Life Science ePrep Course

Sample Key Terms
(for DNA Structure and Functions)

  • Bacteriophage: virus that infects bacteria.
  • DNA sequence: order of nucleotides in a strand of DNA.
  • Autosome: a chromosome that is the same in males and females.
  • Centromere: of a duplicated eukaryotic chromosome, constricted region where sister chromatids attach to each other.
  • Chromosome: a structure that consists of DNA and associated proteins; carries part or all of a cell’s genetic information.
  • Chromosome number: the total number of chromosomes in a cell of a given species.
  • Diploid: having two of each type of chromosome characteristic of the species (2n).
  • Histone: type of protein that structurally organizes eukaryotic chromosomes.
  • Karyotype: image of an individual’s set of chromosomes arranged by size, length, shape, and centromere location.
  • Nucleosome: a length of DNA wound twice around a spool of histone proteins.
  • Sex chromosome: member of a pair of chromosomes that differs between males and females.
  • Sister chromatids: the two attached DNA molecules of a duplicated eukaryotic chromosome.
  • DNA ligase: enzyme that seals gaps in double-stranded DNA.
  • DNA polymerase: DNA replication enzyme. Uses one strand of DNA as a template to assemble a complementary strand of DNA from nucleotides.
  • DNA replication: process by which a cell duplicates its DNA before it divides.
  • Nucleic acid hybridization: convergence of complementary nucleic acid strands. Arises because of base-pairing interactions.
  • Primer: short, single strand of DNA that base pairs with a targeted DNA sequence.
  • Semiconservative replication Describes the process of DNA replication, which produces two copies of a DNA molecule: one strand of each copy is new and the other is parental.
  • Mutation: permanent change in the nucleotide sequence of DNA.
  • Differentiation: process by which cells become specialized during development; occurs as different cells in an embryo begin to use different subsets of their DNA.
  • Reproductive cloning: technology that produces genetically identical individuals.
  • Somatic cell nuclear transfer (SCNT): reproductive cloning method in which the DNA of an adult donor’s body cell is transferred into an unfertilized egg.
  • Therapeutic cloning: the use of SCNT to produce human embryos for medical purposes.
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