Fad 3220 Chapter 2 terms and concepts
exam questions and answers
Zygote - Answer -the new cell formed by the process of fertilization
Genes - Answer -the basic units of genetic information
- composed of DNA
DNA ( deoxyribonucleic acid) molecules - Answer -the substance that genes are
composed of that determines the nature of every cell in the body and how it will function
Chromosomes - Answer -rod-shaped portions of DNA that are organized in 23 pairs ( 46
total)
Monozygotic twins - Answer -twins who are genetically identical
- occurs when the zygote splits
Dizygotic twins - Answer -twins who are produced when two separate ova are fertilized
by two separate sperm at roughly the same time
- occurs when two separate sperms fertilizes two separate eggs
Boy or Girl? - Answer -in 22 of the 23 matched chromosome pars, each chromosome is
similar to the other member of its pair except the 23rd one
- XX= female
- XY= male
Dominant Trait - Answer -the one trait that is expressed when two competing traits are
present
Recessive Trait - Answer -a trait within an organism that is present, but is not expressed
Genotype - Answer -the underlying combination of genetic material present ( but not
outwardly visible) in an organism
Phenotype - Answer -an observable trait; the trait that is actually seen
Alleles - Answer -genes governing traits that may take alternate form
, Homozygous - Answer -inheriting from parents similar genes for a given trait
Heterozygous - Answer -inheriting from parents different forms of a gene for a given trait
Phenylketonuria ( PKU) - Answer -an inherited disorder in which a child is unable to
make use of phenylalanine, an essential amino acid
Polygenic inheritance - Answer -inheritance in which a combination of multiple gene
pairs is responsible for the production of a particular trait
Reaction Range - Answer -the potential degree of variability in the expression of a trait
due to environmental conditions
X-Linked Genes - Answer -genes that are considered recessive and located only on the
X chromosome
- males have higher risk for a variety of X-linked disorders- because males lack a
second X chromosome that can counteract the genetic information that produces the
disorder
Hemophila - Answer -blood disorder, produced by X-linked genes
Behavioral Genetics - Answer -studies the effect of heredity on behavior and
psychological characteristics
Spontaneous mutation - Answer -sometimes genes, for some unknown reason,
spontaneously change their form
Down Syndrome - Answer -a disorder produced by the presence of an extra
chromosome on the 21st pair
- once referred to as mongolism
Fragile X Syndrome - Answer -a disorder produced by injury to a gene on the X
chromosome, producing a mild to moderate mental mentardation
Sickle-cell Anemia - Answer -a blood disorder that gets its name from the shape of the
red blood cells
Tay-Sachs disease - Answer -a disorder that produces blindness and muscle
degeneration prior to death
- there is no treatment
Klinefelter's syndrome - Answer -a disorder resulting from the presence of an extra X
chromosome that produces underdeveloped genitals, extreme height, and enlarged
breasts
exam questions and answers
Zygote - Answer -the new cell formed by the process of fertilization
Genes - Answer -the basic units of genetic information
- composed of DNA
DNA ( deoxyribonucleic acid) molecules - Answer -the substance that genes are
composed of that determines the nature of every cell in the body and how it will function
Chromosomes - Answer -rod-shaped portions of DNA that are organized in 23 pairs ( 46
total)
Monozygotic twins - Answer -twins who are genetically identical
- occurs when the zygote splits
Dizygotic twins - Answer -twins who are produced when two separate ova are fertilized
by two separate sperm at roughly the same time
- occurs when two separate sperms fertilizes two separate eggs
Boy or Girl? - Answer -in 22 of the 23 matched chromosome pars, each chromosome is
similar to the other member of its pair except the 23rd one
- XX= female
- XY= male
Dominant Trait - Answer -the one trait that is expressed when two competing traits are
present
Recessive Trait - Answer -a trait within an organism that is present, but is not expressed
Genotype - Answer -the underlying combination of genetic material present ( but not
outwardly visible) in an organism
Phenotype - Answer -an observable trait; the trait that is actually seen
Alleles - Answer -genes governing traits that may take alternate form
, Homozygous - Answer -inheriting from parents similar genes for a given trait
Heterozygous - Answer -inheriting from parents different forms of a gene for a given trait
Phenylketonuria ( PKU) - Answer -an inherited disorder in which a child is unable to
make use of phenylalanine, an essential amino acid
Polygenic inheritance - Answer -inheritance in which a combination of multiple gene
pairs is responsible for the production of a particular trait
Reaction Range - Answer -the potential degree of variability in the expression of a trait
due to environmental conditions
X-Linked Genes - Answer -genes that are considered recessive and located only on the
X chromosome
- males have higher risk for a variety of X-linked disorders- because males lack a
second X chromosome that can counteract the genetic information that produces the
disorder
Hemophila - Answer -blood disorder, produced by X-linked genes
Behavioral Genetics - Answer -studies the effect of heredity on behavior and
psychological characteristics
Spontaneous mutation - Answer -sometimes genes, for some unknown reason,
spontaneously change their form
Down Syndrome - Answer -a disorder produced by the presence of an extra
chromosome on the 21st pair
- once referred to as mongolism
Fragile X Syndrome - Answer -a disorder produced by injury to a gene on the X
chromosome, producing a mild to moderate mental mentardation
Sickle-cell Anemia - Answer -a blood disorder that gets its name from the shape of the
red blood cells
Tay-Sachs disease - Answer -a disorder that produces blindness and muscle
degeneration prior to death
- there is no treatment
Klinefelter's syndrome - Answer -a disorder resulting from the presence of an extra X
chromosome that produces underdeveloped genitals, extreme height, and enlarged
breasts
