Lesson 3: Forming a New Life

Cards (80)

  • Fertilization or conception

    The process by which sperm and ovum (the male and female gametes or sex cells) meet and an entirely new individual is created from parental genomes
  • Zygote
    One-celled organism resulting from fertilization
  • Fertile window
    The time during which conception is possible
  • Ovulation
    Rupture of a mature follicle in either ovary and expulsion of its ovum that occurs about once every 28 days until menopause
  • Sperm
    Produced in the testicles (testes), or reproductive glands, of a mature male at a rate of several hundred million a day and are ejaculated in the semen at sexual climax
  • Dizygotic Twins (fraternal twins)

    Result of two separate eggs being fertilized by two different sperm to form two unique individuals
  • Monozygotic Twins (identical twins)

    Result from the cleaving of one fertilized egg and are generally identical
  • Heredity
    The genetic transmission of heritable characteristics from parents to offspring
  • Genetic Code
    Sequence of bases within the DNA molecule; governs the formation of proteins that determine the structure and functions of living cells
  • Deoxyribonucleic Acid (DNA)

    Chemical that carries inherited instructions for the development of all cellular forms of life
  • Chromosomes
    Coils of DNA that consist of genes
  • Genes
    The functional units of heredity; small segments of DNA located in definite positions on particular chromosomes
  • Human Genome
    Complete sequence of genes in the human body; the reference point that shows the location of all genes
  • Meiosis
    The sex cells undergo when they are developing, each sex cell ends up with only 23 chromosomes (one from each pair)
  • Mitosis
    A process by which the non–sex cells divide in half over and over again, the DNA replicates itself, so that each newly formed cell has the same DNA structure as all the others
  • Mutations
    Permanent alterations in genes or chromosomes that may produce harmful characteristics
  • Autosomes
    The twenty-two pairs of chromosomes not related to sexual expression
  • Sex Chromosomes
    The 23rd pair that governs the baby's sex; XX in the normal human female and XY in the normal human male (sex of the baby is determined by the male)
  • Alleles
    Two or more alternative forms of a gene that occupy the same position on paired chromosomes and affect the same trait
  • Homozygous
    Possessing two identical alleles for a trait
  • Heterozygous
    Possessing differing alleles for a trait
  • Dominant Inheritance
    When a child receives different alleles, only the dominant one is expressed
  • Recessive Inheritance
    When a child receives identical recessive alleles, resulting in expression of a nondominant trait
  • Polygenic Inheritance
    Interaction of multiple genes at different sites on chromosomes affect a complex trait
  • Incomplete Dominance
    When a child receives two different alleles, resulting in partial expression of a trait
  • Phenotype
    Observable characteristics of a person
  • Genotype
    Genetic makeup of a person, containing both expressed and unexpressed characteristics
  • Multifactorial Transmission

    Illustrates the interaction of nature (genetic factors) and nurture (environmental factors) to produce certain complex traits
  • Epigenesis or epigenetics
    Mechanism that turns genes on or off, and determines functions of body cells
  • Genome Imprinting
    The differential expression of certain genetic traits, depending on whether the trait has been inherited from the mother or the father
  • Sex-Linked Inheritance of Defects
    Pattern of inheritance in which certain characteristics carried on the X chromosome inherited from the mother are transmitted differently to her male and female offspring
  • Carriers
    Heterozygous females who carry one "bad" copy of a recessive gene and one "good" one
  • Chromosomal Abnormalities
    Typically occur because of errors in cell division, resulting in an extra or missing chromosome
  • Genetic Counseling
    Help prospective parents assess their risk of bearing children with genetic or chromosomal defects
  • Karyotype
    A chart that shows chromosomal abnormalities and can indicate whether a person might transmit genetic defects
  • Behavioral Genetics
    A quantitative study of relative hereditary and environmental influences on behavior
  • Heritability
    Statistical estimate of contribution of heredity to individual differences in a specific trait within a given population
  • Concordant
    Describes the tendency of twins to share the same trait or disorder
  • Reaction Range
    Refers to the potential variability, depending on environmental conditions, in the expression of a hereditary trait
  • Canalization
    Limitation on variance of expression of certain inherited characteristics