4Cell Boundaries Plasma Membrane – semi-permeable membrane Cell Wall Plants, Fungi, and Bacteria have this additional boundaryLocated outside the plasma membraneProvides additional support and protection (cellulose)Allows molecules to pass through (no selection)
5Cytoplasm Clear, jelly-like fluid that supports the cell Site of chemical reactionsHouses all of the other organelles
6Cytoskeleton Organelles don’t float freely in a cell. They are supported by structures in the cytoplasm – the cytoskeleton.The cytoskeleton is a network of long, thin protein fibersProvides a framework for the cellProvides anchorage for organellesMade of microtubules and microfilaments
7Microtubules and Microfilaments of the Cytoskeleton Microtubules – long, hollow protein cylinders that form a rigid skeleton for the cell and assist in moving substances within the cell.Microfilaments – thin protein threads that help give the cell shape and enable the cell and its parts to move.
9Nucleus Nucleolus Inside nucleus Makes ribosomes Contains DNA which stores information for making proteins for cell growth, function, and reproduction.Nuclear Envelope – the membrane surrounding the nucleus. It’s similar to the plasma membrane.NucleolusInside nucleusMakes ribosomes
10Ribosomes Are made in the nucleolus. Found bound to rough ER and floating in the cytoplasm.No membraneSite of protein synthesis (protein assembly) according to directions from the nucleus.Cells have many ribosomes that produce a variety of proteins that are used by the cell or are sent out to be used by other cells.Free-floating ribosomes produce proteins in the cytoplasm to be used by the cell.ER-bound ribosomes produce proteins which will be packaged within membranes or to be used by other cells.
11Endoplasmic Reticulum (ER) Highly folded membranes suspended in the cytoplasmSite of protein synthesis and lipid synthesis2 Types:Rough ER – area on ER where ribosomes attach, make and transport proteins (cellular highway).Smooth ER – area where no ribosomes are attached, makes lipids (like phospholipids, for example), transports proteins, breaks down harmful substances (liver cells).
13Golgi Apparatus Flattened system of tubular membranes Modifies proteins by attaching carbohydrates and lipidsSends proteins to the plasma membrane in packages called vesicles to be exported outside the cell.“Post-Office”
14LysosomesContain digestive enzymes to break-down worn-out organelles, food particles, viruses, and bacteriaCan fuse with vacuoles to digest the contentsFound only in animal cells“Clean-up crew” of the cell
15Centrioles Animal cells only Made of microtubules Function during cell division.More about these in Chapter 9.
16Mitochondria “Powerhouse” – energy-generator for the cell In plant and animal cellsConverts fuel particles (in the form of sugars) to energy
17Chloroplasts Only in plant cells Contain the green pigment chlorophyll Site of photosynthesis – captures light energy and converts it to chemical energy the plant cell can use
18Vacuoles Sac-like structure Plant cells contain one large one Animal cells usually don’t contain vacuoles but if they do, they are small.For temporary storage of water, food, enzymes and/or wastes.
19Cytoskeleton Provides structure and support Works like poles of a tent Assists organelles in moving around the cell
20CiliaShort, hair-like fibers (protein based) that move in a wave-like motion to propel (move) the cell or materials along surface of cellparameciumTracheal cells (#3 is mucous particle)
21Flagella Long, whip-like projections that propel the cell Protein based