2 Prokaryotes The smallest and most common of cells are prokaryotes. They:Exist almost everywhere on earthAre cells that do not have a nucleusDo not have membrane-bound organellesAll prokaryotes are placed into one of two kingdoms:Eubacteria or Archaebacteria
3 Eubacteria Make up the larger of the two prokaryote kingdoms Generally are surrounded by a cell wall composed of complex carbohydratesWithin the cell wall is the cell membrane that surrounds the cytoplasm
5 Cyanobacteria Also known as the blue-green bacteria Are photosynthetic (Contain membranes that carry out the process of photosynthesis)Contain phycocyanin and chlorophyll aCan be found nearly everywhere on earth.Can survive in extremely hot environments and even extremely cold environment
6 ProchlorobacteriaProchlorobacteria are a newly discovered group of organisms.They contain chlorophyll a & b.They are more similar to chloroplasts of green plants.Only 2 species of prochlorobacteria have been discovered.
7 Archaebacteria Lack important carbohydrate found in cell walls Have different lipids in their cell membrane, types of ribosomes, and gene sequencesArchaebacteria can live in extremely harsh environmentsThey do not require oxygen and can live in extremely salty environments as well as extremely hot environments.
10 Bacteria can be arranged in: -cluster-chains-colonies or pairs
11 2) Cell WallsTo study bacterial cell walls, one must stain it. This is called gram staining.Chemical nature of a cell wall can be determined by gram stainingGram’s stain consists of 2 dyes: crystal violet (purple) and safranine (red).By finding out what color the cell produces when it is gram stained you can figure out the type of carbohydrates in the cell wall
12 Gram staining The bacteria will take up either one or the other stain. Gram-positive bacteria with only one thick layer of carbohydrates and proteins will take up the crystal violetStaphylo E. colicoccusGram-negative bacteria with a second, outer layer of lipid and carbohydrate molecules will take up the safranine
13 3) Bacterial Movement Some have 1 or more flagella Some lash, snake, or spiral forwardSome secrete slimy stuffSome don’t move!
14 MovementFlagella ~ Tail like structure the whips around to propel the bacteriumCillia ~ Miniature flagella surround the cell that help to “swim”Non motile ~ Sticky cillia like structures that keep the bacterium from movingCillia
15 4) Bacteria and their energy AutotrophsMake their own food from inorganic moleculesHeterotrophsConsume organic molecules made by other organisms
16 Autotrophs Phototrophic autotrophs trap the energy of the sunlight Eg. CyanobacteriaChemotrophic autotrophs obtain their energy from inorganic molecules
17 HeterotrophsChemotrophic heterotrophs obtain their energy by taking in organic molecules then breaking them down and absorbing themPhototrophic heterotrophs use the sun’s energy but they also need organic compounds for nutrition
18 Review: What type of cells are the most common? prokaryotesWhat are the 4 ways we can identify bacteria?Cell shape, cell wall, movement, obtain energyWhat are the 3 basic shapes of bacteria?Rod (bacilli), sphere (cocci), spiral (spirilla)What is gram-staining?Gram positive (purple), gram negative (red)What are the 2 different ways bacteria obtain energy?Autotrophic, heterotrophic
19 Bacterial Respiration Bacteria need constant energy through respiration and fermentationRespiration is the process that involves oxygen and breaks down food for the release of energy.Fermentation enables cells to carry out energy production without oxygen
20 Bacterial Respiration Obligate AerobesObligate AnaerobesFacultative AnaerobesCannot live without oxygen.Must live without oxygenCan live with or without oxygen
21 Example of an obligate anaerobe: Clostridium botulinum An example of an obligate anaerobe is Clostridium botulinum, which produces toxins. If these bacteria find their way into a place that is free of air (O2), and filled with food material, they will grow very quickly. As they grow, they produce toxins, or poisons, that cause botulism. Botulism produces paralysis and if the breathing muscles are paralyzed, death.
23 Bacteria Reproduction In favorable conditions, bacteria can grow and divide quickly.They can reproduce in the following ways:Binary FissionConjugationSpore Formation
24 Cellular organism copies its genetic information then splits into two identical daughter cells
25 Conjugation A type of Bacteria Sex Two organism swap genetic information, that contains the information such as a resistance to penicillin
26 Spore Formation: Endospore A type of dormant cellHighly resistant to environmental stressesEndospores are formed by cells in response to environmental signals that indicate a limiting factor for growth, such as exhaustion of an essential nutrient.
27 Importance of Bacteria Bacteria is often used in:FoodSourdough bread, cheese, yoghurtIndustryBreak down oilMedical/cosmetic procedures
28 SymbiosisBacteria develop a close relationship with other organisms in which the bacteria and the other organism both benefitFor example: the bacteria E. coliThis is found in the human digestive tract.The intestine provides a warm safe home withlots of food.The bacteria then helps us to digest food andmake some vitamins that we can’t produceby ourselves.For cattle, the bacteria in their intestines help them produce the enzymes necessary to break down cellulose, which is mostly in grass and hay. Bacteria helps cattle digest their food.
29 Other types of relationships ParasitismBacteria exploit the host cell, injuring themEg. Mychobacterium tuberculosisMutualismRelationship in which two species live together in such a way that neither are harmed
30 Bacteria in the Environment Nutrient FlowBacteria recycle and decompose, or break down, dead materialSewage DecompositionIe. Bacteria capable of digesting the hydrocarbons in petroleum are often used to clean up oil spillsNitrogen FixationProcess by which nitrogen in the atmosphere is converted into a form that can be used by living things
32 Review Differentiate between: Name ways in which we use bacteria today Respiration and fermentationObligate aerobes, obligate anaerobes, and facultative anaerobesBinary fission, conjugation, and spore formationSymbiosis, parasitism, and mutualismName ways in which we use bacteria today
Your consent to our cookies if you continue to use this website.