Heredity: Passing of traits from parents to offspring
Gene: A section of DNA that codes for a trait or protein
DNA: The molecule that carries genetic instructions
RNA: A molecule that helps carry out DNA's instructions
Chromosome: A packaged strand of DNA
How many chromosomes do humans have in body cells?: 46 (23 pairs)
Allele: A version of a gene
Dominant allele: One that shows up when present
Recessive allele: One that shows only when two copies are present
Genotype: The set of alleles an organism has
Phenotype: The visible traits of an organism
Homozygous: Having two of the same allele
Heterozygous: Having two different alleles
Punnett square: A grid used to predict the results of a genetic cross
Trait: A characteristic passed from parent to child
Mutation: A change in DNA
Genome: All the DNA of an organism
Base pairs in DNA: A with T, and C with G
Adenine pairs with: Thymine in DNA
Cytosine pairs with: Guanine
In RNA, thymine is replaced by: Uracil
Nucleotide: A building block of DNA: sugar, phosphate and base
Double helix: The twisted-ladder shape of DNA
Who described the double helix in 1953?: James Watson and Francis Crick, using work by Rosalind Franklin
Who is the father of genetics?: Gregor Mendel
What did Mendel study?: Pea plants
Replication: Making a copy of DNA
Transcription: Copying DNA into messenger RNA
Translation: Reading mRNA to build a protein
Codon: Three bases in mRNA that code for one amino acid
Amino acid: A building block of protein
mRNA: Messenger RNA: carries a gene's message to the ribosome
tRNA: Transfer RNA: brings amino acids to the ribosome
Sex chromosomes: X and Y; they help determine sex
Autosome: A chromosome that is not a sex chromosome
Karyotype: A picture of all of an organism's chromosomes
Gamete: A sex cell: sperm or egg
Zygote: A fertilized egg cell
Diploid: Having two sets of chromosomes
Haploid: Having one set of chromosomes
Incomplete dominance: A blend of two alleles, like pink from red and white
Codominance: Both alleles show up fully
Polygenic trait: A trait controlled by many genes, like height
Sex-linked trait: A trait whose gene is on a sex chromosome
Carrier: A person who has one copy of a recessive allele but no symptoms
Pedigree: A chart showing how a trait passes through a family
Hybrid: Offspring of two different parent types
Purebred: An organism with identical alleles for a trait
Selective breeding: Choosing parents with wanted traits to breed
Genetic engineering: Changing an organism's DNA on purpose
Clone: An organism genetically identical to its parent
Biotechnology: Using living things to make products or solve problems
CRISPR: A tool for editing genes
PCR: A method that copies tiny amounts of DNA many times
Gel electrophoresis: A method that separates DNA pieces by size
Human Genome Project: An effort that mapped human DNA, completed in 2003
Law of segregation: Alleles separate when sex cells form
Law of independent assortment: Genes for different traits are passed on separately
Evolution by natural selection: Traits that help survival become more common over time
Adaptation: A trait that helps an organism survive
Variation: Differences among individuals of a species
Epigenetics: Changes in how genes are used without changing the DNA code
Locus: The position of a gene on a chromosome
Down syndrome: A condition caused by an extra copy of chromosome 21

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