Ch 7 - Genes and Inheritance Flashcards
What is a phenotype?
The outward appearance of an individual.
What is a genotype?
An organisms genetic composition. Underlying the phenotype.
Define homozygous.
When an individual inherits the same two alleles for a gene. (Same genetic information)
Define heterozygous.
When an individual inherits a different allele from each parent.
What are Gregor Mendels 3 features?
- Good experimental organism.
- Studied easily categorized traits
- Use true-breeding plants (always produces offspring with same traits).
What is a single-gene trait?
Traits that are determined by the instructions a person carries at one gene.
Define heredity.
The passing of characteristics from parent to offspring through their genes.
What is codominance?
When heterozygous displays characteristics of both homozygotes.
What is incomplete dominance?
When the heterozygote appears to be intermediate between 2 homozygotes.
What is a pedigree?
It’s a type of family tree. It’s useful tool to document a trait of interest across multiple generations of family members.
What is a pleiotropy?
A phenomenon where an individual gene influences multiple traits.
Define multiple allelism.
When a single gene has more then 2 alleles.
What is Mendals law of segregation?
It states that only 1 of the 2 alleles for a gene is put into a gamete. The offspring receive from each parent, one allele for each gene.
What are the different genotypes?
Homozygous vs heterozygous Dominant vs recessive Homozygous dominant Homozygous recessive Heterozygous
What are antigens?
Antigens are a chemical that act as a signpost that tell the immune system whether the cell belongs in the body.
What are antibodies?
An immune system molecule that attack cells with a foreign antigen.
What is a polygenic trait?
Trait that is influenced by many different genes.
What are some examples of a polygenic trait?
Height, eye color, skin color, some behavioral traits
What are linked genes?
Genes on the same chromosome, maybe even right next to each other.
What is the purpose of a test-cross?
It can reveal an unknown genotype.
What characteristic of genes underlie the “Greek theory of autism”?
Additive effects
What are controlled by the genes on the X and Y chromosomes?
The sex-linked traits.
If an individual carries only 2 alleles, is it possible for a single gene to have more then two alleles?
Yes, it is called multiple allelism.
Why is sickle-cell anemia?
A genetic disease caused by the presence of faulty hemoglobin gene.
