1. Introduction to Cells

15. Prokaryotes are single-celled organisms, roughly one micrometer in diameter. The cell's genetic material consists of a large DNA molecule concentrated in an area called the nucleoid region , so it’s not membrane-bound. The plasma membrane encases the cytosol and its contents. Some prokaryotes have a cell wall surrounding the plasma membrane. Not all prokaryotes can move, but those that can often use a flagellum to propel them through the environment. Prokaryotes

18. The most striking differences between eukaryotic cells are between animal cells and plant cells. Plant cells have all of the organelles listed on the previous slide plus three more. The plasma membrane of a plant cell is surrounded by a rigid cell wall . It protects the cell and maintains its shape. Plants have a second power plant in addition to mitochondria. Organelles called chloroplasts convert the sun's energy to chemical energy during photosynthesis. While the large central vacuole is the third distinguishing feature of plant cells. They store chemicals, including large molecules and toxic substances. PLANT CELL