Explain the major differences between a prokaryotic and a eukaryotic cell. Describe the structure and function of the nucleus. Briefly describe and distinguish among the following cell structures: endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, peroxisomes, chloroplasts, and mitochondria. What is the purpose of the cytoskeleton? Describe the nature of the fluid-mosaic model as it relates to membrane structure. Explain why phospholipids play such an important role in the structure of the cell membrane. Distinguish between active and passive transport. Compare diffusion and osmosis across a membrane. Compare facilitated transport with active transport. Define tonicity, and explain its relevance to passive transport. Discuss the relationship between metabolism, anabolism, and catabolism. Use an example in your discussion. Explain what metabolic pathways are. Explain how ATP is used by the cell as an energy source. Describe the structure of a chloroplast. Describe the overall process of photosynthesis. Describe the steps that occur in Calvin cycle reactions.