chapter 2.1 Flashcards
zygote
the new cell formed by the process of fertilization
genes
the basic unit of genetic information
DNA
the substance that genes are composed of that determines the nature of every cell in the body and how each will function
chromosomes
rod shaped portions of dna that are organized in 23 pairs
mitosis
the replication of most types of cells, nearly all the cells of the body will contain the same 46 chromosomes as the zygote
meiosis
each gamete receives one of the two chromosomes that make up each of the 23 pairs
monozygotic twins
twins produced by a single fertilized ovum
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 combination of genetic material present (but not outwardly visible) in an organism
phenotype
an observable trait; the trait that actually is seen
homozygous trait
inheriting from parents similar genes for a given trait
heterozygous trait
inheriting from parents different forms of a gene for a given trait
pku
an inherited disorder in which a child is unable to make use of phenylalanine, an essential amino acid present in proteins found in milk and other foods
polygenic inheritance
inheritance in which a combination of multiple gene pairs is responsible for the production of a particular trait
reaction range
the potential degree of variability in the expression of a trait due to environmental conditions
x-linked genes
genes that are considered recessive and located only on the x chromosome
behavioural genetics
studies the effects of heredity on behaviour
spontaneous mutation
genes spontaneously change their form
down’s syndrom
a disorder produced by the presence of an extra chromosome on the twenty-first 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 intellectual impairment
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 and muscle degeneration prior to death: there is no treatment
klinefelter syndrome
a disorder resulting from the presence of an extra X chromosome; the syndrome produces underdeveloped genitals, extreme height, and enlarged breasts
genetic counselling
the discipline that focuses on helping people deal with issues relating to inherited disorders
karyotype
a chart containing enlarged photos of each of the chromosomes
first trimester screen
combines a blood test and ultrasound sonography in the eleventh to thirteenth week of pregnancy and which can identify chromosomal abnormalities and other disorders such as heart problems
ultrasound sonography
high frequency sound waves scan the mothers womb to produce an image of the unborn baby, whose size and shape can then be assessed
chorionic villus sampling (CVS)
a test that involves taking samples of hairlike material that surround the embryo; used to find genetic defects
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
germ line therarpy
cells with defective genes are taken from an embryo, repaired and replaced
temperament
patterns of arousal and emotionality that represent consistent and enduring characteristics in an individual
multifactorial transmission
the determination of traits by a combination of both genetic and environmental factors in which a genotype provides a range within which a phenotype can be expressed
do we inherit our personality
yes
neuroticism
degree of emotional stability and individual characteristically displays
extroversion
degree to which a person seeks to be with others, to behave in an outgoing manner , and generally to be sociable
how do we know which personality traits reflect heredity?
some evidence comes from direct examination of genes themselves
schizophrenia
genetic factors and run in families but not the sole cause
disorders
heredity often produces a tendency toward a future course of development but when and whether the characteristic will be displayed depends on the environment
three ways a childs genetic predisposition might influence his or her environment
- children tend to focus on aspects of their environment hat are most in tune with their genetic abilities
- the gene-environment influence might be more passive and less direct
- the genetically driven temperament of a child might evoke certain environmental influences
