Prokaryotic/Eukaryotic Cells and Organelles Biology EOCT Review
Prokaryotic and Eukaryotic Cells Both are enclosed by an outer structure (cell membrane) Both are filled with cytoplasm Both contain ribosomes All of which help the cells maintain homeostasis- a balanced internal environment Eukaryotic cells are larger and more complex Eukaryotic cells have a distinct nucleus and organelles All prokaryotes are unicellular and all bacteria are prokaryotes
Nucleus Directs and controls most cell activities Enclosed by a nuclear membrane Contains the DNA which stores genetic information DNA is organized into condensed structures called chromosomes. Prokaryotes do NOT have a nucleus. Their genetic material is located in one circular chromosome that floats in the cytoplasm.
Cell Membrane Thin, flexible layer that surrounds the cytoplasm Supports and shapes the cell Controls what enters and leaves the cells (maintains homeostasis) Made of a lipid bilayer
Ribosomes Scattered through the cytoplasm of a cell Make proteins Not surrounded by membranes like other organelles
Endoplasmic Reticulum (ER) Transports molecules from one part of the cells to another. Rough ER: dotted with ribosomes and makes large amounts of proteins Smooth ER: regulates some cells processes (breaks down toxic substances in liver cells)
Golgi Bodies Modify and refine proteins and lipids according to where they will be used
Mitochondria Site of cellular respiration Cells that need a lot of energy, such as muscle cells, have many more mitochondriia than cells with lower energy requirements
Lysosomes Carry out digestion in the cell Use enzymes to digest organic compounds Break down old organelles Common in animals and fungi, rare in plant cells
Cell Wall Not found in animal cells A rigid structure that surround the cell membrane of some cells giving them additional support Found in bacteria, fungi, plants and some protists
Chloroplasts Not found in animal cells Capture the energy of sunlight for photosynthesis Found in plant cells and some protists
Vacuoles Small in animal cells, large and central in plant cells Stores water and other dissolved materials Pressure helps support heavy structures such as leaves and flowers in plants