Genetics and Cell Division Vocabulary

Complete vocabulary review covering key genetic terms, the stages of mitosis and meiosis, and principles of inheritance.

Autosome

A chromosome that is not a sex chromosome.

Centromere

The middle part of a chromosome that holds it together.

Chromatin

DNA when it is loose and not tightly packed.

Chromosome

A long structure made of DNA that carries genes.

Chromosome mutation

A change that affects a whole chromosome.

Complementary base pairing

DNA bases match in pairs: A with T, C with G.

DNA (Deoxyribonucleic acid)

The molecule that carries genetic information.

Gene

A small section of DNA that gives instructions.

Gene mutation

A change in one gene.

Genetics

The study of genes and inheritance.

Genome

All the DNA in a cell.

Hydrogen bonds

Weak bonds that hold DNA strands together.

Karyotype

A picture of all chromosomes.

Locus

The place of a gene on a chromosome.

Mutation

A change in DNA.

Nucleotide

One building block of DNA.

Sex chromosomes

Chromosomes that decide sex.

Sister chromatids

Two identical copies of one chromosome.

Somatic cells

All body cells except sex cells.

Trisomy

Having one extra chromosome.

Mitosis Cell Division

The process by which a parent cell divides to form new cells.

Mitosis

A type of cell division that produces two identical daughter cells, used for growth and repair.

Interphase

The stage before mitosis where the cell grows, copies its DNA, and prepares to divide.

Prophase

The first stage of mitosis: chromosomes condense, the nuclear membrane breaks down, and spindle fibres begin to form.

Metaphase

Chromosomes line up in the middle (equator) of the cell.

Anaphase

Sister chromatids are pulled apart to opposite ends of the cell.

Telophase

Nuclear membranes reform around each set of chromosomes; chromosomes start to uncoil.

Cytokinesis

The cytoplasm divides, completing cell division and producing two daughter cells.

Spindle Fibres

Protein structures that pull chromatids apart during mitosis.

Daughter Cells

The two new cells produced by mitosis; they are genetically identical to the parent cell.

Parent Cell

The original cell that undergoes mitosis.

DNA Replication

The process of copying DNA during interphase so each daughter cell gets a complete set.

Apoptosis

Cell self-destructs when it is damaged, old, or no longer needed.

Diploid ($2n$)

A cell with two sets of chromosomes.

Embryo

A very early stage of a baby.

Fertilisation

When sperm and egg join together.

Gametes

Sex cells: sperm and egg.

Haploid ($n$)

A cell with one set of chromosomes.

Meiosis

Cell division that makes sex cells.

Recombination

Genes mix during meiosis.

Homologous Chromosomes

Pairs of chromosomes that carry the same types of genes (one from each parent).

Prophase I

Chromosomes condense; homologous chromosomes pair up and crossing over occurs.

Crossing Over

A process where homologous chromosomes exchange segments of DNA — increases genetic variation.

Metaphase I

Homologous pairs line up in the middle of the cell.

Anaphase I

Homologous chromosomes are pulled to opposite ends of the cell (chromatids stay together).

Telophase I

Two nuclei form and the cell divides into two haploid cells.

Prophase II

Chromosomes condense again in each haploid cell.

Metaphase II

Chromosomes line up in the centre of each cell.

Anaphase II

Sister chromatids are pulled apart to opposite sides.

Telophase II

Four haploid cells form, each genetically unique.

Allele

A different version of the same gene.

Carrier

A person who has a gene but does not show the trait.

Codominance

Both alleles show at the same time.

Dominant

A gene that shows even with one copy.

Genotype

The genes an organism has.

Heredity

How traits pass from parents to children.

Heterozygous

Two different alleles.

Homozygous

Two same alleles.

Incomplete dominance

A mix of two traits is shown.

Monohybrid cross

A genetic cross for one trait.

Phenotype

What you can see, like eye colour.

Punnett square

A grid to predict traits.

Recessive

A gene that needs two copies to show.

Sexual reproduction

Making offspring using two parents.

Somatic mutation

A mutation in body cells.

Spontaneous mutation

A mutation that happens naturally.

Telomeres

Protective ends of chromosomes.

Test cross

A cross used to find a genotype.