Cards (37)

  • Who is the presenter of the A Level Biology video?
    Miss Estrich
  • What are the three key features of the genetic code?
    Degenerate, universal, and non-overlapping
  • What is a start codon?
    Three bases at the start of a gene
  • What does the start codon code for?
    Amino acid methionine
  • What are the three bases of the start codon on DNA?
    TAC
  • What is the function of a stop codon?
    It signals the end of translation
  • How many stop codons are there?
    Three
  • What happens when the ribosome reaches a stop codon?
    The ribosome detaches and translation stops
  • What does it mean that the genetic code is degenerate?
    Most amino acids are coded by multiple triplets
  • How many different amino acids are there?
    Twenty
  • What is the mathematical formula to prove the genetic code's combinations?
    4n4^n
  • If the genetic code was one base, how many amino acids could it code for?
    Four
  • If the genetic code was two bases, how many combinations would there be?
    Sixteen
  • How many combinations does a three-base code provide?
    Sixty-four
  • What is a silent mutation?
    A mutation that does not affect the protein
  • What does it mean that the genetic code is universal?
    Same triplet codes for the same amino acid
  • Why is the universality of the genetic code important in gene technologies?
    It allows gene transfer between species
  • What does non-overlapping mean in the genetic code?
    Each base is part of only one triplet
  • What is the advantage of a non-overlapping code?
    Minimizes impact of mutations on proteins
  • What are introns?
    Sections of DNA that don't code for amino acids
  • What percentage of DNA is made up of introns?
    Over 90 percent
  • What are exons?
    Sequences of bases that code for amino acids
  • What is the difference between the genome and the proteome?
    The genome is DNA; the proteome is proteins
  • How does the genome of different organisms vary?
    It varies widely in size and composition
  • How many DNA base pairs are in the human genome?
    About three billion
  • Why do specialized cells produce different proteins?
    They respond to their specific needs
  • What is gene regulation?
    Turning genes on and off as needed
  • What was the first hypothesis regarding genes and enzymes?
    One-gene-one-enzyme hypothesis
  • Why was the one-gene-one-enzyme hypothesis reconsidered?
    Not all proteins are enzymes
  • What is haemoglobin's function?
    Transporting oxygen in the blood
  • What is the structure of haemoglobin?
    Composed of four polypeptide chains
  • What hypothesis was proposed after the one-gene-one-enzyme hypothesis?
    One-gene-one-polypeptide hypothesis
  • What does the one-gene-one-polypeptide hypothesis state?
    Each gene contains multiple triplet codes
  • What are the characteristics of the triplet codes mentioned in the hypothesis?
    Non-overlapping, degenerate, and universal
  • What does each triplet code code for?
    One amino acid
  • What do amino acids combine to form?
    A polypeptide chain
  • What are the key features of the one-gene-one-polypeptide hypothesis?
    • Each gene contains multiple triplet codes
    • Triplet codes are non-overlapping
    • Triplet codes are degenerate
    • Triplet codes are universal
    • Each triplet codes for one amino acid
    • Amino acids combine to form a polypeptide chain