Science Exam Study Notes PDF

Science Exam Study Notes.​ ​ 1. Photosynthesis.​ Overview:​ ​ ​ What is Photosynthesis?​ ​ Photosynthesis is the process by which plants, algae and some bacteria Make food for themselves by using sunlight, carbon dioxide (from the air) and water to produce glucose and oxygen.​ ​ This process happens...

Science Exam Study Notes.​ ​ 1. Photosynthesis.​ Overview:​ ​ ​ What is Photosynthesis?​ ​ Photosynthesis is the process by which plants, algae and some bacteria Make food for themselves by using sunlight, carbon dioxide (from the air) and water to produce glucose and oxygen.​ ​ This process happens mainly in the chloroplasts of plant cells, using a pigment called chlorophyll, which captures the sunlight needed for the reaction. ​ ​ ​ A. Simple Equation 1.​ Word Equation:​ Carbon dioxide + Water + Sunlight → Glucose + Oxygen​ 2.​ Formula:​ 6CO2​+ 6H2​O + Sunlight → C6​H12​O6​+ 6O2​​ ​ ​ ​ B. Importance of Photosynthesis 1.​ Makes Food: Plants make glucose (sugar) to grow and survive. 2.​ Produces Oxygen: Photosynthesis gives oxygen, which animals and humans need to breathe. 3.​ Removes Carbon Dioxide: It helps reduce carbon dioxide from the air. 4.​ Supports Life: Plants are the base of the food chain because they provide energy to all living things. C. Structure and Function of Each Part of the Leaf 1.​ Waxy Cuticle: A waxy layer that protects the leaf and prevents water loss. 2.​ Upper Epidermis: A thin layer that protects the inside of the leaf and allows sunlight to pass. 3.​ Palisade Mesophyll: A layer of cells with lots of chloroplasts where MOST photosynthesis happens. 4.​ Spongy Mesophyll: Irregularly Shaped, contains air spaces for gas exchange (carbon dioxide and oxygen). 5.​ Lower Epidermis: Controls water and gas movement and prevents water loss. 6.​ Stomata: Small openings on the underside of the leaf that allow gases to enter and leave. 7.​ Guard Cells: Surround the stomata and control their opening and closing to save water.  ​ ​ ​ D. Experiment to Test a Leaf for Starch​ ​ Steps: 1.​ Boil the Leaf: Put the leaf in boiling water for 1–2 minutes to soften it.​ 2.​ Remove the Green Color: Place the leaf in alcohol (in a test tube) and heat it in hot water to remove ​ Chlorophyll.​ 3.​ Rinse the Leaf: Wash the leaf in warm water to make it soft again​. 4.​ Test with Iodine: Place the leaf flat on a surface and add iodine solution.​ ​ Result: ​ If parts of the leaf turn blue-black, it means starch is present.​ ​ No color change means there is no starch.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​  ​ Science Exam Study Notes.​ ​ 2. Cells, Tissues, and Organ Systems.​ A. Cell Structure and Functions 1.​ Cell Membrane (Both) ○​ Function: Acts as a barrier, controlling what enters and exits the cell.​ ​ 2.​ Cytoplasm (Both) ○​ Function: Jelly-like fluid where chemical reactions occur; holds organelles. (water in the cell) ○​ Structure: Mostly water, with dissolved nutrients and salts.​ ​ 3.​ Nucleus (Both) ○​ Function: The "control center" of the cell; contains DNA, which directs all cell activities.​ ​ 4.​ Ribosomes (Both) ○​ Function: The "protein factories" of the cell; produce proteins needed for growth and repair.​ ​ 5.​ Cell Wall (plants only) ○​ Function: Provides support and protection for plant cells.​ ​ 6.​ Sap Vacuole (plants only) ○​ Function: Stores water, nutrients, and waste; helps maintain cell shape.​ ​ 7.​ Chloroplasts (Plants only) ○​ Function: Site of photosynthesis; converts sunlight into food (glucose). ○​ Structure: Contains the green pigment chlorophyll.​ 8.​ Mitochondria (Both) ○​ Function: The "powerhouse" of the cell; produces energy through cellular respiration.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ B. Animal and Plant Cells - Similarities and Differences Feature Animal Cell Plant cell Cell Membrane Present Present Cell Wall Absent Present Chloroplast Absent Present Mitochondria Present Present Vacuole (Small or Absent) (Large Central Vacuole) ​ ​ ​ ​ ​ C. Tissues​ ​ 1. Muscular Tissue - Muscular tissue is a type of tissue that helps the body move. It can contract and relax to create movement.​ ​ There is 3 Types:​ ​ 1. Skeletal muscle: Moves bones​ ​ 2. Smooth Muscle: Found in organs like the stomach & blood vessels. It works automatically to move things like food or control blood flow.​ ​ 3. the muscle found only in the heart. It works automatically to pump blood through the body. ​ ​ ​ 2. Glandular Tissue - Glandular tissue is a type of tissue that produces and releases substances like hormones, enzymes, or saliva.​ ​ ​ ​ ​ ​ ​ ​ D. Organs​ (Leave blank for now)​ ​ ​ ​ ​ ​ ​ E. Organ Systems 1.​ Digestive System ○​ Function: Breaks down food into nutrients for energy. ○​ Key Organs: Mouth, esophagus, stomach, intestines, liver, pancreas.​ 2.​ Circulatory System ○​ Function: Transports oxygen, nutrients, and waste throughout the body. ○​ Key Organs: Heart, blood, blood vessels.​ 3.​ Respiratory System ○​ Function: Supplies oxygen to the body and removes carbon dioxide. ○​ Key Organs: Nose, (trachea), lungs, diaphragm.​ 4.​ Nervous System ○​ Function: Sends and receives messages to control body functions. ○​ Key Organs: Brain, spinal cord, nerves.​ ​ 5.​ Urinary System ○​ Function: Removes waste and maintains water balance. ○​ Key Organs: Kidneys, ureters, bladder, urethra.​ 6.​ Muscular System ○​ Function: Enables movement of the body. ○​ Key Parts: Muscles (skeletal, smooth, and cardiac).​ 7.​ Skeletal System ○​ Function: Provides structure, support, and protection; assists with movement. ○​ Key Parts: Bones, joints, cartilage.​ ​ Science Exam Study Notes.​ ​ Unit 3: Respiration​ ​ ​ ​ ​ What is Respiration?​ ​ Respiration is the process where cells convert glucose into energy.​ ​ 1. Aerobic Respiration:​ ​ Is the Process where cells produce energy (ATP) by breaking down glucose with the Presence of Oxygen. It occurs in the Mitochondria and produces a lot of energy. The waste products are Carbon Dioxide and Water.​ ​ ​ ​ ​ ​ ​ 2. Anaerobic Respiration.​ ​ Anaerobic Respiration happens in Animal and Yeast. In Animals Anaerobic Respiration Is the Process where cells produce energy by breaking down glucose Without the presence of Oxygen. It occurs in the cytoplasm and Doesn't produce a lot of Energy. The waste product is Lactic Acid because the glucose is not fully broken down.​ ​ In yeast, anaerobic respiration happens without oxygen. Yeast breaks down glucose to produce energy (ATP), with the waste products being ethanol and carbon dioxide. This process is called fermentation and is used in baking and brewing.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A. Uses of Energy in the Human Body 1.​ Movement: Muscles use energy to contract and move the body. 2.​ Growth and Repair: Energy is needed to make new cells and repair damaged tissues. 3.​ Body Temperature: Energy keeps the body warm by generating heat. 4.​ Nerve Signals: Energy powers the brain and nerves to send messages. 5.​ Digestion: Energy helps break down food and absorb nutrients. ​ ​ ​ B. Outline the sites of respiration (cytoplasm and mitochondria).​ ​ Cytoplasm: The first stage of aerobic respiration, called glycolysis, takes place here. This is where glucose is partially broken down to release a small amount of energy.​ Mitochondria: The next stages happen inside the mitochondria. This is where most of the energy is produced when oxygen is available.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ C. State the equation for aerobic respiration using either words or symbols.​ Glucose + Oxygen → Carbon dioxide + Water + Energy​ ​ ​ ​ ​ Anaerobic Respiration Equation in Yeast:​ Glucose → Ethanol + Carbon dioxide​ ​ ​ ​ ​ ​ ​ ​ D. Anaerobic respiration - role in fermentation - examples. ​ ​ Fermentation is Anaerobic respiration that takes place in yeasts and some bacteria. It produces alcohol and carbon dioxide.​ ​ How Anaerobic Respiration is used as part of the fermentation process.​ ​ 1.​ Anaerobic respiration, also known as fermentation, is a process that occurs in yeast during bread making, and is responsible for the bread's rise Process. Yeast uses glucose in the dough's sugar to respire, producing carbon dioxide and ethanol. The carbon dioxide bubbles cause the bread to rise. ​ 2.​ Yeast is used to make alcoholic drinks. When yeast cells are reproducing rapidly during beer or wine production, the oxygen runs out. The yeast switches to anaerobic respiration. Ethanol and carbon dioxide are produced.​ 3.​ To make yogurt, live bacterial colonies are added to sterilized milk. The bacteria ferment (Anaerobic respiration ) the milk sugar and glucose, producing lactic acid and releasing gas. The lactic acid gives yogurt its distinctive sour taste and texture. ​ ​ ​ ​ ​ ​ ​ ​ E. Comparing aerobic and anaerobic respiration (Yeast is a Fungus) Feature Aerobic Respiration Anaerobic Respiration Oxygen Needed Not Required Energy Produced Produces a lot (ATP) Produces Less Waste Products Carbon Dioxide and Water (Animals) Lactic Acid.) ​ (Yeast Ethanol + Carbon Dioxide Where it Happens Cytoplasm and Mitochondria Cytoplasm Only Example During Normal Breathing Intense Exercise or Fermentation ​ ​ ​ Science Exam Study Notes.​ ​ Unit 4: Ecology​ ​ What is Ecology?​ ​ Ecology is the study of how living things interact with each other and their surroundings. We can study these interactions in different ways:​ ​ ​ ​ Individual organisms,​ ​ Groups of the same species (populations),​ ​ How different species live together (communities),​ ​ How living and nonliving things work together in an area (ecosystems)​ ​ How all life on Earth is connected (biosphere). ​ ​ ​ A. Ecosystems : abiotic and biotic factors.​ ​ ​ Biotic: Living​ ​ ​ Abiotic: Non Living​ ​ ​ In an Ecosystem there are Biotic and Abiotic Components. The Biotic Components are the populations of the organism and the Abiotic Components include non living things like water, soil, temperature, wind, and more.​ ​ ​ ​ So an Ecosystem is a system where Living and Nonliving things react.​ ​ ​ ​ ​ ​ ​ ​ ​ B. Populations, communities, habitats and ecological niche.​ ​ ​ ​ 1. Population: A group of the same species living in the same area, interacting with the environment at a particular place.​ ​ ​ ​ 2. Community: All the living things in one area. ​ Example: Zebras, lions, and grass together make up a community in the grassland.​ ​ ​ ​ 3. Habitats: The natural home of a living thing.​ Example: A pond is the habitat for frogs.​ ​ ​ ​ 4. Ecological Niche: The role of an organism in its environment, including what it eats, where it lives, and how it interacts with other organisms.​ Example: Bees pollinate flowers, which is part of their niche.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ C. Feeding relationships: food chains and food webs, producers - consumers and decomposers (relate to photosynthesis and respiration).​ ​ ​ ​ ​ ​ Food Web - A way to describe multiple Food Chains in the same community in a graphical way (Drawing)​ ​ ​ ​ Food Chains - shows how energy moves from one organism to another. It starts with a producer (like a plant) that makes its own food, then animals eat the producers, and other animals eat those animals.​ ​ Example:​ Grass → Rabbit → Fox​ It shows the path of energy from one organism to the next.​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Producers, consumers, and decomposers all play important roles in an ecosystem by exchanging nutrients and energy. Here's how: ​ Producers (like plants) use photosynthesis to make their own food. They take in carbon dioxide (CO₂) from the air and water (H₂O) to make glucose and release oxygen (O₂) as a waste product.​ ​ Consumers (like animals) eat producers or other consumers to get energy. Through cellular respiration, they break down the glucose they get from food to release energy, and they release carbon dioxide (CO₂) as a byproduct.​ ​ Decomposers (like fungi and bacteria) break down dead plants and animals. As they do this, they release nutrients back into the soil, which can be used by producers to grow. So, photosynthesis and cellular respiration help organisms exchange gases (like CO₂ and O₂) and energy, keeping the cycle of life going in the ecosystem.​ ​ ​ ​ Producers: ​ What they do: Use Photosynthesis to make their own food​ ​ ​ Consumers:​ What they do: Eat producers and other Consumers to gain energy (Herbivore)​ ​ 1. Primary consumers are herbivores (they eat plants). 2. Secondary consumers are carnivores (they eat herbivores). 3. Tertiary consumers are top predators (they eat secondary consumers). 4. Omnivores eat both plants and animals. What they give off:​ When these animals use energy, they release heat and carbon dioxide (CO₂).​ ​ ​ Decomposers:​ ​ What they do: Break down dead and decaying organisms to absorb the nutrients and energy.​ ​ They then release the nutrients back to the environment​ ​ ​ ​ The process by which producers use sunlight to make food.​ Photosynthesis will make the food which will be used by consumers to make energy ​ D. Energy flow in ecosystem (In presentation)​ ​ ​ E. Adaptations of organisms to different ecosystems​ ​ Adaptations are special features or behaviors that help organisms survive in their environment.​ Adaptations help organisms live in different environments by helping them deal with things like temperature, water, food, and predators. ​ ​ ​ ​ F. Human Interference and Conservation Human Interference:​ Human activities often disrupt ecosystems and the natural balance of the environment. This includes: ​ Pollution: Chemicals, plastics, and waste harm air, water, and soil. ​ Deforestation: Cutting down forests reduces habitats for animals and plants. ​ Overfishing: Taking too many fish from oceans disrupts marine life. ​ Climate Change: Human activities (like burning fossil fuels) increase greenhouse gases, causing global warming. Conservation:​ Conservation is the protection and preservation of ecosystems and species. Efforts include: ​ Protected Areas: Establishing national parks or reserves to protect wildlife. ​ Sustainable Practices: Using resources in a way that doesn’t harm the environment (e.g., sustainable farming, fishing). ​ Reforestation: Planting trees to replace those lost in deforestation. ​ Wildlife Protection: Laws to prevent hunting and protect endangered species. Goal of Conservation:​ To maintain biodiversity (the variety of life) and ensure the survival of species, including humans. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​