DNA and RNA

DNA AND RNA

DNA and RNA are the two major nucleic acids found in living organisms. They store, carry, and express genetic information.
Think of DNA as the master blueprint, and RNA as the messenger/worker that brings the instructions to life.

1. DNA (Deoxyribonucleic Acid)

DNA is the molecule that carries hereditary information in almost all living organisms.

Structure of DNA

• Double-stranded helix (twisted ladder shape)

• Made of nucleotides:

  • Sugar: deoxyribose

  • Phosphate group

  • Nitrogenous bases:

    • Adenine (A)

    • Thymine (T)

    • Cytosine (C)

    • Guanine (G)

Base Pairing Rule

• A pairs with T

• C pairs with G
  (Held by hydrogen bonds)

Location

• Mostly in the nucleus

• Small amounts in mitochondria (mtDNA)

Functions of DNA

• Stores genetic information

• Controls cell activities by coding for proteins

• Passes traits from parents to offspring

• Directs cell division and growth

Properties

• Can replicate (copy itself)

• Very stable

• Long and double-stranded

2. RNA (Ribonucleic Acid)

RNA helps carry out the instructions stored in DNA.

Structure of RNA

• Single-stranded

• Nucleotides contain:

  • Sugar: ribose

  • Phosphate group

  • Nitrogenous bases:

    • Adenine (A)

    • Uracil (U) (replaces thymine)

    • Cytosine (C)

    • Guanine (G)

Location

• Cytoplasm

• Ribosomes

• Nucleus (during formation)

Types of RNA

1. mRNA (Messenger RNA)

   • Carries the genetic message from DNA to the ribosome

   • Acts like a delivery rider 🚴‍♂️ of protein instructions

2. tRNA (Transfer RNA)

   • Brings amino acids to the ribosome for protein synthesis

   • Like a loader that brings materials

3. rRNA (Ribosomal RNA)

   • Makes up the ribosomes

   • The “factory” where proteins are made

DNA vs RNA (Comparison Table)

Relationship Between DNA and RNA

• DNA stores instructions

• RNA reads and executes the instructions

• Together, they ensure protein synthesis and heredity