Final answer:
Protozoa can cause diseases as they invade the body and disrupt normal cellular functions. Vaccines work by stimulating the immune system to produce an immune response. Red blood cells transport oxygen, platelets help in blood clotting, and neutrophils are white blood cells involved in the innate immune response. Phagocytes and lymphocytes are different types of white blood cells that play distinct roles in the immune response. Phagocytosis involves chemotaxis, adhesion, engulfment, fusion, and digestion.
Step-by-step explanation:
Q3: Protozoa is considered a pathogen because it can cause diseases in humans and other animals. Pathogenic protozoa can invade the body, multiply, and disrupt normal cellular functions, leading to various infections. For example, the protozoan Plasmodium causes malaria, a serious disease affecting millions of people around the world.
Q4: Vaccines work by stimulating the immune system to produce an immune response against a particular pathogen. They contain weakened or inactive forms of the pathogen or specific components of it. When the vaccine is administered, the immune system recognizes these components as foreign and mounts an immune response, producing antibodies and memory cells that can quickly respond to future infections by the actual pathogen.
Q5: A) Red blood cells (or erythrocytes) transport oxygen from the lungs to the body's tissues and carry carbon dioxide back to the lungs. B) Platelets (or thrombocytes) help in blood clotting, preventing excessive bleeding when a blood vessel is damaged. C) Neutrophils are a type of white blood cells that play a crucial role in the innate immune response, being the first to arrive at the site of infection or injury and engulfing and destroying pathogens.
Q6: Phagocytes (like neutrophils) and lymphocytes are different types of white blood cells involved in the immune response. Phagocytes are able to engulf and digest pathogens through phagocytosis, whereas lymphocytes recognize and directly attack specific pathogens. For example, neutrophils can engulf and destroy bacteria, while lymphocytes can target and destroy infected cells, such as those infected by viruses.
Q7: Phagocytosis is a process by which cells, particularly phagocytes, engulf and ingest foreign particles, such as pathogens. The steps of phagocytosis involve: 1) Chemotaxis, where phagocytes are attracted to the site of infection by chemical signals. 2) Adhesion, where phagocytes attach to the surface of the pathogen. 3) Engulfment, where the phagocyte surrounds and engulfs the pathogen, forming a phagosome. 4) Fusion, where the phagosome fuses with lysosomes, forming a phagolysosome. 5) Digestion, where the pathogen is broken down and destroyed by enzymes within the phagolysosome.
Learn more about Pathogenic protozoa, vaccine mechanism, functions of red blood cells, platelets, and neutrophils, comparison between phagocytes and lymphocytes, steps of phagocytosis