Genes and Genetic Code

• What is the basic unit of genetic information?

  Gene
• What does a gene contain information for?

  Making polypeptides and functional RNA
• How do genes determine inherited characters?

  By coding for polypeptides
• What is the role of DNA in protein synthesis?

  Determines the sequence of amino acids
• What is a locus?

  A fixed location of a gene
• What is an allele?

  Alternate version of a gene
• How many variants of alleles usually occur?

  Usually 2 variants
• What is a triplet code?

  A sequence of three nucleotide bases
• What does each triplet code for?

  A specific amino acid
• How many amino acids regularly occur in proteins?

  20 amino acids
• What happens if there is a different order of amino acids?

  A different protein is produced
• What are introns?

  Non-coding parts of DNA
• What are exons?

  Parts that code for amino acids
• What does it mean for DNA to be non-overlapping?

  Each base can only be in one triplet
• What does it mean for DNA to be degenerate?

  Multiple triplets code for the same amino acid
• What is a codon?

  Three nucleotide bases that code for an amino acid
• What is the effect of a change in the DNA sequence?

  It can lead to a non-functional enzyme
• How does a change in nucleotide sequence affect proteins?

  It alters the primary sequence of amino acids
• What do metabolic pathways help determine?

  The nature and development of an organism
• What is the process of protein synthesis from genes?

  1. DNA sequence determines amino acid sequence
  2. Amino acids join to form polypeptide chains
  3. Different orders of amino acids create different proteins
  4. Proteins determine traits in organisms
• What are the roles of proteins in organisms?

  • Enzymes
  • Hormones
  • Structural proteins
  • Determine characteristics of species
• What are the key features of the genetic code?

  • Non-overlapping
  • Degenerate
  • Universal
  • 64 codons for 20 amino acids