TERM 2 ETA REVIEWER - Microscopy PDF

TERM 2: ETA REVIEWER MICROSCOPY PARTS AND FUNCTIONS Eyepiece (Ocular Lens): Magnifies the image of the specimen, usually by 10x or 15x. Objective Lenses: Provide different levels of magnification (e.g., 4x, 10x, 40x, 100x). Stage: The fl...

TERM 2: ETA REVIEWER MICROSCOPY PARTS AND FUNCTIONS Eyepiece (Ocular Lens): Magnifies the image of the specimen, usually by 10x or 15x. Objective Lenses: Provide different levels of magnification (e.g., 4x, 10x, 40x, 100x). Stage: The flat platform where the slide is placed for viewing. Coarse Adjustment Knob: Moves the stage up and down significantly to focus on the specimen. Fine Adjustment Knob: Makes small adjustments to sharpen the focus. Arm: Connects the body tube to the base; used for carrying the microscope. Base: The bottom part that supports the microscope. Light Source: Provides illumination, either from a built-in light or a mirror. Diaphragm: Controls the amount of light entering through the specimen. Condenser: Focuses light onto the specimen. PROPER HANDLING AND STORAGE Always carry the microscope with two hands: one hand holding the arm, the other supporting the base. Use lens paper to clean the eyepiece and objective lenses to avoid scratches. Ensure the microscope is stored in a dust-free, dry area with its cover on. Set the lowest objective lens (4x) and lower the stage before storing. KEY SKILLS Properly focus on a specimen: Start with the lowest power objective lens and coarse adjustment knob, then switch to higher magnifications using the fine adjustment knob. Adjust lighting using the diaphragm and condenser for clear visibility.  REPRODUCTION DEFINITION Reproduction is the biological process by which organisms produce offspring, ensuring the continuation and survival of their species. It can occur through two main types: sexual reproduction and asexual reproduction. IMPORTANCE Maintains the population of a species. Transfers genetic material to the next generation. Allows adaptation and evolution in response to environmental changes. DIFFERENTIATING SEXUAL AND ASEXUAL REPRODUCTION Feature Sexual Reproduction Asexual Reproduction Number of Parents Two (male and female) One Genetically unique Genetically identical to the Offspring Similarity (combination of both parent (clones) parents’ DNA) Involves meiosis and Involves mitosis or other Process fertilization mechanisms like budding or binary fission Animals, humans, flowering Examples Bacteria, hydra plants IMPORTANCE Sexual reproduction ensures genetic diversity, which is essential for evolution and survival in changing environments. Asexual reproduction allows for rapid population growth, especially in stable environments.  TYPES OF CELL DIVISION DEFINITION Cell division is the process by which a parent cell divides into two or more daughter cells. It is a fundamental process for growth, development, repair, and reproduction in all living organisms. DIFFERENTIATING SEXUAL AND ASEXUAL REPRODUCTION Feature MITOSIS MEIOSIS Purpose Two (male and female) Sexual reproduction Number of Divisions one two Number of Cells two four Produced Genetic Makeup Identical to parent cell Genetically unique Chromosome Diploid (2n) Haploid (n) Number MITOSIS Prophase: Chromosomes condense and become visible. Nuclear membrane starts to break down. Spindle fibers begin to form. Metaphase: Chromosomes align at the equator of the cell. Spindle fibers attach to the centromeres of each chromosome. Anaphase: Sister chromatids are pulled apart and move toward opposite poles. Telophase: Nuclear membranes reform around each set of chromosomes. Cytokinesis The cytoplasm divides, resulting in two identical daughter cells.  MEIOSIS Meiosis I: 1. Prophase I: Homologous chromosomes pair up and exchange genetic material (crossing over). 2. Metaphase I: Homologous pairs align at the center of the cell. 3. Anaphase I: Homologous chromosomes are separated to opposite poles. 4. Telophase I: Nuclear membranes reform around each set of chromosomes. 5. Cytokinesis: The cytoplasm divides, and two haploid cells form, each with half the chromosome number. Meiosis II: 1. Prophase II: Chromosomes prepare for a second division. 2. Metaphase II: Chromosomes align at the equator of each cell. 3. Anaphase II: Sister chromatids are pulled apart. 4. Telophase II: Nuclear membranes reform around each set of chromosomes. 5. Cytokinesis: The cytoplasm divides, producing four genetically unique haploid cells. GENETIC INFORMATION TRANSMISSION THROUGH MEIOSIS AND FERTILIZATION MEIOSIS Produces haploid gametes, ensuring offspring receive half their genetic information from each parent. Crossing over and independent assortment during meiosis create unique combinations of genes. FERTILIZATION Combines the haploid gametes (egg and sperm) to form a diploid zygote. The zygote contains a mix of genetic material from both parents. IMPORTANCE 1. Creates Variety – Meiosis mixes genes, so each person is unique. 2. Keeps Chromosome Number Balanced – Fertilization combines half from each parent to keep the total correct.. 3. Helps Species Survive – Genetic variety helps living things adapt to changes over time. ECOLOGICAL LEVELS POPULATION Definition: A group of organisms of the same species living in the same area at the same time. Example: A herd of zebras, a school of fish. Key Idea: Members of a population can interbreed. COMMUNITY Definition: All the populations of different species living and interacting in a specific area. Example: A forest community (trees, birds, insects, fungi). Key Idea: Communities show biodiversity (variety of life). COMMUNITY Definition: A community of organisms and their non-living environment (abiotic factors) interacting together. Example: A coral reef (fish, coral, water, sunlight). Key Idea: Ecosystems depend on energy flow and nutrient cycles.  BIOMES Definition: A large geographic area with similar climates, plants, and animals. Example: Tropical rainforest, desert, tundra. Key Idea: Biomes are defined by climate, such as temperature and rainfall. BIOSPHERE Definition: The part of Earth where life exists, including land, water, and the atmosphere. Example: Earth’s surface and all living things on it. Key Idea: The biosphere is the sum of all ecosystems. ROLES OF ORGANISMS IN THE FOOD CHAIN AND FOOD WEB PRODUCERS (AUTOTROPHS) Definition: Organisms that make their own food using sunlight (photosynthesis). Role: They are the foundation of the food chain, providing energy for all other organisms. Examples: Plants (e.g., grass, trees), Algae, Phytoplankton Key Idea: Producers convert sunlight or chemical energy into glucose, which is consumed by other organisms. CONSUMERS (HETEROTROPHS) Definition: Organisms that eat other organisms to obtain energy. Types of Consumers: - Primary Consumers: Herbivores that eat producers. Examples: Grasshoppers, deer, rabbits. - Secondary Consumers: Carnivores or omnivores that eat primary consumers. Examples: Frogs, snakes. -Tertiary Consumers: Predators that eat secondary consumers. Examples: Hawks, lions, sharks. -Apex Predators: Top predators with no natural predators in their ecosystem. Examples: Tigers, orcas, eagles, great white sharks. Key Idea: Consumers rely on producers and other consumers for energy. DECOMPOSERS Definition: Organisms that break down dead plants, animals, and waste into simpler substances. Role: Decomposers recycle nutrients back into the ecosystem, making them available for producers. Examples: Fungi (e.g., mushrooms), Bacteria, Worms Key Idea: Decomposers are nature’s recyclers, maintaining the balance of ecosystems.  Feature Food Chain Food Web Energy Pyramid A network of A graphical A linear sequence interconnected food representation of Definition showing energy flow chains representing energy flow across between organisms. complex feeding trophic levels. relationships. Multiple feeding Energy transfer and Single feeding Focus relationships in an efficiency between relationship. ecosystem. trophic levels. Illustrates energy Quantifies energy loss Shows energy flow in flow across various Energy Transfer (typically 10% rule) at one specific path. interconnected each level. paths. Demonstrates Highlights simple Explains why Ecological interdependence and predator-prey ecosystems support Insight ecosystem relationships. fewer top predators. complexity. A food web shows feeding relationships in an ecosystem. Grass, the primary producer, provides energy for herbivores like rabbits, mice, and grasshoppers. Frogs and snakes, as primary carnivores, prey on these herbivores. Secondary carnivores, including owls, foxes, and hawks, hunt frogs, snakes, and other animals. This web illustrates energy flow from plants to predators. In a Energy pyramid with 20,000 kJ from producers, only 10% of energy transfers to each level: Primary consumers get 2,000 kJ, Secondary consumers get 200 kJ, Tertiary consumers get 20 kJ, Quaternary consumers (apex predators) get 2 kJ. This is the 10% rule, where energy decreases by 90% at each level.  OUTCOMES OF POPULATION CHANGES IN FOOD CHAINS AND FOOD WEBS Scenario What Happens Example If bees disappear, plants won’t be Some animals lose their food, An organism pollinated, affecting herbivores while others grow too much disappears like deer and predators like and harm the ecosystem. wolves. Too many of one type of If deer increase, they might eat all animal can eat too much or increase in population the plants, leaving nothing for take over the space, harming smaller animals like rabbits. other organisms. Fewer of one type of animal If sharks decrease, smaller fish decrease in means others might overgrow might overeat algae, damaging population or starve, creating coral reefs. imbalances. SCALAR VS. VECTOR Feature Scalar Vector A physical quantity that has A physical quantity that has both Magnitude only magnitude (size) but no magnitude and direction. direction. Speed, distance, time, mass, Velocity, displacement, force, Example temperature. acceleration. TIPS FOR IDENTIFYING SCALARS AND VECTORS Does it involve direction? Yes → It's a vector. No → It's a scalar. Units alone vs. units with direction: If only units (e.g., 5 m, 2 kg), it's scalar. If units with direction (e.g., 5 m north, 10 N left), it's vector.  DISTANCE VS. DISPLACEMENT Feature DISTANCE DISPLACEMENT The shortest straight-line distance The total path covered by an Definition between two points, including object, regardless of direction. direction. Nature Scalar (magnitude only). Vector (magnitude and direction). SAMPLE PROBLEM Jean walked 5 km to the east, then she turned south and walked for 3 km. Then she turned to the west and walked 5 km more. Lastly, she headed north and walked another 3 km. 1. What is Jean’s total distance covered? 2. What is Jean’s resultant displacement? SOLVING FOR DISTANCE SOLVING FOR DISPLACEMENT GIVEN: GIVEN: UNKNOWN: UNKNOWN: SOLUTION: SOLUTION: FINAL ANSWER: 16.00 km FINAL ANSWER: 0 km  SPEED VS. VELOCITY Feature SPEED VELOCITY The rate at which an object The rate at which an object Definition changes its position, including covers distance. direction. Scalar quantity (only Vector quantity (magnitude and Type magnitude, no direction). direction). SAMPLE PROBLEM Anna jogged 4 km east , then turned west and jogged 2 km. Finally, she jogged 6 km east. The total time it took her to complete the jog was 2 hours. SOLVING FOR SPEED SOLVING FOR VELOCITY GIVEN: GIVEN: UNKNOWN: average SPEED UNKNOWN: average VELOCITY SOLUTION: SOLUTION: FINAL ANSWER: 6.00 km/h FINAL ANSWER: 4.00 km/h east  SOME PRACTICAL APPLICATIONS OF DISTANCE, DISPLACEMENT,SPEED & VELOCITY 1. Estimating travel time and distance when driving or using public transport, factoring in speed and route choices. 2. Measuring athletes' speed and displacement to analyze performance, such as in running, cycling, or swimming. 3. Optimizing delivery routes and calculating travel times based on velocity and distance between destinations. 4. Designing vehicles, such as cars or airplanes, considering speed, displacement, and velocity for safety and efficiency. REMEMBER 1. Make sure to use only black or blue pens. 2. Answer on the answer sheet, not on the questionnaire. Write your answers in print. 3. Bring your own calculator and know how it works. 4. Make sure to always write your final answer with the correct unit and rounded to 2 decimal places. 5. Read the rubrics before answering. You’ve worked hard, so stay focused and do your best! You've got this! Good luck on your end-term exam!