Chapter 3 - Table 1-Table 1 Flashcards
(29 cards)
Structural Genes
Genes that contain the information to make a protein.
Regulatory Genes
Guide the expression of structural genes, without coding for a protein themselves.
Genotype
The genetic makeup of an individual. Can refer to the entire genetic complement or more narrowly to the alleles present at a specific locus on two homologous chromosomes.
Phenotype
An observable or measurable feature of an organism. Can be anatomical, biochemical, or behavioral.
ABO Blood Type System
Refers to the genetic system for one of the proteins found on the surface of red blood cells. Consists of one gene with threes alleles: A, B, and O.
Recessive
In a diploid organism, refers to an allele that must be present in two copies (homozygous) in order to be expressed.
Dominant
In a diploid organism, an allele that is expressed when present on only one of a pair of homologous chromosomes.
Co-dominant
In a diploid organism, two different alleles of a gene that are both expressed in a heterozygous individual.
Blending Inheritance
Discredited 19th century idea that genetic factors from the parents averaged-out or blended together when they were passed on to offspring.
Particulate Inheritance
The concept of heredity based on the transmission of genes (alleles) according to Mendelian principles.
Mendel’s Law of Segregation
The two alleles of a gene found on each of a pair of chromosomes segregate independently of one another into sex cells.
Mendel’s Law of Independent Assortment
Genes found on different chromosomes are sorted into sex cells independently of one another.
Linkage
Genes that are found on the same chromosome are said to be linked. The closer together two genes are on a chromosome, the greater the linkage and the less likely they are to be separated during crossing over.
Point Mutation
A change in the base sequence of a gene that results from the change of a single base to a different base.
Sickle Cell Disease
An autosomal recessive disease caused by a point mutation in an allele that codes for one of the polypeptide chains of the hemoglobin protein.
Autosomal Recessive Disease
A disease caused by a recessive allele; one copy of the allele must be inherited from each parent for the disease to develop.
Insertion Mutation
A change in the base sequence of a gene that results from the addition of one or more base pairs in the DNA.
Deletion Mutation
A change in the base sequence of a gene that results from the loss of one or more base pairs in the DNA.
Tri-nucleotide Repeat Diseases
A family of autosomal dominant diseases that is caused by the insertion of multiple copies of a three-base pair sequence (CAG), which codes for the amino acid glutamine. Typically, the more copies inserted into the gene, the more serious the disease.
Autosomal Dominant Disease
A disease that is caused by a dominant allele; only one copy needs to be inherited from either parent for the disease to develop.
X-Linked Disorders
Genetic conditions that result from mutations to genes on the X chromosome. They are almost always expressed in males, who have only one copt of the X chromosome; in females, the second X chromosome containing the normally functioning allele protects them from developing X-Linked disorders.
Pedigree
A diagram used in the study of human genetics that shows the transmission of a genetic trait over several generations of a family.
Qualitative Variation
Phenotypic variation that can be characterized as belonging to discrete, observable categories.
Quantitative Variation
Phenotypic variation that is characterized by the distribution of continuous variation (expressed using a numerical measure) within a population (for example, a bell curve).
