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A.p bio 🧪 UNIT 1 CHEMISTRY OF LIFE — TEST CRAM Q&A 🟣 TOPIC 1: BIOLOGY REVIEW & STATISTICS Experimental Design Q: What is the independent variable? A: The variable the scientist changes/manipulates. Q: What is the dependent variable? A: The variable that is measured/observed. Q: Easy way to remember independent vs. dependent? A: Independent = I change it. Dependent = data I collect. Q: In an experiment, fertilizer concentration is changed and plant height is measured. What is the independent variable? A: Fertilizer concentration. Q: What is the dependent variable? A: Plant height. Q: What are constants? A: Things kept the same for every experimental group. Q: What is a control group? A: A group used as a comparison/baseline. Q: What is a positive control? A: A group that should produce a known positive result. Q: What is a negative control? A: A group that should produce no response/result. ⸻ Data & Statistics Q: What is qualitative data? A: Descriptive data that isn’t measured numerically. Example: color, texture, smell. Q: What is quantitative data? A: Numerical/measurable data. Example: 15 cm, 20°C, 5 grams. Q: What is the mean? A: The average: add all values and divide by the number of values. Q: What is the median? A: The middle value when data is arranged from least to greatest. Q: What is the mode? A: The value that occurs most often. Q: What is the range? A: Highest − lowest. Q: What does standard deviation tell you? A: How spread out the data is around the mean. Q: Small standard deviation means what? A: Data points are close together/consistent. Q: Large standard deviation means what? A: Data points are more spread out/variable. Q: If Group A and Group B have similar means, but Group A has a much smaller standard deviation, what does that mean? A: Group A’s data is more consistent and clustered around the mean. Q: What is SEM? A: Standard error of the mean; it estimates how accurately the sample mean represents the population mean. Q: What does a small SEM mean? A: The mean is more precise/reliable. Q: What do error bars show? A: The amount of variation or uncertainty around a mean, depending on what the graph specifies. Q: What should you look for when reading graphs? A: Specific data points, trends, patterns, increases/decreases, and relationships between variables. ⸻ 💧 TOPIC 2: STRUCTURE OF WATER & HYDROGEN BONDING Q: Why is water polar? A: Oxygen is more electronegative than hydrogen, so oxygen becomes partially negative and hydrogen becomes partially positive. Q: What does δ− mean? A: Partial negative charge. Q: What does δ+ mean? A: Partial positive charge. Q: What type of bond holds the H and O together inside one water molecule? A: Covalent bond. Q: What type of attraction occurs between different water molecules? A: Hydrogen bonds. Q: What causes water’s cohesion? A: Hydrogen bonding between water molecules. Q: What is cohesion? A: Water molecules sticking to other water molecules. Q: What is adhesion? A: Water sticking to other surfaces/materials. Q: What causes surface tension? A: Cohesion/hydrogen bonding between water molecules at the surface. Q: What is capillary action? A: Water moving upward through a narrow space because of cohesion + adhesion. Q: Why can water move upward through plants? A: Hydrogen bonding creates cohesion between water molecules, while adhesion helps water interact with the plant’s xylem walls, allowing capillary action. Q: Which interaction is primarily responsible for water cohesion? A: Hydrogen bonds. Q: What is a solute? A: The substance being dissolved. Q: What is a solvent? A: The substance that does the dissolving. Q: What is a solution? A: A solute + solvent mixture. ⭐ MUST KNOW: Polarity → hydrogen bonding → cohesion/adhesion → capillary action → water movement in plants ⸻ 🧬 TOPIC 2: ELEMENTS OF LIFE Q: Why is carbon so important to life? A: Carbon has 4 valence electrons, allowing it to form four stable covalent bonds and create many different structures. Q: Why can carbon create such a huge diversity of molecules? A: It can bond with itself and many other elements, creating chains, rings, branches, and complex structures. Q: What four major macromolecules are built from carbon? A: Carbohydrates, proteins, lipids, and nucleic acids. Q: What element is especially important in amino acids and nitrogenous bases? A: Nitrogen. Q: What element is found in nucleic acids and certain lipids? A: Phosphorus. Functional Groups Q: What is a functional group? A: A group of atoms that gives an organic molecule specific chemical properties and behaviors. Q: What are the major functional groups you need to know? A: Hydroxyl, carbonyl, carboxyl, amino, and phosphate. Q: What is a hydroxyl group? A: –OH Q: What is a carboxyl group? A: –COOH Q: What is an amino group? A: –NH₂ Q: What is a phosphate group? A: –PO₄ group. Q: What is a carbonyl group? A: A carbon double-bonded to oxygen: C=O. Q: What is a hydrocarbon? A: A molecule made only of carbon and hydrogen. ⸻ 🔗 TOPIC 3: INTRODUCTION TO BIOLOGICAL MACROMOLECULES Q: What is a monomer? A: A small building block that can join with others. Q: What is a polymer? A: A large molecule made from repeating monomers. Q: What are the four major biological macromolecules? A: Carbohydrates, proteins, lipids, nucleic acids. Q: What is dehydration synthesis? A: A process that joins monomers by forming a covalent bond and removing H₂O. Q: What is hydrolysis? A: A process that breaks covalent bonds by adding H₂O. 🧠 REMEMBER: Dehydration = take water OUT → build Hydrolysis = add water → break Q: Which process joins monomers to form a polymer? A: Dehydration synthesis. Q: Which process breaks polymers apart? A: Hydrolysis. Q: What happens to water during dehydration synthesis? A: Water is removed/released. Q: What happens to water during hydrolysis? A: Water is added. ⸻ 🍞 TOPIC 4: PROPERTIES OF BIOLOGICAL MACROMOLECULES Carbohydrates Q: What is a monosaccharide? A: A single sugar monomer. Q: What is a polysaccharide? A: A carbohydrate polymer made of many sugar units. Q: What is starch used for? A: Energy storage in plants. Q: What is glycogen used for? A: Energy storage in animals. Q: What is cellulose used for? A: Structural support in plant cell walls. ⸻ Proteins Q: What are proteins made of? A: Amino acids. Q: What is the monomer of a protein? A: Amino acid. Q: What part of an amino acid varies between amino acids? A: The R group. Q: Why are R groups important? A: Their different properties affect how a protein folds and functions. ⸻ Lipids Q: Are lipids generally polar or nonpolar? A: Mostly nonpolar/hydrophobic. Q: What does hydrophobic mean? A: Water-fearing; doesn’t mix well with water. Q: What does hydrophilic mean? A: Water-loving; interacts with water. Q: What is the difference between saturated and unsaturated fatty acids? A: Saturated = no C=C double bonds. Unsaturated = one or more C=C double bonds. Q: Which fatty acid has more bends/kinks? A: Unsaturated fatty acid. Q: Why do unsaturated fatty acids have kinks? A: Their double bonds bend the carbon chain. ⸻ Phospholipids Q: What two types of regions does a phospholipid have? A: A polar hydrophilic head and nonpolar hydrophobic tails. Q: Why are phospholipids important in cells? A: They form the cell membrane bilayer. Q: Why do phospholipids form a bilayer? A: The hydrophilic heads face the watery environments while the hydrophobic tails face inward away from water. ⸻ Nucleic Acids Q: What do nucleic acids do? A: They store and transmit biological information. Q: What is the monomer of nucleic acids? A: Nucleotide. Q: What are nucleotides made of? A: A 5-carbon sugar + phosphate group + nitrogenous base. ⸻ 🧩 TOPIC 5: STRUCTURE & FUNCTION OF BIOLOGICAL MACROMOLECULES Protein Structure Q: What determines a protein’s primary structure? A: The sequence of amino acids. Q: What is secondary protein structure? A: Local folding into structures such as alpha helices and beta sheets, stabilized by hydrogen bonds. Q: What is tertiary structure? A: The overall 3D shape of one polypeptide. Q: What is quaternary structure? A: Multiple polypeptide chains/subunits working together. ⭐ KNOW THIS ORDER: Primary → Secondary → Tertiary → Quaternary Q: Why can changing one amino acid affect protein function? A: It can change interactions between amino acids, which can change the protein’s shape, potentially changing its function. Q: What is denaturation? A: When a protein loses its normal shape, causing it to lose or reduce its function. Q: What can cause protein denaturation? A: Things such as high temperature or extreme pH. ⸻ DNA Structure Q: What does antiparallel mean? A: The two DNA strands run in opposite directions: one 5’ → 3’ and the other 3’ → 5’. Q: Why is DNA directionality important? A: DNA strands have specific 5’ and 3’ ends, which determines how they are read and copied. ⸻ Carbohydrate Structure Q: Why can two carbohydrates made from similar sugar monomers have different functions? A: Their monomers can have different arrangements, bonding, branching, and structures, which changes their properties and functions. Q: Example of this? A: Starch and cellulose are both made from glucose, but their different bonding/arrangements give them different functions. ⸻ 🧬 TOPIC 6: NUCLEIC ACIDS Q: What are the three parts of a nucleotide? A: 5-carbon sugar + phosphate group + nitrogenous base. Q: What sugar is found in DNA? A: Deoxyribose. Q: What sugar is found in RNA? A: Ribose. Q: What nitrogenous base is found in DNA but not RNA? A: Thymine (T). Q: What nitrogenous base is found in RNA instead of thymine? A: Uracil (U). Q: Is DNA usually single- or double-stranded? A: Double-stranded. Q: Is RNA usually single- or double-stranded? A: Single-stranded. Q: What does DNA store? A: Genetic/biological information. Q: What connects nucleotides together? A: Covalent bonds form the sugar-phosphate backbone. ⸻ 🧬 Base Pairing Q: What does A pair with in DNA? A: T Q: What does T pair with? A: A Q: What does C pair with? A: G Q: What does G pair with? A: C RNA: A ↔ U C ↔ G Q: If one DNA strand is 5’-ACGTAC-3’, what is the complementary strand? A: 3’-TGCATG-5’ Q: Why is it written 3’ → 5’? A: Because DNA strands are antiparallel. ⸻ 🔥 UNIT 1 BIG CONNECTIONS — YOUR TEACHER WILL LOVE THESE Q: Explain the water connection. A: Water’s polarity causes hydrogen bonding, which produces properties like cohesion and adhesion that are important for biological functions such as water movement through plants. Q: Explain the carbon connection. A: Carbon’s four valence electrons allow it to form many covalent bonds, creating the huge diversity of biological molecules. Q: Explain the macromolecule connection. A: Monomers join → polymers/macromolecules form → their structure determines their properties and function. Q: Explain the protein connection. A: Amino acid sequence → protein shape → protein function. Q: Explain the DNA connection. A: Nucleotide sequence → biological/genetic information. Q: Explain the experiment connection. A: Experimental design → data → analysis → evidence → biological conclusion. ⸻ 🚨 15 QUESTIONS YOU SHOULD BE ABLE TO ANSWER WITHOUT LOOKING What is the independent variable? → What you change. What is the dependent variable? → What you measure. Small standard deviation means…? → Data is consistent/close together. Why is water polar? → Oxygen is more electronegative than hydrogen. What causes cohesion? → Hydrogen bonding. What causes capillary action? → Cohesion + adhesion. Why is carbon so versatile? → Four valence electrons. What joins monomers? → Dehydration synthesis. What breaks polymers? → Hydrolysis. Protein monomer? → Amino acid. Nucleic acid monomer? → Nucleotide. Unsaturated fatty acids have what? → Double bonds and kinks. What determines protein shape? → Amino acid sequence/interactions. DNA sugar/base? → Deoxyribose + thymine. DNA strands are…? → Double-stranded and antiparallel. 🧠 LAST-MINUTE MEMORY CHAIN Memorize this exact chain: Water: POLAR → H-BONDS → COHESION/ADHESION → CAPILLARY ACTION Macromolecules: MONOMER → DEHYDRATION → POLYMER Breaking: POLYMER → HYDROLYSIS → MONOMERS Protein: AMINO ACID SEQUENCE → SHAPE → FUNCTION DNA: NUCLEOTIDE SEQUENCE → INFORMATION Experiment: INDEPENDENT → DEPENDENT → DATA → EVIDENCE → CONCLUSION

parts. PART I — Multiple Choice 1. Which statement best describes soil fertility? A. The ability of soil to produce maximum yield under any condition B. The soil’s ability or potential to supply essential nutrients needed by plants C. The ability of soil to prevent erosion D. The ability of soil to retain only water 2. Which statement correctly describes soil productivity? A. The ability of soil to supply nutrients only B. The ability of soil to produce a good crop yield under a given management system C. The amount of organic matter in soil D. The ability of soil to retain water 3. Which statement is correct regarding soil fertility and productivity? A. All fertile soils are productive B. All productive soils are fertile, but not all fertile soils are productive C. Fertility and productivity are exactly the same D. Productive soils do not need nutrients 4. Soil fertility is best described as the soil’s: A. Performance B. Potential or inherent capability to supply nutrients C. Rate of erosion D. Amount of sand 5. Soil productivity depends on: A. Soil fertility only B. Fertility and other factors including management C. Soil color only D. Soil texture only 6. What are edaphic factors? A. Factors related to climate B. Factors related to animals C. Factors related to soil that affect plant growth D. Factors related to sunlight only 7. Soil texture refers to the relative amounts of: A. Organic matter, water, and air B. Sand, silt, and clay C. Nitrogen, phosphorus, and potassium D. Roots, microorganisms, and water 8. Which soil generally holds more water? A. Sandy soil B. Clayey soil C. Gravelly soil D. Rocky soil 9. Soil structure refers to: A. The color of soil B. The amount of sand in soil C. How soil particles group together into aggregates D. The amount of water in soil 10. Which practice can improve soil structure? A. Excessive tillage B. Continuous heavy machinery use C. Adding organic matter D. Repeated soil compaction 11. Soil aeration refers to: A. The amount of water in soil B. The amount of air in spaces between soil particles C. Soil temperature D. Soil acidity 12. What happens to soil aeration when soil becomes compacted? A. Air spaces increase B. Air spaces decrease C. Nutrients automatically increase D. Root growth improves 13. Soil temperature directly affects: A. Seed germination and root growth B. Soil texture C. Soil classification only D. Amount of sand 14. Soil pH affects: A. Nutrient availability and microorganism activity B. Only soil color C. Only soil temperature D. Crop spacing 15. Which condition can restrict root growth? A. Loose soil B. Well-aerated soil C. Soil compaction D. Good soil structure 16. Which is a common cause of soil compaction? A. Crop rotation B. Heavy machinery and repeated traffic C. Adding organic matter D. Leaving crop residues 17. Beneficial soil microorganisms are important because they: A. Stop all plant diseases B. Decompose organic matter and help release nutrients C. Remove all water from soil D. Cause soil erosion 18. Organic matter can improve: A. Water-holding capacity B. Soil structure C. Nutrient availability D. All of the above 19. Which two elements are important sources of food/nutrients involved in microbial activity and decomposition? A. Carbon and nitrogen B. Calcium and iron C. Potassium and sulfur D. Sodium and chlorine 20. Which cropping system involves growing the same crop repeatedly? A. Crop rotation B. Monocropping C. No-tillage D. Minimum tillage 21. Which is an example of crop rotation? A. Corn → corn → corn B. Corn → soybean → corn C. Rice → rice → rice D. Corn → corn → soybean only once 22. One advantage of crop rotation is that it can: A. Always eliminate all pests B. Help maintain soil fertility and reduce some pests and diseases C. Increase soil compaction D. Always increase erosion 23. Conventional tillage generally involves: A. No soil disturbance B. Repeated plowing and harrowing C. Leaving all soil untouched D. Planting without any preparation 24. Minimum tillage: A. Uses less soil disturbance than conventional tillage B. Uses more plowing than conventional tillage C. Always removes crop residues D. Completely prevents erosion 25. No-tillage means: A. Soil is heavily plowed before planting B. Crops are planted with minimal soil disturbance C. Soil is completely removed D. Crops are never planted 26. Soil erosion is: A. The addition of nutrients to soil B. The removal and movement of soil by water or wind C. The movement of water into soil D. The decomposition of organic matter 27. Why is soil erosion harmful to soil fertility? A. It removes fertile topsoil containing nutrients and organic matter B. It increases all nutrients C. It increases soil organic matter D. It improves root growth ⸻ PART II — True or False 28. A fertile soil is always a productive soil. 29. All productive soils are fertile. 30. Soil fertility is one factor that affects soil productivity. 31. Soil productivity considers the crop yield obtained under a given management system. 32. Soil texture refers to the amount of sand, silt, and clay. 33. Sandy soil generally drains water faster than clayey soil. 34. Soil structure refers to how individual soil particles group together into aggregates. 35. Soil structure can never be changed by management practices. 36. Good soil structure promotes movement of air and water and supports root growth. 37. Compacted soil usually has fewer pore spaces. 38. Plants need soil water for germination, nutrient absorption, and growth. 39. Soil pH has no effect on nutrient availability. 40. Very acidic or very alkaline soils can make some nutrients unavailable. 41. Soil microorganisms help in decomposition and nutrient cycling. 42. Having more microorganisms automatically means the soil is always more fertile. 43. Organic matter can improve water-holding capacity and soil structure. 44. Monocropping means growing different crops in sequence. 45. Crop rotation can help maintain soil fertility. 46. Minimum tillage causes more soil disturbance than conventional tillage. 47. No-tillage minimizes soil disturbance. 48. Soil erosion can remove nutrient-rich topsoil. ⸻ PART III — Identification 49. Ability of soil to supply essential nutrients needed by plants. 50. Ability of soil to produce a good crop yield under a given management system. 51. Factors related to soil that affect plant growth. 52. The relative amounts of sand, silt, and clay in soil. 53. The arrangement or grouping of soil particles into aggregates. 54. The amount of air present in the spaces between soil particles. 55. The pressing of soil particles closely together, reducing pore spaces. 56. Dead plants, animals, and other organic materials present in or added to soil. 57. Growing the same crop repeatedly on the same land. 58. Growing different crops in sequence on the same land. 59. A tillage system involving more intensive soil disturbance such as repeated plowing and harrowing. 60. A tillage system that uses less soil disturbance than conventional tillage. 61. A system where crops are planted with minimal soil disturbance and crop residues are often left on the surface. 62. The removal and movement of soil by water or wind. ⸻ PART IV — Situational Questions 63. A farmer has soil that contains enough nutrients, but the soil is heavily compacted. The roots cannot penetrate properly and the crop grows poorly. Is the soil fertile, productive, or both? Explain. 64. A clayey field retains a lot of water, while a sandy field drains water quickly. Which soil property is responsible for this difference? 65. A farmer repeatedly uses heavy machinery on the same field. The soil becomes dense, roots struggle to grow, and water movement decreases. What soil condition has developed? 66. A farmer adds organic matter to the soil. After some time, the soil has better structure, improved water-holding capacity, and increased nutrient cycling. What soil component caused these improvements? 67. A farmer plants corn every year on the same land: Corn → Corn → Corn → Corn. What cropping system is being practiced? 68. Another farmer plants Corn → Soybean → Corn → Soybean. What cropping system is this? 69. A farmer reduces plowing and harrowing to protect the soil from erosion. What tillage system is being practiced? 70. A farmer plants crops without conventional plowing and leaves crop residues on the soil surface. What management system is this? 71. A field has good fertility and sufficient nutrients, but poor drainage, severe compaction, and poor management result in low crop yield. What does this demonstrate about soil fertility and productivity? 72. Heavy rainfall causes the removal of the nutrient-rich topsoil from a field. Which soil management problem is occurring? ⸻ PART V — Challenge Questions 73. Why is a fertile soil not necessarily a productive soil? 74. Why is soil fertility considered a potential or inherent capability, while soil productivity refers more to actual performance or yield? 75. Explain how soil texture, soil structure, soil water, and soil aeration work together to affect plant growth. 76. Explain how soil compaction can lead to stunted plant growth. 77. Explain why organic matter is important in maintaining soil fertility. 78. Compare monocropping and crop rotation in terms of soil fertility and management. 79. Compare conventional tillage, minimum tillage, and no-tillage. 80. Explain how soil erosion can cause both soil fertility decline and reduced soil productivity. Quick distinction to memorize Soil Fertility = POTENTIAL → ability to supply essential nutrients. Soil Productivity = PERFORMANCE → ability to produce a good crop yield under a given management system.