Genetic code

• 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 in 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?

  Four to the power of 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 are there with three bases?

  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 definition of a genome?

  Complete set of DNA in one cell
• What is the definition of a proteome?

  Full range of proteins in one cell
• How does the genome differ from the proteome?

  The genome is stable, while the proteome changes
• How many DNA base pairs are in the human genome?

  About three billion
• How many DNA base pairs are in the average bacterial genome?

  About six hundred thousand
• 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 is alternative splicing?

  A process involving introns and exons
• What is junk DNA?

  DNA that does not code for proteins
• Why are introns sometimes called junk DNA?

  They are often spliced out and not used
• What is the significance of the genetic code in protein synthesis?

  It determines the sequence of amino acids
• How does the genetic code facilitate genetic engineering?

  It allows gene transfer across species
• What is the role of the ribosome in translation?

  It assembles amino acids into proteins
• What happens to the mRNA after translation?

  It is used to synthesize proteins
• What is the relationship between genes and proteins?

  Genes code for the synthesis of proteins
• How do mutations affect protein synthesis?

  They can change the amino acid sequence
• What is the importance of the genetic code in evolution?

  It allows for variation and adaptation
• How does the genetic code contribute to biodiversity?

  It enables different traits to be expressed