Chapter 3 Flashcards
(22 cards)
Chromosomes
Molecules of DNA
DNA
Molecule that contains the chemical instructions for cells to manufacture various proteins: promotes growth & sustains life.
Allele
A variation that makes a gene different in some way from other genes for the same characteristics.
Genome
The full set of genes that are the instructions to make an individual member of a certain species.
Genotype
An organism’s genetic inheritance or genetic potential.
Homozygous
Two genes of one pair that are exactly the same in every letter of their code.
Heterozygous
Two genes of one pair that differ in some way.
Zygote
Two gametes come together (1 sperm, 1 ovum)
Stem cells
From which any other specialized type of cell can form into one kind of cell.
Monozygotic (identical) twins
Originate from one zygote that splits very early in development and have the same genotype.
Dizygotic (fraternal) twins
Result from fertilization of two separate ova by two separate sperm.
Phenotype
The observable characteristics of a person including appearance personality intelligence and all other traits.
Polygenic traits
Every trait is affected by many genes
Multifactorial traits
Almost every trait is influenced by many factors.
Additive traits
Height is affected by the contributions of about 100 genes.
Dominant genes
Completely controls the phenotype with no noticeable effect of recessive genes.
Carrier
A person whose genotype includes a gene that is not expressed in the phenotype
X-linked
A gene carried on the X chromosome.
Heritability
Statistical term that indicates what portion of the variation in a particular trait within a particular population is inherited. Environment can affect expression of these genes.
Down syndrome
Three copies of chromosome 21
Genetic counseling
Consultation and testing by trained professionals
Phenylketonuria
Recessive condition results in inability to mobilize phenylalanine and can cause brain damage mental retardation and other symptoms.
