Biology Module 6 & 7: Cell Functions

Module 6: Cell Functions and Prokaryotic vs. Eukaryotic Cells

• All cells share three core functions:

  • Metabolism
  • Reproduction
  • Maintain homeostasis

• Prokaryotic cells lack membrane-bound organelles, while eukaryotic cells possess them.

Module 7: Eukaryotic Cell Structures and Functions

• Compartmentalization increases eukaryotic cell efficiency by separating cellular processes.

• Endomembrane system components:

  • Endoplasmic Reticulum (ER): Rough ER (protein synthesis) and Smooth ER (lipid synthesis, detoxification).
  • Golgi apparatus: Modifies, sorts, and packages proteins and lipids.
  • Vesicles: Transport materials between organelles.
  • Lysosomes: Contain digestive enzymes that break down cellular waste.

• Mitochondria carry out cellular respiration (ATP production).

• Chloroplasts carry out photosynthesis (energy conversion).

• Plant cell walls provide support and structure, primarily composed of cellulose.

Module 8: Cell Size and Surface Area-to-Volume Ratio

• Cell size is limited by the ratio of surface area to volume (SA:V).
• A smaller surface area-to-volume ratio is associated with larger cells.
• Larger SA:V favors exchange of materials with the environment.

Module 9: Cell Membranes

• Phospholipids are amphipathic molecules (both hydrophobic and hydrophilic).
• Membrane fluidity is affected by temperature and cholesterol content.
• Integral proteins span the membrane; peripheral proteins are bound to a surface.
• Membrane proteins can perform transport, signal reception, or enzymatic activities.

Module 10: Membrane Transport

• Hydrophobic molecules readily cross cell membranes via passive diffusion.
• Diffusion is the movement of a substance down a concentration gradient, a spontaneous process.
• Potential energy is created by a concentration gradient.
• Osmosis, facilitated diffusion, and active transport are different types of membrane transport.

Module 11: Osmosis and Water Potential

• Hypertonic solutions have a higher solute concentration than the cell; hypotonic solutions have lower solute concentration; isotonic solutions have equal solute concentration.
• Osmosis is the diffusion of water across a semipermeable membrane.
• Water moves toward the region of higher solute concentration to maintain equilibrium.
• Water potential (Ψ) is used to predict water movement. Water will move from high Ψ to low Ψ.
• Living cells regulate water balance differently based on the presence of a cell wall.

Module 12: Endosymbiotic Theory

• Endosymbiotic theory proposes that mitochondria and chloroplasts evolved from prokaryotic cells engulfed by larger cells.
• Evidence for the theory includes the double membrane of these organelles and their similar size and DNA replication process to prokaryotes.

Explore the essential functions of cells and the differences between prokaryotic and eukaryotic cells in this quiz. Delve into cell structures, including the endomembrane system and organelles involved in energy processes like cellular respiration and photosynthesis. Test your understanding of how these components work together to maintain cellular efficiency.