BL/CH401 Biochemistry 1 - Lecture 2 - Cell Structure

Typical Animal Cell: Eukaryotic Cell Organelles (Fig. 15 to 18)

Figure 15. Eukaryotic Cell - Nucleus
Nucleus contains DNA molecules, nucleolus, and RNA molecules. Histones (Proteins) bind to DNA to organize the chromosomes and chromosomal replication or mitosis.

Nucleolus processes RNA for export, perinuclear membrane controls export of RNA and import of cytoplasmic proteins. Proteins from cytoplasm regulate the genes to be expressed as messenger RNA.

Figure 16. Eukaryotic Cell - Mitochondria
Mitochondria are cellular energy producers. They have two membranes and entrap an aqueous phase separated from the cytoplasm. They also contain DNA and synthesize their own proteins for insertion into their inner membrane. Their outer membrane controls access to the matrix and allows in only proteins with special target sequences.

Eukaryotic Cell - Microbodies:

Figure 17. Eukaryotic Cell - Peroxisome
Microbodies (Peroxisomes) and lysozomes both have single membrane and no DNA. Peroxisomes oxidize amino acids and generate hydrogen peroxide, which is broken down by catalase. Catalase sometimes forms a crystal within the peroxisome.

Figure 18. Eukaryotic Cell - Lysozome
Lysozomes- garbage disposal system- contain degradative enzymes and digest cell when it dies.

Figures 3-10; and 13-25 are modified from Lehninger, Biochemistry, ©19??, Worth Publishing Co.

©Wilbur H. Campbell, 1995, 1996; wcampbel@mtu.edu

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