Energetics 


Biological systems use energy and molecular building blocks to grow, reproduce and maintain dynamic homeostasis.



Prokaryotic Cells - contain NO membrane bound organelles, dna is naked and circular. Usually no introns and no nucleus. No membrane bound, 705 ribosomes. Binary fission single chromosome (haploid)

Eukaryotic Cells - contain membrane bound organelles (mitochondria and chloroplast) and membrane systems (ER, Golgi)

  • ARE COMPARTMENTALIZED

  • Animal, plant, fugi, protist

Prokaryotic Cells & Eukaryotic Cells Similarities

  • A cell membrane and cytoplasm 

  • DNA

  • Ribosomes

  • Metabolic activity 

  • (anabolism = synthesis rxn's) (catabolism = break down rxn's)



Prokaryotic cells and eukaryotic cells difference

  • DNA (composition and structure)

  • Organelles (types present and relative sizes)

  • Reproduction (mode differs according to chromosome structure)

  • Average size (exceptions may exist)

  • Compartamentalizing

  • Two kinds of partitioning are present in eukaryotic cells:

  • Membrane bound organelles, nucleus, mitochondria,

Benefits of Compartamentalizing

  • Creates "microenvironments" where specific metabolic processes can occur at the same time 

  • Mitochondria (glucose metabolism & ATP production)

  • Chloroplast 

  • The endomembrane system is made up of a series of membranes suspended within the cytoplasm. These membranes are known as internal membranes and divide the cell into various compartments.

  • As  discussed in Topic 2.2, these membrane-bound structures are called organelles and have specific roles that help the cell survive and maintain homeostasis.  They are found only in eukaryotes.

  • Because organelles are membrane-bound, their contents are considered to be compartmentalized.  This means they are able to maintain an internal chemistry different from the rest of the cell.

  • Internal membranes
    facilitate cell processes by minimizing competing interactions. They also greatly increase the surface area. The more surface area that is available, the more membrane-bound enzymes that can be utilized

Membranes and membrane-bound organelles localize intracellular metabolic processes.They also isolate specific enzymatic reactions.Examples include: Nuclear Envelope, Endoplasmic reticulum, (ER)Mitochondria

  • The nuclear envelope is a membrane that surrounds the genetic material and nucleolus.  It contains the enzymes and materials necessary to maintain DNA (e.g. DNA polymerase for replication)

  • The membrane of the endoplasmic reticulum has many folds, which greatly increases its surface area.  This allows the rough ER to synthesize, package and modify vast amounts of molecules.

  • The internal membrane plays many roles.  In addition to compartmentalizing the enzymes needed for cell respiration, it also increases the surface area where ATP can be synthesized (Topic 4).