STRUCTURE AND FXN PT.2

CYTOPLASM Gelatinous material inside the cell membrane It is semitransparent, fluid, elastic and aqueous It contains cytosol, inclusions, ribosomes, cytosomes and, in some bacteria, endospores

CYTOSOL Liquid portion of cytoplasm Mostly water Holds ions, carbohydrates, proteins, lipids and wastes Also contains the nucleoid region containing the DNA Cytosol is the site of the chemical rxns in the cell Enzymatic production of amino acids and degradation of sugar

INCLUSIONS (INCLUSION BODIES) Storehouses of the cells components Presence of specific types of inclusions are diagnostic for certain pathogenic bacteria Bacteria can store carbon and energy in the form of glycogen (polymer of glucose) or PHB a lipid polymer PHBs can be slightly modified to make a biodegradable plastic

ENDOSPORES Formed as a defense strategy against hostile or unfavorable conditions (pH, moisture, oxygen level) High heat required to kill them Bacillus and Clostridium (botulinum and tetani) are two pathogenic families that produce them Not rust but dirt on a nail Vegetative cells are in active growth phase Vegetative cells transform themselves into endospores under certain conditions Scientists claim to have revived 250 million year old Bacillus endospores

RIBOSOMES Non membranous organelle Thousands per cell Sites of protein synthesis Size measured in Svedbergs (S) based on sedimentation rates in a centrifuge Larger more dense particles move to bottom faster Prokaryotic ribosomes are 70S compared to 80S in Eukaryotic cells Prok. 70S ribosomes have a 30S and 50S subunit Diff. sizes of ribosomes betw. pro/euk. cells is important to some treatments

CYTOSKELETON Structural framework Provides shape In some cases movement for non flagellated bacteria

GLYCOCALYX MADE OF BOTH POLYSACCHARIDES (SUGARS) AND POLYPEPTIDES (PROTEINS) Capsule Organized and tightly attached Provides protection from drying (desiccation) Provides protection from detection Strep. pneumoniae and Klebsiella pneumoniae capsules help avoid detection in the respiratory system Slime layer Loose, water soluble Provides protection from drying (desiccation) Sticky and helps adhere to host Ex. Dental caries

MOVEMENT AND ATTACHMENT STRUCTURES Fimbriae and Pili Provide attachment Necessary for pathogenicity in some species Neisseria gonorrhea that lack fimbriae are non- pathogenic Pili are slightly longer and also provide a means of transferring genetic material Flagella Long whip-like structure Provides movement Taxis = movement in response to a stimulus Chemotaxis – chemical stimulus Phototaxis – light stimulus