QE Review

• Nutrition is the process by which an animal takes in and makes use of food to meet its needs.
• ATP powers processes from DNA replication to cell division.
• Essential nutrients include amino acids, fatty acids, vitamins, and minerals.
• Antigenic variation is a strategy used by pathogens to evade the immune response.
• If a pathogen changes the epitopes that it expresses to ones that a host has not previously encountered, it can reinfect or remain in the host without triggering the rapid and robust response mediated by memory cells.
• Essential nutrients serve as substrates of enzymes and as coenzymes.
• Ascorbic acid, also known as vitamin C, is an essential nutrient.
• The 20 amino acids are the complete set of proteins.
• Human infants also need one more amino acid: histidine.
• Fatty acids synthesize like membrane phospholipids, which signal molecules and storage fats.
• Vitamins are organic molecules required in diet.
• Dietary minerals are inorganic nutrients like iron and sulfur.
• Malnutrition occurs when an animal lacks essential nutrients, its diet fails to provide enough chemical energy, leading to deformities, diseases, or death.
• Epidemiology is the study of human health and disease at the population level.
• Food processing involves four stages: ingestion, digestion, absorption, and elimination.
• Intracellular digestion occurs inside food vacuoles, which are cellular organelles in which hydrolytic enzymes break down food.
• Phagocytosis is a cell eating something large.
• Pinocytosis is fluid phase endocytosis.
• Lysosomes contain hydrolytic enzymes.
• Extracellular digestion involves the breakdown of food in compartments that are continuous with the outside of the animal’s body.
• The mammalian digestive system includes the oral cavity, pharynx, and alimentary canal.
• The oral cavity is where food processing begins, with teeth cutting, smashing, grinding, and breaking food into smaller pieces, facilitating swallowing, and when food arrives, it triggers the release of saliva by the salivary glands.
• Saliva is a complex mixture of materials with a number of vital functions, including buffers to avoid tooth decay, antimicrobial agents, and large amounts of the enzyme amylase, which breaks down starch and glycogen.
• Mucus is a viscous mixture of water, salts, cells, and slippery, slippery glycoproteins, making food for easy swallowing, protecting gums, facilitating taste and smell, and the tongue distinguishes which foods should be processed, manipulates the mixture of saliva and food, and helps shape them into a ball called a bolus, then during swallowing, it pushes the bolus to the back of the oral cavity and into the pharynx.
• The pharynx is the throat region which leads to two passageways: esophagus and trachea.
• One class of hemocytes produces a type of defense molecule that helps trap larger pathogens, such as Plasmodium, the single-celled parasite of mosquitoes that causes malaria in humans.
• Immune cells produce receptor molecules that bind specifically to molecules from foreign cells or viruses and activate defense responses.
• Adaptive immunity is a set of molecular and cellular defense found only among vertebrates.
• Each mammalian Toll-like receptor binds to fragments of molecules characteristic of a set of pathogens: TLR3 binds to double-stranded RNA, TLR4 recognizes lipopolysaccharide, and TLR5 recognizes flagellin.
• The specific binding of immune receptors to foreign molecules is a type of molecular recognition and is the central event in identifying nonself molecules, particles, and cells.
• One part of the innate immunity of invertebrates is a set of barrier defenses, including the insect exoskeleton.
• The exoskeleton of insects is composed largely of the polysaccharide chitin and lines the insect intestine, where it blocks infection by many pathogens.
• The innate defenses found among invertebrates are barrier defenses, phagocytosis, and antimicrobial peptides.
• Hemocytes are the major immune cells in insects and some hemocytes are phagocytic cells, such as amoebas, that ingest and break down microorganisms by a process known as phagocytosis.
• Dendritic cells mainly populate tissues, such as skin, that contact the environment and stimulate adaptive immunity against pathogens that they engulf.
• Many of these molecules are components of fungal or bacterial cell walls and function as “identity tags” for pathogen recognition.
• Phagocytic innate immune cells in vertebrates recognize viral, fungal, or bacterial components and rely on several types of receptors.
• Neutrophils are a type of phagocytic cell in the mammalian body that circulate in the blood, are attracted by signals from infected tissues and then engulf and destroy the infecting pathogens.
• Once bound to a pathogen molecule, a recognition protein triggers an innate immune response.
• Barrier defenses in the innate immunity of vertebrates include mucous membranes, mucus, lysozyme in tears, saliva, and mucous secretions, and secretions from oil and sweat glands.