Lab1 semester2 (1).pdf

Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab1 Bacteria Bacteria are unicellular microorganisms that are prokaryotic, meaning that they lack a nucleus and other membrane-bound organelles. Instead, their genetic material is lo...

Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab1 Bacteria Bacteria are unicellular microorganisms that are prokaryotic, meaning that they lack a nucleus and other membrane-bound organelles. Instead, their genetic material is located in a single circular chromosome in the cytoplasm. Bacteria come in a variety of shapes and sizes, including: 1. Coccus: spherical or ovoid shaped bacteria, such as Streptococcus and Staphylococcus. 2. Bacillus: rod-shaped bacteria, such as Escherichia coli and Salmonella. 3. Spirillum: spiral-shaped bacteria, such as Vibrio cholerae and Helicobacter pylori. The structure of bacteria can be divided into several parts: 1. Cell wall: The cell wall is a rigid outer layer that provides shape and support to the cell. It is made up of peptidoglycan, a complex molecule that gives the cell wall its strength. 2. Cell membrane: The cell membrane is a semi-permeable membrane that separates the cell's cytoplasm from its environment. It controls the movement of molecules in and out of the cell. 3. Cytoplasm: The cytoplasm is a gel-like substance that contains the cell's genetic material, ribosomes, and other cellular machinery. It is the site of many of the cell's metabolic processes. 4. Flagella: Some bacteria have flagella, which are long, whip-like structures that enable the bacteria to move around. 1 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab1 5. Pili: Some bacteria have pili, which are short, hair-like structures that enable the bacteria to attach to surfaces and other cells. 6. Capsule: Some bacteria have a capsule, which is a protective layer that surrounds the cell wall. It can help the bacteria to evade the host's immune system. Overall, the structure of bacteria is relatively simple compared to eukaryotic cells, but it is still highly specialized and well-adapted to their environment.\ Classification of bacteria Bacteria are classified into different groups based on their physical and biochemical characteristics. The classification of bacteria is constantly evolving as new species are discovered and new technologies are developed for their identification. The following is a general overview of the main groups of bacteria: 1. Gram-positive bacteria: These bacteria have a thick peptidoglycan layer in their cell wall that stains purple when exposed to a Gram stain. 2. Gram-negative bacteria: These bacteria have a thinner peptidoglycan layer in their cell wall that stains pink when exposed to a Gram stain. 2 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab1 3. Cyanobacteria: These bacteria are photosynthetic and use chlorophyll to convert light energy into organic compounds. They are important producers of oxygen in the environment. 4. Spirochetes: These bacteria are spiral-shaped and have a flexible cell wall. They are responsible for a number of diseases, including syphilis and Lyme disease. 5. Chlamydia: These bacteria are obligate intracellular parasites and rely on the host cell for replication. They are responsible for a number of diseases, including chlamydia and trachoma. 6. Actinobacteria: These bacteria have a filamentous structure and are responsible for producing a number of antibiotics, including streptomycin and tetracycline. Bacterial infections Bacterial infections are caused by harmful bacteria that can invade the human body and cause a range of symptoms, from mild to severe. Bacteria are single-celled microorganisms that can live on or inside the human body, and while some bacteria are helpful and necessary for health, others can cause infections. Bacterial infections can affect any part of the body, including the skin, respiratory system, urinary tract, gastrointestinal tract, and bloodstream. Some common types of bacterial infections in humans include: Staph infections: These are caused by the Staphylococcus aureus bacteria and can cause skin infections, pneumonia, and sepsis. Streptococcal infections: These are caused by the Streptococcus bacteria and can cause strep throat, scarlet fever, and skin infections. E. coli infections: These are caused by the Escherichia coli bacteria and can cause food poisoning, urinary tract infections, and sepsis. 3 Biology practical 2 First class, Second semester Ass. Lec.Dunya.A.Mohammed Lab1 Salmonella infections: These are caused by the Salmonella bacteria and can cause food poisoning, gastroenteritis, and typhoid fever. Pneumococcal infections: These are caused by the Streptococcus pneumoniae bacteria and can cause pneumonia, meningitis, and sepsis. Bacterial infections can spread through contact with infected people, contaminated food or water, or contact with surfaces that have been contaminated with bacteria. Symptoms of bacterial infections can include fever, fatigue, inflammation, pain, and difficulty breathing, among others. Treatment of bacterial infections usually involves antibiotics, which are medications that kill or stop the growth of bacteria. It is important to take antibiotics exactly as prescribed and for the full duration of the prescription, even if symptoms improve, to ensure that all the bacteria are eliminated from the body. Preventing bacterial infections can be achieved by practicing good hygiene, such as washing your hands regularly, avoiding close contact with sick people, and avoiding sharing personal items like towels or utensils. Vaccines are also available for some bacterial infections, such as pneumococcal and meningococcal infections, which can help to prevent these infections from occurring in the first place. 4