Unit 9 Study Guide Joint

1. Sketch and label the structure of a bacteriophage. A bacteriophage has a very specific shape that helps it infect bacteria. It includes a head that contains genetic material (DNA), a capsid (protein coat), a tail used to inject DNA, and tail fibers that help it attach to the host cell. Each part has a job in infection. Even without drawing, you should remember it looks like a spider-like robot that grabs onto bacteria. 2. Name the structure in which viruses store genetic instructions for replication. Viruses store their genetic instructions in either DNA or RNA. This genetic material is located inside the capsid, which protects it. The instructions tell the host cell how to make more viruses. Without this genetic material, the virus cannot reproduce. 3. Explain how viruses reproduce. Viruses cannot reproduce on their own, so they must infect a host cell. Once inside, they inject their genetic material and take over the cell’s machinery. The host cell then produces new virus parts. These parts assemble into new viruses that leave the cell. 4. Describe what happens after a virus infects a cell. After infection, the virus either immediately takes over the cell or hides inside it. In the lytic cycle, the virus quickly makes copies and destroys the cell. In the lysogenic cycle, the viral DNA becomes part of the host DNA and stays inactive for a while. Eventually, it may switch to the lytic cycle. Either way, the cell is affected or destroyed. 5. Compare and contrast the lytic and lysogenic cycles. Both cycles involve a virus infecting a host cell and using it to reproduce. The lytic cycle is fast and results in the cell bursting and dying. The lysogenic cycle is slower because the virus hides in the host DNA before becoming active. The key difference is timing and whether the cell is destroyed immediately. 6. Determine whether a virus is a living thing using GREGS CAR. Viruses are not considered living because they do not meet all the characteristics of life. They are not made of cells and cannot reproduce on their own. They also do not use energy or maintain homeostasis. However, they do have genetic material and can evolve. 7. Explain how viruses cause disease. Viruses cause disease by entering and damaging cells in the body. They take over cell functions and often destroy the cells. This damage disrupts normal body processes. The immune system reacts, which causes symptoms like fever and fatigue. 8. Name seven viral diseases that affect humans. Common viral diseases include the flu, COVID-19, HIV/AIDS, measles, rabies, chickenpox, and hepatitis. These diseases affect different systems in the body. Some are mild, while others can be life-threatening. They spread in different ways such as air, contact, or bodily fluids. 9. Identify how viral diseases can be prevented and treated. Viral diseases are best prevented with vaccines, which prepare the immune system to fight infections. Good hygiene, like washing hands, also helps reduce spread. Antiviral medications can help treat some infections but do not kill viruses like antibiotics kill bacteria. Prevention is usually more effective than treatment. 🦠 Ch. 21.2 — Bacteria 10. Identify how prokaryotes are classified. Prokaryotes are classified based on their shape, cell structure, and how they obtain energy. Scientists also look at their cell walls and genetic differences. The three main shapes are coccus, bacillus, and spirilla. These classifications help scientists understand how they function. 11. Contrast how prokaryotes vary in structure, shape, movement, and energy. Prokaryotes can have different shapes like round, rod, or spiral. Some can move using flagella, while others cannot move at all. They also vary in how they get energy—some make their own food while others consume it. These differences help them survive in many environments. 12. Describe how prokaryotes reproduce. Most prokaryotes reproduce through binary fission, where one cell splits into two identical cells. This process is very fast and allows populations to grow quickly. Some bacteria can also exchange genetic material through conjugation. This increases genetic diversity. 13. Describe the five roles that prokaryotes play in the living world. Prokaryotes play many important roles in ecosystems. They act as decomposers, breaking down dead organisms. Some help humans digest food, while others produce oxygen or fix nitrogen in soil. However, some also cause diseases. 14. Explain how bacteria cause disease. Bacteria cause disease by invading the body and multiplying. Some release toxins that damage tissues. Others directly destroy cells as they grow. This leads to symptoms like swelling, pain, and fever. 15. Explain how bacteria can be controlled. Bacteria can be controlled through cleaning, disinfecting, and sterilizing surfaces. Heat and chemicals can kill bacteria. Antibiotics are also used to kill harmful bacteria inside the body. Proper hygiene helps reduce their spread. 16. Explain how bacterial diseases can be prevented. Bacterial diseases can be prevented by practicing good hygiene like washing hands. Vaccines can protect against certain bacterial infections. Safe food handling and clean water also reduce risk. Prevention stops bacteria from entering the body. 17. Explain how bacterial diseases can be treated. Bacterial infections are usually treated with antibiotics. These medicines kill bacteria or stop them from growing. It is important to take the full dose to prevent resistance. If not treated properly, bacteria can become harder to kill. 18. Name five bacterial diseases that affect humans. Examples include strep throat, tuberculosis, cholera, salmonella, and Lyme disease. These diseases affect different parts of the body. Some spread through food, air, or insect bites. Many can be treated with antibiotics. 🦠 Disease Section 19. Describe the rise of superbugs and explain why they are dangerous. Superbugs are bacteria that have become resistant to antibiotics. This happens when bacteria evolve after being exposed to medications. They are dangerous because normal treatments no longer work. This makes infections harder and sometimes impossible to cure. 20. Explain why taking unnecessary antibiotics is harmful. Taking antibiotics when not needed can kill helpful bacteria in your body. It also allows harmful bacteria to become resistant. This leads to the development of superbugs. Overuse makes antibiotics less effective over time. 21. Describe the term emerging disease and give an example. An emerging disease is a disease that is new or rapidly increasing in cases. These diseases can spread quickly because people have little immunity. They are often difficult to control at first. An example is COVID-19. 🧫 Protists 22. Describe how protists are classified. Protists are classified based on how they move, how they get energy, and their structure. Some act like plants, others like animals, and some like fungi. Scientists group them this way because they are very diverse. This helps organize them for study. 23. Explain the protist dilemma. The protist dilemma refers to how protists don’t fit neatly into one category. They share traits with plants, animals, and fungi. Because of this, scientists struggle to classify them. They are grouped together mainly for convenience. 24. Describe how protists move and name the structures used. Protists move in different ways depending on the type. Some use pseudopods, which are temporary extensions of the cell. Others use cilia, which are tiny hair-like structures. Some move with flagella, which are long whip-like tails. 25. Describe the two ways that protists reproduce. Protists can reproduce both asexually and sexually. Asexual reproduction usually happens through cell division. Sexual reproduction involves combining genetic material from two cells. This increases genetic diversity. 26. Describe the three ecological roles that protists play. Protists can act as producers, consumers, or parasites. Producers like algae make food through photosynthesis. Consumers eat other organisms. Parasites live off hosts and can cause disease. 27. Name three human diseases caused by protists. Protists cause diseases such as malaria, dysentery, and sleeping sickness. These diseases are often spread by water or insects. They can be serious if untreated. Many affect the blood or digestive system. 28. Identify the types of protists studied in the lab. Common protists studied include amoeba, paramecium, and euglena. Each has a different way of moving and getting energy. These examples help show protist diversity. They are easy to observe under a microscope. 🍄 Fungi 29. Name two differences between fungi and plants. Fungi do not perform photosynthesis like plants do. Instead, they absorb nutrients from their environment. Their cell walls are made of chitin, while plants have cellulose. These differences show that fungi are not plants. 30. Describe the basic characteristics of fungi. Fungi are eukaryotic organisms that obtain nutrients by absorption. They grow as networks of hyphae that form a mycelium. They reproduce using spores. Most thrive in moist environments. 31. Explain how fungi help ecosystems maintain homeostasis. Fungi act as decomposers, breaking down dead organisms and waste. This returns nutrients to the soil. Plants can then reuse these nutrients to grow. This keeps ecosystems balanced. 32. Describe two ways that humans use fungi. Humans use fungi for food, such as mushrooms and yeast in bread. They are also used to make medicines like antibiotics. Fungi are important in fermentation processes. These uses make them valuable to society. 33. Name three diseases caused by fungi. Fungi cause diseases like athlete’s foot, ringworm, and plant infections such as rust. These diseases can affect skin, nails, or crops. They spread in moist environments. Some are easy to treat, while others are more serious.