1 Review What is the function of lysosomes Review what is the difference between rough and smooth ER Infer You examine an unknown cell under a microscope and discover that the cell contains chloroplasts. From What type of organism does the cell likely come 2 Review Why is the cell membrane sometimes referred to as a fluid mosaic? What part of the cell membrane acts like a fluid? And what makes it like a mosaic? Explain How do the properties of lipids help explain the structure of a cell membrane Infer Why do you think it’s important that cell membranes are selectively permeable? CH 7 CELL STRUCTURE AND FUNCTION 7.2 Cell Structure Organelles Cellular structures that act as if they are specialized organs. Nucleus Contains the DNA Control center of cell. Nucleolus Synthesis and assembly of tRNA and rRNA Contains one or more. Vacuole Giant storage space Half or more of the space in plant cells Often holds water. Vesicle Small packet for storage or transportation of materials. Lysosome Packet of digestive enzymes Removes “junk.” Cytoskeleton Shape Internal organization Movement Think your own skeleton. Cytoskeleton Microfilaments Threadlike structures made up of actin Tough, flexible framework for support Help cells move. Cytoskeleton Microtubules Hollow structures made up of tubulins Maintaining cell shape Arranged in a “9 + 2” pattern. Centrioles Major role in mitosis Animal cells. Ribosome Site of protein synthesis Made of RNA May be attached on Endoplasmic Reticulum or free. Endoplasmic Reticulum Compartmentalizes cell Site of biosynthesis (lipids) May be smooth or rough depending on presence of ribosomes. Endoplasmic Reticulum Compartmentalizes cell Site of biosynthesis (lipids) May be smooth or rough depending on presence of ribosomes. Golgi Apparatus Modifies Sorts Packages. Golgi Apparatus Modifies Sorts Packages. Golgi Apparatus Modifies Sorts Packages. Chloroplast Site of photosynthesis Plant cells. Mitochondria Site of Cellular Respiration Converts sugar into ATP “Makes” energy “Powerhouse of the cell”. Cell Wall Rigid Provides structure and shape Found in plant cells. Cell Membrane Plasma Membrane Controls what goes in and out of cell Protective boundary Semi fluid Similar to skin. The Properties of Lipids Fatty acid tail are hydrophobic, or “water-hating” Opposite end of the molecule is hydrophilic, or “water-loving.” Selectively permeable Some materials can pass through the membrane and some cannot.