Glossary

active transport

Uses energy to move molecules against the concentration gradient (area of lower concentration to area of higher concentration).

adenosine triphosphate (ATP)

Coenzyme found in all lifeforms, that is important for metabolism as an energy molecule.

amphitrichous

Flagellum or tufts of flagella at each end of the cell.

anabolism

Simpler molecules are combined into more complex substances.

antigen

Any substance that induces an immune response by the body to that substance.

ATPases

Also known as ATP synthases, they are a class of enzymes that catalyse the decomposition of ATP (adenosine triphosphate) into ADP (adenosine diphosphate) and a free phosphate ion.

autotrophs

Able to fix inorganic carbon and synthesise organic molecules from carbon dioxide.

bacterial capsule

Polysaccharide layer that integrates firmly around bacterial cell wall, offers protection to the cell and enhances the cells’ ability to cause disease.

binary fission

Binary fission is a method of asexual reproduction used by many prokaryotic organisms, including bacteria and archaea.

biofilms

A colony of bacteria attached to a biotic or abiotic surface enclosed within a matrix of extracellular polymeric substances produced by the colony.

carbohydrates

Biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells and form arthropods’ cellular exoskeleton.

catabolism

More complex substances are broken down into simpler molecules.

chemoheterotrophs

Chemotrophs that can use organic and inorganic compounds as energy.

chemolithoautotrophs

Autotrophs that obtain energy from inorganic compounds.

chemolithotrophs

Chemotrophs that can use organic and inorganic compounds as energy.

chemoorganotrophs

Chemotrophs that can use organic compounds as energy sources.

chemoreceptors

Specialised sensory receptors that convert chemical signals in the environment.

chemotrophs

Obtain energy from chemical compounds.

chloroplasts

Found within plant cells and algae and are the organelles where photosynthesis occurs.

chromosomes

Made of organised and packaged DNA in the form of genes and are found within the cell nucleus.

cilia

Hair-like organelle found in large numbers on some cells allowing movement or propulsion.

cyclins

Proteins associated with progression of cell cycle.

cytokine interferon-gamma

Category of small proteins that are important in cell signalling.

cytoplasm

Gel-like substance composed of water and dissolved chemicals.

cytoskeletal

Gel-like substance composed of water and dissolved chemicals.

cytoskeleton

Gel-like substance composed of water and dissolved chemicals.

diffusion

Movement of molecules along the concentration gradient.

DNA

‘Deoxyribonucleic acid’. Contains genetic information for cell function, growth and division.

DNA genome

Full complement of DNA within a cell organised into smaller, discrete units called genes, arranged on chromosomes and plasmids.

endocytosis

Absorption of materials into a cell.

endomembrane system

Series of membranous tubules, sacs and flattened disks in eukaryotic cells that synthesise many cell components and move materials around within the cell.

endoplasmic reticulum (ER)

Interconnected array of tubules and cisternae with single lipid bilayer. Made up of rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).

enzymes

Catalyst in a biochemical reaction that is usually a complex or conjugated protein.

eukaryotes

Plants, animals, protozoans, algae and fungi.

eukaryotic

Plants, animals, protozoans, algae and fungi.

exocytosis

Secretory vesicles release the contents to the cell’s exterior.

extracellular matrix

Three-dimensional network of proteins and molecules that surround cells to give structure and provide support.

facilitated diffusion

Diffusion of molecules across the plasma membrane with assistance from membrane proteins.

flagella

Structures used by cells to move in aqueous environments – propeller-like.

genes

Functional length of DNA that provides the genetic information necessary to build a protein.

genome

Full complement of DNA within a cell organised into smaller, discrete units called genes, arranged on chromosomes and plasmids.

Golgi apparatus

Stacked membranous disks called dictyosomes where lipids and proteins are modified by enzymes and repackaged for transport within the cell, to the cell membrane for use or for exocytosis from the cell.

glucose

Simple sugar (monosaccharide) that is an important energy source in living organisms and is a component of many carbohydrates.

heterotrophic

Organisms that cannot carbon fix and therefore obtains energy by ingesting other plants or animals.

histones

Proteins that play a critical role in organising DNA within the nucleus of eukaryotic cells.

hydrogen bonds

Attachment of a covalently bonded hydrogen atom to another atom.

intermediate filaments

Structural elements of animal cells comprised of anti-parallel dimers.

ligands

Molecule that irreversibly binds with a receptor protein molecule.

lipid

Macromolecule that is nonpolar and insoluble in water.

lophotrichous

Flagella with a tuft at one end of the cell.

lysosomes

Membrane-bound organelles of endomembrane system containing digestive enzymes.

macromolecules

Large molecule necessary for life that is built from smaller organic molecules

macronutrients

Essential nutrients required for healthy functioning in large quantities.

mammals

Eukaryotic, warm blooded, vertebrate animals characterised by having mammary glands.

MHC (major histocompatibility complex) molecules

Gene cluster whose proteins present antigens to T cells.

microfilaments

Thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support.

micronutrients

Essential nutrients required for healthy functioning in small quantities (vitamins and minerals).

microtubules

Form part of the cytoskeleton to provide support and are composed of beta and alpha tubulin.

mitochondria

Large, complex organelles in which aerobic cellular respiration occurs in eukaryotic cells. Often referred to as the ‘powerhouse’ of the cell.

monotrichous

Singular flagellum typically located at one end of the cell.

morphology

Science investigating the size, shape and structure of organisms.

morphologies

Science investigating the size, shape and structure of organisms.

nuclear envelope

Complex nuclear membrane that surrounds the nucleus, consisting of two distinct lipid bilayers contiguous with each other.

nuclear pores

Large, rosette-shaped protein complexes that control the movement of materials into and out of the nucleus.

nucleolus

Found in eukaryotic cells and contains the DNA genome.

nucleus

Membrane-bound organelle found in most eukaryotic cells, often considered the control center of the cell because it houses the cell’s genetic material, DNA (deoxyribonucleic acid).

osmosis

Movement of water across a semipermeable membrane from areas of low concentration to areas of high concentration.

passive transport

Movement of molecules along the concentration gradient that does not require energy.

pathogenicity

Ability of an organism, typically a microorganism, to cause disease in another organism.

peptidoglycan

Complex sugar and amino acid polymer that forms a tough, protective mesh-like structure in the cell walls of bacteria, providing structural integrity and shape.

peroxisomes

Membrane-bound organelles that form independently in the cytoplasm from synthesis of peroxin proteins by free ribosomes and incorporation of these proteins in existing peroxisomes which then divide to multiply.

phagocytosis

Immune cell that surrounds, ingests and destroys foreign material.

photoautotrophs

Generates energy using sunlight and carbon.

phototrophs

Obtain energy from sunlight.

phospholipid-derived fatty acid analysis (PLFA)

PLFA analysis estimates the total biomass of microbiota community composition by analysing cell membrane fatty acids.

plasma membrane

Selectively permeable barrier that separates the interior of a cell from its external environment.

plasmids

Small, circular, double-stranded DNA molecules, often found in bacteria, less common in archaea and eukaryotic organisms.

polysaccharide

Membranes’ major constituent; comprised of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

prokaryotes

Archaea and bacteria.

prokaryotic

Archaea and bacteria.

protein

Large, complex molecules that play critical roles in the body, such as assisting in metabolism, transport, stimulation, and cellular replication.

proton

Subatomic particle with positive electrical charge, present in the nuclei of all atoms and slightly lower mass of a neutron.

ribosome

Site of protein synthesis. Converts mRNA into amino acid chain that is folded into a protein and further processed in the Golgi apparatus.

RNA

Ribonucleic acid, similar in structure to DNA. Single stranded and shorter than DNA, RNA carries genetic information to ribosomes to be translated into proteins.

regulatory particle

A component of the proteasome, responsible for recognition of proteins tagged for degradation.

T cells

White blood cell, leukocyte, attack pathogens as part of the adaptive immune system.

tonicity

Ability of a surrounding solution to cause a cell to gain or lose water.

traits

Different forms of a characteristic.

transmembrane

Refers to something that extends through a biological membrane, most typically a cell membrane. This term is often used to describe certain types of proteins that span the entirety of the biological membrane.

ubiquitin

Small protein that targets proteins for destruction.