1. haploid -
the condition of having only one set of chromosomes per cell (n)
2. diploid -
the condition of having two sets of chromosomes per cell (2n)
3. gamete -
a haploid (n) sex cell in plants and animals (egg or sperm)
4. zygote -
diploid (2n) cell resulting from the union of two gametes in sexual reproduction
5. chromatin -
the complex of DNA, RNA and proteins that makes up uncondensed eukaryotic
6. chromosome -
structures within the nucleus of eukaryotic cells composed of chromatin and
visible at cell division (condensed chromatin).
chromosomes - chromosomes
that are similar in morphology (shape and form) and genetic constitution. In
animals one set comes from the father and the other from the mother.
8. chromatids -
one of the two halves of a duplicated chromosome
9. centromeres -
specialized constricted region of a chromatid, that contains the kinetochore;
sister chromatids are joined at the centromere during cell division
recombination - exchange of
genetic material between chromosomes
11. crossover -
the breaking and rejoining of homologous (non-sister) chromatids during early
prophase I of meiosis, resulting in recombination
- the pairing of homologous chromosomes during prophase I of meiosis.
- separation of homologous chromosomes (or sister chromatids) during anaphase.
- the genetic make-up (the assemblage of alleles) of an individual.
- the physical or chemical expression of an organismís genes.
16. gene -
a discrete unit of hereditary information that usually specifies a protein; a
region of DNA (locus) located on a chromosome that specifies a trait
alleles - genes governing variations of the same characteristic (trait) that
occupy corresponding positions (loci) on homologous chromosomes; alternative
forms of a gene.
allele - an allele that is
always expressed when present, regardless of whether the organism is homozygous
or heterozygous for that gene.
allele - an allele that is
only expressed when the organism is homozygous for that allele and not expressed
when heterozygous (when paired with a dominant allele).
- possessing a pair of identical alleles for a particular locus (gene).
heterozygous - possessing a pair of unlike alleles for a particular locus
carrier - a heterozygous individual not expressing a recessive trait but
capable of passing it on to its offspring.
parent generation (P) - the generation that supplies gametes to the filial
filial generation (F,) - the generation that receives gametes from the
hybrid - an offspring resulting from the mating between individuals of two
different genetic constitutions.
dihybrid cross - a genetic cross that takes into account the effect of
alleles at two separate loci (two different genes).
27. monohybrid cross - a genetic cross that takes into account the effect of alleles at a single locus (single gene).