Cytoplasm: is a partly fluid material, which can flow slowly and in which many other substances are suspended such as large fat and protein molecules. Many of the chemical reactions take place in the cytoplasm, which will provide the cell with energy and allow it to build up larger molecules that it needs. Studying the cell further and using better more powerful microscopes has shown that the cytoplasm actually contains lots of small structures called organelles. These have different roles and separate the reactions. In a cell. Examples are mitochondria where energy is released and ribosomes where proteins are made in a cell.
Plasma membrane: consists of two layers of phospholipids (a fatty substance) with some protein molecules embedded in them.
The membrane protein performs several functions. Branched carbohydrate molecules attached to the outside of some membrane protein molecules give the cell its immunological identity. They can act as specific receptors for hormones and other chemicals massagers. Some of them are enzymes and some are involved in transport across the membrane.
Nuclear membrane: the layer that surrounds the nucleus. The nuclear membrane is a double membrane formed by two lipid bilayers separated by a gap of20-40nm (the perinuclear space). About 15% of its surface is made of nuclear pores, which indicate that it too has a large amount of substances passing in and out of the nucleus.
Nucleus: in every cell in the body has a nucleus, with the exception of the mature e erythrocytes (the red blood cells). The nucleus is the largest structure inside the cell and is contained with in a membrane similar to the plasma membrane, but it has tiny pores through which some substances can pass between it and the cytoplasm. The nucleus contains the entire DNA and its main function is to control all the activities of the cell.
Nucleolus: The Nucleolus also known as nucleoli is a dense spherical structure within the cell. These dark staining spherical structures are ribosome-producing centers. The nucleolus contains RNA for the synthesis of ribosome’s and plays an important part in RNA and protein synthesis.
What are Electron Microscopes?
Electron Microscopes use a beam of electron rather than visible light. An electron microscope not only gives a high resolution. This means that details can be seen clearly.
An electron microscope is very similar to a light microscope in the ways in which it works. Instead of using glass lenses to focus a beam of light, it uses magnets to focus a beam of electrons. Specimens that are to be examined must be cut into very thin sections.
The main differences between a light microscope and an electron microscope are the methods of focusing glass lenses magnets; the specimens can be dead or alive; and that the electron can magnify up to 50,0000 times.
Functions of the components seen under an electron microscope.
Nucleus: The positively charged central mass of an atom about which the orbital electrons revolve. The nucleus is composed of nucleons, that is, protons and neutrons, and it accounts for nearly all the mass of the atom.
Membrane: A membrane surrounds each organ in the body. Extensions of which often anchored the organ to the body wall. These membranes are made up of layers of cells, often only a very few cells thick.
Vacuoles: Vacuoles are surrounded by membranes. They are sort of like a storage bubble in the cytoplasm. Food cannot pass through membranes until it is broken into smaller particles. The lysosome can fuse with the vacuole membrane and squirt 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 the indigestible wastes until they can fuse with the cell membrane and squirt the wastes outside.
Ribosome: Have sub cellular particles on which proteins are synthesized. Bacterial ribosome is approximately 20 nm or 200 A (angstroms) in diameter. In higher organisms, ribosome is associated with internal cell membranes (the endoplasmic reticulum) protein synthesis in mitochondria or chloroplasts uses ribosome smaller than and different from those in the cytoplasm.
Lysosome: A lysosome is a membrane bag containing digestive enzymes. When a cell needs to digest food, the lysosome membrane fuses with the membrane of a food vacuole and squirts the enzymes inside. The digested food can then diffuse through the vacuole membrane and enter the cell to be used for energy or growth. The only thing that keeps the cell itself from being digested is the membrane surrounding the lysosome.
