-
Blue eyes are an example of a ______.
phenotype
-
Chromosomes ______ genetic information.
store and transmit
-
A ______ is a segment of a ______ molecule.
gene; DNA
-
If the alleles from both parents are different at the same place on a pair of chromosomes, the child is said to be ______.
heterozygous
-
Gametes contain ______ chromosomes.
23
-
______ is a situation in which two different alleles for a genetic trait are being expressed.
codominance
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Most chromosomal defects are results of mistakes during ______.
meiosis
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The most common chromosomal abnormality is _______.
Down's syndrome
-
A/an ______ involves high-frequency sound waves that are beamed at the uterus.
ultrasound
-
Fertilization usually takes place in the
fallopian tubes
-
Pregnancy can be divided into three phases. The order in which they occur is:
-
The zygote is:
the union of sperm and ovum at conception
-
What takes place during the period of the zygote?
- - the blastocyst is formed
- - the fertilized ovum begins to duplicate at an increasingly rapid rate
- - the amnion forms and encloses the developing organism in amniotic fluid
-
The outer membrane that forms a protective covering around the prenatal organism and sends out tiny hairlike villi, from which the placenta begins to emerge is called the:
chorion
-
The period of the embryo is defined as:
the prenatal organism from 2 to 8 weeks after conception, during which time the foundations of all body structures and internal organs are laid down
-
The period of the embryo is particularly critical because:
the groundwork for all body structures and internal organs is laid down
-
The age of viability is reached somewhere between:
22 and 26 weeks
-
A teratogen is best defined as:
any environmental agen that causes damage during the prenatal period
-
What are defects that result from fetal alcohol syndrome?
- - facial abnormalities
- - impaired motor coordination
- - mental retardation
-
Maternal age is a factor in what?
chromosomal defects
-
The longest stage of labor is:
dilation and effacement of the cervix
-
Some possible consequences of anesthesia include:
- - weakened uterine contractions during the first stage of labor
- - interference with mother's ability to feel contractions and push during the second stage of labor
- - use of forceps or a vacuum extractor
-
What are conditions that causes anoxia?
- - squeezing of the umbilical cord
- - incompatability between mother and baby in Rh factor
-
Small for date infants are:
infants whose birth weight is below normal when length of pregnancy is taken into account
-
Heritability estimate is defined as:
a statistic that measures the extent to which individual differences in complex traits in a specific population are due to genetic factors
-
The tendency to actively choose environments that complement our heredity is called:
niche-picking
-
How is DNA different from all other molecules?
- - it duplicates itself through mitosis
- - a long, double stranded molecule
- - consists of pairs of chemical substances called bases
- - allows for a single cell to develop into a complex human being
-
Zygote
- - united sperm and ovum through fertilization
- - has 46 chromosomes
-
Crossing Over
- - chromosomes next to each other break at one or more points along their length and exchange segments
- - genes from one are replaced by genes from another
- - creates new hereditary combinations
- - chromosome pairs separate into different cells
- - chance determines which member of each pair will gather with others and end up in the same gamete
- - each chromosome leaves its partner and becomes part of a gamete containing only 23 chromosomes
-
Polygenic inheritances
a pattern of inheritance in which many genes determine a characteristic that varies on a continuum among people
-
Midifier genes
enhance or dilute the effects of other genes
-
What characteristics are likely to show polygenic inheritance?
- - height
- - weight
- - intelligence
- - personality
-
Inheritance patterns for blood type
- type A - dominant
- type B - dominant
- type O - recessive
-
defective genes vs. defective chromosomes
- - defective chromosomes are more harmful
- - defective chromosomes almost always result in miscarriage
- - gene defects usually do not cause chromosome structure or number to be abnormal
-
Down's Syndrome
- - 1 in 1000 births
- - result of failure of 21st pair of chromosomes to separate (individual has 3 of these chromosomes instead of 2)
- - mental retardation, memory and speech problems, limited vocabulary, slow motor development
- - small brain
- - short, stocky body; flattened face; protruding tongue; almond shaped eys; unusual crease in palm of hand
- - eye cataracts, hearing loss, heart and intestinal defects
-
Turner's Syndrome
- - 1 in 2500 to 8000 female births
- - missing X chromosome
- - short stature; webbed neck, thyroid and heart
- abnormalities; incomplete development of sex characteristics at puberty; sterility; impaired spatial intelligence
- - requires hormone therapy and special education
-
Klinefelter's Syndrome
- - 1 in 900 male births
- - extra X chromosome
- - tallness; body fat distribution similar to
- females; incomplete development of sex characteristics at puberty; sterility; impaired verbal intelligence
- - requires hormone therapy and special education
-
XYY Syndrome
- - 1 in 1000 male births
- - extra Y chromosome
- - above-average height; large teeth; severe acne; intelligence and sexual development are normal
- - no special treatmentnecessary
-
Fragile X Syndrome
- - repetition of gene FMR1 on X chromosome
- - most common form of ID in boys
- - delay in gross motor skills; mental retardation; hyperactivity or impulsive behavior; speech and language delay; tendency to avoid eye contact
- - flat feet; flexible joints; low muscle tone; large body size; large forehead or ears; prominent jaw; long face; soft skin
-
Amniocentesis
- - prenatal diagnostic method
- - most widely used technique
- - hollow needle is inserted through abdominal wall to obtain sample of fluid in uterus
- - cells are examined for genetic defects
- - performed at or after 14th week after conception
- - 1 to 2 weeks required for results
- - small risk of miscarriage
-
Chorionic villi biopsy
- - prenatal diagnostic method used ot get results early in pregnancy
- - thin tube inserted in uterus through vagina or hallow needle inserted through abdomin wall
- - small plug of tissue is removed from chorionic villi (hairlike projections on membrane surrounding baby
- - cells are examined
- - performed at 9 weeks after conception
- - results available 24 hours
- - slightly greater risk of miscarriage than amniocentesis
- - small risk of limb deformities (higher risk the earlier procedure is performed)
-
Ultrasound
- - prenatal diagnostic method
- - high-frequency sound waves are beamed at uterus
- - reflection is translated into a picture on a video screen that reveals size, shape and placement of fetus
- - permits assessment of fetal age, detection of multiple pregnancies, identification of gross physical defects
- - used to guide amniocentesis, chorionic villus sampling, and fetoscopy
- - when used five or more times, may increase chance of low birth weight
-
Fetoscopy
- - prenatal diagnostic method
- - small tube with light source at one end is inserted into uterus
- - used to inspect fetus for defects of limbs and face
- - allows a sample of fetal blood to be obtained, permitting
-
How long do the sperm and egg live before they
become nonviable?
- - sperm live up to six days and can wait for the ovum
- - ovum survives for one day after being released into fallopian tube
-
Period of the Zygote
- - two weeks long
- - from fertilization to a tiny mass of cells that flows out of the fallopian tube and attaches to wall of uterus
- - first cell duplication is complete 30 hours after conception
- - fourth day - 60 to 70 cells exist that form a hollow, fluid filled ball (blastocyst)
- - cells inside, become organism
- - cells outside, become protective covering
- - delicate and uncertain events
- - 30% of zygotes do not survive this period
-
Period of the Fetus
- - the prenatal organism from the ninth week to the end of pregnancy
- - the period when body structures are completed and dramatic growth in size occurs
-
thalidomide (as a teratogen)
- - 4 to 6 weeks
- - gross deformities of arms and legs; damage to ears, heart, kidneys and genitals; decreased intelligence
-
diethylstilbestrol (as a teratogen)
- - causes daughters to have cancer of vagina; malformation of uterus; infertility - causes sons to have genital abnormalities
- and cancer of testes
-
accutane (as a teratogen)
- - first trimester
- - abnormalities of eye, ear, skull, brain, heart, cns, immune system
-
aspirin (as a teratogen)
- low birth weight, infant death around time of birth, poor motor development, low intelligence test scores
-
caffeine (as a teratogen)
- low birth weight, miscarriage, newborn withdrawal symptoms
-
Cocaine and Heroin (as teratogen)
- - prematurity, low birth weight, physical defects, breathing difficulties, death at or around time of birth
- - born drug addicted
- - feverish and irritable
- - cries are abnormally shrill and piercing
- - trouble sleeping
- - less attentive, slow motor development, jittery and inattentive
-
Tobacco
- - low birth weight, misscarriage, prematurity, impaired heart rate and breathing during sleep, infant death, asthma, cancer in later childhood
- - constricted blood vessels, lessens blood flow to uterus, causes placenta to grow abnormally
-
Alcohol (as a teratogen)
- FASD
- - physical, mental and behavioral outcomes
- FAS
- p-FAS
- ARND
-
FAS
- -
- slow physical growth
- - pattern of three facial abnormalities (short
- eyelid openings, thin upper lip, smooth or flatened philtrum, indentation
- running from bottom of nose to center of upper lip)
- - brain injury
- - memory, language, and communication impaired
- - attention span and activity level impaired
- - planning and reasoning impaired
- - motor coordination impaired
- - social skills impaired
-
p-FAS
- - two of the three facial abnormalities
- - brain injury
-
ARND
- - at least three areas of mental functioning are impaired
- - typical physical growth
- - absence of facial abnormalities
-
Radiation (as teratogen)
- - mutation, damaging DNA in ova and sperm
- - underdeveloped brains, physical deformities, slow physical growth
- - problems may appear later
- - childhood cancer
- - abnormal EEG brain-wave activity
- - lower inteligence test score
- - language and emotional disorders
-
environmental pollution (as teratogen)
- - many babies are "born polluted"
- - mercury, polychlorinated biphenyls, lead
- - physical deformities, mental retardation, low birth rate, delayed cognitive development, intense physiological reactions to stress, prematurity, brain damage
-
maternal disease (as teratogen)
- - viruses, bacterial, parasitic diseases
- - low birth weight, hearing loss, bone defects, severe mental illness, visual and cognitive impairments
- - learning or visual disabilities later in life
-
Three stages of childbirth
- Dilation and effacement of cervix
- - longest stage
- - 4 to 6 hours
- - contractions
- Delivery of the baby
- - when cervix is fully open
- - 50 minutes
- - contractions
- Birth of the placenta
- - few final contractions
- - 5 to 10 minutes
-
Apgar Scale
- Used by doctors and nurses to assess the baby's physical condition
- - heart rate
- - respiratory effort
- - reflex irritability
- - muscle tone
- - color
-
Breech position
infant is turned in such a way that buttocks or feet would deliver first
-
Rh factor incompatibility
- - between mother and baby's blood types
- - result in reduced blood supply
- - mother creates anitbodies to infants foreign Rh factor
-
Range of reaction
- each person's unique, genetically determined
- response to a range of environmental conditions
-
Canalization
- the tendency of heredity to restrict the
- development of some characteristics to just one or a few outcomes
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