Plant Cell Organelle Functions 1. Each cell has a thick, waxy protective outer layer – the cell wall that prevents the cell from drying out. It is lined on the inside by the plasma membrane, which lets certain things into the cell that it needs, but keeps other things out. This is called semipermeable. 2. Inside the cell is a watery medium in which everything floats, called cytoplasm. It contains all the working parts of the cell, the organelles. 3. Little grains floating around inside the cell are ribosomes, where proteins are made. 4. The nucleus has the DNA that contains the genetic information fr the plant. 5. The nucleus is surrounded by a nuclear membrane, which controls what goes in and out. 6. Rough endoplasmic reticulum (rough ER) is a series of folded membrane pathways spotted with ribosomes. Together the ribosomes and the rough ER make new proteins and new membranes that the cell needs. 7. Chloroplasts contain chlorophyll, a green pigment that traps the light energy needed for photosynthesis to occur. The cells that contain the most chloroplasts are on the upper surface of a leaf exposed to the sun. 8. Golgi apparatus are made up of saccules that package up things to be transported around the cell or that need to leave the cell, like hormones. 9. Lysosomes are vesicles that have digestive enzymes inside them and break down the things that the cell doesn’t need. They also kill bacteria that invades the body. 10. Vacuoles are membrane large membranous sacs for storing things. Vesicles are smaller sacs. cristae 11. Mitochondria have a double membrane that folds in on itself forming little finger-like projections called cristae. Inside is a gel-like matrix with enzymes that break down sugars to make ATP, which is used by the cell as energy. These very important organelles contain their own DNA and ribosomes, reproduce by division and can even produce some of their own proteins.