DEP2004 Chapter 2 – Flashcards
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additive gene
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A gene that adds something to some aspect of the phenotype. Its contribution depends on additions from the other genes, which may come from either the same or the other parent.
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age of viability
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The age (about 22 weeks after conception) at which a fetus may survive outside the mother's uterus if specialized medical care is available.
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allele
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Any of the possible forms in which a gene for a particular trait can occur.
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anoxia
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A lack of oxygen that, if prolonged, can cause brain damage or death.
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apgar scale
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: A quick assessment of a newborn's body functioning. The baby's heart rate, respiratory effort, muscle tone, color, and reflexes are given a score of 0, 1, or 2 twice—at one minute and five minutes after birth—and each time the total of all five scores is compared with the ideal score of 10 (which is rarely attained).
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behavioral teratogens
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Agents and conditions that can harm the prenatal brain, impairing the future child's intellectual and emotional functioning.
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Brazelton Neonatal Behavioral Assessment Scale (NBAS)
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A test often administered to newborns that measures responsiveness and records 46 behaviors, including 20 reflexes.
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carrier
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A person whose genotype includes a gene that is not expressed in the phenotype. Such an unexpressed gene occurs in half the carrier's gametes and thus is passed on to half the carrier's children, who will most likely be carriers, too. Generally, the characteristic appears in the phenotype only when such a gene is inherited from both parents.
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cerebral palsy
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A disorder that results from damage to the brain's motor centers. People with cerebral palsy have difficulty with muscle control, so their speech and/or body movements are impaired.
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cesarean section (c-section)
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A surgical birth, in which incisions through the mother's abdomen and uterus allow the fetus to be removed quickly, instead of being delivered through the vagina.
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chromosome
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One of the 46 molecules of DNA (in 23 pairs) that each cell of the human body contains and that, together, contain all the genes. Other species have more or fewer chromosomes.
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couvade
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Symptoms of pregnancy and birth experienced by fathers.
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dizygotic twins
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Twins who are formed when two separate ova are fertilized by two separate sperm at roughly the same time. (Also called fraternal twins.)
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DNA
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The molecule that contains the chemical instructions for cells to manufacture various proteins.
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dominant-recessive pattern
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The interaction of a pair of alleles in such a way that the phenotype reveals the influence of one allele (the dominant gene) more than that of the other (the recessive gene).
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doula
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A woman who helps with the birth process. Doulas are trained to offer support to new mothers, including massage and suggestions for breast-feeding positions.
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down syndrome
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A condition in which a person has 47 chromosomes instead of the usual 46, with three rather than two chromosomes at the 21st position. People with Down syndrome typically have distinctive characteristics, including unusual facial features (thick tongue, round face, slanted eyes), heart abnormalities, and language difficulties. (Also called trisomy-21.)
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embryo
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The name for a developing human organism from about the third through the eighth week after conception.
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embryonic period
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The stage of prenatal development from approximately the third through the eighth week after conception, during which the basic forms of all body structures, including internal organs, develop.
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extremely low birth weight (ELBW)
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A body weight at birth of less than 2 pounds, 3 ounces (1,000 grams).
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fetal alcohol syndrome (FAS)
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A cluster of birth defects, including abnormal facial characteristics, slow physical growth, and intellectual disabilities, that may occur in the child of a woman who drinks alcohol while pregnant.
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fetal period
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The stage of prenatal development from the ninth week after conception until birth, during which the fetus grows in size and matures in functioning.
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fetus
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The name for a developing human organism from the start of the ninth week after conception until birth.
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gamete
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A reproductive cell; that is, a sperm or an ovum that can produce a new individual if it combines with a gamete from the other sex to form a zygote.
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gene
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A small section of a chromosome; the basic unit for the transmission of heredity. A gene consists of a string of chemicals that provide instructions for the cell to manufacture certain proteins.
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genome
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The full set of genes that are the instructions to make an individual member of a certain species.
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genotype
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An organism's entire genetic inheritance, or genetic potential.
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germinal period
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The first two weeks of prenatal development after conception, characterized by rapid cell division and the beginning of cell differentiation.
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heritability
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A statistic that indicates what percentage of the variation in a particular trait within a particular population, in a particular context and era, can be traced to genes.
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hispanic paradox
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The surprising discovery that, although low SES usually correlates with poor health, this is not true for Hispanics in the United States. For example, when compared with the U.S. average LBW rate, Hispanic newborns are less often of low birthweight.
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implantation
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The process, beginning about 10 days after conception, in which the developing organism burrows into the tissue that lines the uterus, where it can be nourished and protected as it continues to develop.
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kangaroo care
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A child-care technique in which a new mother holds the baby between her breasts, like a kangaroo that carries her immature newborn in a pouch on her abdomen.
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low birthweight (LBW)
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A body weight at birth of less than 5½ pounds (2,500 grams).
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monozygotic twins
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Twins who originate from one zygote that splits apart very early in development. (Also called identical twins.)
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parent-infant bond
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The strong, loving connection that forms as parents hold, examine, and feed their newborn.
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phenotype
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The observable characteristics of a person, including appearance, personality, intelligence, and all other traits.
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postpartum depression
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The sadness and inadequacy felt by some new mothers in the days and weeks after giving birth.
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preterm birth
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A birth that occurs three or more weeks before the full 38 weeks of the typical pregnancy have elapsed—that is, at 35 or fewer weeks after conception.
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reflex
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An unlearned, involuntary action or movement in response to a stimulus. A reflex occurs without conscious thought.
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small for gestational age (SGA)
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Having a body weight at birth that is significantly lower than expected, given the time since conception. For example, a 5-pound (2,265-gram) newborn is considered SGA if born on time but not SGA if born two months early. (Also called small-for-dates.)
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stem cells
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Cells from which any other specialized type of cell can form.
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teratogens
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Any agent or condition, including viruses, drugs, and chemicals, that can impair prenatal development, resulting in birth defects or complications.
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threshold effect
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A situation in which a certain teratogen is relatively harmless in small doses but becomes harmful once exposure reaches a certain level (the threshold).
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ultrasound
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An image of a fetus (or an internal organ) produced by using high-frequency sound waves. (Also called sonogram.)
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very low birthweight (VLBW)
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A body weight at birth of less than 3 pounds, 5 ounces (1,500 grams).
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x-linked
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A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses that trait because the Y from his father has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them.
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xx
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A 23rd chromosome pair that consists of two X-shaped chromosomes, one each from the mother and the father. XX zygotes become females.
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xy
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A 23rd chromosome pair that consists of an X-shaped chromosome from the mother and a Y-shaped chromosome from the father. XY zygotes become males.
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zygote
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The single cell that is formed from the fusing of two gametes, a sperm and an ovum.
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The instructions in the 46 chromosomes are organized into units called ______.
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genes
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According to your text, instructions are transmitted to the cell via pairs of four chemicals called _____.
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bases
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Two ova have been fertilized by two sperm at roughly the same time. What will be the result?
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dizygotic twins
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Human genome research cannot pinpoint the exact number of genes because:
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it is hard to figure out where one gene stops and another starts.
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Everyone also has additional DNA and RNA that are not genes but that enhance, transcribe, connect, empower, and alter genes. This material used to be called _____, but no longer.
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junk
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A genome is:
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a full set of instructions to make a living organism.
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The entire packet of _____ to make a living organism is called the genome.
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instructions
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Females are _____ likely to be carriers of X-linked traits and are less likely to express them than males.
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more
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Although every zygote is genetically _____, about once in 250 human conceptions, the zygote not only duplicates but splits apart completely, creating two, or four, or even eight separate zygotes, each identical to that first single cell.
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unique
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Your friend has just had a baby boy and is very happy. You know from your genetics studies that the Y chromosome played a major role. You tell her all of these things EXCEPT:
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females have an impact on whether or not a zygote becomes a boy.
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Additional DNA and RNA that are not genes but that enhance, transcribe, connect, empower, and alter genes used to be called _____, but no longer.
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junk
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All of a person's genetic inherited potential is called the:
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genotype
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A slight variation of a particular gene is called a(n) _____.
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allele
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Each cell manufactures certain _____ according to instructions stored by molecules of deoxyribonucleic acid (DNA) at the heart of each cell.
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proteins
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Kiley and Riley developed from the same zygote when it split soon after conception. Which of the following statements is FALSE?
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Kylie and Riley have the same phenotype.
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Rick and Ross are fraternal twins. Which of the following statements is TRUE?
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Rick and Ross are typical of about 1 in every 125 births.
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Dr. Snider, a geneticist, is looking for a slight variation of a particular gene that would cause a certain abnormality. He is looking for an:
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allele
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Monozygotic twins appear to be most physically alike because:
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genetically they are identical
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Gavin has brown hair and green eyes, he is outgoing and a risk-taker, and he excels at his job as a financial analyst. All of these traits are part of his:
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phenotype
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The doctor has determined that a couple will be having monozygotic (MZ) twins. What has occurred for this to take place?
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One zygote has split into two.
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Nan is pregnant with her first child. She just found out that the baby has grown one pound since her last doctor's appointment. She is in the _____ period of prenatal development.
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fetal
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"There it is! That's my son!" Cole jubilates as he and Wanda view the sonogram of Wanda's fetus. Because the fetus' sex organ is visible, the fetus is in the _____ period of prenatal development.
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fetal
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The beginning of central nervous system development marks the start of the _____ period of prenatal development.
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embryonic
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Lucy has been hired to provide support to Dan and Deb while Deb is in labor. Lucy meets Deb and Dan at their house after labor begins and is timing Deb's contractions, massaging Deb during her contractions, and giving Dan ideas about how to help Deb manage the pain. She is also giving them information to help them decide when they want to go to the hospital to meet their doctor, who will be delivering the baby. Lucy is most likely a(n):
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doula
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When Rachel was playing with her infant son, Leo, she brushed a cloth gently against his cheek. Leo moved his mouth toward the cloth and started to suck it. He was exhibiting the _____ reflex.
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rooting
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In the process of _____ new neurons are developed in the brain.
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neurogenesis
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The Apgar scale measures all of the following except:
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size
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Which of the following prenatal tests uses high-frequency sound waves?
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ultrasound
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What percent of US births occur in stand-alone birthing centers?
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5
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One sign of _____ maturation is that a fetus's heart beats faster during activity.
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brain
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A baby born at full term has almost a(n) _____ percent survival rate.
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100
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The strong, loving connection between a parent and newborn is called the parent-infant _____.
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bond
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Belinda gave birth 36 weeks after conception. Her baby weighed 5 lbs. 2 oz. Belinda's baby was ____ birthweight.
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low
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Alaina is pregnant and has undergone prenatal testing. The initial tests raised some red flags, and a subsequent DNA test confirmed that the fetus does in fact have three copies of chromosome 21, or:
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down syndrome
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Kareem was born 36 weeks after conception. He weight 5 lbs., 3 oz. Kareem was:
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SGA & LBW
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Yuko is a 32-year-old woman in Kyoto, Japan. She has accepted a job in San Jose, CA and is preparing to emigrate to the United States. In the U.S., Yuko's alcohol consumption:
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increase greatly
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Two common causes of low birthweight are maternal _____ and maternal drug use, including smoking cigarettes.
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malnutrition
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Low birthweight (LBW) is defined as a body weight of less than ____ at birth.
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5 1/2
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A researcher selects a sample of children with two myopic parents. She assess the children over a 10-year period, when they are 6, 8, 10, 12, 14, and 16 years old. Because the same participants are tracked for an extended period, this study exemplifies ______ research.
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longitudinal
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Lily has always been considered thin, and she only gained 12 pounds in the last six months of her pregnancy. Her baby will likely be _____ at birth.
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underweight
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Ann gave birth 37 weeks after conception. Her baby weighed 6 lbs. 1 oz. Ann's baby was:
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normal
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At birth, Clarence was classified as small for gestational age. It is likely that Clarence:
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suffered several months of prenatal malnutrition.
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Bonnie gave birth 36 weeks after conception. Her baby weighed 3 lbs. 8 oz. Bonnie's baby was ____ birthweight.
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very low
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When Meg, a radiation technologist, discovered she was pregnant, she asked the hospital for a temporary job transfer. She knew that high doses of radiation could cause:
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microcephaly
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One explanation for the correlation between maternal age and chromosomal abnormalities is that older mothers have older ova that:
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are more fragile
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Jillian is 22 years old and pregnant, is on food stamps, and often skips meals. Her baby may be at an increased risk of:
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low birthweight
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Seven-year-old Sam can't sit still in class and is often disruptive. His teacher has noticed that he has difficulty reading and playing with other children. She knows that his mother has a drinking problem. Sam could be displaying effects of behavioral _____ that his mother ingested while he was in the womb.
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teratogens
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Lila is 17 years old, pregnant, and believes a nutritious meal consists of a slushie and nachos. It is likely her baby will be _____ at birth.
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underweight
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Chromosomal abnormalities occur when the zygote's cells have:
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more or fewer than 46 chromosomes.
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Agents and conditions that harm the prenatal brain and impair learning and behavior are called:
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behavioral teratogens
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An increase in food insecurity could be linked to an increase in:
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low birthweight babies
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Undergoing _____ before pregnancy is one way to prevent contracting rubella.
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immunization
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One maternal _____ producing low levels of folic acid can cause neural tube defects.
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allele
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Preterm babies are ____ weeks early
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