Chapter two page 23

Cell theory- states that all living things consist of one or more organised structures that are called cells.  Cells are the basic building blocks of life Cell  tissue  organs  organ systems  human

 Cells can be divided into two categories  Prokaryotic cells  Eukaryotic cells

 Smallest living cells  Have a cell membrane and cytosol  Lack membrane bound organelles  Have no nuclear membrane  Have just one circular chromosome Eg- bacteria, archaebacteria and eubacteria (any kind of microbe)

 Are larger than prokaryotic cells  Animals, plants, fungi and protists (protists are unicellular or very simple multicellular life forsm)  Eukaryotic cells are often specialized and organized into complex multicellular life forms

 Contain membrane bound organelles suspended in a fluid and semi-fluid matrix known as cytosol (when organelles, the membrane and cytosol are together this is referred to as cytoplasm)  Have a distinct double layered nuclear membrane  Have many linear chromosomes

 A light microscope allows us to examine cells, but they usually only have a magnification of 400X.  Not all organelles are visible due to them being to small to see with a light microscope with a magnification of 400X  Many organelles are transparent and require staining to high light them under a microscope.

 A double layer of phospholipids embedded with protein molecules, glycoproteins and some carbohydrates. Function: encloses cell contents regulates the movement of materials into and out of the cell, helps to maintain shape and communicated with neighbouring cells  Found in prokaryotic cells, plant and animal cells

 Surrounded by a double membrane. The nucleus is usually large compared to other organelles. Contain chromosomes and nucleolus Function: information in the chromosomes controls the production of proteins in the cell. These proteins in turn control cellular functions.  Found in animal and plant cells

 A double membrane containing many pores, which separates the nucleoplasm from the rest of the cell Function: Regulates the movement of material between the cytoplasm and nucleus.  Present in animal and plant cells

 Few to thousands found in the cytoplasm  Sacs made up of two membranes. The inner membrane is folded to create cristae which increase the surface area. The cristae enclose the fluid filled matrix. Function: the site of aerobic cellular respiration, they are responsible for most of the cell’s energy production. They are most abundant in cells that require high energy i.e. muscle cells, kidney cells Found in animal and plant cells

 Some are free within the cytosol, others are attached to rough E.R  Small spherical bodies composed of RNA and protein. Function: The site of protein synthesis Found in prokaryotic, animal and plant cells

 Throughout the cytoplasm  A network of membranes creating channels in the cytoplasm, from the nucleus to the cell membrane Function: the site of lipid synthesis and transport of many material through the cell. Abundant in cells which produce steroid hormones Found animal and plant cells

 Found throughout the cytoplasm  A network of membranes creating channels in the cytoplasm. Rough E.R. is studded with ribosomes Function: transport and folding of proteins produced by ribosomes, synthesis of glycoproteins. Parts of the E.R. pinch off to become vesicles for the transport of proteins to the membrane or to other organelles including Golgi bodies Found in animal and plant cells

 Stacks of flattened membrane sacs Function: packages proteins into vesicles for secretion from the cell or to be sent to other organelles; synthesises cellulose in plant cells. Abundant in cells which export cell products. found in animal and plant cells

 Found throughout the cytoplasm of animal cells.  A membrane sack containing many digestive enzymes. Basically are a sac that breaks things down  Contain enzymes which digest ingested materials and wastes. Important in programmed cell death. Only found in animal cells

 One large one is found in plant cells. Within animal cells there can be one to many small ones  A membrane bound sac containing fluid, sugars and ions. Appear as clear areas when seen through a microscope Function: important in plant cells by helping keep the plant leaves shape, also is used for storage of sugars, ions and food. Found in plant cells

 Surrounded by a double membrane, contains stacks of membrane embedded in less dense membrane and fluid  Few to many cells found in cells which photosynthasise Function: the site of photosynthesis, contains chlorophyll, the pigment that traps light energy. Abundant in leaf cells Found in some plant cells

 Not really an organelle is on the outside of the cell.  A layer of cellulose (in plants) that completely surrounds the cell membrane. Other chemicals make up the cell wall in bacteria and fungi Function: provides structural support and defines the shape of the cell Found in plants and prokaryotic cells