Year 1 and AS Biology Glossary

A comprehensive set of flashcards covering key terms and concepts in Year 1 and AS Biology.

What are abiotic factors?

Non-living conditions in a habitat.

What is activation energy?

The energy required to initiate a reaction.

What is the active site of an enzyme?

Area of an enzyme with a shape complementary to a specific substrate, allowing the enzyme to bind a substrate with specificity.

What is active transport?

Movement of particles across a plasma membrane against a concentration gradient, requiring energy.

What does ADP stand for?

Adenosine diphosphate, a nucleotide composed of a nitrogenous base, a pentose sugar, and two phosphate groups.

What is ATP?

Adenosine triphosphate, a nucleotide composed of a nitrogenous base, a pentose sugar, and three phosphate groups; the universal energy currency for cells.

What are agglutinins?

Chemicals (antibodies) that cause pathogens to clump together for easier engulfing by phagocytes.

What are alleles?

Different versions of the same gene.

What are amino acids?

Monomers used to build polypeptides and thus proteins.

What is anabolism?

Metabolic reactions that construct molecules from smaller units, requiring energy from ATP hydrolysis.

What are analogous structures?

Structures that have adapted to perform the same function but have a different origin.

What occurs during anaphase in mitosis?

Chromatids are separated to opposite poles of the cell.

What are antibiotic-resistant bacteria?

Bacteria that undergo mutation to become resistant to an antibiotic and increase in number.

What are antibiotics?

Chemicals or compounds that kill or inhibit the growth of bacteria.

What are antibodies?

Y-shaped glycoproteins made by B cells of the immune system in response to an antigen.

What is an antigen?

Identifying chemical on the surface of a cell that triggers an immune response.

What is an antigen-antibody complex?

The complex formed when an antibody binds to an antigen.

What is an antigen-presenting cell (APC)?

A cell that displays foreign antigens complexed with major histocompatibility complexes on their surfaces.

What is the antisense strand of DNA?

The strand of DNA that runs 3’ to 5’ and is complementary to the sense strand; acts as a template during transcription.

What are anti-toxins?

Chemicals (antibodies) that bind to toxins produced by pathogens.

What is the apoplast?

The cell walls and intercellular spaces of plant cells.

What is the role of the apoplast route?

Movement of substances through cell walls and cell spaces by diffusion and into cytoplasm by active transport.

What is arrhythmia?

An abnormal rhythm of the heart.

What are artefacts in microscopy?

Objects or structures seen through a microscope created during the processing of the specimen.

What is artificial active immunity?

Immunity that results from exposure to a safe form of a pathogen, such as through vaccination.

What is artificial passive immunity?

Immunity resulting from the administration of antibodies from another animal against a dangerous pathogen.

What is asexual reproduction?

The production of genetically identical offspring from a single parent.

What are assimilates?

Products of photosynthesis that are transported around a plant, e.g., sucrose.

What is atrial fibrillation?

An abnormal rhythm of the heart when the atria beat very fast and incompletely.

What is the function of the atrio-ventricular node (AVN)?

Stimulates the ventricles to contract after a slight delay to ensure atrial contraction is complete.

What is an autoimmune disease?

Condition or illness resulting from an autoimmune response.

What is an autoimmune response?

When the immune system acts against its own cells and destroys healthy tissue.

What do autotrophic organisms do?

Acquire nutrients by photosynthesis.

What are B effector cells?

B lymphocytes that divide to form plasma cell clones.

What are B lymphocytes?

Lymphocytes that mature in the bone marrow and are involved in antibody production.

What are B memory cells?

B lymphocytes that live a long time and provide immunological memory for antibodies against specific antigens.

What is a belt transect?

Two parallel lines marked along the ground for sampling specified area points.

What is Benedict’s reagent?

An alkaline solution of copper(II)sulfate used to test for reducing and non-reducing sugars.

What constitutes a beta pleated sheet?

A sheet-like secondary structure of proteins.

What is binomial nomenclature?

The scientific naming of a species using a Latin name made of two parts: genus and species.

What is biodiversity?

The variety of living organisms present in an area.

What is the biuret test?

A chemical test for proteins; peptide bonds form violet complexes with copper ions in alkaline solutions.

What is the Bohr effect?

The effect of carbon dioxide concentration on oxygen uptake and release by haemoglobin.

What is bradycardia?

A slow heart rhythm of less than 60 beats per minute.

What is breathing rate?

The number of breaths taken per minute.

What is bulk transport?

A form of active transport for large molecules or cells moved by endocytosis or exocytosis.

What is the bundle of His?

Conducting tissue composed of Purkyne fibres that passes through the septum of the heart.

What is callose?

A polysaccharide important in the plant response to infection.

What is carbaminohaemoglobin?

The compound formed when carbon dioxide combines with haemoglobin.

What are carbohydrates?

Organic polymers composed of carbon, hydrogen, and oxygen in the ratio Cx(H2O)y; also known as saccharides or sugars.

What is carbonic anhydrase?

An enzyme that catalyses the reversible reaction between carbon dioxide and water to form carbonic acid.

What is the cardiac cycle?

The events of a single heartbeat, composed of diastole and systole.

What are carrier proteins?

Membrane proteins that facilitate the transport of substances through a membrane.

What is cartilage?

Strong, flexible connective tissue found in various areas of the human and animal bodies.

What is catabolism?

Metabolic reactions that break down molecules into smaller units, releasing energy.

What is catalase?

An enzyme that catalyses the breakdown of hydrogen peroxide.

What is the cell cycle?

A highly ordered sequence of events in a cell resulting in nuclear division and formation of two identical daughter cells.

What is cell signalling?

A complex system of intercellular communication.

What is cellulose?

A polysaccharide formed from beta glucose; a major component of plant cell walls.

What is the cell wall?

A strong but flexible layer surrounding some cell types.

What are centrioles?

Components of the cytoskeleton of most eukaryotic cells, composed of microtubules.

What is a centromere?

The region where two chromatids are held together.

What are channel proteins?

Membrane proteins that provide a hydrophilic channel through a membrane.

What are checkpoints in the cell cycle?

Control mechanisms that ensure proper progression through the cell cycle.

What are chiasmata?

Sections of DNA that become entangled during crossing over in meiosis.

What is the chloride shift?

The movement of chloride ions into red blood cells as hydrogen ions move out.

What are chloroplasts?

Organelles responsible for photosynthesis in plant cells.

What are chromatids?

Two identical copies of DNA (a chromosome) held together at a centromere.

What is chromatin?

Uncondensed DNA complexed with histones.

What are chromosomes?

Structures of condensed and coiled DNA that become visible when cells prepare to divide.

What is the circulatory system?

The transport system of an animal.

What is clonal expansion?

The mass proliferation of antibody-producing cells by clonal selection.

What is clonal selection?

Theory that exposure to an antigen increases proliferation of the specific antibody-forming cell.

What is a closed circulatory system?

A system where blood is enclosed in vessels and does not contact body cells directly.

What is Clostridium difficile?

A Gram-positive bacterium that is resistant to most antibiotics.

What is a codon?

A three-base sequence of DNA or RNA that codes for an amino acid.

What are cofactors?

Non-protein components necessary for enzyme function.

What is the cohesion-tension theory?

The model explaining water movement through plants during transpiration.

What are communicable diseases?

Diseases that can be transmitted between organisms.

What is a community in ecology?

All populations of living organisms in a specific habitat.

What are companion cells?

Active cells next to sieve tube elements that supply phloem with metabolic needs.

What is a competitive inhibitor?

An inhibitor that competes with a substrate to bind to the active site on an enzyme.

What is complementary base pairing?

Specific hydrogen bonding between nucleic acid bases where A binds to T or U, and C binds to G.

What is a compound light microscope?

A microscope that uses two lenses to magnify an object.

What is a condensation reaction?

A reaction yielding a larger molecule and releasing a water molecule.

What is continuous variation?

A characteristic with a range of values, e.g., height.

What is contrast in microscopy?

The treatment of specific cell components to make them visible.

What is convergent evolution?

Evolution of similarities due to adaptation to similar environments.

What is correlation coefficient?

Statistical test assessing relationships between two data sets.

What is a countercurrent exchange system?

System for exchanging materials with two components flowing in opposite directions.

What is counterstain in microscopy?

Applying a second stain of contrasting color to make a sample visible.

What is crossing over?

Genetic material exchange between homologous chromosomes during meiosis.

What are cytokines?

Cell-signalling molecules produced by mast cells that attract phagocytes.

What is cytokinesis?

Cell division stage that produces two identical daughter cells.

What is cytolysis?

The bursting of an animal cell due to hydrostatic pressure.

What is cytoplasm?

Internal fluid of cells, composed of cytosol and organelles.

What is the cytoskeleton?

A network of fibers in the cytoplasm of a eukaryotic cell.

What does denatured mean?

A change in protein structure resulting in loss of function.

What is DNA?

The molecule responsible for the storage of genetic information.

What is diastole?

The cardiac cycle stage where the heart relaxes and fills with blood.