Lecture Notes on Cell Organelles

Overview

• Focus on cell organelles: nucleus, ribosomes
• Summary at the end

Cells: Basic Unit of Life

• Types of Cells
  • Eukaryotic cells: plants, animals, fungi
  • Prokaryotic cells: typically bacterial cells
• Eukaryotic Cells
  • Larger, more features than prokaryotic
  • Membrane-bound organelles

Membrane Structure

• Cell surface membrane: lipid bilayer
• Organelles have their own membranes for specific functions

Ribosomes

• Function: protein synthesis
• Found in eukaryotic cells

The Nucleus

• Definition: Largest organelle in eukaryotic cells, contains DNA
• Structure
  • Spherical shape with a dark patch (nucleolus) inside
  • Double membrane: nuclear envelope
• Function
  • Contains DNA, which codes for protein production
  • DNA packed with histone proteins, forming chromatin
  • Nuclear pores allow mRNA and ribosomes to move in/out

DNA and Chromatin

• DNA contains genetic information
• Packed efficiently with histone proteins
• Human cells contain 2 meters of DNA
• Chromatin: DNA + histone proteins

Nuclear Envelope

• Double membrane structure
• Protects DNA from cytoplasm
• Contains nuclear pores

Nucleolus

• Dense DNA and protein structure inside the nucleus
• Involved in ribosome production

Ribosome Production

• Ribosomes made in the nucleolus
• Ribosomes help in protein synthesis

Cytoplasm and Nucleoplasm

• Cytoplasm: Fluid environment of the cell
• Nucleoplasm: Fluid inside the nucleus, surrounds chromatin and nucleolus

Ribosomes

• Translate genetic material into proteins
• Found in two locations:
  • On the endoplasmic reticulum (ER) membrane
  • Free in the cytoplasm
• Structure
  • Composed of ribosomal RNA (rRNA) and protein
  • Two subunits: 40S and 60S

Endoplasmic Reticulum

• Structure: elongated, sac-like
• Ribosomes attach to its membrane

Conclusion

• Ribosomes and nucleus play critical roles in protein synthesis
• Understanding organelles is crucial for cell biology

Additional Resources

• Consider exploring more on DNA structure and function
• Engage with bite-size video tutorials for deeper understanding

Note: For detailed understanding, refer to additional resources and video tutorials mentioned.