36 terms

Biology 6.1

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Gametes
sex cells
Somatic Cells
body cells, make up most of your body tissues and organs
Homologous Chromosones
two chromosones- one inherited from the mother, one from the father- that have the same lenght and general appearance
Autosomes
Chromosones that contain genes for characteristics not directly related to the sex of an organism
Sex Chromosones
Directly control the develpment of sexual characteristics
Sexual reproduction
Involves the fusion of two gametes, resulting in offspring that are a genetic mixture of both parents
Fertalization
Fusion of an egg and a sperm cell
Diploid
A cell has two copies of each chromosone: one copy from the mother, and one copy from the father
Haploid
A cell has only one copy of each chromosone
Meiosis
A from of nuclear division that divides a diploid cell into haploid cells
Gametogenesis
The production of gametes
Sperm
The male gamete
Egg
The female gamete
Polar Bodies
Cells with little more than DNA that are eventually broken down
Traits
Distinguishing characteristics that are inherited, such as eye color, leaf shape, and tail length
Genetics
The study of biological inheritance patterns and varation in organisms
Purebred
A line of plants that has self-pollinated for long enough, and that line becomes genetically uniform
Cross
The mating of two organisms in genetics
Law of segregation
Mendel's two other key conclusions are called the
Gene
A piece of DNA that provides a set of instructions to a cell to make a certain protein
Allele
Any of the alternative forms of a gene that may occur at a specific locus
Homozygous
Describes two of the same alleles at a specific locus
Heterozygous
Describes two different alleles at a specific locus
Genome
All of an organism's genetic material
Genotype
Refers to the genetic makeup of a sepcific set of genes
Phenotype
The physical characteristics, or traits, of an individual organism make up
Dominant
The allele that is expressed when two different alleles or two dominant alleles are present
Recessive
The allele that is expressed only when two copies are present
Punnett Square
A grid system for predicting all possivle genotypes resuting from a cross. The axes of the grid represent the possible gamete genotypes of each parent
Monohybrid Crosses
Crosses that examine the inheritance of only one specific trait
Testcross
A cross between an organism with an unknown genotype with the recessive phenotype must be homozygous
Dihybrid Crosses
Crosses that examine the inheritance of two different traits
Law of independent assortment
States that allele pair seperate independently of each other during gamete formation, or meiosis
Probability
The likelihood that a particular event will hapen
Crossing Over
Process in which homologous chromosomes exchange portions of their chromatids during meiosis.
Genetic Linkage
tendency for genes located close together on the same chromosome to be inherited together