Biology Answer Note #28

Question 1 Which of the following organs are part of the foregut in the earthworm digestive system? A. Crop and gizzard B. Esophagus and gizzard C. Crop and intestine D. Pharynx and intestine Answer After reviewing several academic Biology sources, it is clear that the correct answer to this question is option A, Crop and gizzard. According to the book "Essentials of Biology" by Sylvia S. Mader, the earthworm digestive system is divided into three parts: foregut, midgut, and hindgut. The foregut includes the mouth, pharynx, esophagus, crop, and gizzard. Question 2 A characteristic not present in all living things is _____. Answer The characteristic that is not present in all living things is the ability to carry out photosynthesis. According to the most reliable and up-to-date sources in Biology, photosynthesis is the process by which organisms, such as plants, use energy from sunlight to convert carbon dioxide and water into organic compounds, such as glucose. This process is not present in all living things and is exclusive to autotrophic organisms, which are able to produce their own food. Heterotrophic organisms, on the other hand, rely on consuming organic compounds from other organisms for their energy needs. Photosynthesis requires several components and processes, including photosynthetic pigments (such as chlorophyll), light energy, and enzymes. These components are only found in certain organisms, such as plants, algae, and some bacteria, which possess specialized organelles called chloroplasts. Question 3 make a mind map summarizing the metabolism unit from grade 13 bio Answer Metabolism is a vital process that occurs in all living organisms. It is the set of chemical reactions that take place to maintain life and support growth and development. The metabolism unit from grade 13 bio covers the different aspects of metabolism, including anabolism, catabolism, and homeostasis. Let's break down the key concepts of this unit and create a mind map. Anabolism: - Anabolism is the process of building molecules and structures that the body needs. This includes the synthesis of complex molecules such as proteins, carbohydrates, and lipids. - It requires energy in the form of ATP, which is produced during cellular respiration. - This process is essential for growth, development, and repair of tissues in the body. Catabolism: - Catabolism is the process of breaking down molecules to release energy for the body to use. - It involves the breakdown of complex molecules into simpler ones, such as the breakdown of glucose to release energy. - This process produces ATP, which is used as energy currency in the body. Homeostasis: - Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. - Metabolism plays a crucial role in maintaining homeostasis by continuously adjusting and balancing various metabolic processes. - This allows the body to function efficiently and adapt to different conditions. Question 4 Rotaviruses are a group of RNA viruses and are a common cause of diarrhoea among infants and young children. Usually, most people recover from a rotavirus infection after 3–7 days, however, in some cases, severe dehydration and death can sometimes occur. a Outline how the body would eliminate cells infected by rotavirus. (4 MARKS) Answer The body has a complex and effective defense mechanism against viral infections such as rotavirus. The specific immune response to rotavirus infection involves both innate and adaptive immunity. Firstly, the innate immune system is the body's first line of defense against pathogens. In the case of rotavirus, the initial response is triggered by the virus entering the gastrointestinal tract, where it infects the cells lining the intestinal walls. The infected cells release alarm signals called cytokines, which recruit immune cells to the site of infection. These cells, including macrophages and natural killer cells, are responsible for engulfing and killing the infected cells. In addition, the innate immune system produces interferons, which are small proteins that help to inhibit viral replication and spread. Furthermore, the mucus lining of the intestines acts as a physical barrier and contains antibodies that can neutralize rotavirus particles before they can enter and infect the cells. However, if the infection is not stopped by the innate immune system, the adaptive immune response is activated. This involves the production of specific antibodies and Tcells that target and eliminate the rotavirus particles. The adaptive immune system also creates long-term memory cells, which can quickly recognize and respond to future infections by the same virus. To eliminate the cells infected by rotavirus, the body relies on a process called apoptosis. This is the programmed cell death of the infected cells, which prevents the virus from spreading to neighboring healthy cells. Apoptosis is triggered by a signaling pathway that involves various enzymes and proteins, and it ensures that the infection is contained and cleared. In conclusion, the body eliminates cells infected by rotavirus through a coordinated response of the innate and adaptive immune systems, which involves physical barriers, cytokine signaling, phagocytosis, production of specific antibodies and T-cells, and apoptosis. Overall, the body's immune response is tailored to efficiently and effectively control the infection and prevent it from causing severe dehydration and death. Question 5 measlles is a virus. Say how the body wouldvget rid of it. Itis a 4 mark question. Answer Measles is a highly contagious viral infection that affects the respiratory system and skin. It can easily spread through coughing, sneezing, or direct contact with an infected person. The body has several immune responses to combat and eventually get rid of this virus. Firstly, the body's innate immune system recognizes the presence of the measles virus and triggers an immediate response. White blood cells, specifically macrophages, engulf and destroy the virus, preventing it from spreading further. This process is known as phagocytosis, and it is an important initial defense mechanism against harmful pathogens. Secondly, the measles virus triggers the production of specific antibodies by the body's adaptive immune system. These antibodies are Y-shaped proteins that bind to the virus, neutralizing it and preventing it from infecting other cells. The antibodies also stimulate the destruction of infected cells by activating the complement system, a group of proteins that work together to eliminate pathogens. Furthermore, infected cells produce interferons, which are signaling proteins that help to inhibit the replication of the measles virus. Interferons also activate other immune cells, such as natural killer cells, which target and destroy virus-infected cells. Finally, as the immune response progresses, T cells (a type of white blood cell) become activated and target specific epitopes (molecular markers) on the surface of the virus. This process, known as cell-mediated immunity, helps to eliminate the measles virus from the body. In summary, the body gets rid of the measles virus through a coordinated and effective response by the innate and adaptive immune systems. This process involves various cells and proteins working together to neutralize, destroy, and eliminate the virus.