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 mainly in...

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. ○ Structure: Thin, flexible layer made of lipids and proteins. 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. ○ Structure: Spherical, surrounded by a membrane. 4. Ribosomes (Both) ○ Function: The "protein factories" of the cell; produce proteins needed for growth and repair. ○ Structure: Small, round structures found in the cytoplasm or attached to the rough endoplasmic reticulum. 5. Cell Wall (plants only) ○ Function: Provides support and protection for plant cells. ○ Structure: Rigid and made of cellulose. 6. Sap Vacuole (plants only) ○ Function: Stores water, nutrients, and waste; helps maintain cell shape. ○ Structure: Large, fluid-filled sac in plant cells. 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. ○ Structure: Bean-shaped, with inner folded membranes (cristae). 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 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 Aerobic 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