Genetics - Middle School

Dive into the gene pool and review this list of terms related to genetics. You'll learn all about DNA, heredity, chromosomes, and more.

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definitions & notes only words
  1. adenine
    purine base found in DNA and RNA
  2. allele
    any of the forms of a gene that can occupy the same locus
  3. asexual reproduction
    reproduction without the fusion of gametes
  4. base
    a phosphoric ester of a nucleoside
  5. base pair
    one of the pairs of chemical bases joined by hydrogen bonds that connect the complementary strands of a DNA molecule or of an RNA molecule that has two strands; the base pairs are adenine with thymine and guanine with cytosine in DNA and adenine with uracil and guanine with cytosine in RNA
  6. carrier
    organism with a recessive gene masked by a dominant allele
  7. cell
    the basic structural and functional unit of all organisms
  8. cell division
    the process in reproduction and growth by which a cell divides to form daughter cells
  9. chromatid
    one of two identical strands into which a chromosome splits during mitosis
  10. chromosomal mutation
    any event that changes genetic structure
  11. chromosome
    a threadlike strand of DNA that carries genes
  12. clone
    a genetically identical organism derived from a single cell
  13. codon
    a specific sequence of three adjacent nucleotides on a strand of DNA or RNA that specifies the genetic code information for synthesizing a particular amino acid
  14. cross-fertilization
    fertilization by the union of male and female gametes from different individual of the same species
  15. cross-pollination
    fertilization by transfer of pollen from the anthers of one flower to the stigma of another
  16. crossing over
    the interchange of sections between pairing homologous chromosomes during the prophase of meiosis
  17. cytosine
    a base found in DNA and RNA and derived from pyrimidine
  18. daughter cell
    a cell formed by the division or budding of another cell
  19. deletion
    (genetics) the loss or absence of one or more nucleotides from a chromosome
  20. dihybrid
    a hybrid produced by parents that differ only at two gene loci that have two alleles each
  21. diploid
    an organism or cell having the normal amount of DNA per cell
  22. DNA
    a long linear polymer found in the nucleus of a cell
  23. DNA fingerprint
    biometric identification obtained by examining a person's unique sequence of DNA base pairs; often used for evidence in criminal law cases
  24. dominant
    an allele that produces the same phenotype
  25. dominant allele
    an allele that produces the same phenotype whether its paired allele is identical or different
  26. double helix
    a pair of parallel helices intertwined about a common axis
  27. Francis Crick
    English biochemist who (with Watson in 1953) helped discover the helical structure of DNA (1916-2004)
  28. gamete
    a mature sexual reproductive cell
  29. gene
    part of DNA controlling physical characteristics and growth
  30. gene expression
    conversion of the information encoded in a gene first into messenger RNA and then to a protein
  31. genetic disorder
    a disease or disorder that is inherited genetically
  32. genetic engineering
    the technology of preparing recombinant DNA in vitro by cutting up DNA molecules and splicing together fragments from more than one organism
  33. geneticist
    a biologist who specializes in genetics
  34. genetics
    the study of heredity and variation in organisms
  35. genome
    the full DNA sequence of an organism
  36. genomics
    the branch of genetics that studies organisms in terms of their genomes (their full DNA sequences)
  37. genotype
    the alleles at specified loci present in an organism
  38. Gregor Mendel
    Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)
  39. guanine
    a purine base found in DNA and RNA; pairs with cytosine
  40. haploid
    (genetics) an organism or cell having only one complete set of chromosomes
  41. heredity
    the transmission of genetic factors to the next generation
  42. heterozygous
    having dissimilar alleles at corresponding chromosomal loci
  43. homologous
    similar in position, structure, function, or characteristics
  44. homozygous
    having identical alleles at corresponding chromosomal loci
  45. hybrid
    the offspring of genetically dissimilar parents or stock
  46. inherited
    occurring among members of a family usually by heredity
  47. inversion
    a kind of mutation in which the order of genes is reversed
  48. James Watson
    United States geneticist who (with Crick in 1953) helped discover the helical structure of DNA (born in 1928)
  49. karyotype
    the appearance of the chromosomal makeup of a somatic cell in an individual or species (including the number and arrangement and size and structure of the chromosomes)
  50. law of independent assortment
    each member of a pair of homologous chromosomes separates independently of the members of other pairs so the results are random
  51. law of segregation
    members of a pair of homologous chromosomes separate during the formation of gametes and are distributed to different gametes so that every gamete receives only one member of the pair
  52. linked genes
    any pair of genes that tend to be transmitted together
  53. meiosis
    cell division in sexually reproducing organisms
  54. mitosis
    the process by which a cell divides into two smaller cells
  55. monohybrid
    a hybrid produced by crossing parents that are homozygous except for a single gene locus that has two alleles (as in Mendel's experiments with garden peas)
  56. mutation
    any event that changes genetic structure
  57. nondisjunction
    meiosis in which there is a failure of paired homologous chromosomes to separate; results in an abnormal number of chromosomes in the daughter cells
  58. nucleotide
    a phosphoric ester of a nucleoside
  59. nucleus
    a part of the cell responsible for growth and reproduction
  60. offspring
    the immediate descendants of a person or organism
  61. pedigree
    the ancestry or lineage of an individual
  62. phenotype
    what an organism looks like
  63. polygenic
    of or relating to an inheritable character that is controlled by several genes at once; of or related to or determined by polygenes
  64. probability
    a measure of how likely it is that some event will occur
  65. protein
    an organic compound essential to living cells
  66. purebred
    bred for many generations from member of a recognized breed or strain
  67. recessive
    of a gene that produces a feature if present in both parents
  68. recessive allele
    an allele that produces its characteristic phenotype only when its paired allele is identical
  69. self-pollination
    fertilization by transfer of pollen from the anthers to the stigma of the same flower
  70. sex cell
    a spermatozoon or an ovum
  71. sex chromosome
    a chromosome that determines the sex of an individual
  72. sex-linked
    concerning characteristics that are determined by genes carried on the sex chromosomes (on the X chromosome in particular)
  73. sexual reproduction
    reproduction involving the union or fusion of a male and a female gamete
  74. somatic cell
    a cell that does not participate in reproduction
  75. substitution
    an event in which one thing is replaced by another
  76. thymine
    a base found in DNA and derived from pyrimidine
  77. trait
    a distinguishing feature of your personal nature
  78. translocation
    (genetics) an exchange of chromosome parts
  79. transposition
    (genetics) a kind of mutation in which a chromosomal segment is transfered to a new position on the same or another chromosome
  80. X chromosome
    the sex chromosome that is present in both sexes: singly in males and doubly in females
  81. Y chromosome
    the sex chromosome that is carried by men
  82. zygote
    the cell from the union of a haploid spermatozoon and ovum
Created on February 7, 2017 (updated April 5, 2017)

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