Bacteria BY LILAH BOJANOSKI, JENNA CAVALIERE, CHRISTINA FONTANAROSA, TESSA PRUSHAN

Overview Prokaryotes Anaerobes Reproduction Genetic recombination Bacterial recombination Drug resistance

Characteristics of Prokaryotic Cells DNA is found in a single prokaryotic bacterial chromosome. Bacterial cells divide by binary fission Binary fission – a type of asexual reproduction The bacteria in a colony are identical to the parent cell TP

Transformation “the uptake of foreign DNA from the surrounding environment” Frederick Griffith experimented with harmless bacteria that had DNA from dead cells. This bacteria carried a gene that animals were immune to. Now this previously harmful bacteria can infect animals when they gain this gene. TP

Transduction “The transfer of bacterial genes by a phage” Phage - a virus that is in bacteria A DNA fragment that belongs to a phage’s host cell is accidentally packaged within the phage’s coat instead of phage DNA. When the phage infects the bacterial cell, the DNA from the other host is injected into the new host. TP

Conjugation “This union of cells and the DNA transfer between them” “Male” donor cell has a sex pili that is attached to the “female” recipient cell. Outside layers of the cell conjoined, cytoplasmic bridge formed between them. The donor cell replicates its DNA so it doesn’t lose any genes. TP

Background Anaerobes and Aerobes Superoxide- An oxide containing the negatively charged ion O2 Superoxide is deadly to obligate anaerobes Fermentation used when there is no oxygen Fermentation creates less energy than aerobic respiration Oxidative stress occurs when a cell has a lot of oxygen inside it CF

Obligate Anaerobes Obligate= strictly Does not require oxygen to survive Lives in an area without oxygen Deadly for them to be exposed to atmospheric levels of oxygen Do not have enzymes that change superoxide formed in their cells Fermentation Use sulfate, nitrate, iron, manganese, or carbon monoxide as electron carriers CF Superoxide Dismutase is an enzyme that breaks down superoxide in the cells. Clostridium botulinum is an example of an obligate anaerobe.

Facultative Anaerobes Can produce energy through aerobic respiration, but can switch to use anaerobic respiration Depends on oxygen levels and the amount of fermentable material in the area If oxygen is available, they use aerobic respiration If oxygen is NOT available, some ferment and use anaerobic respiration Include fungi such as yeasts CF Yeast is an example of a facultative anaerobe.

Obligate Aerobes Oxygen is needed To get energy, they need oxygen to oxidize substrates such as sugars and fats Oxygen is the final electron acceptor Create more energy than obligate anaerobes, but they deal with high levels of oxidative stress Includes most fungi, almost all animals, and some bacteria CF Aerobic respiration

How bacterial cells reproduce Bacteria cells are asexual and don’t need a mate to reproduce Bacteria reproduce by binary fission The bacterium (single cell), divides into 2 identical daughter cells Binary fission begins when DNA of bacterium divides into 2 (replicates) The bacterial cell lengthens and splits into 2 daughter cells Each daughter cell is a clone of the parent cell JC

How bacterial cells reproduce When conditions are right, temperature and nutrients are available to bacteria That’s why we become ill when pathogenic microbes (sickness causing bacteria) infect our bodies JC

Genetic recombination A process in which pieces of DNA are broken and recombined to produce new combinations of alleles involves exchanging of genetic material between multiple chromosomes or between different parts of the same chromosome JC

Genetic recombination One ex. of recombination in diploid eukaryotic organisms is exchange of genetic information between duplicated chromosomes during meiosis outcome of recombination is to make sure each gamete includes maternal and paternal genetic info, so the child inherits from all 4 grandparents, resulting in a max amount of genetic diversity JC

Obtaining Energy Photosynthesis Use solar energy to turn CO 2 and water into glucose and oxygen Glucose is food for bacteria Decomposers Break down waste and dead organisms Use organic substrates broken down for energy LB

Obtaining Energy Mutualism Depend on other organisms for survival Live in roots of legumes Turn nitrogen-containing molecules into nitrogen for plants to use Parasitism Cause illness Bacteria benefits, organism harmed LB

Autotrophs and Heterotrophs AUTOTROPHS Make their own food Chemoautotroph Synthesize organic compounds from carbon dioxide Photoautotroph Convert inorganic materials into organic materials for biosynthesis Inorganic material- not derived from living organisms and contains no organically produced carbon Biosynthesis- the production of complex molecules within living organisms or cells HETEROTROPHS Have to consume their energy Chemoheterotroph Use carbon for energy from sulfur, carbohydrates, lipids, and proteins Photoheterotroph Depend on light for their source of energy LB

Antimicrobial Resistance When bacteria is able to resist antibacterial drugs Standard treatments become ineffective Bacteria evolve to become resistant/immune to medicine LB

Summary Bacteria can consume or produce its own energy Oxygen may (aerobic) or may not (anaerobic) need to be present to make energy Meiosis is an example of genetic recombination Bacterial cells divide by binary fission Bacteria can develop a resistance to antibacterial drugs