microbe and cellular bio

• cell 


  is the fundamental unit of any living organism because it exhibits the basic characteristics of life
• eukaryotic and prokaryotic

  two categories of cells
• true nucleus 


  consists of nucleoplasm, chromosomes, and a nuclear membrane
• Eukaryotic cells 


  contain a true nucleus, possess a complex system of membranes and membrane-bound organelles and a cell membrane
• prokaryotic cells


  do not have a true nucleus, a complex system of membranes and membrane-bound organelles but have a cell membrane
• Eukaryotic Cell membranes

  have selective permeability, allowing only certain substances to pass through them
• ekuaryotic nucleus


  the “command center” of the cell, has three components (nucleoplasm, chromosomes, and a nuclear membrane), and the chromosomes, consisting of linear DNA molecules and proteins, are embedded in the nucleoplasm.
• Gene


  are located along chromosomes. and contain the information to produce one or more gene products (usually proteins).
• genotype or genome


  An organism’s complete collection of genes
• Ribosomal ribonucleic acid (rRNA) and Transfer ribonucleic acid (tRNA)


  Although most genes code for proteins, some code for two types of ribonucleic acid, which are
• 46 chromosomes (23 pairs)


  Human diploid cells have
• Eukaryotic Cytoplasm

  A semifluid, gelatinous, nutrient matrix, contains storage granules and a variety of organelles, and is where most metabolic reactions occur
• Endoplasmic reticulum


  A highly convoluted system of membranes arranged to form a transport network in the cytoplasm
• Eukaryotic Ribosomes

  consist of ribosomal RNA and protein and the sites of protein synthesis
• Golgi complex


  connects or communicates with ER, and completes the transformation of newly synthesized proteins and packages them for storage or export (“packaging plants”)
• Lysosomes and peroxisomes


  these organelles originate in the Golgi complex
• Lysosomes 


  contain lysozyme and other digestive enzymes
• Peroxisomes 


  are membrane-bound vesicles where H2O2 is generated and broken down
• Eukaryotic Mitochondria

  ATP molecules are produced within mitochondria by cellular respiration and its number varies depending on the activities of the cells
• Plastids


  Membrane-bound structures containing photosynthetic pigments and the sites of photosynthesis
• Chloroplasts 


  a type of plastid that contains chlorophyl
• Cytoskeleton


  A system of fibers throughout the cytoplasm
• eukaryotic cell wall

  an external structure to provide shape, protection, and rigidity, which is simpler in structure than prokaryotic cell walls
• Chitin 


  found in cell walls of fungi
• Cellulose 


  found in cell walls of algae and plants
• flagella


  long, thin, whiplike organelles of locomotion
• cilia


  shorter, thinner, and more numerous than flagella, and described as being hair-like
• Prokaryotic cells


  are about 10 times smaller than eukaryotic cells, more simple and reproduce by binary fission
• prokaryotic Cell membrane

  Selectively permeable with many enzymes are attached to this as it is where metabolic reactions take place
• Prokaryotic Chromosome


  usually consists of a single, long, supercoiled, circular DNA molecule and serves as the control center of the cell
• Plasmids


  small, circular molecules of DNA that are not part of the chromosome (extra chromosomal)
• prokaryotic Cytoplasm

  a semiliquid that consists of water, enzymes, waste products, nutrients, proteins, carbohydrates, and lipids—materials required for metabolic functions
• Prokaryotic ribosomes


  some occur in clusters, are smaller than eukaryotic ribosomes, but their function is the same—they are the sites of protein synthesis
• Bacterial cell wall


  A rigid exterior that defines the shape of bacterial cells—chemically complex
• peptidoglycan 


  Main constituent of most bacterial cell walls, which is found only in bacteria
• Gram-positive bacteria 


  have a thick layer of peptidoglycan
• Gram-negative bacteria


  have a much thinner layer
• Mycoplasma spp.

  do not have a cell wall. thus, they are pleomorphic
• Glycocalyx


  a slimy, gelatinous material produced by the cell membrane and secreted outside the cell wall
• slime layer and capsule 


  two types of glycocalyx