Science Exam Review PDF

### **Photosynthesis and Cellular Respiration** 1. **Photosynthesis**: a. Definition: The process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. b. Word equation: Carbon **dioxide + Water + Light energy → G...

### **Photosynthesis and Cellular Respiration** 1. **Photosynthesis**: a. Definition: The process by which plants, algae, and some bacteria convert light energy into chemical energy stored in glucose. b. Word equation: Carbon **dioxide + Water + Light energy → Glucose + Oxygen** 6CO2 +6H2 O+light→C6 H12 O6 +6O2 c. Reactants: Carbon dioxide (*CO2) water* (*H2O)* light energy d. Products: Glucose (*C6H*), oxygen (O*2*) 2. **Cellular Respiration**: e. Definition: The process by which organisms break down glucose to produce energy (ATP). f. Word equation: **Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP)** g. *C6H12O6+6O2→6CO2+6H2O+ATP* h. Reactants: Glucose (*C6H12O6)*, oxygen (O2) i. Products: Carbon dioxide (*CO2*), energy (ATP) 3. **Relationship**: j. Photosynthesis produces glucose and oxygen, which are used as reactants in cellular respiration. k. Cellular respiration releases carbon dioxide and water, which are used in photosynthesis. l. Importance: This cycle sustains life by providing energy (ATP) and maintaining oxygen and carbon dioxide levels in the atmosphere. 4. **Organisms**: m. Photosynthesis: Plants, algae, some bacteria n. Cellular respiration: All living organisms (plants, animals, fungi, bacteria, etc.) ### **Trophic Levels** - **Producers**: Organisms (e.g., plants, algae) that create energy-rich compounds via photosynthesis. - **Primary Consumers**: Herbivores that feed on producers (e.g., rabbits, deer). - **Secondary Consumers**: Carnivores or omnivores that feed on primary consumers (e.g., snakes, foxes). - **Tertiary Consumers/Top Carnivores**: Predators at the top of the food chain (e.g., hawks, lions). ### **Predator-Prey Relationships** - **Graphing**: Predator and prey populations influence each other, creating cyclical patterns in population graphs. - When prey increases, predator populations also rise. - A high predator population leads to a decline in prey, followed by a decline in predators. - **Limiting Factors**: - **Biotic**: Availability of prey, competition, disease. - **Abiotic**: Weather, water, temperature. ### **Types of Interactions** 1. **Parasitism**: One benefits, the other is harmed (e.g., ticks on deer). 2. **Mutualism**: Both benefit (e.g., bees and flowers). 3. **Competition**: Organisms compete for the same resources (e.g., food, habitat). 4. **Predation**: One organism preys on another (e.g., lions hunting zebras). 5. **Commensalism**: One benefits, the other is unaffected (e.g., barnacles on whales). ### **Population Dynamics** - **Exponential Growth**: Rapid population increase under ideal conditions (J-shaped curve). - **Carrying Capacity**: The maximum population size an environment can support sustainably (S-shaped curve). ### **Invasive Species** - Definition: Non-native species that disrupt ecosystems by outcompeting native species. - Examples: Zebra mussels, kudzu vine, cane toads. ### **Biogeochemical Cycles** 1. **Nitrogen Cycle**: Converts nitrogen between atmospheric, soil, and biological forms. Key processes include nitrogen fixation, nitrification, and denitrification. 2. **Phosphorus Cycle**: Movement of phosphorus through rocks, soil, water, and organisms. No atmospheric component. 3. **Carbon Cycle**: Exchange of carbon among the atmosphere, oceans, soil, and living organisms. Includes photosynthesis and respiration. 4. **Water Cycle**: Movement of water through evaporation, condensation, precipitation, and infiltration. ### ### **Conserving Biodiversity** - Habitat preservation and restoration. - Establishing protected areas (national parks). - Reducing pollution, recycling, and sustainable practices. - Controlling invasive species. ### **Earth's Spheres** - **Biosphere**: All living organisms. - **Atmosphere**: Gaseous layer around Earth. - **Hydrosphere**: Water bodies. - **Lithosphere**: Earth\'s crust and landforms. ### **Eutrophication** - Excess nutrients (nitrogen and phosphorus) in water cause algal blooms, reducing oxygen levels and harming aquatic life. ### **Bioaccumulation and Biomagnification** - **Bioaccumulation**: Build-up of toxins in an organism over time. - **Biomagnification**: Increase in toxin concentration as it moves up the food chain. ### **Biodiversity and Climate Change** - Loss of species due to habitat destruction, pollution, and climate shifts. - Impacts ecosystems, food security, and global health. ### **Restoration and Sustainability** - **Initiatives**: Pesticide bans, recycling programs, reforestation, renewable energy. - **Methods**: Wetland restoration, wildlife corridors, green technologies. ### **Electrostatic Series** - **Definition**: A list of materials arranged based on their tendency to gain or lose electrons. - Materials at the top tend to lose electrons (become positively charged). - Materials at the bottom tend to gain electrons (become negatively charged). - **Example**: Glass loses electrons to silk when rubbed together. ### **Calculating Appliance Costs and Efficiency** 1. **Cost Calculation**: a. Formula: Cost=Power (kW)×Time (h)×Rate (\$/kWh) b. Example: A 1000 W appliance used for 2 hours at \$0.12/kWh: Cost=1kW×2h×0.12=0.24dollars. 2. **Efficiency**: c. Formula: Efficiency (%) =(Total Energy Input Useful Energy Output)×100 d. Example: A device with 80 J of useful output energy from 100 J input: Efficiency=10080 ×100=80%. ### **Ohm's Law and Circuits** 1. **Ohm's Law**: V=I×R a. V: Voltage (Volts, V) b. I: Current (Amperes, A) c. R: Resistance (Ohms, *Ω\\Omega*Ω) 2. **Series Circuits**: d. **Current (I)**: Same throughout the circuit. e. **Voltage (V)**: Divided across components. 3. **Resistance (R)**:Total *R=R1+R2+R3+...* f. **Current (I)**: Divided across branches. g. **Voltage (V)**: Same across each branch. h. **Resistance (R)**: 1 =R1 1 +R2 1 +.... ### **Ways to Save Energy** - Use energy-efficient appliances (e.g., LED lights). - Unplug devices when not in use. - Install smart thermostats. - Use renewable energy sources. - Improve home insulation. ### **Renewable and Non-Renewable Energy Sources** 1. **Renewable**: Solar, wind, hydro, geothermal, biomass. a. **Advantages**: Sustainable, less pollution. b. **Disadvantages**: Intermittent availability, high initial costs. 2. **Non-Renewable**: Coal, oil, natural gas, nuclear. c. **Advantages**: High energy output, reliable. d. **Disadvantages**: Limited supply, environmental damage. ### **Law of Electric Charges** - Like charges repel, opposite charges attract. - Neutral objects can be attracted to charged objects due to induced charges. ### **Charging an Electroscope and Grounding** 1. **Charging**: a. **Contact**: Touching the electroscope with a charged object transfers electrons. b. **Induction**: Bringing a charged object close, then grounding, causes redistribution of charges. 2. **Grounding**: c. Allows excess charge to flow to or from the Earth, neutralizing the object. ### **Conductors vs. Insulators** - **Conductors**: Allow electrons to flow freely (e.g., metals like copper, silver). - **Insulators**: Restrict electron flow (e.g., rubber, glass, plastic). ### **Units of Measurement** - **Current**: Amperes (A). - **Resistance**: Ohms (*Ω\\Omega*Ω). - **Potential Difference**: Volts (V). ### **Factors Affecting Resistance** 1. **Material**: Conductors have lower resistance; insulators have higher resistance. 2. **Length**: Longer wires have higher resistance. 3. **Thickness**: Thicker wires have lower resistance. 4. **Temperature**: Higher temperatures usually increase resistance. ### ### **Static Electricity vs. Current Electricity** 1. **Static Electricity**: a. Accumulation of electric charge on a surface. b. Charges do not flow. c. Example: Hair standing up after rubbing with a balloon. 2. **Current Electricity**: d. Continuous flow of electric charge through a conductor. e. Requires a closed circuit. f. Example: Electricity powering appliances. ### **Atomic Theory and Key Scientists** 1. **John Dalton**: Proposed the atomic theory stating: a. Atoms are indivisible particles (later found to be incorrect). b. Atoms of the same element are identical. c. Atoms combine in whole-number ratios to form compounds. 2. **J.J. Thomson**: d. Discovered the electron using a cathode ray tube. e. Proposed the **\"Plum Pudding Model\"**: Electrons are embedded in a positively charged \"pudding.\" 3. **Ernest Rutherford**: f. Conducted the gold foil experiment. g. Discovered the nucleus: a small, dense, positively charged center surrounded by electrons. 4. **Niels Bohr**: h. Proposed that electrons orbit the nucleus in specific energy levels or shells. i. Introduced the **Bohr Model** of the atom. ### **Bohr-Rutherford Diagrams** - **Represent**: The arrangement of subatomic particles (protons, neutrons, electrons) in an atom. - **Structure**: - **Nucleus**: Contains protons (+) and neutrons (neutral). - **Electron shells**: Surround the nucleus, each holding a specific number of electrons (e.g., 2, 8, 18). - **Example**: Oxygen (atomic number 8): - Protons = 8, Neutrons = 8, Electrons = 8. - Diagram: Nucleus (8p, 8n), with 2 electrons in the first shell, 6 in the second. ### **Counting Atoms in a Compound** - **Example**:C6H12O6 (glucose). - Carbon: 6, Hydrogen: 12, Oxygen: 6. ### **Standard Atomic Notation** - Format:Z/AxX, where: - *AA*A: Mass number (protons + neutrons). - *ZZ*Z: Atomic number (protons). - *XX*X: Element symbol. - **Example**: Carbon with 6 protons, 6 neutrons, and 6 electrons. ### **Determining Atomic Details** - **Atomic Number**: Number of protons. - **Mass Number**: Protons + Neutrons. - **Number of Neutrons**: Mass Number−Atomic Number. - **Number of Electrons**: Equal to protons in a neutral atom. ### **Reactivity and Atomic Structure** - **Groups**: - Reactivity increases down Group 1 (alkali metals). - Reactivity decreases down Group 17 (halogens). - **Periods**: Reactivity depends on how close an element is to completing its outer shell. ### **Particle Theory of Matter** - Matter is made up of tiny particles. - Particles are in constant motion. - Particles are attracted to one another. - Each substance has unique particles. ### **Physical and Chemical Properties** 1. **Physical Properties**: a. **Quantitative**: Measurable (e.g., density, boiling point). b. **Qualitative**: Observable (e.g., color, texture). 2. **Chemical Properties**: Describe a substance\'s ability to react (e.g., flammability, reactivity with acid). ### **Subatomic Particles** - **Protons**: Positive charge, found in the nucleus. - **Neutrons**: No charge, found in the nucleus. - **Electrons**: Negative charge, orbit the nucleus. ### **Families of Elements** 1. **Alkali Metals (Group 1)**: Highly reactive, 1 valence electron. 2. **Alkaline Earth Metals (Group 2)**: Reactive, 2 valence electrons. 3. **Halogens (Group 17)**: Very reactive nonmetals, 7 valence electrons. 4. **Noble Gases (Group 18)**: Inert, full outer shell. ### **Ions and Their Formation** - **Cations**: Positive ions formed by losing electrons (e.g., Na+). - **Anions**: Negative ions formed by gaining electrons (e.g.,Cl−). ### **Classification of Matter** 1. **Mixtures**: Combination of substances that retain their properties. a. Homogeneous: Uniform (e.g., saltwater). b. Heterogeneous: Not uniform (e.g., sand and water). 2. **Pure Substances**: Fixed composition. c. Elements: Made of one type of atom. d. Compounds: Made of two or more elements chemically bonded. ### **Density** - Formula: Density= Mass/Voume - Units: g/cm3 or kg/m3. ### **Drawing Common Compounds** - Example: Water (H2 O): Two hydrogen atoms bonded to one oxygen atom. ### **Pure Substances vs. Mixtures; Elements vs. Compounds** 1. **Pure Substance vs. Mixture**: a. Pure substance: Uniform properties throughout (e.g., water). b. Mixture: Combination of substances (e.g., air). 2. **Element vs. Compound**: c. Element: Single type of atom (e.g., oxygen, O2). d. Compound: Two or more elements chemically combined (e.g., CO2). ### **Importance of Earth\'s Tilt** - **Phenomenon Caused**: Seasons. - Earth's axis is tilted at 23.5°, causing varying angles of sunlight at different times of the year. - When the Northern Hemisphere is tilted toward the Sun, it experiences summer, while the Southern Hemisphere experiences winter. ### **Inner Planets vs. Outer Planets** 1. **Inner Planets (Terrestrial)**: Mercury, Venus, Earth, Mars. a. **Characteristics**: i. Small, rocky surfaces. ii. Few or no moons. iii. Closer to the Sun, shorter orbital periods. iv. Higher densities. 2. **Outer Planets (Gas Giants/Jovian)**: Jupiter, Saturn, Uranus, Neptune. b. **Characteristics**: v. Large, composed mostly of gases (hydrogen, helium). vi. Many moons and ring systems. vii. Farther from the Sun, longer orbital periods. viii. Lower densities. ### **Canadian Contributions to Space Exploration** - **Canadarm**: Robotic arm used on the Space Shuttle. - **Canadarm2**: Advanced robotic arm on the International Space Station (ISS). - **Chris Hadfield**: First Canadian to command the ISS. - Contributions to satellite technology, such as RADARSAT for Earth observation. ### **Why Pluto is Considered a Dwarf Planet** - **Redefinition of a Planet (2006)**: - Must orbit the Sun. - Must be spherical in shape. - Must \"clear its orbit\" of other debris. - Pluto does not clear its orbit due to overlapping with Kuiper Belt objects, so it is classified as a dwarf planet. ### **Challenges and Hazards Astronauts Face** 1. **Microgravity**: a. Causes muscle and bone loss. b. Countered by exercise routines in space. 2. **Radiation**: c. Exposure to harmful cosmic rays. d. Countered by protective shielding and monitoring. 3. **Psychological Stress**: e. Isolation and confinement. f. Countered by mental health support and communication with Earth. 4. **Health Issues**: g. Altered fluid distribution (e.g., \"puffy face\"). h. Managed through medical protocols and adaptations. ### **Definition of Celestial Object** - **Celestial Object**: Any natural object found in space. - Examples: Stars, planets, moons, asteroids, comets, galaxies. ### **Earth's Rotation and Revolution** 1. **Rotation**: a. Earth spins on its axis once every 24 hours. b. Causes day and night. 2. **Revolution**: c. Earth orbits the Sun in 365.25 days. d. Combined with axial tilt, it causes seasons. 3. **Orbit Shape**: e. Elliptical (slightly oval-shaped). ### **Astronomical Unit (AU)** - **Definition**: The average distance from Earth to the Sun (approximately 149.6 million km). - **Use**: Measures distances within the solar system. - Example: Mars is about 1.52 AU from the Sun. ### **Asteroid Belt** - Located between Mars and Jupiter. - Contains rocky remnants from the early solar system. - Largest object: Ceres (a dwarf planet). ### **Constellations** - **Definition**: Patterns of stars in the night sky. - Examples: - **Orion** (The Hunter). - **Ursa Major** (The Great Bear). - **Scorpius** (The Scorpion). ### **Why Ancient Cultures Studied the Skies** - Navigation (e.g., by the stars and constellations). - Tracking time (calendars based on lunar and solar cycles). - Religious and cultural significance. ### **Lunar vs. Solar Eclipse** 1. **Lunar Eclipse**: a. Occurs when Earth passes between the Sun and Moon, casting a shadow on the Moon. b. Visible from anywhere on Earth where the Moon is above the horizon. 2. **Solar Eclipse**: c. Occurs when the Moon passes between the Sun and Earth, blocking sunlight. d. Visible only from specific locations. ### **Big Bang Theory vs. Solar Nebula Theory** 1. **Big Bang Theory**: a. Explains the origin of the universe. b. Universe began as a singularity 13.8 billion years ago and has been expanding ever since. 2. **Solar Nebula Theory**: c. Explains the formation of the solar system. d. Solar system formed from a rotating cloud of gas and dust about 4.6 billion years ago. ### **Galaxy** - **Definition**: A massive system of stars, planets, gas, dust, and dark matter bound by gravity. - Example: Milky Way Galaxy (our home galaxy). - **Types**: Spiral (e.g., Milky Way), Elliptical, Irregular.