Unit 2 Flashcards
Chromosomes
Threadlike structures in the nuclei of cells that contain genetic material.
Autosomes
First 22 pairs of chromosomes. They control the inheritance of an organism’s characteristics except for the sex-linked ones.
Sex Chromosomes
The 23rd chromosome pair; these determine the sex of the child.
Deoxyribonucleic Acid (DNA)
Molecule composed of four nucleotide bases that is the biochemical basis of heredity.
Gene
Group of nucleotide bases that provides a specific set of biochemical instructions.
Genotype
The complete set of genes that makes up a person’s heredity.
Phenotype
Physical, behavioral, and psychological features that results from the interaction between one’s genes and the environment.
Alleles
Variations of genes.
Homozygous
When the alleles in a pair of chromosomes are the same.
Heterozygous
When the alleles in a pair of chromosomes differ from each other.
Dominant
Form of an allele whose chemical instructions are expressed phenotypically.
Recessive
Form of an allele whose instructions are ignore in the presence of a dominant allele.
Incomplete Dominance
Situation in which one allele does completely not dominate another.
(ie. Individuals who have one dominant and one recessive allele for sickle-cell anemia will have the sickle-cell trait.)
Phenylketonuria (PKU)
Inherited disorder in which the infant lacks an important liver enzyme, which converts phenylalanine (an amino acid found in dairy products, bread, diet soda, and fish) into tyrosine. This accumulation of phenylalanine poisons the nervous system, resulting in mental retardation (Diamond et al., 1997; Mange & Mange, 1990).
Huntington’s Disease
Progressive and fatal type of dementia caused by dominant alleles. Characterized by progressive degeneration of the nervous system.
Behavioral Genetics
The branch of genetics that studies the inheritance of behavioral and psychological traits.
Polygenic Inheritance
When phenotypes are the result of the combined activity of many separate genes.
Monozygotic Twins
The result of a single fertilized egg splitting to form two new individuals; also called identical twins.
Dizygotic Twins
The result of two separate eggs fertilized by two sperm; also called fraternal twins.
Heritability Coefficient
A measure (derived from a correlation coefficient) of the extent to which a trait or characteristic is inherited.
Niche-picking
Process of deliberately seeking environments that are compatible with one’s genetic makeup.
Nonshared Environmental Influences
Forces within a family that make siblings different from one another.
Zygote
Fertilized egg, created when a sperm cell penetrates an egg.
In Vitro Fertilization
Process by which sperm and an egg are mixed in a petri dish to create a zygote, which is then placed in a woman’s uterus.
Preimplantation Genetic Screening (PGS)
A procedure used to test the heredity of an egg fertilized with assisted reproductive technology, typically to determine the presence of genetic disorders.
Eugenics
Effort to improve the human species by letting only people whose characteristics are valued by a society mate and pass along their genes.
Implantation
Step in which the zygote burrows into the uterine wall and establishes connections with the woman’s blood vessels.
Germ Disc
Small cluster of cells near the center of the zygote that eventually develop into the baby.
Placenta
Structure through which nutrients and wastes are exchanged between the mother and the developing child.
Prenatal Development
The many changes that turn a fertilized egg into a newborn human.
What are the four stages of prenatal development?
- Conception
- Germinal (Zygote) Period - occurs between conception to two weeks
- Embryonic Period - occurs between weeks three to eight
- Fetal Period - occurs between the eighth week to the ninth month (or thirty-eighth week)
Embryo
Term given to a zygote that has been completely embedded in the uterine wall.
What are the three layers of the gastrula called?
The ectoderm (outer layer), the mesoderm (middle layer), and the endoderm (inner layer).
Ectoderm
Outer layer of the embryo, which becomes the hair, outer layer of skin, and nervous system.
Mesoderm
Middle layer of the embryo, which becomes the muscles, bones, and circulatory system.
Endoderm
Inner layer of the embryo, which becomes the lungs and digestive system.
Amnion
Inner sac in which the developing fetus rests.
Amniotic Fluid
Fluid that surrounds the embryo/fetus and maintains a constant temperature.
What two structures links the embryo to the mother?
The placenta and the umbilical cord.
Umbilical Cord
Structure containing veins and arteries that connects the developing fetus to the placenta.
Cephalocaudal Principle
A principle of physical growth that states that structures nearest to the head develop first.
Proximodistal Principle
Principle of physical growth that states that structures nearest to the center of the body develop first.
Period of the Fetus (Fetal Period)
Longest period of prenatal development, extending from the 9th until the 38th week after conception.
Cerebral Cortex
Wrinkled surface of the brain that regulates many functions that are distinctly human.
Vernix
Substance that protects the fetus’ skin during development.
Age of Viability
Age at which a fetus can survive outside the womb because most of its bodily systems function adequately. Around 22-28 weeks (7 months) after conception.
Spina Bifida
Disorder in which the embryo’s neural tube does not close properly.
Stress
Physical and psychological responses to threatening or challenging conditions.
Teratogen
An agent that causes abnormal prenatal development.
Fetal Alcohol Spectrum Disorder (FASD)
Disorder affecting babies whose mothers consumed large amounts of alcohol while they were pregnant.
Ultrasound
Prenatal diagnostic technique that uses sound waves to generate an image of the fetus.
Amniocentesis
Prenatal diagnostic technique that uses a syringe to withdraw a sample of amniotic fluid through the mother’s abdomen.
Chorionic Villus Sampling (CVS)
Prenatal diagnostic technique that involves taking a sample of tissue from the placenta.
Non-Invasive Prenatal Testing (NIPT)
A prenatal diagnostic technique that analyzes genetic material released from the placenta that circulates in a pregnant woman’s blood stream.
Fetal Therapy
Field of medicine concerned with treating prenatal problems before birth.
Stages of Labor
- Stage 1, which may last from 12 to 24 hours for a first birth, where the uterus starts to contract. First contractions are weak and irregular, but become stronger and more rhythmic, enlarging the cervix to around 10cm.
- Stage 2, the baby passes the cervix and enters the vagina. The mother contracts the muscles in her abdomen to push the baby along. Within an hour, the baby is delivered.
- Stage 3, which lasts a few minutes, the mother pushes a few more times to expel the placenta (also known as afterbirth).
Crowning
Appearance of the top of the baby’s head during labor.
Hypoxia
A birth complication in which umbilical blood flow is disrupted and the infant does not receive adequate oxygen.
Cesarean Section (C-section)
Surgical removal of an infant from the uterus through an incision made in the mother’s abdomen.
Preterm (Premature)
Babies born before the 36th week after conception.
Low Birth Weight
Newborns who weigh less than 2,500 grams (5.5 pounds).
Very Low Birth Weight
Newborns who weigh less than 1,500 grams (3.3 pounds).
Extremely Low Birth Weight
Newborns who weigh less than 1,000 grams (2.2 pounds).
Infant Mortality
The number of infants out of 1,000 births who die before their first birthday.
