Genetics - Key Terms Flashcards
What is the Phenotype?
Physical characteristics of an individual organism (can include non-visual things e.g. Disease).
What is the Genotype?
The genetic makeup of an individual organism.
What is an Allele?
A version of a gene.
What does Aneuploidy mean?
When an organism has an extra chromosome, usually as a result of the failure of chromosomes to separate during division.
What does Polyploidy mean?
When an organism has one or more extra sets of chromosomes, meaning their gametes have more than the haploid number of chromosomes.
What does haploid mean?
the number of chromosomes that are in a normal gamete of an organism e.g. humans haploid number is 23.
What does diploid mean?
double the haploid number, the number of chromosomes in a body cell.
What does homozygous mean?
A genotype containing two of the same alleles.
What does Heterozygous mean?
A genotype containing two different alleles.
What does Dominant mean?
The individual only requires one dominant allele to express the dominant phenotype (physical characteristics)
When a genotype is heterozygous and contains 2 different alleles, the phenotype is whatever is the dominant phenotype.
What does Recessive mean?
The individual requires both recessive alleles to express the recessive phenotype.
What is the Locus?
The location of a gene on the chromosome (plural: loci)
What is a chromosome?
a thread-like structure that carries the genes in the nucleus.
What is a Codon?
a sequence of three nucleotide bases in RNA that codes for a specific amino acid.
what is an Exon?
a coding region of DNA.
They are transcribed to the final mRNA molecule.
They contrast with introns which are non-coding regions that are spliced out from the tRNA molecule.
What is a Gamete?
A gamete is a sex cell.
Gametes are produced by meiosis. They have half the number of chromosomes found in somatic cells.
what is cell potency?
Cell potency refers to the varying ability of stem cells to differentiate into specialised cell types.
Cells with the greatest potency can generate more cells types than those with lower potency.
what does multipotent mean?
Multipotent cells can develop into more than one cell type, but are more limited than pluripotent cells.
Adult stem cells are considered multipotent.
what does pluripotent mean?
Pluripotent cells can give rise to all of the cell types that make up the body.
Embryonic stem cells are considered pluripotent.
what does totipotent mean?
Totipotent cells can form all the cell types in a body, plus the placental cells.
Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent.
