Amino Acids, Proteins and DNA

• Who is the presenter of the video on amino acids, proteins, and DNA?

  Chris Harris
• What specification is the video dedicated to?

  AQA specification
• What topics are covered in the video?

  Amino acids, proteins, enzymes, DNA
• What is the purpose of the revision videos mentioned?

  To help students prepare for AQA exams
• What is the structure of an amino acid?

  Amino group, carboxyl group, R group
• What does the R group in amino acids represent?

  The organic side chain of the amino acid
• What is unique about glycine compared to other amino acids?

  Its R group is a hydrogen atom
• What does it mean for amino acids to be amphoteric?

  They can act as both acids and bases
• What is the term for amino acids that can exist as zwitterions?


  Zwitterions
• What is the isoelectric point of an amino acid?

  The pH at which the average charge is zero
• How does the pH affect the charge of amino acids?

  Low pH adds H+ ions, high pH removes H+
• What is thin layer chromatography (TLC) used for?

  To separate and identify amino acids
• What is the stationary phase in TLC?

  Silica or alumina on a plate
• Why must the solvent level be below the pencil line in TLC?

  To prevent spots from dissolving in the solvent
• How can amino acids be visualized on a chromatogram?

  Using iodine, ninhydrin, or fluorescent dye
• What happens to amino acids when treated with ninhydrin?

  They develop a purple color
• What is the purpose of calculating RF values in chromatography?

  To identify the amino acids present
• What does RF stand for in chromatography?

  Retention factor
• What does the RF value represent?

  The ratio of distance traveled by solute to solvent
• How do you determine the RF value?

  Distance traveled by amino acid / distance traveled by solvent
• What is the purpose of iodine vapor in chromatography?

  It is a locating agent.
• How can we apply hydrogen solution in chromatography?

  By spraying it onto the chromatogram.
• What is the effect of spraying hydrogen solution on the chromatogram?

  It highlights the amino acid spots.
• What does the number of spots on a chromatogram indicate?

  It indicates the number of amino acids present.
• How do we calculate the RF value in chromatography?

  By dividing the distance traveled by the spot by the distance traveled by the solvent.
• What does RF stand for in chromatography?

  Retention factor.
• What must be the same to compare RF values of amino acids?

  The conditions under which the chromatograms were conducted.
• What are proteins made of?

  Amino acid monomer units.
• What type of polymerization forms proteins?

  Condensation polymerization.
• What links amino acids together in proteins?

  Peptide links.
• What is hydrolysis in the context of proteins?

  Breaking down proteins using water.
• What is formed when two amino acids join together?

  A dipeptide molecule.
• What happens during a condensation reaction of amino acids?

  Water is eliminated while forming peptide links.
• What are the four levels of protein structure?

  Primary, secondary, tertiary, and quaternary.
• What does the primary structure of a protein represent?

  The sequence of amino acids in the protein.
• What is the secondary structure of proteins characterized by?

  Hydrogen bonds forming coils or pleated sheets.
• What is the tertiary structure of a protein?

  The overall 3D shape formed by coiling and folding.
• What types of bonds hold the tertiary structure of proteins together?

  Hydrogen bonds and disulfide bonds.
• How does temperature affect protein structure?

  It can change the shape by affecting bonds.
• What role do enzymes play in biological processes?

  They speed up chemical reactions.