6. Genetics and Heredity Flashcards
(28 cards)
True- Breeding
Organisms that produce offspring identical to themselves if allowed to self-pollinate
Ex. Mendel’s pea plants would true-breed and create offspring identical to themselves because essentially the plant would have 1 parent
Fertilization
Process in sexual reproduction in which make and female reproductive cells join to form a new cell
Ex. The flower was fertilized when it’s male sperm joined with the female egg.
Trait
Specific characteristic that varies from one individual to another
Ex. Mendel used pea plant breeding to determine which traits were dominant and recessive in the plants.
Hybrid
Offspring of crosses between parents with different traits
Ex. The hybrid pea plant had 1 purple parent and 1 pink parent so it’s a pink-purple hybrid.
Gene
Sequence of DNA that codes for a protein and thus determines a trait
Ex. I have a gene for fiery red hair.
Allele
One of a number of different forms of a gene
Ex. The pea plant’s great height was determined by the dominant allele it carried.
Segregation
Segregation of alleles during gamete formation
Ex. When Tt and Tt plants breed, there are 4 gametes. There are 2 T’s and 2 t’s. When the gametes come together the they are the variations of these alleles.
Probability
Likelihood that a particular event will occur
Ex. The probability of Pea plants having tall characteristics is increased when both parents have the tall Gene.
Punnett square
Diagram showing the gene combinations that might result from a genetic cross.
Ex. A punnet square shows the gene combinations that might result from a genetic cross.
Homozygous
Term used to refer to an organism that has two identical alleles for a particular trait
Ex. The pea plants with two tt (recessive genes and TT genes are homozygous.
Heterozygous
Term used to refer to an organism that has two different alleles for the same trait.
Ex. Tt (one dominant and one recessive)
Phenotype
Physical characteristics of an organism
Ex. My phenotype is blue eyes and blonde haired.
Genotype
Genetic makeup of an organism
Ex. My genotype is my genes
Independent assortment
Independent segregation of genes during the formation of gametes.
Ex.
Independent assortment
Independent segregation of genes during the formation of gametes
Ex. Variations in phenotype are caused by independent assortment of genes during gamete formation.
Incomplete dominance
Situation in which one allele isn’t completely dominant over another
Ex. There is an allele for red petals of a flower and an allele for white petals. Incomplete dominance results in a white flower
Codominance
Situation in which both alleles of a gene contribute to the phenotype of the organism.
Ex. The cow has black and white spots
Multiple alleles
Three or more alleles of the same gene
Ex. Aaa
Gene map
Diagram showing the relative locations of each known gene on a particular chromosome
Ex. A gene map shows where certain genes are located on a specific chromosome
Polygenic traits
Trait controlled by two or more traits
Ex. Your fat earlobes are a polygenic trait because they are caused by a gene for fatness and a gene for detached earlobes
Karyotype
Set of photos of chromosomes grouped and ordered in pairs
Ex. The normal diploid somatic cell of a human has 46 chromosomes
Sex chromosome
One of two chromosomes that determine an individual’s sex; females have two x’s and males have one x and one Y chromosome
Ex. You are a boy because you have the teeny Y chromosome
Autosome
Autosomal chromosome ; chromosome that is not a sex chromosome
Ex. All the chromosomes other than the last 2 (usually) on a karyotype are autosomes
Pedigree
Chart that shows relationships in a family
Ex. My mom made me do a mediated chart when we learned about family hx in church
