cells

• cells - are the building blocks of all organisms
• four common components of all cells: plasma membrane, cytoplasm, DNA , ribosomes
• prokaryotic cell - mostly single-celled (unicellular) organism lacks a nucleus, or any other membrane-bound organelle (Bacteria and archae)
• flagella- used for locomotion
• pili - used to exchange genetic material during reproduction
• fimbria - used to attach to a host cell
• eukaryotic cell - cell that contains a nucleus and other membrane-bound organelles (cells of animal , plants, fungi, and protists)
• Anthony van Leeuwenhoek - observed the movements of protista and sperm which he collectively termed "animalcules"
• Robert Hooke - coined the term "cell" for the box-like structures he observed when viewing cork tissue through a lens
• Matthias Schleiden (botanist) and Theodor Schwann (zoologist) - were studying tissues and proposed the unified cell theory
• Why are cells small?

  as cells grow, it becomes less efficient. Its surface area-to-volume ratio decreases.
• organelle - means little organs with specialized cellular funtions
• Animal cells each have a centrosome and lysosomes, whereas plant cells do not. Plant cell have a cell wall, chloroplast and other special plastids, and a large central vacuole, whereas animal cells do not.
• Eukaryotic cells is typically larger than prokaryotic cells
• cell membrane - controls the passage of organic molecules, ions, water, and oxygen into and out of the cell.
• wastes also leave the cell by passing through the cell membrane
• phospholipids - permit lipid-soluble materials to easily enter or leave the cell by diffusion through the cell membrane
• the presence of cholesterol decreases the fluidity of the membrane, thus , making it more stable
• proteins - are embedded in the phospholipid bilayer as extrinsic or intrinsic proteins
• extrinsic proteins - occur either on the surface of the bilayer or only partly embedded in it
• intrinsic proteins - completely span the phospholipid bilayer from one side to the other
• nucleus - contains the organism's hereditary material, controls the cell's activities
• nuclear envelope - a double membrane that surround the nucleus, controls the exit and entry of materials in and out of the nuecleus and contains the reactions taking place within it
• nuclear pores - allows the passage of large molecules, such messenger RNA, out of the nucleus
• nucleoplasm - jelly-like materials that makes up the bulk of the nucleus
• chromatin - the DNA found within the nucleoplasm , diffuse form that chromosomes take up when the cell is not dividing
• nucleolus - manufactures the RNA and assembles the ribosomes
• Cytoplasm - cell organelles that is found between the cell membrane and the nucleus
• cytosol - the water portion of cytoplasm, and many chemical reactions take place within it
• organelles -allow different functions to be compartmentalized in different areas of the cell
• Endoplasmic reticulum (ER) - continous with the outer nuclear membrane
• rough ER - has ribosomes present on the outer surfaces of the membranes,

  • provide a large surface are for synthesis of proteins and glycoproteins
  • provide a pathway for the transport of proteins throughout the cell
• smooth ER - lacks ribosomes on its surface and is often tubular in appearance , synthesize, store and transport lipids- synthesize, store, and transports carbohydrates
• ribosomes - synthesize proteins, small cytoplasmic granules found in all cells
• proteasome - cut protein molecules apart, particularly important during cell division and during embryonic development, when great changes are taking place very rapidly cells become specialized
• Golgi apparatus - more compact than smooth er , add carbohydrate to proteins to form glycoproteins, produce secretory enzymes and carbohydrates, transport, modify and store lipids, form lysosomes
• lysosomes - produced by Golgi apparatus contain enzymes such as proteases and lipases , isolate potentially harmful enzymes from the rest of the cell before releasing them
• exocytosis - releases enzymes to the outside of the cell
• autolysis - completely break down cells after they have diesd
• mitochondria - responsible for the production of ATP, an energy carrier molecules derived from carbohydrates