34 terms

Chapter 9- Genes, Chromosomes and patterns of inheritance

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Albinism
Absence of pigment in the skin, hair, and eyes
Gene
A segment of DNA that stores genetic information
Heterozygous
An organism that has two different alleles for a trait
Homologous
Chromosomes that have the same sequence of genes and the same structure
Homozygous
An organism that has two identical alleles for a trait.
Meiosis
Cell division that produces reproductive cells in sexually reproducing organisms
Gamete
A haploid cell such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote.
Alleles
Different forms of a gene
Asexual reproduction
Process by which a single parent reproduces by itself.
Autosomes
Any chromosome that is not a sex chromosome
Centromere
Area where the chromatids of a chromosome are attached
Co-dominance
Situation in which both alleles of a gene contribute to the phenotype of the organism
Diploid
(genetics) an organism or cell having two sets of chromosomes or twice the haploid number
Haploid
(genetics) an organism or cell having only one complete set of chromosomes
Dominant
Describes a trait that covers over, or dominates, another form of that trait.
Genotype
An organism's genetic makeup
Phenotype
An organism's physical appearance, or visible traits.
Pedigree
A diagram that shows the occurrence of a genetic trait in several generations of a family.
Hemizygous
Describes an individual who has only one member of a chromosome pair or chromosome segment rather than the usual two; refers in particular to X-linked genes in males who under usual circumstances have only one X chromosome
Gonads
REPRODUCTIVE ORGANS
Karyotype
A display of the chromosome pairs of a cell arranged by size and shape.
Locus
A specific place along the length of a chromosome where a given gene is located.
Nonhomologous
Double stranded DNA repair in which damaged DNA ends are joined together regardless of homology
Somatic cells
Any cells in the body other than reproductive cells
Translocation
(genetics) an exchange of chromosome parts
Trisomic
Referring to a diploid cell that has three copies of a particular chromosome instead of the normal two.
Traits
Characteristics that are inherited
Pure breeding
Individuals that are homozygous that will always produce the same offspring when crossed together
Recessive
An allele that is masked when a dominant allele is present
Adenine
"A" base
Thymine
Adenine always pairs with
Guanine
G
Cytosine
The base that pairs with Guanine with DNA
Uracil
replaces thyamine in RNA