Lecture Notes: DNA and RNA

Introduction

• DNA often gets a lot of attention for its structure and role in genetics.
• RNA is equally important in genetic expression and protein synthesis.
• RNA might have preceded DNA (RNA World Hypothesis).

Location in Cells

• Eukaryotic Cells:
  • DNA is found in the nucleus.
  • RNA is found both in and out of the nucleus.
• Prokaryotic Cells:
  • Lack a nucleus.

Structure

• Nucleic Acids:
  • Both DNA and RNA are nucleic acids containing nucleotides.
  • Nucleotides consist of a phosphate, a sugar, and a base.
• DNA:
  • Double-stranded, with strands running antiparallel.
  • Sugar: Deoxyribose.
  • Bases: Adenine (A), Thymine (T), Guanine (G), Cytosine (C).
  • Mnemonic for base pairing: "Apples in the tree" (A-T), "Car in the garage" (C-G).
• RNA:
  • Single-stranded.
  • Sugar: Ribose.
  • Bases: Adenine (A), Uracil (U), Guanine (G), Cytosine (C).
  • Mnemonic adjustment: "Apples under" (A-U).

Functions

• DNA:
  • Codes for genetic traits, requires RNA to express traits.
• RNA Types in Protein Synthesis:
  • mRNA (Messenger RNA): Carries DNA message to ribosomes.
  • rRNA (Ribosomal RNA): Major component of ribosomes.
  • tRNA (Transfer RNA): Transfers amino acids matching mRNA codon.

Example Questions

• Question 1: 8 DNA nucleotides have 8 bases; 4 base pairs.
• Question 2: Complementary DNA bases for A, T, T, G, A, C: T, A, A, C, T, G.
• Question 3: RNA complement for DNA: A, U, U, G, A, C (Use U instead of T).

Further Exploration

• Links provided for additional resources and detailed study of DNA and RNA structures and functions.
• Encouragement to explore more on these fascinating biomolecules.

Eukaryotic cells are organisms whose cells contain a membrane-bound nucleus and other membrane-bound organelles. The lecture notes mention that in eukaryotic cells, DNA is primarily found within the nucleus, while RNA can be found both inside and outside the nucleus. This is in contrast to prokaryotic cells, which lack a nucleus and other membrane-bound organelles.

Prokaryotic cells are simpler than eukaryotic cells and lack a nucleus and other membrane-bound organelles. In prokaryotes, the DNA is located in a region called the nucleoid, which is not enclosed by a membrane. RNA, like in eukaryotes, is involved in protein synthesis and can be found throughout the cell. The absence of a nucleus and other organelles is a key difference between prokaryotes and eukaryotes.