Genes and Chromosomes

• What is a gene?

  A sequence of DNA bases coding for proteins
• What does the sequence of amino acids in a polypeptide form?

  The primary structure of a protein
• What determines the order of amino acids in a polypeptide?

  The order of bases in a gene
• What is a triplet or codon?

  A sequence of three bases in a gene
• What is the first stage of protein synthesis?

  DNA is copied into messenger RNA (mRNA)
• What do genes that don't code for polypeptides code for?

  Functional RNA
• What are examples of functional RNA?

  tRNA and ribosomal RNA (rRNA)
• What is the complete set of genes in a cell called?

  The cell's genome
• What is the full range of proteins a cell can produce called?

  The cell's proteome
• What does non-coding DNA refer to in eukaryotes?

  Nuclear DNA that doesn't code for polypeptides
• What are introns?

  Sections of DNA that don't code for amino acids
• What happens to introns during protein synthesis?

  They are removed
• Do prokaryotic DNA have introns?

  No, prokaryotic DNA doesn't have introns
• What are exons?

  Bits of a gene that code for amino acids
• What are non-coding multiple repeats?

  DNA sequences that repeat and don't code for amino acids
• What is an allele?

  A different form of a gene
• How do alleles differ from each other?

  The order of bases in each allele is slightly different
• What are the three alleles for blood type?

  Type O, type A, and type B
• How many pairs of chromosomes do humans have?

  23 pairs
• What are homologous chromosomes?


  Pairs of matching chromosomes in a nucleus
• What is the characteristic of homologous chromosomes?

  Same size and same genes, different alleles
• What is the fixed position of a gene on a chromosome called?

  Locus
• Where are alleles coding for the same characteristic found?

  At the same fixed position on homologous chromosomes
• What are the key components of genes and chromosomes?

  • Genes are sequences of DNA bases.
  • Genes code for polypeptides or functional RNA.
  • Chromosomes are structures that store DNA in eukaryotic cells.
  • Humans have 23 pairs of chromosomes.
• What are the differences between introns and exons?

  • Introns: Non-coding sections of DNA, removed during protein synthesis.
  • Exons: Coding sections of DNA that determine amino acid sequences.
• What is the relationship between genes, alleles, and chromosomes?

  • Genes: Basic units of heredity.
  • Alleles: Different forms of a gene.
  • Chromosomes: Structures containing genes in pairs.