Chapter 2 Flashcards
What is the new cell formed by the process of fertilization?
Zygote
What is the basic unit of genetic information?
genes
What is the substance that genes are composed of that determines the nature of every cell in the body and how it will function?
DNA
What is the rod-shaped portions of DNA that are organized in 23 pairs?
Chromosomes
What are twins who are genetically identical?
monozygotic twins
What are twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time?
dizygotic twins
What is the one trait that is expressed when two competing traits are present?
dominant trait
What is the underlying combination of genetic material present in an organism?
genotype
What is a trait within an organism that is present, but is not expressed?
recessive trait
What is inheriting from parents similar genes for a given trait?
homozygous
What is an observable trait; the trait that actually is seen?
phenotype
What is inheriting from parents different forms of a gene for a given trait?
heterozygous
What is inheritance in which a combination of multiple gene pairs is responsible for the production of a particular trait?
Polygenic inheritance
What are genes that are considered recessive and located only on the X-chromosome?
x-linked genes
What is the study of the effects of heredity on behavior?
behavioral genetics
What is a disorder produced by the presence of an extra chromosome on the 21st pair; once referred to as mongolism?
Down syndrome
What is a disorder produced by injury to a gene on the x chromosome, producing mild to moderate mental retardation?
fragile x syndrome
What is a blood disorder that gets its name from the shape of the red blood cells in those who have it?
sickle-cell anemia
What is a disorder that produces blindness and muscle degeneration prior to death; there is no treatment?
tay-sachs disease
What is a disorder resulting from the presence of an extra x chromosome that produces underdeveloped genitals, extreme height, and enlarged breasts?
klinefelter’s syndrome
What is the disciple that focuses on helping people deal with issues relating to inherited disorders?
genetic counseling
What is a process in which high-frequency sound waves scan the mothers womb to produce an image of the unborn baby, who’s size and shape can than be assessed?
ultrasound songraphy