Glossary of Terms

actin filaments

components of the cytoskeleton; composed of polymers of actin, and interact with numerous other intracellular proteins

adenylate cyclase

enzyme with key regulatory roles in all cells

adrenocorticotropic hormone

polypeptide produced by the anterior pituitary; increases production and release of cortisol

amino acids

an organic compound containing a carboxyl group ((-COOH) and an amino group (-NH2) attached to a central carbon atom. The identity of an amino acid is based on what other molecules are attached to the central carbon atom.

anaerobic metabolism

process resulting in energy release which utilizes carbohydrates and fats, using nitrates as a terminal electron acceptor

anergy

absence of a normal immune response to a particular antigen or allergen

anticodon

a triplet of nucleobases on tRNA; corresponds to specific codons on mRNA

antigen-presenting cell

any cell that assists in the immune responses by displaying antigens in association with their MHC II receptor; T cells may then recognize these antigens via their T cell receptors

antiporter

membrane-bound protein which carries two similarly-charged molecules in opposite directions

antisense strands

non-coding strand of DNA

ATP synthase

proton-transporting complex that phosphorylates ADP into ATP

centrioles

nonmenranous intracellular organelles composed of tubulin; serves as an organizing center for spindle fibres which attach to the centromere of chromosomes during cell division

chemokine

small signalling proteins which induce chemotaxis or cell movement

chief

cell of the gastric mucosa that produces pepsinogen

clonal expansion

production of identical daughter cells from a single cell

codon

a set of three nucleotides in mRNA which correspond to the anticodon on tRNA

collagen

main extracellular structural protein; main component of connective tissues

conformation

shape or structure of a molecule

corticotropin releasing hormone

peptide produced by the hypothalamus; part of the stress response

cortisol

glucocorticoid involved in the stress response; regulates metabolism and sugar homeostasis

cytokine

factors secreted by cells (particularly but not exclusively immune cells) which affect other cells; includes interferons and interleukins

damage-associated molecular patterns

danger or alarm signals that can initiate an inflammatory response; may be nuclear or cytoplasmic proteins released by damaged cells

elastin

extracellular matrix protein that is able to coil, and uncoil; allows many tissues in the body to resume shape after stretching

electron transport chain

aerobic process which occurs via electron-carrying molecules anchored on the inner mitochondrial membrane; electrons are transferred from donors to receptors via redox reactions, releasing energy

endoplasmic reticulum

intracellular membranous organelle (ER). Rough ER is the site of protein synthesis. Smooth ER is the site of fat and steroid metabolism.

endosomes

membrane-bound intracellular compartment that is part of the endocytotic pathway

ependymal cells

type of glial cell lining the ventricles of the brain

euchromatin

lightly-packed chromatin that is enriched in genes

FC portion of antibodies

tail region of an antibody that interacts with cell surface receptors

flagellin

a protein that is a principal component of bacterial flagella

G protein

guanine nucleotide-binding protein; a family of proteins that act as molecular 'switches' in cells

germ cells

cells which give rise to gametes (sperm or eggs)

glial

supporting cell of the nervous system

glycolipids

lipids with an attached carbohydrate; help maintain stability of cell membrane

glycolysis

metabolic pathway that converts glucose into pyruvate and hydrogen; produces ATP

glycoproteins

proteins with attached oligosaccharides

Golgi

packages secreting proteins into vesicles

heterochromatin

tightly-packed DNA, coiled around histone proteins

histamine receptors

a class of G-protein-coupled receptors that bind histamine; four types have been identified

insulin-like growth factor

proteins with a sequence similarity to insulin; part of a complex signalling system between cells and the environment.

intercalated discs

junction between cardiac cells; contains gap junction and specialized adhesion proteins

intermediate filaments

component of the cytoskeleton; form a fibrous network within cells

ion channel

pore-forming membrane proteins which allow specific ions to pass via concentration gradients

ischemia

inadequate blood supply to an organ or part of the body

kinase

enzyme that catalyzes the transfer of a phosphate group to a specific molecule

lactic acid

product of anaerobic metabolism

ligands

molecule that binds to a receptor; may be a protein or lipids

lipids

class of non-polar molecules including fats, waxes, sterols, and lipid-soluble proteins

LPS

lipopolysacchride; large molecule consisting of a lipid, a polysaccharide, and an 'O-antigen'. Component of gram-negative bacterial cell walls

lysosomes

small membranous intracellular vacuole containing various hydrolases involved in protein degradation

major histocompatibility complex (MHC) II

cell surface proteins that bind to non-self proteins, making them accessible to binding with other receptors

messenger ribonucleic acid

a form of RNA from which genetic information is translated into protein

microtubules

polymers of tubulin proteins that form part of the cytoskeleton; help maintain cell structure and are involved in intracellular transport

milliequivalents

the amount of substance that will react with a certain number of hydrogen ions

mitochondria

membranous intracellular organelle; site of energy production and calcium storage

molecular motors

proteins which translocate along the cytoskeleton, utilizing energy to move other molecules. Examples include dynein and kinesin, which are involved in neuronal transport.

nucleobases

nitrogen-containing compounds which can pair with other compatible nucleobases by means of hydrogen bonding

nucleoplasm

a type of protoplasm contained within the nucleus; includes chromosomes as well as nucleotides, enzymes, and cofactors

nucleotide

a molecule consisting of a nucleoside (a 5-carbon sugar) with a phosphate group

nucleus

double-membrane intracellular organelle; location of genetic material

opsonizing

coating and making a molecule more susceptible to phagocytosis

parietal cells

gastric epithelial cell which secretes hydrochloric acid and intrinsic factor

pathogen-associated molecular patterns

small molecules conserved in microbes; activate innate immune responses

peroxisomes

membrane-bound intracellular organelle; generates peroxides that are involved in lipid metabolism and bacterial killing

plasma membrane receptor

membrane-bound protein that binds to specific molecules called ligands

polypeptide

a polymer consisting of a few or many amino acid molecules; forms part (or the whole) of a protein

polyribosomes

clusters of ribosomes attached to a single strand of RNA

promoter

DNA sequences that determine where transcription of a gene by RNA polymerase begins

pyruvate

three-carbon molecule that is an intermediate in several metabolic pathways, including the TCA cycle

ribosomal RNA

non-coding RNA that is a component of ribosomes

sense strand

coding strand of DNA

sodium/potassium ATPase

electrogenic enzyme which utilizes ATP to pump 3 sodium ions out of the cell for every 2 potassium transported into the cell

symporter

membrane-bound protein which carried two different ions in the same direction

syncytium

multiple nuclei in a common cytoplasmic compartment

terminator

nucleic acid sequence at the end of a gene; triggers the release of a newly-synthesized mRNA sequence

titre

a way of expressing concentration; corresponds to a dilution factor that still yields a positive reading

TNF-α

Tumor Necrosis Factor alpha, or cachexin, a cell signalling protein involved in systemic inflammation and the acute phase reaction

toll-like receptors

class of transmembrane proteins that recognize structurally-conserved molecules from microbes' found on immune sentinel cells such as dendritic cells or macrophages

transcription factors

proteins which control the rate of transcription of DNA into mRNA; specific transcription factors bind to specific DNA sequences

translation

the process by which a sequence of mRNA is converted into a protein

trichloroacetic acid (TCA) cycle

series of chemical reactions occurring within mitochondria; releases stored energy via oxidation of acetyl-CoA

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Introduction to Pathophysiology Copyright © 2020 by William Diehl-Jones is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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