Module 8 Flashcards
(31 cards)
True Breeding:
If an organism has a certain characteristic that is always passed on to its offspring, we say that this organism bred true with respect to that characteristic.
Allele:
One of a pair of genes that occupies the same position of homologous chromosomes.
Genotype:
Two-letter set that represents the alleles an organism possesses for a certain trait.
Phenotype:
The observable expressions of an organism’s genes.
Homozygous genotype:
A genotype in which both alleles are identical.
Heterozygous genotype:
A genotype with 2 different alleles
Dominant allele:
An allele that will determine phenotype if just one is present in the genotype.
Recessive allele:
An allele that will not determine the phenotype unless the genotype is homozygous in that allele.
Mendel’s Principles:
- The traits of an organism are determined by its genes.
- Each organism has 2 alleles that make up the genotype for a given trait.
- In sexual reproduction, each parent contributes ONLY ONE of its alleles to its offspring.
- In each genotype, there is a dominant allele. If it exists in an organism, the phenotype is determined by that allele.
Pedigree:
A diagram that follows a particular phenotype through several generations.
Monohybrid cross:
A cross between two individuals, concentrating on only one definable trait.
Dihybrid cross:
A cross between 2 individuals, concentrating on two definable traits.
Autosomes:
Chromosomes that do not determine the sex of an individual.
Sex Chromosomes:
Chromosomes that determine the sex of an individual.
Antigen:
A protein that, when introduced in the blood, triggers the production of an antibody.
Autosomal inheritance:
Inheritance of a genetic trait not on a sex Chromosome
Genetic disease carrier:
A person who is heterozygous in a recessive genetic disorder.
Sex-linked inheritance:
Inheritance of a genetic trait located on the sex chromosomes.
Mutation:
A radical chemical change in one or more alleles.
Change in chromosome structure:
A situation in which a chromosome loses or gains genes during meiosis.
Change in chromosome number:
A situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one chromosomes in the gamete.
Three pea plants have the following alleles for Yellow (“Y”) and green (“y”) peas. What are the genotype and phenotype of each? Note whether they are homozygous or heterozygous.
a. YY
b. Yy
c. yy
a. Homozygous, Genotype: YY, Phenotype: Yellow peas
b. Heterozygous, Genotype: Yy, Phenotype: Yellow peas
c. Homozygous, Genotype: yy, Phenotype: Green peas
What process causes gametes to have only one allele, since other human cells have two of each allele?
Meiosis
In the case of fruit fly eye color again, what must be the genotype of a male fly if, when crossed with a heterozygous female, there is no possibility of having a female with white eyes?
X(R) Y
