Year 10 Biology 2026: Genetics & Evolution

This set of vocabulary flashcards covers the core concepts of DNA structure, inheritance patterns, protein synthesis, genetic technologies, and the principles of evolution as outlined in the Year 10 Biology curriculum.

DNA

Short for deoxyribonucleic acid; a complex molecule stored in the nucleus of plant and animal cells that contains the genetic code for proteins and determines how an organism grows and functions.

Gene

A specific segment of DNA that acts as an instruction or blueprint for making proteins, which in turn control the structure, function, and behavior of cells.

Chromosome

Thread-like structures made of DNA and protein visible in the nucleus during cell division; humans have $46$ chromosomes ($23$ pairs) in each somatic cell.

Genome

The complete set of genetic material or information coded in an organism.

Nucleotide

The basic building block of DNA, consisting of a phosphate group, a sugar molecule, and one of four nitrogenous bases.

Double Helix

The structural shape of DNA, consisting of two chains or backbones that twist around each other like a ladder.

Base Pair

The rungs of the DNA ladder formed by specific combinations of nitrogenous bases: adenine (A) joins with thymine (T), and guanine (G) joins with cytosine (C).

Mitosis

A type of cell division that results in two daughter cells that are identical to the parent cell, used primarily for growth and the repair of damaged cells.

Meiosis

A process of cell division that produces gametes (sex cells) and leads to genetic variation through processes like crossing over.

Protein Synthesis

The two-step process (transcription and translation) used by the body to produce proteins from the genetic code found in DNA.

Transcription

The first step of protein synthesis, occurring in the nucleus, where mRNA copies the DNA sequence, substituting uracil (U) for thymine (T).

Translation

The second step of protein synthesis, occurring at the ribosome, where the mRNA sequence is read in codons to assemble a polypeptide chain.

mRNA

Messenger RNA; a molecule that transcribes the genetic code from DNA in the nucleus and carries it to the cytoplasm for translation.

tRNA

Transfer RNA; a molecule that brings specific amino acids to the ribosome during translation, matching its anti-codon to the mRNA codon.

Codon

A sequence of $3$ bases on an mRNA strand that codes for one specific amino acid.

Mutation

A change in the genetic material of a cell, ranging from a single DNA nucleotide sequence change to an alteration of a whole chromosome.

Mutagen

External factors that cause mutations, such as electromagnetic radiation, chemicals, or naturally occurring substances.

Allele

An alternative form of a gene that occupies a specific spot on a chromosome (locus) and controls the same trait.

Genotype

The specific combination of alleles an organism possesses for a particular gene (e.g., $Bb$).

Phenotype

The observable physical characteristics or traits of an organism, determined by its genotype and environmental factors.

Homozygous

A condition where an individual has two identical alleles for a specific gene (e.g., $BB$ or $bb$).

Heterozygous

A condition where an individual has two different alleles for a specific gene (e.g., $Bb$).

Dominant Allele

An allele that masks the effect of a recessive allele; it is represented by a capital letter in genotype notation.

Recessive Allele

An allele whose effect is masked by a dominant allele; it is only expressed in the phenotype if the individual is homozygous for that allele.

Continuous Variation

Variation that shows a range of phenotypes between two extremes with no distinct categories, often controlled by many genes and the environment (e.g., height).

Discontinuous Variation

Variation that falls into distinct, limited categories with no intermediates, usually controlled by only a few genes (e.g., blood groups).

Autosome

Any chromosome that is not a sex chromosome; humans normally have $22$ pairs of autosomes.

Sex Linkage

Phenomenon where a gene controlling a characteristic is located on a sex chromosome, typically the X chromosome.

Genetic Engineering

The deliberate modification of the characteristics of an organism by manipulating its genetic material, often involving the transfer of genes between species.

Transgenics

A branch of genetic engineering where an organism is created to contain DNA from a different species.

CRISPR

An emerging genetic technology used for precise gene editing.

HeLa

An immortal cell line derived from Henrietta Lacks in $1951$, used extensively in medical research for studying cancer, viral infections, and drug testing.

Gel Electrophoresis

A laboratory technique used to separate DNA fragments according to size by moving them through a gel using an electric field; smaller fragments travel further.

Natural Selection

The process by which organisms with favorable traits for their environment are more likely to survive and reproduce, passing those traits to the next generation.

Speciation

The formation of a new and distinct species through the process of evolution.

Divergent Evolution

When a population is divided by a barrier and different selection pressures cause the groups to become so different they can no longer interbreed.

Convergent Evolution

When unrelated species evolve similar features or adaptations because they occupy similar ecological niches and face similar selection pressures.