Biological Foundations Flashcards
phenotypes
directly observable characteristics
genotypes
complex blend of genetic information that determines our species and influences all our unique characteristics
chromosomes
rodlike structures which store and transmit genetic information
DNA
long double-stranded molecule that looks like a twisted ladder
gene
segment of DNA
mitosis
unique feature of DNA that it can duplicate itself
gametes
sex cells–the sperm and ovum
meiosis
forms gametes
zygote
when sperm and ovum unite at fertilization
crossing over
chromosomes next to each other break at one or more points along their length and exchange segments
autosomes
not sex chromosomes
identical / monozygotic twins
identical genetic makeup
fraternal / dizygotic twins
most common type of multiple birth from the release and fertilization of two ova
allele
each form of a gene
homozygous
alleles from both parents are alike
heterozygous
alleles differ
dominant-recessive inheritance
only one allele affects the child’s characteristics (dominant vs recessive)
carriers
children that have just one recessive allele
modifier genes
enhance or dilute effects of other genes
incomplete dominance
pattern of inheritance in which both alleles are expressed in the phenotype–combined trait or intermediate between the two
X-linked inheritance
males are more likely to be affected because their sex chromosomes do not match
genetic imprinting
alleles are imprinted, chemically marked, so that one pair member is activated regardless of makeup
mutation
sudden but permanent change in a segment of DNA
polygenic inheritance
many genes determine the characteristic in question
genetic counselling
communication process designed to help couples assess their chances of giving brith to a baby with a hereditary disorder and choose the best course of action in view of risks and family goals
prenatal diagnostic methods
medical procedures that permit detection of developmental problems before birth
amnion
membrane that encolses the developing organism in amniotic fluid which helps keep the temperature of the prenatal world constant and provides a cushion against any jolts caused by the woman’s movement
chorion
protective membrane which surrounds the amnion
placenta
permits food and oxygen to reach the developing organism and waste products to be carried away
umbilical cord
contains one large vein that delivers blood loaded with nutrients and two arteries that remove waste products
embryo
most rapid prenatal changes take place
fetus
longest prenatal period of “growth and finishing”
vernix
protects skin from chapping during long months spent in amniotic fluid
lanugo
covers entire body to help vernix stick to skin
age of viability
baby can survive
teratogen
environmental agent that causes damage during hte prenatal period
fetal alcohol spectrum disorder
physical, mental and behavioral outcomes caused by prenatal alcohol exposure
Apgar scale
assesses baby’s physical condition
natural or prepared childbirth
group of techniques aimed at reducing pain or medical intervention and making childbirth as rewarding an experience as possible
breech position
turned in such a way that the buttocks or feet would be delivered first
RH factor incompatibility
when mother is Rh negative and father is Rh positive, baby may inherit father’s –> formation of antibodies to the foreign protein
preterm infants
born several weeks before due date
small for date infants
below their expected weight considering length of the pregnancy
behavioral genetics
field devoted to uncovering the contributions of nature and nurture to the diversity of human traits and abilities
heritability estimates
measure the extent to which individual differences in complex traits in a specific population are due to genetic factors
kinship studies
compare the characteristics of family members
gene-envrionment interaction
because of genetic makeup, idnviduals differ in their responsiveness to qualities of the environment
canalization
tendency of heredity to restrict the development of some chracteristics to just one or a few outcomes
gene-environment correlation
our genes influence the envrionments to which are exposed
niche-picking
tendency to actively choose environments that complement our heredity
epigenesis
development resulting from ongoing bidirectional exchanges between heredity and all levels of the environment
