Study Notes
DNA is the blueprint of life, containing the genetic instructions for the development and functioning of living organisms. It is composed of two strands forming a double helix, with each strand made up of nucleotides.
- DNA — a molecule that carries genetic information. Example: Found in the nucleus of eukaryotic cells.
- Griffith's Experiment — demonstrated that harmless bacteria could transform into harmful bacteria. Example: Transformation of rough strain bacteria into smooth strain in mice.
- Nitrogenous Bases — components of nucleotides that form the genetic code. Example: Adenine, Thymine, Cytosine, Guanine.
- Phosphodiester Bonds — link nucleotides together in a DNA strand. Example: Connects the 5’ phosphate group of one nucleotide to the 3’ hydroxyl group of another.
- Mutation — a change in the DNA sequence that can lead to different phenotypes. Example: Sickle cell anemia caused by a mutation in the hemoglobin gene.
- Gene Editing — the alteration of DNA sequences to modify genetic information. Example: CRISPR technology used for precise gene modifications.
Exam Tips
Key Definitions to Remember
- DNA
- Griffith's Experiment
- Nitrogenous Bases
- Phosphodiester Bonds
- Mutation
- Gene Editing
Common Confusions
- Confusing DNA with RNA
- Misunderstanding the role of nitrogenous bases in genetic coding
Typical Exam Questions
- What was the main conclusion of Griffith’s experiment with Streptococcus pneumoniae? Harmless bacteria can transform into harmful bacteria.
- Which part of the DNA structure is responsible for the genetic code? Nitrogenous bases
- How does DNA influence an organism's traits? By encoding instructions for protein production
What Examiners Usually Test
- Understanding of DNA structure and function
- Knowledge of historical experiments related to DNA
- Ability to explain the process and implications of mutations