• DNA & RNA: Both have four bases, but one of them is different in each.
• What are they called? Nitrogenous bases because of the nitrogen element in them (think of them as the DNA's own nitrogen superheroes!).
• The Combo Meal: Each nucleotide (the building block) has one base. So there are four types of nucleotides.

Real-World Example: Think of DNA as a super long train with four types of cars (nucleotides). You can connect them in any way because the connectors (phosphate and sugar) are universal, like universal charger plugs!

• Any Sequence Possible: DNA or RNA molecules can have almost infinite sequences of bases.
• The Universal Code: This sequence stores info in a coded form, like a secret spy code for all organisms!

Real-World Example: Imagine DNA as an endless LEGO tower. You can arrange the 4 different bricks (bases) in any order, creating countless designs. It's like the world's most complex jigsaw puzzle!

• Difference in Adenine: It has a unique feature that sets it apart from other bases.
• Nitrogen's Role: The nitrogen bonded to hydrogen helps in assembling the nucleotide.
• Adenine & Guanine Twins: They share three similarities, like two peas in a pod.
• Cytosine & Thymine Comparison: Though similar, they differ in structure.
• Importance of Distinct Bases: Having a distinctive chemical structure ensures that the DNA functions properly, like keys fitting into specific locks.

Real-World Example: Imagine the bases as unique puzzle pieces. If the pieces (bases) were not distinctive, you wouldn't be able to fit them together in the correct way. It would be like trying to build a puzzle with pieces from different boxes!