细胞器图(Organelles Chart)

Cell Wall
• Cell walls are made of cellulose fiber. • Since plants don't have bones, they need a little something extra to support them. When you combine the stiff cell wall with the outward pressure of a full central vacuole, you get enough strength to hold up large plants. Tree cell walls contain other tough materials such as lignin, which make them even stronger.
Vesicles
• Animal Vacuoles (vesicles) are surrounded by membranes. They are small, round structures that transport material around the cell. Vacuoles in animal cells are considerably smaller than those in plant cells. In animal cells vacuoles may store food that needs to be digested. Food cannot pass through membranes until it is broken into smaller particles. The lysosome can fuse with the vacuole membrane and move digestive enzymes into the food vacuole to break down what is in there. Your white blood cells do this when they eat invading bacteria. Vacuoles can also store indigestible wastes until they can fuse with the cell membrane and move the wastes outside. Vesicles in animal cells can also form when the cell membrane surrounds a material and pinches off to bring the substance inside the cell. This process is called endocytosis.
Ribosome
• Through an electron microscope, ribosomes look like tiny dark dots. Sometimes they are floating free in the cytoplasm and sometimes they are attached to membranes like the endoplasmic reticulum and nuclear membrane. • The job of the ribosomes is to help make proteins. They are also needed to translate the genetic code brought from the nucleus to the cytoplasm by messenger RNA (mRNA) molecules.
Central Vacuole
• The central vacuole in plants is much larger than a vesicle in animals. In addition to storing important substances, it also helps support the plant. The turgor pressure of water filling the central vacuole pushes out against the cell wall. This gives the wall enough strength to hold up fairly large green (non-woody) plants. When plants start to wilt it is an indication that it doesn’t have enough water.
Smooth Endoplasmic Reticulum
• The smooth endoplasmic reticulum (SER) has no ribosomes attached; cell membrane lipids are assembled; contain enzymes that detoxify drugs.
Nucleus, Nuclear Membrane, and Nucleolus
The nucleus is one of the most important organelles in the cell. It is sometimes referred to as the brain or control center because of its role in controlling development and life activities. The nuclear membrane surrounds material made up of thin, thread-like chromosomes. The individual chromosomes twist up and become visible only when the cell divides. One or more dense areas can often be seen inside the nucleus. This area is called the nucleolus and is the site of ribosome synthesis.
Cytoplasm and Cytoskeleton
Baidu Nhomakorabea
• The jelly-like insides of a cell is called cytoplasm. We call the fluid part cytosol; cytoplasm includes the cytosol and all the organelles (except the nucleus). • Throughout the cytoplasm are fiber-like proteins -microfilaments and thicker microtubules. These fibers help the cell keep its shape, anchor organelles, and allow for movement inside the cell.
Centrioles
• Centrioles generally appear in animal cells as two cylinders at right angles to one another, close to the nucleus. When viewed with an electron microscope, the cylinders show up as nine bundles of three tiny microtubules arranged in a circle. The centrioles help to form spindle fibers which are microtubules that move chromosomes around when the cell is dividing.
Rough Endoplasmic Reticulum
• The rough endoplasmic reticulum has ribosomes on its surface. Proteins are synthesized on the RER. It is connected to the nuclear envelope.
Animal Cell
Plant Cell
Cell Membrane
The cell membrane is a structure that is the outer boundary of the cell and also surrounds the cytoplasm. The cell (or plasma) membrane serves as a gateway which helps to control materials going in and out of the cell. The membrane is a lipid bilayer composed of phospholipids with "water fearing" (hydrophobic) tails and “water loving” (hydrophilic) phosphate groups. The membrane forms when the phosphate ends point out, attracted to the watery environment of the cell and the lipid ends point in, trying to avoid the water. Embedded in this lipid bilayer are several different kinds of protein molecules.
Golgi Apparatus (Body)
The Golgi complex is like the cell's packaging and shipping department. It is made up of a stack of flattened membrane sacks. Some of the protein transported through the canals of the endoplasmic reticulum ends up in the Golgi complex. Here it may be joined with other molecules before being "packaged". The packages are little pieces of the Golgi body which form vesicles, break off, and move to the cell membrane and fuse with it. It may move its contents outside of the cell as a secretion, or the product assembled in the Golgi complex may be a new piece of the cell membrane itself. In that case the vesicle fuses with the membrane and becomes a part of it. (In plant cells the Golgi complex can assemble material needed for the cell wall.)