International A Level Biology / Proteins and DNA

Meselson and Stahl: proving semi-conservative replication

Edexcel International A Level Biology (YBI11), chapter 5: Proteins and DNA, specification point 2.10. Part of the full course.

Read the revision notes · International A Level Biology past papers

Meselson and Stahl used heavy and light nitrogen to test how DNA replicates. The DNA bands showed that replication is semi-conservative: each new DNA molecule contains one original strand and one new strand.

More lessons in Proteins and DNA

• Enzymes: biological catalysts
• Active sites, specificity and induced fit
• Core practical 4: measuring the initial rate of an enzyme reaction
• Temperature, pH, enzyme and substrate concentration
• Nucleotides, DNA and RNA
• Semi-conservative DNA replication
• The genetic code
• Transcription: DNA to mRNA
• Translation: mRNA to polypeptide