2.3 + 2.4 Nucleic acids and enzymes

• What is the process of transcription?

  It is the synthesis of RNA from DNA.
• What role does gyrase play in transcription?

  It unwinds the double helix of DNA.
• What does helicase do during transcription?

  It breaks hydrogen bonds between nitrogenous bases.
• What is the function of RNA polymerase in transcription?

  It uses a gene as a template to form a complementary strand of RNA. RNA polymerase forms the phospdiester bonds
• What does mRNA carry and where does it go?

  It carries genetic information to ribosomes.
• Why does transcription take place in the nucleus?

  Because DNA is too big to leave the nucleus.
• What is translation in the context of protein synthesis?

  It is the process of making a protein from mRNA code.
• What attaches to a ribosome during translation?

  mRNA attaches to a ribosome.
• How is mRNA read during translation?

  In sets of 3 bases called codons.
• What is the role of tRNA in translation?

  It brings a specific amino acid to the ribosome.
• What does each tRNA molecule have?

  A specific anti-codon that pairs with mRNA codons.
• What is the function of peptidyl transferase?

  It forms peptide bonds between amino acids.
• What signals the end of protein synthesis?

  A stop codon signals the end.
• How does the order of amino acids affect proteins?

  It determines the structure of the protein.
• What are the components of a nucleotide?

  • Phosphate group
  • Pentose sugar
  • Nitrogenous base
• What type of sugar is found in DNA?

  Deoxyribose
• What is the structure of DNA?

  Double helix
• What type of sugar is found in RNA?

  Ribose
• What is the structure of mRNA?

  Single strand
• What is the role of mRNA?

  Template for protein synthesis
• Where is DNA found?

  In the nucleus
• Where is mRNA found?

  In the nucleus and cytoplasm
• Where is tRNA found?

  In the cytoplasm and ribosomes
• Where is rRNA found?

  In the ribosomes
• Where is DNA found in chloroplasts?

  In the chloroplasts
• What type of bond connects nucleotides?

  Phosphodiester bond
• What type of bond connects nitrogenous bases?

  Hydrogen bond
• What type of bond connects sugars to bases?

  Glycosidic bond
• What is the definition of anabolic processes?

  Building up large molecules
• What is the definition of catabolic processes?

  Breaking down large molecules
• What is the lock and key model in enzyme activity?

  • Enzyme's active site has a complementary shape
  • Substrate fits into the active site
  • Temporary hydrogen bonds form an enzyme-substrate complex
• What is the induced fit hypothesis in enzyme activity?

  • Substrate fits into the active site
  • Active site changes shape slightly to mold around substrate
  • Active site remains complementary but fits more precisely
• How does decreasing temperature affect enzyme activity?

  It decreases kinetic energy and reaction rate
• How does increasing temperature affect enzyme activity?

  It increases kinetic energy and reaction rate
• What happens to enzymes at too high temperatures?

  They denature and lose their active site shape
• What is the consequence of enzyme denaturation on enzyme-substrate complexes?

  No more enzyme-substrate complexes can form
• What role do temporary hydrogen bonds play in enzyme activity?

  They hold the enzyme-substrate complex together
• What is formed when an enzyme and substrate bind together?

  Enzyme-substrate complex
• What is the effect of less successful collisions on enzyme activity?

  It leads to a lower rate of reaction
• What happens to the active site when an enzyme denatures?

  It changes shape and is no longer complementary