genetics terminology Flashcards
What is a gene?
A segment of DNA that codes for a particular characteristic.
What are alleles?
Different forms of a gene that occur at the same locus on homologous chromosomes.
What is a genotype?
The genetic composition of an organism (e.g., TT, Tt, tt).
What is a phenotype?
The physical appearance of an organism based on its genotype (e.g. tall or short).
What is a dominant allele?
An allele that is expressed in the phenotype even if only one copy is present (T).
What is a recessive allele?
An allele that is only expressed in the phenotype when two copies are present (tt).
What does homozygous mean?
Having two identical alleles for a characteristic (TT or tt).
What does heterozygous mean?
Having two different alleles for a characteristic (Tt).
What is a monohybrid cross?
A genetic cross involving only one characteristic.
What is a dihybrid cross?
A genetic cross involving two different characteristics.
What is complete dominance?
When the dominant allele completely masks the recessive allele in a heterozygous individual (e.g., Tt = tall).
What are multiple alleles?
More than two alternative forms of a gene at the same locus (e.g., blood groups: IA, IB, and i)
What are sex-linked characteristics?
Traits carried on the sex chromosomes, like color blindness and hemophilia.
What is a karyotype?
The number, shape, and arrangement of chromosomes in a cell.
What is cloning?
The process of creating genetically identical organisms using biotechnology.
What is genetic modification?
The manipulation of an organism’s DNA to create desired changes (e.g., inserting the human insulin gene into bacteria).
What is the human genome?
A complete map of all human genes and their locations on chromosomes.
