traits
Characteristic that is inhereted.
genetics
Study of heredity patterns and variation of organisms.
purebred
Type of organism whose ancestors are genetically uniform.
law of segregation
Mendel's first law, stating that (1) organisms inherit two copies of genes, one from each parent, and (2) organisms donate only one copy of each gene in their gametes because the genes separate during gamete formation.
Who was Gregor Mendel?
An Austrian monk in the 1800s, discovered hereditary units. Gardner & teacher
gene
Specific region of DNA that codes (provides a set of instructions to a cell) for a particular protein.
allele
Any of the alternative forms of a gene that occurs at a specific place on a chromosome.
homozygous
Characteristic of having two of the same alleles at the same locus of sister chromatids.
heterozygous (hybrid)
Characteristic of having two different alleles that appear at the same locus of sister chromatids. Mendel cross-pollinated pea plants w/ different characteristics. the offspring produced are called _________
genome
All of an organism's genetic material.
genotype
Collection of all of an organism's genetic information that codes for traits.
phenotype
Collection of all of an organism's physical characteristics.
dominant
Allele that is expressed when two different alleles are present in an organism's genotype.
recessive
Allele that is not expressed unless two copies are present in an organism's genotype.
Punnett square
Model from predicting all possible genotypes resulting from a cross, or mating.
monohybrid cross
Cross, or mating, between organisms that involves only one specific trait
test cross
cross between an organism with an unknown genotype and an organism with the recessive phenotype
Law of Independent assortment
states that allele pairs separate independently of each other during gamete formation, or meiosis. Different traits appear to be inherited separately. Genes aren't connected (eye and hair color)
crossing over
the exchange of chromosome segments between homologous chromosomes during prophase I of meiosis I.
genetic linkage
genes located close together on the same chromosome tend to be inherited together
incomplete dominance
a heterozygous phenotype is somewhere between the two homozygous phenotypes.
codominance
heterozygous genotype that equally expresses the traits from both alleles. both are fully and separately expressed.
polygenic traits
traits produced by two or more genes
sex-linked genes
the phenotypic expression of an allele related to the chromosomal sex of an individual
cross
Mating of two organisms
dihybrid cross
crosses that examine the inheritance of two different traits.
four-o'clock flowering plant
when plants that are homozygous for red flowers are crossed with plants that are homozygous for white flowers, the offspring have pink flowers. the pink color is a 3rd, distinct phenotype. neither of the original phenotypes of the plants in the parent's g
Blood Type
come from 3 different alleles in the human population (multiple-allele trait). multiple alleles called IA, IB, & i. both IA & IB result in a protein called antigen, on the surface of red blood cells. allele i is recessive & doesn't result in an antigen. s
Eye Color
in humans, often thought of a s a single gene trait. It's polygenic. At least 3 genes w/ complicated patterns of expression play roles in determining _____ ______
example of polygenic traits
green allele is dominant to blue alleles, but it's recessive to all brown alleles.
hemophilia
a lack of proteins needed for blood to clot. people w/ this condition don't stop bleeding easily. It is a sex-linked genetic disorder.
Why did Gregor Mendel choose to use pea plants for his experiments?
1.reproduce quickly 2.he could easily control how they mate 3.view multiple generations 4.he was familiar with them
peass have the ability to self-pollinate. Explain.
the plant mates with itself
describe the relationship between self-pollinating parents and offspring
self-pollinating=purebred. offspring of purebred parents inherit all of the parent organisms' characteristics. Identical. Purebred (homozygous)
cross-pollination
the mating of 2 organisms (plants) pollen from one to another
how did Mendel carryout cross pollination with the pea plants?
Crossed a purebred white flowered pea plant with purebred purple flowered pea plant. Used a brush to dust pollen from one plant onto another.