Lecture Notes: DNA and RNA

Introduction

• DNA often gets credit for genetic storage and coding traits.
• RNA is equally important for transferring genetic messages for protein production.
• Hypothesized that RNA may have existed before DNA (RNA World Hypothesis).

DNA vs. RNA

Location

• DNA: Found in all living organisms, usually in the nucleus (in eukaryotes).
• RNA: Found both inside and outside the nucleus (in eukaryotes).
• Prokaryotes: Lack a nucleus, but contain both DNA and RNA.

Structure

• Both are nucleic acids and consist of nucleotides.
• Nucleotide Components:
  • Phosphate
  • Sugar
  • Base

DNA

• Double-stranded, strands run antiparallel.
• Sugar: Deoxyribose
• Bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C)
• Base pairing mnemonic: A-T (apples in the tree), C-G (car in the garage)

RNA

• Single-stranded.
• Sugar: Ribose
• Bases: Adenine (A), Uracil (U), Guanine (G), Cytosine (C)
• Base pairing mnemonic: A-U (apples under), C-G (car in the garage)

Role in Protein Synthesis

• RNA is crucial for expressing DNA's genetic information.
• Types of RNA:
  • mRNA (Messenger RNA): Carries genetic message from DNA to ribosome.
  • rRNA (Ribosomal RNA): Major component of ribosomes.
  • tRNA (Transfer RNA): Transfers amino acids to ribosome, matching mRNA codons.

Protein Formation

• Amino acids are linked into polypeptide chains.
• Proteins consist of one or more polypeptide chains.

Quiz Questions

Question 1

• Q: 8 DNA nucleotides have how many bases and base pairs?
• A: 8 bases; 4 base pairs.

Question 2

• Q: Complementary DNA sequence for A, T, T, G, A, C?
• A: T, A, A, C, T, G.

Question 3

• Q: Complementary mRNA to DNA sequence A, T, T, G, A, C?
• A: U, A, A, C, U, G (replace T with U).

Additional Information

• Models in video: Simplified representation, not showing 3D structure or chirality.
• Encourage further exploration with provided links.

Note: Always stay curious and continue learning about these fascinating biological molecules.