DNA and Chromosomes

• What does it mean when the DNA code is described as degenerate?

  Most amino acids are coded by multiple codons
• What is a gene?

  A section of DNA coding for a characteristic
• What is an allele?

  A different version of the same gene
• What is a locus?

  A point on a chromosome where a gene is found
• How can a food substance be tested for lipids, proteins, and starch?

  • Lipids: Add ethanol then water for a milky emulsion
  • Proteins: Biuret test changes from blue to purple
  • Starch: Add iodine, turns dark blue/black
• What does it mean that the genetic code is non-overlapping?

  Each base is only within one triplet codon
• What is meant by the genetic code being universal?

  Each triplet codes for the same amino acid in all organisms
• How many chromosomes do humans have in each cell?

  46 chromosomes
• What is a homologous pair of chromosomes?

  Two chromosomes carrying the same genes
• What determines the sex of an individual in humans?

  The 23rd chromosome pair, XX or XY
• What is an allele described as?

  An alternative form of the same gene
• What is the definition of a chromosome?

  Thread-like structure made of DNA and protein
• What are homologous chromosomes?

  Matched pairs of chromosomes based on size and shape
• Where do homologous chromosomes come from?

  One from each parent during inheritance
• What is the shape of prokaryotic DNA?

  Short and circular
• How is prokaryotic DNA condensed?

  By supercoiling
• What is the association of prokaryotic DNA with proteins?

  Not associated with proteins (no histones)
• What type of DNA do mitochondria and chloroplasts contain?

  Short, circular DNA similar to prokaryotic DNA
• What are the features of DNA in prokaryotic and eukaryotic cells?

  Prokaryotic DNA:

  • Short and circular
  • Not associated with proteins
  • No nucleus

  
  

  Eukaryotic DNA:

  • Long and linear
  • Associated with histones
  • Found in the nucleus
• What is the total number of chromosomes in diploid cells?

  46 chromosomes
• What are haploid cells?

  Cells containing half the number of chromosomes
• What is the definition of a genome?

  The complete set of genes in a cell
• What is a proteome?

  The proteins produced by a given cell
• What is non-coding DNA called?

  Intron
• Is non-coding DNA found in prokaryotic cells?

  False
• What form of cell division is for growth and repair?

  Mitosis
• What are the key features of eukaryotic DNA?

  • Long and linear
  • Wrapped around histones
  • Forms chromosomes
• What are the key features of prokaryotic DNA?

  • Short and circular
  • No histones
  • Supercoiling
• What is the difference between exons and introns?

  • Exons: Coding regions of DNA
  • Introns: Non-coding regions of DNA
• What is the difference between diploid and haploid cells?

  • Diploid: Cells with 46 chromosomes
  • Haploid: Cells with 23 chromosomes