Genetics -- final exam review

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Genetics -- final exam review
2013-05-05 19:11:54

genetics -- final exam review
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  1. Genetics
    The scientific study of heredity.
  2. Trait
    Any observable property of an organism.
  3. Gene
    The fundamental unit of heredity and the basic structural and functional unit of genetics.
  4. DNA
    A helical molecule consisting of two strands of nucleotides that is the primary carrier of genetic information.
  5. Transmission Genetics
    The branch of genetics concerned with the mechanism by which genes are transferred from parent to offspring.

    Studies the pattern of inheritance that results when traits are passes from generation to generation.
  6. Pedigree Analysis
    The construction of family trees and their use to follow the transmission of genetic traits in families. It is the basic message of studying the inheritance of traits in humans.
  7. Cytogenetics
    The branch of genetics that studies the organization and arrangement of genes and chromosomes by using the techniques of microscopy.
  8. Karyotype
    A complete set of chromosomes from a cell that has been photographed during cell division and arranged in a standard sequence.
  9. Molecular Genetics
    The study of genetic events at the biochemical level.
  10. Recombinant DNA Technology
    A series of techniques in which DNA fragments from an organism are linked to self-replicating vectors to create recombinant DNA molecules which are replicated or cloned in a host cell.
  11. Clones
    Genetically identical molecules, cells, or organisms all derived from a single ancestor.
  12. Gene Therapy
    Procedure in which normal genes are transplanted into humans carrying defective copies, as a means of treating genetic diseases.
  13. Genome
    The set of DNA sequences carried by an individual.
  14. Genomics
    The study of the organization, function, and evolution of genomes.
  15. Population Genetics
    The branch of genetics that studies inherited variation in populations of individuals and the forces that alter gene frequency.
  16. Eugenics
    The attempt to improve the human species by selective breeding.
  17. Hereditarianism
    The mistaken idea that human traits are determined solely by genetic inheritance, ignoring the contribution of the environment.
  18. Single Nucleotide Repeat (SNP)
    Single nucleotide differences between and among individuals in a population or species.
  19. Haplotype
    A set of genetic markers located close together on a single chromosome or chromosome region.
  20. Genome Wide Association Study (GWAS)
    Analysis of genetic variation across an entire genome searching for associations (linkages) between variations in DNA sequence and a genome region encoding a specific phenotype.
  21. Biotechnology
    The use of recombinant DNA technology to produce commercial goods and services.
  22. Macromolecules
    Large cellular polymers assembled by chemically linking monomers together.
  23. Carbohydrates
    Macromolecules including sugars, glycogen, and starches composed of sugar monomers linked and cross-linked together.
  24. Lipids
    A class of cellular macromolecules including fats and oils that are insoluble in water.
  25. Proteins
    A class of cellular macromolecules composed of amino acid monomers linked together and folded into a three-dimensional shape.
  26. Nucleic Acids
    A class of cellular macromolecules composed of nucleotide monomers linked together. There are two types of nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), which differ in the structure of the monomers.
  27. Molecules
    Structures composed of two or more atoms held together by chemical bonds.
  28. Organelles
    Cytoplasmic structures that have a specialized function.
  29. Endoplasmic Reticulum (ER)
    A system of cytoplasmic membranes arranged into sheets and channels whose function it is to synthesize and transport gene products.
  30. Ribosomes
    Cytoplasmic particles that aid in the production of proteins and are the site of protein synthesis.
  31. Golgi Complex
    Membranous organelles composed of a series of flattened sacs. They sort, modify, and package proteins synthesized in the rough endoplasmic reticulum. They produce lysosomes.
  32. Lysosomes
    Membrane enclosed organelles in eukaryotic cells that contain digestive enzymes.
  33. Mitochondria
    Double-membrane bound organelles, present in the cytoplasm of all eukaryotic cells, that are the sites of energy production. (site of cellular respiration and ATP production; contain their own DNA)
  34. Nucleus
    The membrane bound organelles in eukaryotic cells that contain the chromosomes.
  35. Nucleolus
    A nuclear region that functions in the synthesis of ribosomes.
  36. Chromatin
    The DNA and protein components of chromosomes, visible as clumps or threads in nuclei.
  37. Chromosomes
    The thread-like structures in the nucleus that carry genetic information.
  38. Sex Chromosomes
    In humans, the X and Y chromosomes that are involved in sex determination.
  39. Autosomes
    Chromosomes other than the sex chromosomes. In humans, chromosomes 1 through 22.
  40. Cell Cycle
    The sequence of events that takes place between successive mitotic divisions.
  41. Interphase
    The period of time in the cell cycle between mitotic divisions.
  42. Mitosis (karyokinesis)
    Form of cell division that produces two cells, each of which has the same complement of chromosomes as the parent cell.
  43. Cytokinesis
    The process of cytoplasmic division that accompanies cell division. A cleavage furrow forms and deepens and the cytoplasm divides.
  44. Prophase
    A stage in mitosis during which the chromosomes become visible (condense) and contain sister chromatids joined at the centromere. The nuclear membrane breaks down and the spindle fibers form.
  45. Chromatid
    One of the strands of a duplicated chromosome, joined by a single centromere to its sister chromatid.
  46. Centromere
    A region of a chromosome to which spindle fibers attach during cell division. The location of a centromere gives a chromosome its characteristic shape.
  47. Sister Chromatids
    Two chromatids joined by a common centromere. Each chromatid carries identical genetic information.
  48. Metaphase
    A stage in mitosis during which the chromosomes become arranged near the middle of the cell with spindle fibers attached to the centromeres.
  49. Anaphase
    A stage in mitosis during which the centromeres split and the daughter chromosomes begin to separate.
  50. Telophase
    The last stage of mitosis, during which the chromosomes of the daughter cells decondense and the nuclear membrane reforms.
  51. Meiosis
    The process of cell division during which one cycle of chromosomal replication is followed by two successive cell divisions to produce four haploid cells.
  52. Diploid (2n)
    The condition in which each chromosome is represented twice as a member of a homologous pair.
  53. Haploid (n)
    The condition in which each chromosome is represented once in an unpaired condition.
  54. Homologous Chromosomes
    Chromosomes that physically associate (pair) during meiosis. Homologous chromosomes have identical gene loci.
  55. Assortment
    The results of meiosis I that puts random combinations of maternal and paternal chromosomes into gametes.
  56. Crossing Over
    A process in which chromosomes physically exchange parts.
  57. Allele
    One of the possible alternative forms of a gene, usually distinguished from other alleles by its phenotypic effects.
  58. Spermatogonia
    Mitotically active cells in the gonads of males that give rise to primary spermatocytes.
  59. Spermatids
    The four haploid cells produced by meiotic division of a primary spermatocyte.
  60. Oogonia
    Mitotically active cells that produce primary oocytes.
  61. Secondary Oocyte
    The large cell produced by the first meiotic division.
  62. Oocyte
    A cell from which an ovum develops by meiosis.
  63. Ovum
    The haploid cell produced by meiosis that becomes the functional gamete.
  64. Polar Bodies
    Cells produced in the first and second meiotic division and female meiosis that contains the little cytoplasm and will not function as gametes.
  65. Gene
    The fundamental unit of heredity and the basic structural and functional unit of genetics.

    A sequence of nucleotides in DNA.

    Controls cells by directing protein synthesis.
  66. Dominant Trait
    The trait expressed in the F1 (or heterozygous) condition.
  67. Recessive Trait
    The trait unexpressed in the F1, but re-expressed in some members of the F2 generation.
  68. Phenotype
    The observable properties of an organism.
  69. Genotype
    The specific genetic constitution of an organism.
  70. Segregation
    The separation of members of a gene pair from each other during gamete formation.
  71. Homozygous
    Having identical alleles for one or more genes.
  72. Heterozygous
    Carrying two different alleles for one or more genes.
  73. Independent Assortment
    The random distribution of alleles into gametes during meiosis.
  74. Locus
    The position occupied by a gene on a chromosome.
  75. Pedigree Construction
    Use of family history to determine how a trait is inherited and to estimate risk factors for family members.
  76. Pedigree
    A diagram listing the members and ancestral relationships in a family; used in the study of human heredity.
  77. Proband
    First affected family member who seeks medical attention for a genetic disorder.
  78. Incomplete Dominance
    Expression of a phenotype that is intermediate to those of the parents.
  79. Co-dominance
    Full phenotypic expression of both members of a gene pair in the heterozygous condition.
  80. Multiple Alleles
    Genes that have more than two alleles.
  81. Epistasis
    The interaction of two or more non-allelic genes to control a single phenotype.
  82. Cystic Fibrosis
    An often fatal recessive genetic disorder associated with abnormal secretions of the exocrine glands. It's associated with a change in a protein that makes up the chlorine channel of the cell membrane.
  83. Marfan Syndrome
    An autosomal dominant genetic disorder that affects the skeletal system, the cardiovascular system, and the eyes. Gene is located on chromosome 15.
  84. X-linked
    The pattern of inheritance that results from genes located on the X chromosome.
  85. Y-linked
    The pattern of inheritance from genes located on the Y chromosome.
  86. Hemizygous
    The gene present on the X chromosome that is expressed in males in both the recessive and dominant conditions.
  87. Color Blindness
    Defective color vision caused by reduction or absence of visual pigments. There are three forms: red, green, and blue blindness.
  88. Muscular Dystrophy
    A group of genetic diseases associated with progressive degeneration of muscles. Two of these, Duchenne and Becker muscular dystrophy, are inherited as X-linked recessive traits.
  89. Huntington Disease (HD)
    An autosomal dominant disorder associated with progressive neural degeneration and dementia. Adult onset is followed by death 10 to 15 years after symptoms appear.
  90. Penetrance
    The probability that a disease phenotype will appear when a disease related genotype is present.
  91. Expressivity
    The range of phenotypes resulting from a given genotype.
  92. Camptodactyly
    A dominant human genetic trait that is expressed as immobile, bent, little fingers.
  93. Discontinuous Variation
    Phenotypes that fall into two or more distinct, non-overlapping classes.
  94. Continuous Variation
    A distribution of phenotypic characteristics that is distributed from one extreme to another in an overlapping, or continuous, fashion.
  95. Complex Traits
    The contributions of genes and the environment are not yet established. 

    example: behavior, intelligence, etc.
  96. Polygenic Traits
    Traits controlled by two or more genes. Traits are usually quantified by measurement. They're better analyzed in populations than in individuals.

    example: human eye color
  97. Multifactorial Traits
    Traits that result from the interaction of one or more environmental factors and two or more genes.

    example: human height

    Studied using threshold model and recurrence risk model.
  98. Regression to the mean
    In a polygenic system, the tendency of offspring of parents with extreme differences in phenotype that is the average of the two parental phenotypes.
  99. Genetic Variance
    The phenotypic variance of a trait in a population that is attributed to genotypic differences.
  100. Environmental Variance
    The phenotypic variance of a trait in a population that is attributed to differences in the environment.
  101. Heritability
    The measurement of the genetic contribution to phenotypic variation. Estimated based on known levels of genetic relatedness.
  102. Correlation Coefficients
    Measures the degree of interdependence of two or more variables.
  103. Monozygotic (MZ)
    Twins derived from a single fertilization involving one egg and one sperm; such twins are genetically identical.
  104. Dizygotic (DZ)
    Twins derived from two separate and nearly simultaneous fertilizations, each involving one egg and one sperm. Such twins share, on average, 50% of their genes.
  105. Concordance
    Agreement between traits exhibited by both twins.
  106. Leptin
    The hormone produced by fat cells that signals the brain and ovary. As fat levels become depleted, secretion of leptin slows and eventually stops.
  107. Intelligence Quotient (IQ)
    A score derived from standardized tests that is calculated by dividing the individual's mental age (determined by tests) by his or her chronological age and multiplying the quotient by 100.
  108. General Cognitive Ability
    Characteristics that include verbal and spatial abilities, memory, speed of perception, and reasoning.
  109. Centromere
    A region of a chromosome to which spindle fibers attach during cell division. The location of a centromere gives a chromosome its characteristic shape.
  110. Metacentric
    Describes a chromosome that has a centrally placed centromere.
  111. Submetacentric
    Describes a chromosome whose centromere is placed closer to one end than the other.
  112. Acrocentric
    Describes a chromosome whose centromere is placed very close to, but not at, one end.
  113. Telomere
    Short repeated DNA sequences located at each end of chromosomes.
  114. Amniocentesis
    A method of sampling the fluid surrounding the developing fetus by inserting a hollow needle and withdrawing suspended fetal cells and fluid; used in diagnosing fetal genetic and developmental disorders; usually performed in the 16th week of pregnancy.
  115. Chorionic Villous Sampling
    A method of sampling fetal chorionic cells by inserting a catheter through the vagina or abdominal wall into the uterus. Used in diagnosing biochemical and cytogenic defects in the embryo. Usually performed in the eighth or ninth week of pregnancy.
  116. Polyploidy
    A chromosomal number that is a multiple of the normal haploid chromosomal set.
  117. Aneuploidy
    A chromosomal number that is not an exact multiple of the haploid set.
  118. Monosomy
    A condition in which one member of a chromosomal pair is missing; having one less than the diploid number (2n-1).
  119. Trisomy
    A condition in which one chromosome is present in three copies, whereas all others are diploid; having more than one diploid number (2n+1).
  120. Triploidy
    A chromosomal number that is three times the haploid number, having three copies of all autosomes and three sex chromosomes.
  121. Tetraploidy
    A chromosomal number that is four times the haploid number, having four copies of all autosomes and four sex chromosomes.
  122. Nondisjunction
    The failure of homologous chromosomes to separate properly during meiosis or mitosis.
  123. Trisomy 21
    Aneuploidy involving the presence of an extra copy of chromosome 21, resulting in Down Syndrome.
  124. Turner Syndrome
    A monosomy of the X chromosome (45,X) that results in female sterility.
  125. Klinefelter Syndrome
    Aneuploidy of the sex chromosomes involving an XXY chromosomal constitution.
  126. XYY Karyotype
    Aneuploidy of the sex chromosomes involving an XYY chromosomal constitution.
  127. Cri du chat Syndrome
    A deletion of the short arm of chromosome 5 associated with an array of congenital malformations, the most characteristic of which is an infant cry that resembles a meowing cat.
  128. Uniparental Disomy (UPD)
    A condition in which both copies of a chromosome are inherited from one parent. Autosomal recessive disorders. 

    example: Prader-Willi from mom and Angelman from dad
  129. Copy Number Variation (CNV)
    A DNA segment at least 1,000 base pairs long with a variable copy number in the genome.

    examples of human diseases associated with CNV: Alzheimer's, Charcot-Marie-Tooth, HIV/AIDS. Lupus, Parkinson's, etc.
  130. Fragile X Syndrome
    An X chromosome that carries a gap, or break, at band q27; associated with mental retardation in males. FRAX A is usually associated with Fragile-X Syndrome in males.
  131. Classical (aka Mendelian) Genetics
    Deals with transmission and interactions of one or two genes in individuals.
  132. Quantitative Genetics
    The study of traits controlled by several to many genes.
  133. Molecular Genetics
    Deals with the chemistry of gene structure and function.
  134. Population Genetics
    The study of processes that influence gene distribution in populations.
  135. Genomics
    The study of the entire DNA of an organism.
  136. Proteomics
    The study of the entire expressed (translated) component of an organism.
  137. Genetic Disease That Affect Lysosomal Function
    Gaucher Disease: recessive; lack enzyme to break down membranes; treated with recombinant DNA enzyme

    Tay-Sachs: recessive; the first identified as a lysosomal disease

    Pompe Disease: recessive
  138. G1
    • part 1 of interphase
    • Gap 1 Phase (pre-synthesis)
    • cells that cease division usually arrest in this phase (G0)
    • RNA, protein, and other molecules are synthesized
    • cell size nearly doubles
  139. S
    • part 2 of interphase
    • (synthesis)
    • DNA replication occurs and chromosomes become double stranded (formation of 2 sister chromatids attached at the centromere)
  140. G2
    • part 3 of interphase
    • Gap 2 Phase (post-synthesis)
    • mitochondria divide
    • precursors of spindle fibers are synthesized
    • (more cell growth)
  141. Disorders of Accelerated Aging
    Progeria and Werner Syndrome
  142. True Breeding
    Self-fertilization produces the same traits for many generations.
  143. P1
    parental generation
  144. F1
    • first filial
    • offspring of P1
  145. F2
    • second filial
    • offspring of F1xF1
  146. Principle of Segregation
    • Mendel's first law
    • members of a gene pair separate during the formation of gametes
  147. Principle of Independent Assortment
    • Mendel's second law
    • alleles of one pair of genes separate into gametes independently of the alleles from another gene pair
  148. Autosomal Recessive Human Genetic Traits
    • albinism: absence of pigment
    • blood syndrome: dwarfism and increased cancer rate
    • cystic fibrosis: disabling and fatal; affects sweat glands and glands that produce mucous and digestive enzymes; located on q arm of chromosome 7
    • Fanconi anemia: slow growth/high rate of leukemia
    • phenylketonuria: accumulation of phenylalanine; mental retardation
    • sickle cell anemia: caused by 1 SNP
    • xeroderma pigmentosum: lack of DNA repair enzyme (can't repair thymine-thymine bonds) and often get skin cancer
  149. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)
    Regulates the flow of chloride ions across the plasma membrane; reduces fluid in glandular secretions
  150. Examples of Autosomal Dominant Traits
    • Brachydactyly
    • Camptodactyly
    • Huntington Disease
    • Marfan Syndrome
    • Nail-patella Syndrome
  151. X-linked Dominant Trait
    • affected males produce all affected daughters but no affected sons
    • heterozygous females have equally affected and unaffected sons and daughters
  152. X-linked Recessive Traits
    • hemizygous males and homozygous females are affected (males are more likely to be affected)
    • affected males receive it from mother and affected females must receive it from both parents
  153. Muscular Dystrophy
    • autosomal (rare) and X-linked forms
    • most common is X-linked recessive Duchenne muscular dystrophy
    • rapidly progressing weakness and loss of muscle tissue
  154. Y-linked Genes
    • H-Y Antigen: plasma membrane protein
    • ZFY: DNA binding protein that may regulate gene expression
  155. Mitochondrial Traits
    Leber Optic Atrophy (LHON): loss of vision in center of visual field; adult onset
  156. Threshold Model
    Frequency of disorder among relatives is compared with the frequency of the disorder among the general population.
  157. Recurrence Risk
    Estimates the risk that the disease will recur.
  158. G-banding
    • named for Giemsa stain
    • granddaddy of methods...still used today
    • dark bands are where proteins are located and light bands are where the proteins have been degraded by trypsin
  159. Q-banding
    stands for quinacrine, which fluoresces really brightly and is used in mustard gas (liquid form is used in the lab because it's safer)
  160. R-banding
    • "reverse bands"
    • stained with giemsa stain
  161. C-banding
    • banding pattern only around the centromere
    • stained with giemsa stain
  162. CML (chronic myelogenous leukemia)
    • tranlocation between chromosome 9 and 22 (a piece of chromosome 9 attaches itself to chromosome 22)
    • pseudo gene gets turned on when those two pieces come together and can't be turned off
    • onca gene: cells continuously go through mitosis, causing leukemia
  163. Charcot-Marie-Tooth Syndrome
    neuromuscular degenerative disease
  164. Zygote
    The fertilized egg that develops into a new individual.
  165. Sperm
    male gamete
  166. Oocyte
    A cell from which an ovum develops by meiosis.
  167. Gametes
    unfertilized germ cells
  168. Gonads
    Organs where gametes are produced.
  169. Testes
    Male gonads that produce spermatozoa and sex hormones.
  170. Ovaries
    Female gonads that produce oocytes and female sex hormones.
  171. Scrotum
    A pouch of skin outside the male body that contains the testes.
  172. Seminiferous Tubules
    Small, tightly coiled tubes inside the testes where sperm are produced.
  173. Spermatogenesis
    The process of sperm production.
  174. Spermatocytes
    Diploid cells that undergo meiosis to form haploid spermatids.
  175. Epididymis
    A part of the male reproductive system where sperm are stored.
  176. Vas Deferens
    A duct connected to the epididymis, which sperm travels through.
  177. Ejaculatory Duct
    In males, a short connector from the vas deferens to the urethra.
  178. Urethra
    A tube that passes from the bladder and opens to the outside. It functions in urine transport and, in males, also carries sperm.
  179. Seminal Vesicles
    Glands in males that secrete fructose and prostaglandings into the semen.
  180. Prostaglandins
    Locally acting chemical messengers that stimulate contractions of the female reproductive system to assist in sperm movement.
  181. Prostate Gland
    A gland that secretes a milky, alkaline fluid that neutralized acidic vaginal secretions and enhances sperm viability.
  182. Bulbourethral Glands
    Glands in the male that secrete a mucous-like substance that provide lubrication for intercourse.
  183. Semen
    A mixture of sperm and various glandular secretions containing 5% spermatozoa.
  184. Follicle
    A developing egg surrounded by an outer layer of follicle cells, contained in the ovary.
  185. Ovulation
    The release of a secondary oocyte from the follicle; usually occurs monthly during a female's reproductive lifetime.
  186. Oviduct
    A duct with finger-like projections partially surrounding the ovary and connecting to the uterus. Also called the fallopian, or uterine, tube.
  187. Uterus
    A hollow, pear-shaped muscular organ where an early embryo will implant and develop throughout pregnancy.
  188. Endometrium
    The inner lining of the uterus that is shed at menstruation if fertilization has not occurred.
  189. Cervix
    The lower neck of the uterus, opening into the vagina.
  190. Vagina
    The opening that receives the penis during intercourse and also serves as the birth canal.
  191. Oogenesis
    The process of oocyte production.
  192. Oogonia
    Cells that produce primary oocytes by mitotic division.
  193. Fertilization
    The fusion of two gametes to produce a zygote.
  194. Blastocyst
    The developmental stage at which the embryo implants into the uterine wall.
  195. Inner Cell Mass
    A cluster of cells in the blastocyst that gives rise to the embryonic body. The inner cell mass  contains the embryonic stem cells.
  196. Trophoblast
    The outer layer of cells in the blastocyst that gives rise to the membranes surrounding the embryo.
  197. Chorion
    A two-layered structure formed during embryonic development from the trophoblast.
  198. Teratogen
    Any physical or chemical agent that brings about an increase in congenital malformations.
  199. Fetal Alcohol Syndrome (FAS)
    A constellation of birth defects caused by maternal alcohol consumption during pregnancy.
  200. Sex Ratio
    The proportion of males to females, which changes throughout the life cycle. The ratio is close to 1:1 at fertilization, but the ratio of females to males increases as a population ages.
  201. SRY
    A gene, called the sex determining region of the Y, located near the end of the short arm of the Y chromosome that plays a major role in causing the undifferentiated gonad to develop into a testis.
  202. Testosterone
    A steroid hormone produced by the testis; the male sex hormone.
  203. Anti-Mullerian Hormone (AMH)
    A hormone produced by the developing testis that causes the breakdown of the Mullerian ducts in the embryo.
  204. Complete Androgen Insensitivity (CAIS)
    An X-linked genetic trait that causes XY individuals to develop into phenotypic females.
  205. Pseudohermaphroditism
    An autosomal genetic condition that causes XY individual to develop the phenotypic sex of females.
  206. Dosage Compensation
    A mechanism that regulates the expression of sex linked genes.
  207. Barr Body
    A densely staining mass in the somatic nuclei of mammalian females; an inactivated X chromosome.
  208. Lyon Hypothesis
    The proposal that dosage compensation in mammalian females is accomplished by partially and randomly inactivating 1 of the 2 X chromosomes.
  209. X inactivation center (XIC)
    A region on the X chromosome where inactivation begins.
  210. Sex Influenced Traits
    Traits controlled by autosomal genes that are usually dominant in one sex but recessive in the other sex.
  211. Pattern Baldness
    A sex influenced trait that acts like an autosomal dominant trait in males and an autosomal recessive trait in females.
  212. Sex Limited Genes
    Loci that produce a phenotype in only one sex.
  213. Imprinting
    A phenomenon in which expression of a gene depends on whether it is inherited from the mother or the father.
  214. Transformation
    The process of transferring genetic information between cells by DNA molecules.
  215. Transferring Factor
    The molecular agent of transformation; DNA.
  216. Covalent Bonds
    Chemical bonds that result from electron sharing between atoms. Covalent bonds are formed and broken during chemical reactions.
  217. Hydrogen Bond
    A weak chemical bonding force between hydrogen and another atom.
  218. Deoxyribonucleic Acid (DNA)
    A molecule consisting of anti-parallel strands of polynucleotides that is the primary carrier of genetic information.
  219. Ribonucleic Acid (RNA)
    A nucleic acid molecule that contains the pyrimidine uracil and the sugar ribose. The several forms of RNA function in gene expression.
  220. Nucleotide
    The basic building block of DNA and RNA. Each nucleotide consists of a base, a phosphate, and a sugar.
  221. Nitrogen Containing Base
    A purine or pyrimidine that is a component of nucleotides.
  222. Purine
    A class of double ringed organic bases found in nucleic acids.
  223. Pyrimidine
    A class of single rained organic bases found in nucleic acids.
  224. Adenine and Guanine
    Nitrogen containing purine bases found in nucleic acids.
  225. Thymine, Uracil, and Cytosine
    Nitrogen containing pyrimidine bases found in nucleic acids.
  226. Sugar
    In nucleic acids, either ribose, found in RNA, or deoxyribose, found in DNA. The difference between the two sugars is an OH group present in ribose and absent in deoxyribose.
  227. Phosphate Group
    A compound containing phosphorous chemically bonded to four oxygen molecules.
  228. Ribose and Deoxyribose
    Pentose sugars found in nucleic acids. Deoxyribose is found in DNA, ribose in RNA.
  229. Template
    The single stranded DNA that serves to specify the nucleotide sequence of a newly synthesized polynucleotide strand.
  230. Semiconservative Replication
    A model of DNA replication that provides each daughter molecule with one old strand and one newly synthesized strand. DNA replicates in this fashion.
  231. DNA Polymerase
    An enzyme that catalyzes the synthesis of DNA using a template DNA strand and nucleotides.
  232. Chromatin
    The complex of DNA and proteins that makes up a chromosome.
  233. Histones
    DNA binding proteins that help compact and fold DNA into chromosomes.
  234. Nucleosomes
    A bead-like structure composed of histone wrapped with DNA.
  235. Telomerase
    An enzyme that adds telomere repeats to the ends of chromosomes, keeping them the same length after each cell division.
  236. Alkaptonuria
    An autosomal recessive trait with altered metabolism of homogentisic acid. Affected individuals do not produce the enzyme needed to metabolize this acid, and their urine turns black.
  237. Amino Acid
    One of the 20 subunits of proteins. Each contains an amino group, a carboxyl group, and an R group.
  238. Codon
    Triplets of nucleotides in mRNA that encode the information for a specific amino acid in a protein.
  239. Stop Codon
    A codon in mRNA that signals the end of translation. UAA, UAG, and UGA are stop codons.
  240. Start Codon
    A codon present in mRNA that signals the location for translation to begin. The codon AUG functions as a start codon and codes for the amino acid methionine.
  241. Pre-messenger RNA (pre-mRNA)
    The transcript made from the DNA template that is processed and modified to form messenger RNA.
  242. Transcription
    Transfer of genetic information from the base sequence of DNA to the base sequence of RNA, mediated by RNA synthesis.
  243. Messenger RNA (m-RNA)
    A single stranded complimentary copy of the amino acid coding nucleotide sequence of a gene.
  244. Translation
    Conversion of information encoded in the nucleotide sequence of an mRNA molecule into the linear sequence of amino acids in a protein.
  245. Introns
    DNA sequences present in some genes that are transcribed but are removed during processing and therefore are not present in mature mRNA.
  246. Exons
    DNA sequences that are transcribed, joined to other exons during mRNA processing, and translated into the amino acid sequence of a protein.
  247. Cap
    A modified base (guanine nucleotide) attached to the 5' end of eukaryotic mRNA molecules.
  248. Poly-A Tail
    A series of A nucleotides added to the 3' end of mRNA molecules.
  249. Amino Group
    A chemical group (NH2) found in amnio acids and at one end of a polypeptide chain.
  250. Carboxyl Group
    A chemical group (COOH) found in amino acids and at one end of a polypeptide chain.
  251. R Group
    Each amino acid has a different side chain, called an R group. An R group can be positively or negatively charged or neutral.
  252. Polypeptide
    A molecule made of amino acids joined together by peptide bonds.
  253. N-terminus
    The end of a polypeptide or protein that has a free amino group.
  254. C-terminus
    The end of a polypeptide or protein that has a free carboxyl group.
  255. Ribosomal RNA (rRNA)
    RNA molecules that form part of the ribosome.
  256. Transfer RNA (tRNA)
    A small RNA molecule that contains a binding site for a specific type of amino acid and has a three-base segment known as an anticodon that recognized a specific base sequence in messenger RNA.
  257. Anticodon
    A group of three nucleotides in a tRNA molecule that pairs with a complementary sequence (known as a codon) in an mRNA molecule.
  258. Initiation Complex
    Formed by the combination of mRNA, tRNA, and the small ribosome subunit. The first step in translation.
  259. Peptide Bond
    A covalent chemical link between the carboxyl group of one amino acid and the amino group of another amino acid.
  260. Polysomes
    A messenger RNA (mRNA) molecule with several ribosomes attached.
  261. Primary Structure
    The amino acid sequence in a polypeptide chain.
  262. Secondary Structure
    The pleated or helical structure in a protein molecule generated by the formation of bonds between amino acids.
  263. Tertiary Structure
    The 3-D structure of a protein molecule brought about by folding on itself.
  264. Quaternary Structure
    The structure formed by the intersection of 2 or more polypeptide chains in a protein.
  265. Prion
    A protein folded into an infectious conformation that is the cause of several disorders, including Creutzfeldt-Jakob disease and mad cow disease.
  266. Mad Cow Disease
    A prion disease of cattle, also known as bovine spongioform enchephalopathy, or BSE.
  267. Chromatin Remodeling
    The process of chemical changes to the DNA and histones that activate and inactivate gene expression.
  268. RNA Interference (RNAi)
    A mechanism of gene regulation that controls the amount of mRNA available for translation.
  269. Substrate
    The specific chemical compound that is ACTED on by an enzyme.
  270. Product
    The specific chemical compound that is the result of enzymatic action. In biochemical pathways, a compound can serve as the product of one reaction and the substrate for the next reaction.
  271. Metabolism
    The sum of all biochemical reactions by which cells convert and utilize energy.
  272. Inborn Error of Metabolism
    The concept advanced by Archibald Garrod that many genetic traits result from alterations in biochemical pathways.
  273. Essential Aminio Acids
    Amino acids that cannot be synthesized in the body and must be supplied in the diet.
  274. Phenylketonuria (PKU)
    An autosomal recessive disorder of amino acid metabolism that results in mental retardation if untreated.
  275. Galactosemia
    A heritable trait associated with the inability to metabolize the sugar galactose. If it is left untreated, high levels of galactose-1-phosphate accumulate, causing cataracts and mental retardation.
  276. Hemoglobin Variants
    Alpha and beta globin with variant amino acid sequences.
  277. Thalassemias
    Disorders associated with an imbalance in the production of alpha or beta globin.
  278. Pharmacogenetics
    A branch of genetics concerned with the identification of protein variants that underlie differences in the response to drugs.
  279. Ecogenetics
    A branch of genetics that studies genetic traits related to the response to environmental substances.
  280. Mutation Rate
    The number of events that produce mutated alleles per locus per generation. (The number of mutated alleles PER gene PER generation.)
  281. Trinucleotide Repeats
    A form of mutation associated with the expansion in copy number of a nucleotide triplet in or near a gene.
  282. Radiation
    The process by which electromagnetic energy travels through space or a medium such as air.
  283. Ionizing Radiation
    Radiation that produces ions during interaction with other matter, including molecules in cells.
  284. Background Radiation
    Radiation in the environment that contributes to radiation exposure.
  285. Rem
    The unit of radiation exposure used to measure radiation damage in humans. It is the amount of ionizing radiation that has the same effect as a standard amount of x-rays.
  286. Millirem
    A rem is a measure of radiation dose equal to 1000 millirems.
  287. Base Analogs
    A purine or pyrimidine that differs in chemical structure from those normally found in DNA or RNA.
  288. Nucleotide Substitutions
    Mutations that involve replacement of one or more nucleotides in a DNA molecule with other nucleotides.
  289. Frameshift Mutation
    Mutational events in which a number of bases (other than multiples of three) are added to or removed from DNA, causing a shift in the codon reading frame.
  290. Missense Mutations
    Mutations that cause the substitution of one amino acid for another in a protein.
  291. Sense Mutations
    Mutations that change a termination (stop) codon into one that codes for an amino acid. Such mutations produce elongated proteins.
  292. Nonsense Mutations
    Mutations that change an amino acid specifying a codon to one of the three termination codons.
  293. Allelic Expansion
    Increase in gene size caused by an increase in the number of trinucleotide sequences.
  294. Anticipation
    Onset of a genetic disorder at earlier ages and with increasing severity in successive generations.
  295. Thymine Dimer
    A molecular lesion in which chemical bonds from between a pair of adjacent thymine bases in a DNA molecule.
  296. Genomic Imprinting
    • Phenomenon in which the expression of a gene depends on whether it is inherited from the mother or the father; also known as a genetic or parental imprinting.
    • -Does not affect all genes.
    • -Not a mutation, but a modification of DNA.
  297. Epigenetics
    Reversible chemical modifications of chromosomal DNA (such as methylation of bases) and/or associated histone proteins that change the pattern of gene expression without affecting the nucleotide sequence of the DNA.
  298. Metastasis
    A process by which cells detach from the primary tumor and move to other sites, forming new malignant tumors in the body.
  299. Loss of Heterozygosity (LOH)
    In a cell, the loss of normal function in one allele of a gene where the other allele is already inactivated by mutation.
  300. Signal Transduction
    A cellular molecular pathway by which an external signal is converted into a functional response.
  301. Tumor Suppressor Genes
    Genes encoding proteins that suppress cell division.
  302. Proto-oncogenes
    Genes that initiate or maintain cell division and that may become cancer genes (oncogenes) by mutation.
  303. Oncogenes
    Genes that induce or continue uncontrolled cell proliferation.
  304. Retinoblastoma
    A malignant tumor of the eye arising in retinoblasts (embryonic retinal cells that disappear at about two years of age). Because mature retinal cells do not transform into tumors, this is a tumor that usually occurs only in children.

    • -familial retinoblastoma usually occurs bilaterally
    • -sporadic retinoblastoma usually occurs unilaterally
  305. Familial Adenomatous Polyposis (FAP)
    An autosomal dominant trait resulting in the development of polyps and benign growths in the colon. Polyps often develop into malignant growths and cause cancer of the colon and/or rectum.
  306. Hereditary Nonpolyposis Colon Cancer (HNPCC)
    An autosomal dominant trait associated with genomic instability of microsatellite DNA sequences and a form of colon cancer.
  307. Philadelphia Chromosome
    An abnormal chromosome produced by translocation of parts of the long arms of chromosomes 9 and 22.
  308. Clones
    Genetically identical molecules, cells, or organisms, all derived from a single ancestor.
  309. Recombinant DNA Technology
    A series of techniques in which DNA fragments from an organism are linked to self-replicating vectors to create recombinant DNA molecules, which are replicated or cloned in a host cell.
  310. Restriction Enzyme
    A bacterial enzyme that cuts DNA at specific sites.
  311. Vectors
    Self-replicating DNA molecules that are used to transfer foreign DNA segments between host cells.
  312. Genomic Library
    In recombinant DNA terminology, a collection of clones that contains all the genetic information in an individual.
  313. Yeast Artificial Chromosome (YAC)
    A cloning vector that has telomeres and a centromere that can accommodate large DNA inserts and used the eukaryote yeast as a host cell.
  314. Probe
    A labeled nucleic acid used to identify a complementary region in a clone or genome.
  315. Polymerase Chain Reaction (PCR)
    • A method for amplifying DNA segments using cycles of denaturation, annealing to primers, and DNA polymerase-directed DNA synthesis.
    • PCR copies a DNA molecule without restriction enzymes, vectors, or host cells (faster and easier than conventional cloning)
    • PCR doubles the amount of DNA with each cycle (copies DNA without cloning).
  316. Southern Blot
    A method for transferring DNA fragments from a gel to a membrane filter, developed by Edwin Southern for use in hybridization experiments.
  317. DNA Sequencing
    • A technique for determining the nucleotide sequence of a DNA molecule.
    • example: Automated Sanger Method: DNA is separated into two strands; DNA polymerase, a primer, and 4 altered nucleotides are added, stopping synthesis and causing strands of every length to accumulate.
  318. Biotechnology
    The use of recombinant DNA technology to produce commercial goods and services.
  319. Enzyme Replacement Therapy
    • Treatment of a genetic disorder by providing a missing enzyme encoded by the mutant allele responsible for the disorder.
    • examples: Pompe Disease: treated this way; inability to make alpha-glucosidase (GAA) which leads to reduced heart and muscle function (transgenic female rabbits produce human GAA in their milk; human GAA is produced in transgenic hamster cells).
  320. Embryonic Stem Cells (ESC)
    Cells in the inner cell mass of early embryos that will form all the cells, tissues, and organs of the adult. Because of their ability to form so many different cell types, these cells are called pluripotent.
  321. Pluripotent
    The ability of a stem cell to form any fetal or adult cell type.
  322. Adult Stem Cells
    Stem cells recovered from bone marrow and other organs of adults. These cells can differentiate to form a limited number of adult cells, and are called multipotent cells.
  323. Multipotent
    The restricted ability of a stem cell to form only one or a few different cell types.
  324. Induced Pluripotent Stem Cells (iPS)
    Adult cells that can be reprogrammed induced by gene transfer to form cells with most of the developmental potential of embryonic stem cells. Because of this development potential, such cells are pluripotent.
  325. Genetically Modified Organisms (GMOs)
    • A general term used to refer to transgenic plants or animals created by recombinant DNA techniques.
    • 60-70% of foods in US supermarkets contain transgenic plant material.
  326. Transgenic
    Refers to the transfer of genes between species by recombinant DNA technology; transgenic organisms have received such a gene.
  327. Minisatellite
    Nucleotide sequences 14 to 100 base pairs long, organized into clusters of varying lengths, on many different chromosomes; used in the construction of DNA fingerprints.
  328. DNA Fingerprint
    Detection of variations in minisatellites used to identify individuals.
  329. Short Tandem Repeats (STR)
    Short nucleotide sequences 2 to 9 base pairs long found throughout the genome that are organized into clusters of varying lengths; used in the construction of DNA profiles.
  330. DNA Profile
    • The pattern of STR allele frequencies used to identify individuals.
    • In the US, a standard set of 13 STRs (CODIS) is used to prepare a profile.
  331. Linkage
    A condition in which two or more genes located on the same chromosome tend to be inherited together. When the degree of recombination between linked genes is measured, the distance between them can be determined. 

    example: blue eyes and light skin
  332. Genome
    • The set of DNA sequences carried by an individual.
    • The human genome contains over 3 billion nucleotides (only ~5% of them encode genetic information), and has 20,000-30,000 genes. (there are more proteins in the body than genes -- ~300,000)
  333. Centimorgan (cM)
    A unit of distance between genes on chromosomes. One centimorgan equals a frequency of 1% crossing over between two genes.

    **1 cM typically equals ~1 million base pairs of DNA**
  334. Lod Method
    A probability/statistical technique used to determine whether two genes are linked.
  335. Lod Score
    The ratio of probabilities that two genes are linked to the probability that they are not linked, expressed as a log10. Scores of 3.0 or higher are taken as establishing linkage.
  336. Positional Cloning
    • A recombinant DNA based method of mapping and cloning genes with no prior information about the gene product or its function.
    • Inheritance of molecular markers is used to track the inheritance of genetic disorders in pedigrees and thus the gene responsible.
  337. Genomics
    The study of the organization, function, and evolution of genomes.
  338. Bioinformatics
    The use of computers and software to acquire, store, analyze, and visualize the information from genomics.
  339. Comparative Genomics
    Compares the genomes of different species to look for clues to the evolutionary history of genes or a species.
  340. Structural Genomics
    A branch of genomics that generates 3-D structure of proteins from their amino acid sequences.
  341. Pharmacogenomics
    The branch of genetics that analyze genes and proteins to identify targets for therapeutic drugs.
  342. Map Based Sequencing
    A method of genome sequencing that begins with genetic and physical maps; clones are sequenced after they have been placed in order.
  343. Whole Genome Sequencing
    A method of genome sequencing that selects clones at random from a genomic library and, after sequencing them, assembles the genome sequence by using software analysis.
  344. Genetic Map
    • A diagram of a chromosome showing the order of genes and the distance between them based on recombination frequencies (centimorgans).
    • Constructed using crossover frequencies.
    • The first step in developing diagnostic tests and treatments for these disorders.
  345. Physical Map
    A diagram of a chromosome showing the order of genes and the distance between them measured in base pairs.
  346. Annotation
    The analysis of genomic nucleotide sequence data to identify the protein coding genes, the non protein-coding genes, their regulatory sequences, and their function(s).
  347. Open Reading Frame (ORF)
    The codons in a gene that encode the amino acids of the gene product.
  348. Haplotype
    A set of genetic markers located close together on a single chromosome or chromosome region.
  349. Friedreich Ataxia
    A progressive and fatal neurodegenerative disorder inherited as an autosomal recessive trait with symptoms appearing between puberty and the age of 25.
  350. Proteome
    The set of proteins present in a cell at a specific time under a specific set of conditions.
  351. Proteomics
    The study of the structure and function of proteins, which is important in the development of new diagnostic tests and drugs.
  352. Assisted Reproductive Technologies (ART)
    The collection of techniques used to help infertile couples have children.
  353. Intracytoplasmic Sperm Injection (ICSI)
    A treatment to overcome defects in sperm count or motility; an egg is fertilized by microinjection of a single sperm.
  354. Gamete Intrafallopian Transfer (GIFT)
    An ART procedure in which gametes are collected and placed into a woman's oviduct for fertilization.
  355. Zygote Intrafallopian Transfer (ZIFT)
    An ART procedure in which gametes are collected, fertilization takes place in vitro, and the resulting zygote (fertilized egg) is transferred to a woman's oviduct.
  356. In Vitro Fertilization (IVF)
    A procedure in which gametes are collected and fertilized in a dish in the laboratory; the resulting zygote is implanted in the uterus for development.
  357. Preimplantation Genetic Diagnosis (PGD)
    Removal and gentic analysis of a single cell from a three to five day old embryo. Used to select embryos free of genetic disorders for implantation and development.
  358. Gene Therapy
    • The transfer of cloned genes into somatic cells as a means of treating a genetic disorder.
    • The only successful gene therapy has been in a very few cases of severe combined immunodeficiency disease (SCID).
  359. Somatic Gene Therapy
    • Gene transfer to somatic target cells to correct a genetic disorder.
    • The only form of a gene therapy used to date.
    • Involves a single target tissue treating only one person.
  360. Germline Gene Therapy
    Gene transfer to gametes or the cells that produce them. Transfers a gene to all cells in the next generation, including germ cells.
  361. Enhancement Gene Therapy
    Gene transfer to enhance traits such as intelligence and athletic ability rather than to treat a genetic disorder.
  362. Genetic Counseling
    A process of communication that deals with the occurrence or risk of a genetic disorder in a family.
  363. Gene Mutations
    • A detectable and heritable change in genetic material that is not caused by genetic recombination. (heritable changes in the nucleotide sequence or chromosome)
    • May be: 1. spontaneous as a result of errors in DNA replication or 2. induced by exposure to radiation, chemicals, viruses, or other mutagenic agents
  364. Somatic Mutations
    • Occur in cells of the body that do not form gametes.
    • Are not transmitted to future generations.
  365. Germ-Line Mutations
    • Occur in cells that produce gametes.
    • Are transmitted to future generations -- inherited.
  366. Base Pair Substitutions or Point Mutations
    i.e. AT changed to GC

    • -forward mutations: wild-type to mutant
    • -reverse mutations: mutant to wild-type
    • -suppressor mutations: diminishes the effect of a mutation at another site

    • -ITRAgenic: within a gene
    • -INTERgenic: between genes
  367. Transition Mutation
    Purine to purine or pyrimidine to pyrimidine change.
  368. Transversion Mutation
    Purine/pyrimidine or pyrimidine/purine
  369. Neutral Mutations
    A base-pair change with a change in the amino acid sequence but with no change in the function of the protein.
  370. Silent Mutations
    Nucleotide change but the same amino acid inserted in the protein.
  371. Intercalating Agents
    Insert themselves into the DNA and distort its shape...replication of distorted region can cause a deletion or insertion.
  372. Anticipation
    The appearance of increasing symptoms in succeeding generations.
  373. Photoreactivation
    Photolase: requires light energy (blue) and repairs dimer formation by splitting T=T bonds.
  374. Uracil DNA Glycosylace Repair
    Removed uracil from DNA.
  375. Skin Cancer
    • basal cell carcinoma: tend not to metastasize, usually aren't life threatening
    • squamous cell carcinoma: more serious than basal cell, if left untreated they can metastasize and can be deadly
    • malignant melanoma: very prone to metastasize and are very serious, can definitely kill you
  376. ras proto-oncogene
    Mutations occur at either amino acid 12 or 61 and both lead to tumor formation.
  377. Genetic Disorders Caused by Mutations in DNA Repair Genes
    Autosomal recessive; ataxia telangiectasia, bloom syndrome, fanconi anemia, and xeroderma pigmentosum
  378. Gleevac
    • inactivates the BCR-ABL protein; cancer cells stop dividing
    • has very few side effects and has been very successful at treating CML (chronic myelogenous leukemia)
  379. Charles Steward
    Grew individual carrot cells which grew and divided to form a callus which then grew into full sized carrots (clones).
  380. Embryo Splitting
    After in vitro fertilization, early embryonic cells are divided and grown into clones.
  381. Nuclear Transfer
    Enucleated eggs are fused with embryonic or adult cells and grown into clones. (Dolly the sheep)
  382. Dr. Mullis
    • nobel prize in chemistry in 1993
    • invented PCR
  383. PCR steps
    1. DNA is heated to break down the hydrogen bonds between the two polynucleotide strands (2 single-stranded DNA molecules serve as templates)

    2. Short nucleotide sequences (primers for DNA replication) are mixed with the DNA and bind to complementary regions on single-stranded DNA (takes place at lower temperature; primers are 20-30 nucleotides long)

    3. The enzyme Taq polymerase is added to synthesize a complementary DNA strand (Taq is a DNA polymerase from a bacterium in hot springs).
  384. Clone-by-Clone Method of Genome Sequencing
    • 1. a genomic library is developed
    • 2. physical maps are prepared
    • 3. clones are organized into overlapping groups
    • 4. DNA is cut with restriction enzymes
    • 5. each clone is sequenced and software assembles sequence from the libraries
  385. Shotgun Cloning Method of Genome Sequencing
    • 1. genomic library prepared
    • 2. no genetic or physical maps are created
    • 3. restriction enzymes are used to cut DNA, and overlapping fragments are created
    • 4. clones are selected at random from each library and sequenced
    • 5. assembler software programs organize the information into genomic sequences
  386. Louise Joy Brown
    The first human to have been born after conception through IVF (1978).
  387. Xenotransplants
    Cells, tissues, or organs that are transplanted from one species to another.
  388. Pathogens
    Disease-causing agents.
  389. Antibody-mediated Immunity
    Immune reaction that protects primarily against invading viruses and bacteria using anitbodies produced by plasma cells.
  390. Cell-mediated Immunity
    Immune reaction mediated by T cells directed against body cells that have been infected by viruses or bacteria.
  391. Histamine
    A chemical signal produced by mast cells that triggers dilation of blood vessels.
  392. Inflammatory Response
    The body's reaction to invading microorganisms, a nonspecific active defense mechanism that the body employs to resist infection.
  393. Complement System
    A chemical defense system that kills microorganisms directly, supplements the inflammatory response, and works with (complements) the immune system.
  394. Membrane-attack Complexes (MAC)
    A large, cylindrical multiprotein that embeds itself in the plasma membrane of an invading microorganism and creates a pore through which fluids can flow, eventually bursting the microorganism.
  395. Lymphocytes
    White blood cells that originate in bone marrow and mediate the immune response.
  396. B cell
    A type of lymphocyte that matures in the bone marrow and mediates antibody-directed immunity.
  397. T cell
    A type of lymphocyte that undergoes maturation in the thymus and mediates cellular immunity.
  398. Stem Cells
    Cells with two properties: the ability to replicate themselves, and the ability to form a variety of cell types in the body.
  399. Antibody
    A class of proteins produced by B cells that bind to foreign molecules (antigens) and inactivate them.
  400. Antigens
    Molecules usually carried or produced by viruses, microorganisms, or cells that initiate antibody production.
  401. T-cell Receptors (TCRs)
    Unique proteins on the surface of T cells that bind to specific proteins on the surface of cells infected with viruses, bacteria, or intracellular parasites.
  402. Major Histocompatibility Complex (MHC)
    A set of genes on chromosome 6 that encodes recognition molecules that prevent the immune system from attacking a body's own organs and tissues.
  403. Helper T-cell
    A lymphocyte that stimulates the production of antibodies by B cells when an antigen is present and stimulates division of B cells and cytotoxic T cells.
  404. Plasma Cells
    Daughter cells of B cells, which synthesize and secrete 2,000 to 20,000 antibody molecules per second into the bloodstream.
  405. Memory B Cell
    A long-lived B cell produced after exposure to an antigen that plays an important role in secondary immunity.
  406. Immunoglobulins (Ig)
    The five classes of proteins to which antibodies belong.
  407. Vaccine
    A preparation containing dead or weakened pathogens that elicits an immune response when injected into the body.
  408. Blood Type
    One of the classes into which blood can be separated on the basis of the presence or absence of certain antigens.
  409. Hemolytic Disease of the Newborn (HDN)
    A condition of immunological incompatibility between mother and fetus that occurs when the mother is Rh- and the fetus is Rh+.
  410. Haplotype
    A set of genetic markers located close together on a single chromosome or chromosome region.
  411. Allergens
    Antigens that provoke an inappropriate immune response.
  412. Anaphylaxis
    A severe allergic response in which histamine is released into the circulatory system.
  413. X-linked agammaglobulinemia (XLA)
    A rare, X-linked recessive trait characterized by the total absence of immunoglobulins and B cells.
  414. Severe Combined Immunodeficiency Disease (SCID)
    A genetic disorder in which affected individuals have no immune response; both the cell-mediated and antibody-mediated responses are missing.
  415. Acquired Immunodeficiency Syndrome (AIDS)
    A collection of disorders that develop as a result of infection with the human immunodeficiency virus (HIV).
  416. Epistasis
    The interaction of two or more non-allelic genes to control a single phenotype.
  417. Huntington Disease (HD)
    An autosomal dominant disorder associated with progressive neural degeneration and dementia. Adult onset is followed by death 10 to 15 years after symptoms appear.
  418. Schizophrenia
    A behavioral disorder characterized by disordered thought processes and withdrawal from reality. Genetic and environmental factors are involved in this disease.
  419. Bipolar Disorder
    A behavioral disorder characterized by mood swings that vary between manic activity and depression.
  420. Alzheimer Disease (AD)
    A heterogeneous condition associated with the development of brain lesions, personality changes, and degeneration of intellect. Genetic forms are associated with genes on chromosomes 14, 19, and 21.
  421. Population
    A local group of organisms belonging to a single species, sharing a common gene pool.
  422. Allele Frequency
    The frequency with which alleles of a particular gene are present in a population.
  423. Hardy-Weinberg Law
    The statement that allele and genotype frequencies remain constant form generation to generation when the population meets certain assumptions.
  424. Genetic Equilibrium
    The situation when the allele frequency for a particular gene remains constant from generation to generation.
  425. Gene Pool
    The set of genetic information carried by the members of a sexually reproducing population.
  426. Founder Effects
    Allele frequencies established by chance in a population that is started by a small number of individuals (perhaps only a fertilized female).
  427. Genetic Drift
    The random fluctuations of allele frequencies form generation to generation that take place in small populations.
  428. Evolution
    Changes in allele frequencies in a population over time.
  429. Natural Selection
    The differential reproduction shown by some members of a population that is the result of differences in fitness.
  430. Fitness
    A measure of the relative survival and reproductive success of a specific individual or genotype.
  431. Hominoids
    The superfamily of primates that includes apes and humans.
  432. Hominins
    A classification that includes all bipedal primates from australopithecines to our species.