material within a vesicle, exemplified by phagocytosis.

Exocytosis

The transport mechanism in which intracellular vesicles fuse with the plasma membrane to discharge their contents into the extracellular environment (e.g., secretion of hormones or neurotransmitters).

Glycolysis

The anaerobic metabolic pathway occurring in the cytoplasm that breaks down one glucose molecule ($6\text{C}$) into two pyruvate molecules ($3\text{C}$), yielding a net $2\,\text{ATP}$ and reduced NAD.

Link reaction

The mitochondrial matrix stage where pyruvate ($3\text{C}$) is converted into acetyl-CoA ($2\text{C}$), releasing carbon dioxide and producing reduced NAD.

Krebs cycle

A cyclical series of reactions in the mitochondrial matrix where acetyl-CoA-derived $2\text{C}$ units are oxidised, generating carbon dioxide, reduced NAD, reduced FAD, and a small yield of ATP.

Oxidative phosphorylation

The process on the inner mitochondrial membrane where electrons from reduced coenzymes drive proton pumping to generate a gradient that powers ATP synthase; oxygen serves as the terminal electron acceptor, forming water.

Totipotent

The developmental potency of a stem cell with the capacity to differentiate into all possible cell types, including both embryonic tissues and extra-embryonic tissues (such as the placenta).

Pluripotent

The developmental potency of a stem cell capable of forming almost all body cell types, but not extra-embryonic membranes.

Multipotent

The developmental potency of an adult stem cell restricted to differentiating into a limited lineage of related specialised cell types.

Negative feedback

A homeostatic mechanism that monitors conditions, detects deviation from a normal physiological set point, and triggers corrective responses that counteract and oppose that change.

Saltatory conduction

The rapid transmission of a nerve impulse along a myelinated axon, where the action potential jumps discontinuously between successive nodes of Ranvier.

Coronary heart disease (CHD)

A cardiovascular condition caused by narrowing of the coronary arteries that reduces blood and oxygen supply to the myocardium, causing angina or myocardial infarction.

Stroke

A cerebrovascular event in which blood supply to a region of the brain is interrupted by a thrombus, embolus, or hemorrhage, leading to acute neurological deficits such as facial drop, limb weakness, and speech loss.

Chronic obstructive pulmonary disease (COPD)

A progressive respiratory condition featuring persistent airflow limitation, chronic cough, excess sputum production, and exertional breathlessness, strongly associated with smoking.

Hypertension

Persistently elevated arterial blood pressure that often presents without overt initial symptoms but significantly elevates the long-term risk of stroke, coronary heart disease, and renal failure.

Hypotension

Abnormally low blood pressure that may reduce organ perfusion, causing dizziness, fainting (syncope), or weakness, especially upon standing.

Assimilation

The biological process whereby absorbed nutrients are taken up, incorporated, and utilised by body cells for energy production, structural repair, or storage.

Antidiuretic hormone (ADH)

A hormone regulating systemic fluid balance that enhances the water permeability of the kidney collecting ducts, increasing water reabsorption and producing more concentrated urine.

Type I diabetes

An autoimmune metabolic disorder characterised by the immune-mediated destruction of pancreatic beta cells, resulting in severe insulin deficiency that requires exogenous insulin administration.

Type II diabetes

A metabolic disorder wherein target body tissues exhibit impaired peripheral responsiveness (resistance) to insulin, accompanied by progressive beta-cell dysfunction.

Cellular swelling

An early manifestation of cell injury occurring when ATP-driven ion pumps fail, causing intracellular accumulation of $\text{Na}^+$ and subsequent osmotic influx of water.

Hyperplasia

An adaptive increase in the total number of cells in an organ or tissue, resulting in increased overall volume.

Hypertrophy

An adaptive increase in the physical size of individual cells, leading to enlargement of the involved tissue or organ without an increase in cell number.

Atrophy

A reduction in cell size and functional tissue mass resulting from factors such as disuse, loss of innervation, ischaemia, or chronic malnutrition.

Metaplasia

A reversible phenotypic adaptation in which one mature adult cell type is replaced by another differentiated adult cell type that is better adapted to survive a stressful environment.

Ischaemia

A localized deficiency of arterial blood flow to an organ or tissue, precipitating hypoxia and impaired aerobic ATP synthesis.

Necrosis

Uncontrolled cell death occurring secondary to severe, irreversible biological or physical injury, accompanied by membrane breakdown and local inflammatory activation.

P wave

The electrocardiogram (ECG) waveform component representing electrical depolarisation of the atria prior to mechanical contraction.

QRS complex

The electrocardiogram (ECG) waveform configuration reflecting rapid electrical depolarisation of the ventricular myocardium.

T wave

The electrocardiogram (ECG) deflection following the QRS complex that denotes electrical ventricular repolarisation.

C-reactive protein (CRP)

An acute-phase plasma biomarker synthesised during systemic inflammation; raised levels indicate infection, inflammatory disorders, or tissue necrosis without identifying the exact cause.

Natural killer cells

Innate cytotoxic lymphocytes capable of recognising and eliminating virus-infected or malignant cells without prior exposure or antigen-specific clonal priming.

Mast cells

Tissue-resident granulocytes that degranulate in response to allergens or injury, releasing inflammatory mediators such as histamine.

Humoral response

The arm of adaptive immunity mediated by B lymphocytes and plasma cells that produce soluble, antigen-specific antibodies to bind, neutralise, or opsonise targets.

Cell-mediated response

The arm of adaptive immunity driven by T lymphocytes, wherein helper T cells coordinate the response and cytotoxic T cells directly destroy abnormal or infected cells.

Passive immunity

Transient immunological protection acquired via the administration or transfer of pre-formed antibodies (e.g., via the placenta, breast milk, or antiserum), which does not stimulate memory cell formation.

Multiple sclerosis (MS)

An autoimmune inflammatory disorder of the central nervous system (CNS) resulting in progressive demyelination of nerve axons, causing motor, sensory, and visual deficits.

Severe combined immunodeficiency (SCID)

A rare primary genetic immunodeficiency characterised by defective development or function of both B and T lymphocytes, presenting with severe, recurrent infant infections.

Anaphylaxis

A severe, rapid, life-threatening systemic hypersensitivity reaction causing airway constriction, facial and laryngeal swelling, and severe hypotension; managed emergently with adrenaline.

RNA splicing

A post-transcriptional eukaryotic nuclear process wherein non-coding introns are excised from pre-mRNA and coding exons are ligated to assemble mature mRNA.

Allele

An alternative sequence variant of a specific gene residing at the same locus on homologous chromosomes.

Sex linkage

The pattern of inheritance characteristic of genes situated on sex chromosomes (most commonly the X chromosome), causing recessive conditions to appear more frequently in males.

Carrier

A heterozygous individual possessing one normal allele and one recessive mutant allele who does not display the clinical phenotype but can transmit the mutation to offspring.

Cystic fibrosis (CF)

An autosomal recessive genetic disorder caused by mutations in the CFTR gene, resulting in impaired chloride and fluid transport that causes thick, viscous secretions in the lungs and pancreas.

Huntington's disease

An autosomal dominant neurodegenerative condition caused by a mutation in the HTT gene, leading to progressive cognitive, motor, and psychiatric impairment typically beginning in adulthood.

Down's syndrome

A genetic condition typically caused by trisomy 21 (three copies of chromosome 21), associated with variable developmental and cognitive profiles and specific health needs.

Haemophilia

An X-linked recessive coagulopathy characterised by a functional deficiency in specific blood clotting factors, resulting in prolonged bleeding and spontaneous haemarthroses.

Benign tumour

A non-cancerous, encapsulated, or slow-growing mass of differentiated cells that remains localized and does not invade neighbouring tissues or metastasise.

Malignant tumour

A cancerous neoplasm of poorly differentiated cells demonstrating uncontrolled growth, local invasion of adjacent tissues, and metastasis via blood or lymph.

Proto-oncogenes

Normal genes encoding proteins that stimulate cell cycle progression and growth; gain-of-function mutations can convert them into oncogenes that drive tumorigenesis.

Tumour-suppressor genes

Genes whose protein products normally inhibit inappropriate cell division, promote DNA repair, or induce apoptosis; loss-of-function mutations eliminate these protective controls.

Amniocentesis

An invasive prenatal diagnostic technique where a transabdominal needle collects amniotic fluid containing desquamated foetal cells for chromosomal and genetic analysis.

Chorionic villus sampling (CVS)

An invasive prenatal procedure performed early in pregnancy to biopsy placental chorionic villi transabdominally or transcervically for definitive foetal genetic testing.