Cell Types and Bacteria PDF

**CELL TYPES-** Cell types refer to the different kinds of cells that make up all living organisms. Just like how different parts of a car have different functions, different cell types in a body or plant have different roles. **Examples of Cell Types:** 1. **Muscle Cells**: These cells make up y...

**CELL TYPES-** Cell types refer to the different kinds of cells that make up all living organisms. Just like how different parts of a car have different functions, different cell types in a body or plant have different roles. **Examples of Cell Types:** 1. **Muscle Cells**: These cells make up your muscles. They are designed to contract and expand, allowing you to move your body. 2. **Nerve Cells (Neurons)**: These cells are like the body\'s communication system. They send signals between your brain and other parts of your body, helping you think, feel, and move. 3. **Red Blood Cells**: These cells carry oxygen from your lungs to all parts of your body and bring carbon dioxide back to the lungs to be exhaled. 4. **Skin Cells**: These cells form a protective barrier on the outside of your body, keeping harmful things out and moisture in. 5. **Plant Cells**: In plants, you might have leaf cells that are packed with chloroplasts to help the plant make food using sunlight (photosynthesis). Each cell type is specialized to perform its specific function, and together, they all work to keep an organism alive and healthy. In prokaryotic cells, such as bacteria, the **capsule** is an outer layer that surrounds the cell wall. It is made up of polysaccharides (sugar molecules) and sometimes proteins. **Functions of the Capsule:** 1. **Protection**: The capsule protects the bacterial cell from being eaten or destroyed by the immune system of a host organism. It helps the bacteria to avoid detection and destruction by immune cells, making it harder for the host to fight off an infection. 2. **Preventing Desiccation**: The capsule helps the bacterial cell retain moisture, preventing it from drying out in harsh environments. 3. **Attachment**: The capsule can help bacteria stick to surfaces, such as tissues in a host organism or non-living surfaces like rocks or medical devices. This ability to adhere is important for forming colonies or biofilms. 4. **Resistance to Chemicals**: The capsule can provide some resistance to harmful chemicals, making it harder for antibiotics or disinfectants to penetrate and kill the bacterial cell. Probiotics are live microorganisms, usually bacteria or yeast, that are beneficial to your health, especially your digestive system. They are often called \"good\" or \"friendly\" bacteria because they help keep your gut healthy. **How Probiotics Work:** - **Balancing Gut Bacteria**: Your digestive system naturally contains both good and bad bacteria. Probiotics help maintain a healthy balance by increasing the number of good bacteria, which can reduce the growth of harmful bacteria. - **Supporting Digestion**: Probiotics can help break down food, absorb nutrients, and produce vitamins that are important for your health. - **Boosting Immune System**: Some probiotics can enhance the immune system, helping your body fight off infections more effectively. - **Preventing and Treating Digestive Issues**: Probiotics are often used to prevent or treat digestive problems like diarrhea, especially after taking antibiotics, which can kill both good and bad bacteria in the gut. **Sources of Probiotics:** - **Fermented Foods**: Yogurt, kefir, sauerkraut, kimchi, and miso are all examples of foods that naturally contain probiotics. - **Supplements**: Probiotics are also available as dietary supplements in the form of capsules, tablets, or powders. When lactose is converted into lactic acid, a process called lactic acid fermentation occurs. This is a type of anaerobic respiration (meaning it happens without oxygen) and is commonly used by certain bacteria, such as Lactobacillus, and some fungi. 1. **Lactose Breakdown**: Lactose is a sugar found in milk. It is made up of two simpler sugars, glucose and galactose. Certain bacteria produce an enzyme called lactase, which breaks down lactose into these simpler sugars. 2. **Fermentation**: After lactose is broken down into glucose and galactose, these sugars are further metabolized by the bacteria through a series of chemical reactions. The end product of this process is **lactic acid**. 3. **Lactic Acid Production**: As the bacteria consume the sugars, they produce lactic acid as a waste product. The buildup of lactic acid lowers the pH of the environment, making it more acidic. **Effects of Lactic Acid Production:** - **In Foods**: This process is crucial in the production of various fermented dairy products like yogurt, cheese, and sour cream. The lactic acid gives these foods their tangy flavor and also acts as a preservative by lowering the pH and preventing the growth of harmful bacteria. - **In Muscles**: A similar process happens in human muscles during intense exercise when oxygen is limited. The muscles temporarily switch to lactic acid fermentation to produce energy, resulting in the production of lactic acid. This buildup can lead to a burning sensation and muscle fatigue, which is often relieved when oxygen becomes available again and the lactic acid is cleared. Bacteria are incredibly diverse microorganisms, and they can be classified in several ways based on their shape, the way they get energy, their response to oxygen, and more. Here are some common types of bacteria based on these different classifications: **1. By Shape:** - **Cocci**: These are spherical-shaped bacteria. Examples include *Streptococcus* (which can cause strep throat) and *Staphylococcus* (which can cause skin infections). - **Bacilli**: These are rod-shaped bacteria. An example is *Escherichia coli* (E. coli), which is found in the intestines and can be both harmless and harmful. - **Spirilla**: These bacteria have a spiral or corkscrew shape. An example is *Helicobacter pylori*, which can cause stomach ulcers. - **Vibrio**: These bacteria are comma-shaped and include *Vibrio cholerae*, which causes cholera. **Function or Role:** - **Pathogenic Bacteria**: These bacteria cause diseases in humans, animals, or plants. Examples include *Mycobacterium tuberculosis* (causes tuberculosis) and *Salmonella* (causes food poisoning). - **Probiotic Bacteria**: These are beneficial bacteria that help with digestion and maintaining a healthy gut flora. *Lactobacillus* and *Bifidobacterium* are examples found in yogurt and other fermented foods. - **Nitrogen-Fixing Bacteria**: These bacteria convert nitrogen from the air into a form that plants can use. *Rhizobium* bacteria, found in the root nodules of legumes, are an example.