Cell Structure

• A system of internal membranes synthesizes and modifies proteins, lipids, and carbohydrates.
• Chloroplasts convert light energy to chemical energy.
• Mitochondria break down molecules, generating ATP.
• The plasma membrane controls what goes into and out of the cell.
• Plant cells have a protective cell wall.
• DNA in the nucleus contains instructions for making proteins.
• Ribosomes are the sites of protein synthesis.
• The fundamental components of the Cell:

  1. Nucleus
  2. Ribosomes
  3. Endomembrane: RER, SER, Golgi Apparatus, Lysosomes, and Vacuoles
  4. Mitochondria and Chloroplasts
  5. Cytoskeleton
  6. Extracellular Components
• Basic features of all cells

  • Cell membrane (plasma membrane) - selective barrier
  • Cystosol - semifluid, jellylike substance n which subcellular components are suspended
  • Chromosomes - carry genes in the form of DNA

  Ribosomes - complexes that make proteins according to instructions from the genes.
• Fimbriae are attachment structures on the surface of some prokaryotes.
• Nucleoid is the region where the cell's DNA is located, not enclosed by a membrane.
• Ribosomes are complexes that synthesize proteins.
• Plasma membrane is the membrane enclosing the cytoplasm.
• Cell wall is the rigid structure of the plasma membrane.
• Glycocalyx is the outerlayer of many prokaryotic cell consisting of a slime layer.
• Flagella are locomotion organelles of some prokaryotes.
• In eukaryotic cell, the DNA is in an organelle called the nucleus, with a double membrane.
• In prokaryotic cell, the DNA is in a region that is not membrane-enclosed, called the nucleoid.
• Eukaryotic cells have organelles, which are membrane-bound structures that perform specific functions, while prokaryotic cells do not have organelles.
• Eukaryotic cells are generally much larger than prokaryotic cells.
• Eukaryotic cells need to maintain a high ratio of surface area to volume in order to exchange materials with their environment.
• Eukaryotic cells have extensive internal membranes that divide the cell into compartments called organelles.
• The plasma membrane and organelle membranes also participate directly in the cell's metabolism by containing enzymes that carry out important chemical reactions.
• The basic fabric of most biological membranes is a double layer of phospholipids and other lipids, with proteins embedded in or attached to the bilayer.
• Each type of membrane has a unique composition of lipids and proteins suited to its specific functions.
• In Nucleus, Nuclear Envelope is the double membrane enclosing the nucleus; perforated by pores; continuous with ER.
• In Nucleus, Nucleolus is the nonmembranous structure involved in production of ribosomes. A Nucleus has one or more nucleoli.
• In Nucleus, Chromatin is the material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes.
• Plasma Membrane is a membrane enclosing the cell. It is also a semi-permeable.
• Ribosomes are complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelope.
• Golgi Apparatus is an organelle active in synthesis, modification, sorting, and secretion of cell products.
• Lysosome is a digestive organelle where macromolecules are hydrolyzed.
• Mitochondrion is an organelle where cellular respiration occurs and most ATP is generated.
• Peroxisome is an organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product and then converts it to water.
• Microvilli are membrane projections that increase the cell's surface area.
• Cytoskeleton reinforces cell's shape; functions in cell movement; components are made of protein. Includes Microfilaments, Intermediate Filaments, and Microtubules.
• Centrosome is the region where the cell's microtubules are initiated; contains a pair of centrioles.
• Flagellum is a motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane.
• Endoplasmic Reticulum is a network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; has rough (ribosome-studded) and smooth (lipid-studded) regions.
• The nucleus houses most of the genes in the eukaryotic cell, which contain the instructions for building and maintaining the cell.