First Semestral Exam Guide 2024 Answer Key (PDF)

Euroamerican School Science 7th grade First Semestral Guide Name: ________________________________________ Date: ________________________ Group: ___________ Ms. Gabriela Garza I. Nutrition I...

Euroamerican School Science 7th grade First Semestral Guide Name: ________________________________________ Date: ________________________ Group: ___________ Ms. Gabriela Garza I. Nutrition II. Living Things III. Scientific Method IV. The Microscope Date of the exam: Tuesday, December 17  I. Nutrition 1. Why do you need food? Because they contain all the nutrients that we need to live and have good health; they provide nutrients to have energy and help your body grow ,repairing tissues. 2. Definition of nutrients. Substances in food that provide the raw materials and energy that the body needs to carry out its functions. 3. Types of nutrients (6) carbohydrates, fats, proteins, vitamins, minerals and water 4. Carbohydrates a) Definition nutrients composed of carbon, oxygen and hydrogen that are a major source of energy. b) Types simple carbohydrates (glucose-sugar) and complex carbohydrates (starches-fiber), simple carbs examples donuts candy brownies.complex carbs examples apple 5. Fats a) Definition energy containing nutrients composed of carbon, oxygen and hydrogen which provide twice the energy of an equal amount of carbs. b) Types unsaturated (liquid at room temperature, most cooking oils), saturated (solid at room temperature, meat or dairy products) and trans fat (manufacturers add hydrogen to vegetable oil, margarine, chips, commercially baked goods) c) cholesterol waxy fat like substance only found in animal products 6. Proteins a) Definition nutrients that contain nitrogen, carbon, oxygen and hydrogen that are needed for tissue growth and repair. b) Amino acids: are small units that make proteins which are linked together chemically to form large protein molecules. 7. Minerals a) Definition: nutrients that are not made by living things. b) Examples: calcium, chlorine, iodine, iron, magnesium, potassium, phosphorous, sodium, water 8. Vitamins a)Definition act as helper molecules in a variety of chemical reactions in the body b) Types and Characteristics water-soluble: dissolve in water (Vitamin C and B) fat- soluble: dissolve and store in fat (A, D, E, K) 9. Water a) Definition is the most important nutrient because it helps in the body's vital process, including chemical reactions such as breakdown of nutrients. b) How much is needed: 2 liters per day. 10. The Food Guide Pyramid a) Draw it and explain it.  11. Mention the functions of the digestive system a) Digestion: your body breaks down food into small nutrient molecules. b) Absorption: molecules are absorbed in the blood and carried throughout the body. c) Elimination: wastes are eliminated from the body. 12. Explain how each organ helps the Digestive System work. a) mouth: where chemical and mechanical digestion BEGINS, saliva is a helper b) esophagus: peristalsis, 10 seconds to the food to get to the stomach. muscular tube connecting mouth to the stomach. c) stomach: J-shaped muscular pouch in the abdomen, where most chemical and mechanical digestion take place, churning motion. d) small intestine: where chemical digestion and absorption take place, 6 meters long, it has villi. e) liver: produce bile which breaks up fat particles. f) gallbladder: stores the bile g) pancreas: produces enzymes that flow into the small intestine and helps break down starches, proteins and fats. h) large intestine: last section of the digestive system. 1.5 meters long. As the material moves through it, water is absorbed into the bloodstream, the remaining is ready for elimination from the body. 13. Explain the most important characteristics of each disease caused by the lack of nutrients. a) Scurvy: deficiency of Vit C. Gums become spongy, spots may develop on the skin and the mucus membrane might bleed. Common in sailors with no access to fresh fruit.vitamin C is found in orange,kiwi,guabas. b) Osteoporosis/rickets: Osteoporosis in adults and rickets in children. Deficiency of Calcium or Vit D. Calcium is important for growth and strength in bones. c) Anemia: Caused by iron deficiency. It results in general lack of energy and  easily getting tired. Iron is important for hemoglobin in the red blood cells to transport oxygen in the blood. d) Beri beri: Deficiency of Vit B1. The person experiences emotional disturbances, weak heart rate, edema, lethargy and weakness in limbs. May cause partial paralysis and severe heart failure and death; the condition is not reversible. e) Pellagra: Deficiency of Vit B3 in the diet or the body cannot synthesize it from protein. Reddish skin lesions, aggressive behavior, insomnia, ataxia, diarrhea and glossitis. 14. Diabetes. a) Definition: Metabolism disorder in which the amount of glucose is too elevated in blood. Glucose enters our cells because the insulin makes it possible for the cells. b) Why does it happen? Because our body doesn't produce insulin or doesn't produce enough. Glucose accumulates in the blood because it doesn't get to the cells. c) Organs affected: kidneys, eyes, brain Types of Diabetes 1. In childhood, dependent on insulin, the body does not produce it or not enough. 2. In adults, consume a lot of carbs, fats in childhood. Obesity is a factor and doesn't produce enough insulin. How to prevent it: Frequent exercise, a healthy diet, and avoiding high levels of glucose. 15. Eating Disorders. Explain their characteristics. a) Obesity: excess proportion of body fat. An obese person is when his or her weight is 20% or more above normal weight. Overweight when it is only 10%. A person consumes more calories than what he or she burns.  II. Living things 16. Classification of living things. a) Autotrophs Definition: organisms able to produce their own food. They take energy from the sun. Characteristics: photosynthetic bacteria, plants, chemical autotrophs, algae b) Heterotrophs Definition: not able to produce their own food. Characteristics: depend on others; protists, fungus, animals 17. The Five Kingdoms a) Bacteria Definition: unicellular organisms in water, air, land and our body which live in humid places or internal liquids inside living things. Types: chemosynthetic and photosynthetic; autotrophs (parasites and saprophytes). Heterotrophs (feed from dead things or in decomposition). Most important characteristics: different shapes,first living thing found,monera kingdom b) Protists Definition: heterotroph unicellular organisms which live in water and humid places. Classification: autonomous and parasites. The ones who are predators are amoebas and paramecium. Most important characteristics: They are more recent than bacteria. Most of them are microscopic, but they can grow to become much bigger. c) Fungi Definition: multicellular and heterotrophic organism Classification: saprophytes and parasites; they can cause athlete's foot. Most important characteristics: help dead animals and plants to decompose, live in water, land and inside organisms and are made up by hyphae d) Plants Definition: autotroph multicellular organism Classification: autotrophs most of them; some are heterotrophs like the cuscuta, orchids and venus flytrap Most important characteristics: they go through the process of photosynthesis to create glucose and oxygen e) Animals Definition: multicellular organisms Classification according to what they eat (explain the 6 types and give examples of each): herbivores (eat plants), carnivorous (meat), omnivorous (meat and plants), decomposers (breakdown dead organisms) scavengers and detritivores (feed from dead) Classification according to their digestive system: complete (two openings), incomplete (one opening) – hydra, corals, sponges, cnidarians 18.Interactions among living things. a) Predator Definition: organism that does the killing with strategies to get their food Characteristics: strong claws, big teeth, fast reactions, hiding colors (camouflage) Examples of predators: sharks, snakes, eagles, humans b) Prey Definition: organisms killed by predators Characteristics: spines, thorns, needles, as things to adapt Examples of prey: fish, birds, mice, rabbits, gazelle c) Write 5 prey-predator relationships. Explain who is the prey and who is the predator. bobcat (prey) and leopard( predator) answers may vary 19. Photosynthesis a) Definition: process in which autotrophs get solar energy to transform it into glucose (chemical energy) b) Formula : carbon dioxide + water + solar energy = glucose + oxygen c) What is needed for it to happen? sunlight, carbon dioxide and water d) Two things produced: glucose and oxygen 20. Energy Roles a) producers: organisms that produce their own food. b) consumers and types of consumers: herbivores, omnivores, carnivores, decomposers, primary consumers, secondary consumers, tertiary consumers c) decomposers: break down wastes d) food chain: series of events in which organisms eat each other e) food web: many food chains overlapping in an ecosystem. f) energy pyramid: shows the level of energy in an ecosystem 21. Draw a food chain, a food web and an energy pyramid and label each organism. Food Web Food Chain Energy Pyramid  Answers may vary 22. Taxonomy a) Definition: science in charge of naming, classifying, describing living things b) Levels: kingdom, phylum, class, order, family, genus, species. c) Father of taxonomy: Carolus Linneaus d)Example of human taxonomy: Kingdom: Animalia Phylum: Chordata Class: Mamallia Order: Primate Family: Hominidae Genus: Homo Species: Sapiens III. Scientific Method 1. Scientific Method  a) Definition: logical order of steps by which scientists come to conclusions about the world around them. It is a problem solving technique. b) Steps: 1. Problem or Question. 2. Observation or Research. 3. Formulate a Hypothesis. 4. Experiment. 5. Collect and Analyze Results. 6. Conclusions. 7. Communicate the Results. 2. Problem / Question a) Definition: a scientific question that must start with How, When, Where, Who, Which or What. b) It must be: interesting. It should be measurable. 3. Research a)Definition: necessary information to design and understand your experiment. b) Why is research important? It helps you understand your theory of your project. It helps you make a prediction of what will happen in your experiment. It provides you the knowledge to understand the behavior you observed better. c) What to research? You need to identify the keywords of your question, use the question words, and answer the following questions (how, when, where, why, which, what, who). 4. Hypothesis a) Definition: an educated guess about how things work out. b) Formula: If I do __this_________, then this will happen. 5. Variables a) Independent: is the one changed by the scientist; it can only be one. You change it to make the observations. b) Dependent: the variable that responds to the change of the independent variable; it is what you measure and observe. c) Controlled: quantities that remain constant. 6. Procedures a) Definition: step by step list of everything you must do to perform your experiment in a detailed and complete way. b) Musts: how will you change your independent variable. Make three times the experiment and how are you going to measure your dependent variable. 7. Materials a)Definition: what type of supplies and equipment do you need to complete your project. b) Tips: List all the necessary material, explain them with details. Get it before you start your project. 8. Results a) How to write results: Calculate average for your three trials. Make data tables and the graphs that you need. Make three questions. Is your project complete? Did you make a mistake? Do you need more data? IV. The Microscope 1. Light microscope: microscopes that use light and are limited by their resolution. They cannot produce clear images of objects smaller than 0.2 micrometers. What can you observe under a light microscope? human, apple, wasp, ant, hair, cell 2. Electron microscope: use beams of electrons, rather than light, to produce images. They can view objects as small as the diameter of an atom. What can you observe under an electron microscope? cell, bacteria, virus, DNA, small molecules, atom, electron orbital 3. Parts of the microscope and their function. a) eyepiece: the lens at the top that you look through. b) arm: Supports the tube and connects it to the base c) base: The bottom of the microscope, used for support d) specimen: what you observe under the microscope e) ocular lens: eyepiece f) coarse focus adjustments: bring the specimen into sharp focus g) fine focus adjustments: bring the specimen into fine focus h) objective lenses: Usually you will find 3 or 4 objective lenses on a microscope. They almost always consist of 4X, 10X, 40X and 100X powers. i) stage clips: hold the slides in place.