Edexcel GCSE Triple Biology Paper 1 Active Recall

A comprehensive collection of vocabulary flashcards covering key definitions across Topics 1 to 5 and practical skills for Edexcel GCSE Triple Biology Paper 1.

Eukaryotic cell

A type of cell that possesses a nucleus and membrane-bound organelles.

Prokaryotic cell

A single-celled organism, such as a bacterium, that lacks a nucleus, has DNA free in the cytoplasm, and may contain plasmids.

Nucleus

An organelle that contains genetic material (DNA) and controls the cell's activities.

Mitochondria

The site of aerobic respiration within the cell, where energy is transferred for cellular processes.

Ribosomes

The cellular structures responsible for protein synthesis.

Cell membrane

A cellular structure that controls the movement of substances into and out of the cell.

Cell wall

A rigid layer made mainly of cellulose in plant cells that supports and strengthens the cell.

Chloroplasts

Plant organelles containing chlorophyll that absorb light energy to drive photosynthesis.

Vacuole

A permanent structure in plant cells filled with cell sap that helps maintain cellular rigidity.

Magnification

The measure of enlargement calculated by the formula $\text{Magnification} = \frac{\text{image size}}{\text{actual size}}$.

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration down a concentration gradient.

Osmosis

The net movement of water molecules through a partially permeable membrane from a dilute solution to a more concentrated solution.

Active transport

The movement of substances from lower to higher concentration against a concentration gradient, requiring energy from respiration.

Enzyme

A biological catalyst that accelerates chemical reactions without being used up.

Active site

The specific region on an enzyme where a substrate with a complementary shape binds to undergo catalysis.

Denaturation

The structural alteration of an enzyme where the active site changes shape, preventing the substrate from fitting and causing a loss of activity.

Mitosis

A type of cell division where one parent cell divides to produce two genetically identical daughter cells with the same chromosome number as the parent.

Cell differentiation

The developmental process through which an unspecialised cell becomes specialised for a particular function.

Stem cells

Undifferentiated cells with the capability to divide and develop into specialised cell types.

Central nervous system (CNS)

The body's primary control and processing centre consisting of the brain and spinal cord.

Reflex arc

The neural pathway controlling an involuntary response: stimulus $\rightarrow$ receptor $\rightarrow$ sensory neurone $\rightarrow$ relay neurone in the CNS $\rightarrow$ motor neurone $\rightarrow$ effector $\rightarrow$ response.

Synapse

A microscopic junction between neurones across which a chemical neurotransmitter diffuses to trigger an electrical impulse in the adjacent neurone.

Accommodation

The process of altering the curvature of the eye's lens to focus light from objects at varying distances onto the retina.

Hormone

A chemical messenger transported in the blood that elicits a response in target organs or cells.

Negative feedback

A regulatory mechanism that detects and reverses deviations from a normal set point to preserve internal stability.

Gene

A discrete section of DNA that codes for a specific protein or functional product.

Chromosome

A long, tightly coiled DNA molecule bearing many genes.

Genome

The entire genetic material present within an organism.

Meiosis

A form of cell division resulting in four genetically distinct haploid cells, each carrying half the chromosome number of the parent cell.

Haploid cell

A cell containing a single set of chromosomes, such as a gamete.

Allele

An alternative version or form of a gene.

Genotype

The specific combination of alleles possessed by an organism.

Phenotype

The observable physical and physiological traits of an organism resulting from its genotype and environmental interactions.

Homozygous

Possessing two identical alleles for a particular gene.

Heterozygous

Possessing two different alleles for a particular gene.

Dominant allele

An allele whose trait is expressed in the phenotype when at least one copy is present in the genotype.

Recessive allele

An allele whose trait is only expressed in the phenotype when two copies are present in simple inheritance.

Variation

The differences observed between individual organisms of the same species, driven by genetic, environmental, or combined factors.

Natural selection

The mechanism whereby individuals possessing advantageous inherited variations survive and reproduce more successfully, increasing the frequency of those alleles over generations.

Evolution

A gradual change in the inherited characteristics of a biological population over successive generations.

Selective breeding

The process by which humans intentionally select and breed individuals with desirable traits across multiple generations.

Genetic engineering

The artificial modification of an organism's genetic makeup, such as inserting a foreign gene to impart a desired trait.

Communicable disease

An infectious illness caused by a pathogen that can be transferred directly or indirectly between organisms.

Non-communicable disease

A medical condition not caused by an infectious pathogen, such as cardiovascular disease or many cancers.

Pathogen

A disease-causing biological agent belonging to bacteria, viruses, fungi, or protists.

Antibiotic resistance

The capacity of bacteria to survive and withstand an antimicrobial compound that would typically kill them or inhibit their growth.

Placebo

An inactive substance with no medical effect used in clinical trials to establish a baseline comparison against a candidate drug.

Independent variable

The specific factor or condition that is deliberately changed by the investigator in an experiment.

Dependent variable

The variable being measured or recorded to evaluate the outcome of an experiment.

Control variable

A variable that is kept constant throughout an experiment to ensure a fair test.

Anomaly

An experimental data point that deviates significantly from the pattern established by other results.

Accuracy

How close a measured experimental value is to the true or accepted value.

Precision

The degree of detail or the closeness of repeated independent measurements to one another.