Lecture 01

• What is the genetic material in organisms?

  DNA
• What is the structure of DNA primarily composed of?

  Nucleotides
• What are the components of a nucleotide?

  Sugar, nitrogenous bases, phosphate
• What did Miescher discover in 1869?

  A non-protein substance named nuclein
• What does bacterial transformation implicate about DNA?

  DNA is the genetic material
• What role do nucleic acids play in heredity?

  They are involved in heredity
• What does DNA stand for?

  Deoxyribonucleic acid
• What are the base pairing rules in DNA?

  A-T and C-G pair together

  
• What is the difference between the R strain and S strain of streptococcus pneumoniae?

  R strain is benign; S strain is virulent
• What does Griffith's experiment demonstrate?

  The transforming principle of DNA

  
• What was the purpose of the Avery, McLeod, McCarty experiment?

  To identify DNA as the transforming principle

  
• What happens when enzymes destroy protein, RNA, or DNA in the Avery experiment?

  Transformation is tested for virulent S cells

  
• What did Chargaff measure in DNA molecules?

  The concentration of nitrogenous bases
• How many hydrogen bonds form between A and T in DNA?

  Two hydrogen bonds

  
• How many hydrogen bonds form between G and C in DNA?

  Three hydrogen bonds

  
• What is the orientation of DNA strands?

  DNA strands are anti-parallel
• What does RNA stand for?

  Ribonucleic acid
• What is a key difference between RNA and DNA?

  RNA contains uracil instead of thymine

  
• How is RNA structured compared to DNA?

  RNA is single-stranded
• How long is the largest chromosome in eukaryotic cells?

  279 Mb in size
• How is DNA packaged during mitotic metaphase?

  Into a chromosome 8 micrometres long
• What are the key differences between RNA and DNA?

  • RNA: ribose sugar, uracil base, single-stranded
  • DNA: deoxyribose sugar, thymine base, double-stranded

  
• What are the steps of Griffith's experiment and its significance?

  1. Used two strains of streptococcus pneumoniae
  2. Observed transformation from R strain to S strain
  3. Demonstrated the concept of the transforming principle
• What are the steps of the Avery, McLeod, McCarty experiment?

  1. Remove lipids and sugars from heat-killed S cells
  2. Treat with enzymes to destroy proteins, RNA, or DNA
  3. Add living R cells and observe for transformation

  
• What is the significance of Chargaff's findings?

  • Measured base concentrations
  • Established base pairing rules

  
• How is DNA organised in eukaryotic cells?

  • Single DNA runs the length of each chromosome
  • Packaged into chromosomes during mitosis