Chao 2 Genetics, Prenatal, Dev & Birth Flashcards
Genes
The basic unit of genetic info
Zygote
The new cell formed by the process of fertilization
DNA (deoxyribonucleic acid) molecules
The substance that genes are composed of that determines the nature of every cell in the body & how it will function
Chromosomes
Rod-shaped portions of DNA that are organized in 23 pairs
Monozygotic twins
Twins who are genetically identical
Dizygotic twins
Twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time
Dominant trait
The one trait that is expressed when two competing traits are present
Recessive trait
A trait within an organism that is present, but is not expressed
Genotype
The underlying combo of genetic material present (but not outwardly visible) in an organism
Phenotype
An observable trait; the trait that is actually seen
Homozygous
Inheriting from parents similar genes for a given trait
Heterozygous
Inheriting from parents different forms of a gene for a given trait
Polygenic inheritance
Inheritance in which a combo of multiple gene pairs is responsible for the production of a particular trait
X-linked genes
Genes that are considered recessive & located only on the X chromosome
Behavioral genetics
The study of the effects of heredity on behavior
Down syndrome
A disorder produced by the presence of an extra chromosome on the 21st pair; once referred to as mongolism
Fragile X syndrome
A disorder produced by injury to a gene on the X chromosome, producing mild to moderate mental retardation
Sickle-cell anemia
A blood disorder that gets its name from the shape of the red blood cells in those who have it
Tay-Sachs disease
A disorder that produces blindness & muscle degeneration prior to death; there is no treatment
Klinefelter’s syndrome
A disorder resulting from the presence of an extra X chromosome that produces underdeveloped genitals; extreme height, & enlarged breasts
Genetic counseling
The discipline that focuses on helping people deal with issues relating to inherited disorders
Ultrasound sonography
A process in which high-frequency sound waves scan the Mom’s womb to produce an image of the unborn baby, whose size & shape can then be assessed
Chorionic villus sampling (CVS)
A test used to find genetic defects that involves taking samples of hairlike material that surrounds the embryo
Amniocentesis
The process of identifying genetic defects by examining a small sample of fetal cells drawn by a needle inserted into the amniotic fluid surrounding the unborn fetus
Temperament
Patterns of arousal & emotionality that represent consistent & enduring characteristics in an individual
Multifactorial transmission
The determination of traits by a combo of both genetic & environmental factors in which a genotype provides a range within which a phenotype may be expressed
Fertilization
The process by which a sperm & an ovum–the male & female gametes, respectively–join to form a single new cell
Germinal stage
The first–and shortest–stage of the prenatal period, which takes place during the first two weeks following conception
Placenta
A conduit between the mom & fetus, providing nourishment & oxygen via the umbilical cord
Embryonic stage
The period from two to eight weeks following fertilization during which significant growth occurs in the major organs & body systems
Fetal stage
The stage that begins at about eight weeks after conception & continues until birth
Fetus
A developing child, from eight weeks after conception until birth
Infertility
The inability to conceive after 12 to 18 months of trying to become pregnant
Artificial insemination
A process of fertilization in which a man’s sperm is placed directly into a women’s vagina by a physician
In vitro fertilization (IVF)
A procedure in which a women’s ova are removed from her ovaries, & a man’s sperm are used to fertilize the ova in a lab
Teratogen
An environmental agent such as a drug, chemical, virus, or other factor that produces a birth defect
Fetal alcohol syndrome (FAS)
A disorder caused by the pregnant mom consuming substantial quantities of alcohol during pregnancy, potentially resulting in mental retardation & delayed growth in the child
Fetal alcohol effects (FAE)
A condition in which children display some, although not all, of the problems of fetal alcohol syndrome due to the Mom’s consumption of alcohol during pregnancy
Episiotomy
An incision sometimes made to increase the size of the opening of the vagina to allow the baby to pass
Preterm infants
Infants who are born prior to 38 weeks after conception (aka premature infants)
Low-birthweight infants
Infants who weigh less than 2,500 grams (around 5 1/2 lbs) at birth
Small-for-gestational-age infants
Infants who, bc of delayed fetal growth, weigh 90%(or less) of the average weight of infants of the same gestational age
Very-low-birthweight infants
Infants who weigh less than 1,250 grams (around 2.25 lbs) or, regardless of weight, have been in the womb less than 30 weeks
Postmature infants
Infants still unborn 2 weeks after the mother’s due date
Cesarean delivery
A birth in which the baby is surgically removed from the uterus, rather than traveling thru the birth canal
Fetal monitor
A device that measures the baby’s heartbeat during labor
Stillbirth
The delivery of a child who is not alive, occurring in less than 1 delivery in 100
Infant mortality
Death within the first year of life
