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Biology Genetics 9th grade

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Chromosomes
threadlike structures made of DNA molecules that contain the genes.
Genes
Sequence of DNA that codes for protein and thus determines a trait.
DNA
(biochemistry) a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix
Mitosis
Part of eukaryotic cell division during which the cell's nucleus divides.
Gametes
Sex cells
Egg
animal reproductive body consisting of an ovum or embryo together with nutritive and protective envelopes
Sperm
Male reproductive organ.
Zygote
Feritilized egg.
Meiosis
Process by which the number of chromosomes per cell is cut in half through the seperation of homologous chromosomes in a diploid cell.
Spermatogenesis
development of spermatozoa
Oogenesis
development of ova
Testes
The male gonads, which produce sperm and secrete male sex hormones.
Ovary
produces eggs
Homologous Chromosome
one of a matching pair of chromosomes, one inherited from each parent
Diploid
Term used to refer to a cell that contains both sets of homologous chromosomes.
Haploid
Term used to refer to a cell that contains only a single set of chromosmes and therfore only a single set of genes.
Genetics
Scientific study of heredity.
Gregor Mendel
Father of Genetics
Heredity
the biological process whereby genetic factors are transmitted from one generation to the next
Stamens
Male part of the flower; made up of an anther and a filament.
Pollen
the fine spores that contain male gametes and that are borne by an anther in a flowering plant
Pistie
the female ovule-bearing part of a flower composed of ovary and style and stigma
Self pollination
when sperm cells in pollen fertilize the egg cells in the same flower; seeds that are produced inherit all of their characteristics from the single plant that bore them
Cross pollination
pollen from one flower transfered to the sticky stigma of another flower
Principle of dominant and recessiveness
States some alleles are dominant and others are recessive.
Dominant
The trait that is most likely to appear in the next generation
Recessive
The trait that is less likely to appear in the next generation
Hybrid
A mixed gene (Gg)
Pure
100% same (GG)
Law of segragation
states that the two alleles for a character segragate when gametes are formed
Genotype
the particular alleles at specified loci present in an organism
Phenotype
what an organism looks like as a consequence of its genotype
Homozygous
having identical alleles at corresponding chromosomal loci
Heterozygous
having dissimilar alleles at corresponding chromosomal loci
Contrasting traits
Traits that differ from eachother, or do not favor each other.
Law of independant assortment
the law that states that genes seperate independantly of one another in meiosis
Alleles
different forms of a gene
Monohybrid cross
hybridization using a single trait with two alleles (as in Mendel's experiments with garden peas)
Dihybrid cross
hybridization using two traits with two alleles each
Incomplete dominance
Traits that are not fully dominant, nor fully recessive