Genetics & Cancer Flashcards
Gene
A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins
Allele
Different versions of the same gene.
Allele X or allele x
Chromosome
Thread-like structures that make up DNA found within the nucleus of a molecule.
Homologous Chromosome
Code for the same gene
Genotype
Genes present in an individual.
Heterozygous Genotype
Exact version of the alleles I have. Bb (different allele).
Homozygous Genotype
Version of the allele I have. bb (same allele)
Genotype
Exact genes you have Bb
Phenotype
Physical expression of a particular trait.
Bb –> the dominant gene B is expressed
Autosomes
One chromosome pair.
Zygote
Formed by the combination of 23 pairs of chromosomes. One set coming from each parent.
Meiosis
Cellular division process in which gametes are produced which contain half the chromosomes of the parent cell.
Mitosis
Type of cell division in which cells are produced with exactly the same kind and number of chromosomes as the parent cell.
Genetic Mutations
Occur as a result of:
- Errors in the copying process during replication of DNA cells
- environmental factors (radiation/chemicals)
Can occur in sex cells which are passed on to future generations.
Mutation
An event that changes the genetic structure or sequence of a cell.
