CAS 101 Chapter 3-5 Flashcards
The process by which a sperm and an ovum- the male and female gametes, respectively- join to form a single new cell
Fertilization/Conception
the sex cells from the mother and father that form a new cell at conception
Gametes
the new cell formed by the process of fertilization
Zygote
The basic unit of genetic information
Genes
the substance that genes are composed of that determines the nature of every cell in the body and how it will function
DNA (deoxyribonucleic acid)
Rod-shaped portions of DNA that are organized in 23 pairs
chromosomes
Accounts for the replication of most types of cells, nearly all the cells of the body will contain the same 46 chromosomes as the zygote.
Mitosis
In this process, each gamete receives one of the two chromosomes that make up each of the 23 pairs.
Meiosis
Twins who are genetically identical
Monozygotic twins
Twins who are produced when two separate ova are fertilized by two separate sperm at roughly the same time
Dizygotic twins
A trait that is expressed when two competing traits are present
Dominant trait
A trait within an organism that is present, but is not expressed. Can only be expressed if paired with a corresponding, mutual trait
Recessive trait
The underlying combination of genetic material present (but not outwardly visible) in an organism
Genotype
An observable trait; the trait that is actually seen
Phenotype
Inheriting from parents similar genes for a given trait (bb, or BB)
Homozygous
inheriting from parents different forms of a gene for a given trait (Bb)
Heterozygous
Inherited disorder, child is unable to process an essential amino acid called phenylalanine (Phe). Phe is toxic to the brain. pp means PKU expression
Phenylketonuria (PKU)
Inherited, a result of damaged genes, spontaneous mutation, or environmental factors
Genetic disorders
A disorder produced by the presence of an extra chromosome on the 21st pair. It occurs in about 1 in 500 births, but the risk is much greater in mothers who are unusually young or old. this is the most frequent cause of mental retardation.
Down syndrome
Occurs when a particular gene is injured on the X chromosome. The result is mild to moderate mental retardation.
Fragile X syndrome
1/10 of Americans of African descent carry genes that produce this disorder, and 1 in 400 actually have the disease. it is a blood disorder that gets its name from the shape of the red blood cell in those who have it. Symptoms include poor appetite, stunted growth, swollen stomach, and yellowish eyes. People w/ the most severe form rarely live beyond childhood, but those with less severe cases have medical advances that have produced significant increases in life expectancy.
sickle-cell anemia
Occurring mainly in Jews of eastern European ancestry and in French Canadians, it usually causes death before its victims reach school age. There is no treatment for the disorder, which produces blindness and muscle degeneration prior to death.
Tay-Sachs disease
One male out of every 400 is born with this syndrome, the presence of an extra X chromosome. Resulting XXY complement produces underdeveloped genitals, extreme height, and enlarged breasts. There are other disorders that are produced by an improper number of sex chromosomes.
Klinefelter’s syndrome
Helps people deal with issues relating to inherited disorders. Possible genetic defects can be identified by assembling a karyotype
Genetic counseling
A chart containing enlarged photos of each of the chromosomes.
Karyotype
Process in which high-frequency sound waves scan the mother’s womb to produce an image of the unborn baby, whose size and shape can then be assessed
Ultrasound sonography
Combines a blood test and ultrasound sonography in the 11th-13th week of pregnancy.
First-trimester screen
a test used to find genetic defects that involves taking samples of hairlike material that surrounds the embryo
Chorionic villus sampling (CVS)
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
Amniocentesis
Patterns of arousal and emotionality that represent consistent and enduring characteristics in an individual
Temperament
Three stages: germinal, embryonic, and fetal
Prenatal period
Fertilization to 2 weeks. The first and shortest stage of the prenatal period in which the zygote begins to divide and grow in complexity during the first 2 weeks following conception. The fertilized egg travels toward the uterus, where it becomes implanted in the uterus’s wall.
Germinal stage
Serves as a conduit between the mother and fetus, providing nourishment and oxygen to the developing zygote.
Placenta
Period from two to eight weeks following fertilization. One of the highlights of this stage is the development of the major organs and basic anatomy.
Embryonic stage
Outer layer of the embryo that will form skin, hair, teeth, sense organs, and the brain and spinal cord.
Ectoderm
Inner layer that produces the digestive system, liver, pancreas, and respiratory system.
Endoderm
The muscles, bones, blood, and circulatory system are forged.
Mesoderm
Starts at about 8 weeks after conception and continues until birth. It formally starts when the differentiation of the major organs has occurred.
Fetal stage
An insulating material that coats the fetus’s neurons and helps speed the transmission of messages from the brain to the rest of the body.
myelin
The inability to conceive after 12-18 months of trying to become pregnant. Some 15% of couples suffer from this, and it is highly correlated with age.
Infertility
a procedure in which a man’s sperm is placed directly into a woman’s vagina by a physician.
artificial insemination
A procedure in which a woman’s ova are removed from her ovaries, and a man’s sperm are used to fertilize the ova in a laboratory.
In vitro fertilization (IVF)
A spontaneous abortion that occurs when pregnancy ends before the developing child is able to survive outside the mother’s womb. The embryo detaches from the wall of the uterus and is expelled. Some 15-20% of all pregnancies end with this result.
miscarriage
A mother voluntarily chooses to terminate pregnancy. It is a complex set of physical, psychological, legal, and ethical issues that make the choice difficult for every woman.
Abortion