What is ATP and How is it Used by Cells

What is ATP and how is it used by cells? ATP (adenosine triphosphate) is the main energy-carrying molecule in cells. It stores and releases energy by breaking and reforming the bonds between its phosphate groups. Cells use ATP to power processes like active transport, movement, and chemical reactions. 2. Compare and contrast ATP and ADP. ATP has three phosphate groups, while ADP (adenosine diphosphate) has two. When ATP loses one phosphate group (releasing energy), it becomes ADP. When a phosphate is added back (storing energy), ADP becomes ATP again. 3. Write the equation for photosynthesis using words and molecular symbols. Words: Carbon dioxide + Water → Glucose + Oxygen Formula: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ 4. Explain why photosynthesis is important to life on earth. Photosynthesis produces the oxygen we breathe and the glucose that serves as food for nearly all living things. It’s the foundation of most food chains and provides energy for life on Earth. 5. Describe the role of chlorophyll in photosynthesis. Chlorophyll is a green pigment found in chloroplasts that absorbs light energy from the sun, mainly in the blue and red wavelengths, and uses it to power the reactions of photosynthesis. 6. Identify the factors that affect the rate of photosynthesis. The main factors are light intensity, carbon dioxide concentration, and temperature. Too little or too much of any of these can slow down photosynthesis. 7. Label the location, purpose, and products of photosynthesis. • • • Location: Chloroplasts (in plant cells) Purpose: To convert solar energy into chemical energy (glucose) Products: Glucose (C₆H₁₂O₆) and oxygen (O₂) Ch. 9 – Cellular Respiration 8. Write the overall equation for cellular respiration in words and molecular symbols. Words: Glucose + Oxygen → Carbon dioxide + Water + Energy (ATP) Formula: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP 9. Identify the three parts of cellular respiration. 1. Glycolysis 2. Krebs Cycle (Citric Acid Cycle) 3. Electron Transport Chain 10. Describe the role of oxygen in cellular respiration. Oxygen is the final electron acceptor in the electron transport chain. It combines with electrons and hydrogen to form water, allowing ATP production to continue. 11. Describe the role of NADP⁺/NADPH in photosynthesis and NAD⁺/NADH in cellular respiration. • • In photosynthesis, NADP⁺ carries electrons and hydrogen to form NADPH, which helps build glucose. In cellular respiration, NAD⁺ carries electrons during glycolysis and the Krebs cycle to form NADH, which delivers them to the electron transport chain to make ATP. 12. Explain how energy flows through living systems. Energy from the sun → captured by plants in photosynthesis → stored in glucose → transferred to animals when they eat plants → released as ATP during cellular respiration → used for cell processes. 13. Identify the organelles involved in photosynthesis and cellular respiration. • Photosynthesis: Chloroplasts • Cellular Respiration: Mitochondria 14. Compare photosynthesis and cellular respiration (opposite processes). • • Photosynthesis: Converts carbon dioxide and water into glucose and oxygen using light energy (stores energy). Cellular Respiration: Breaks down glucose and oxygen into carbon dioxide and water (releases energy). They are opposite reactions — the products of one are the reactants of the other. 15. Identify the location, reactants, and products of cellular respiration • • • Location: Mostly in the mitochondria (starts in the cytoplasm) Reactants: Glucose (C₆H₁₂O₆) and Oxygen (O₂) Products: Carbon dioxide (CO₂), Water (H₂O), and ATP (energy) 16. Write the equation for cellular respiration Glucose + Oxygen → Carbon dioxide + Water + Energy 17. Explain how heterotrophs get energy Heterotrophs (animals, bacteria, humans) eat other organisms to get glucose. They use cellular respiration to break down that glucose into ATP, which powers all cell functions. 18. Explain why cells need cellular respiration Cells need ATP to: • • • Move materials in and out Grow and divide Contract muscles and send nerve signals Without respiration, cells wouldn’t have energy to survive. 19. Summarize the three stages of cellular respiration (location & ATP) Stage Location AT P Description Glycolysis Cytoplasm 2 Krebs Cycle Mitochondrial matrix Electron Transport Chain (ETC) Inner mitochondrial membrane Glucose → 2 pyruvate Pyruvate broken down → CO₂ 2 released 32– Electrons power ATP and make 34 H₂O Total: ~36–38 ATP per glucose molecule. 20. Compare and contrast aerobic and anaerobic respiration Feature Needs oxygen? ATP made Aerobic Anaerobic Yes No 36–38 2 21. Compare and contrast photosynthesis and cellular respiration Feature Reactants Products Location Purpose Photosynthesis Cellular Respiration CO₂ + H₂O Glucose + O₂ Glucose + O₂ CO₂ + H₂O + ATP Chloroplast (plants) Mitochondria (all eukaryotes) Store energy in glucose Release energy from glucose Autotrophs (plants, some All organisms (plants & Organisms bacteria) animals) Describe some of the difficulties a cell faces as it increases in size. • Larger cells have trouble moving nutrients and wastes across the cell membrane efficiently. DNA cannot control all cell functions if the cell gets too large (information overload). • • 2. Compare and contrast asexual and sexual reproduction • Asexual reproduction: One parent, offspring genetically identical, faster. • Sexual reproduction: Two parents, offspring genetically unique, increases genetic diversity. • 3. Explain the role of chromosomes during cell division. • Chromosomes ensure DNA is copied and distributed evenly between new cells 4. Describe the main events in each phase of the cell cycle. • • • • G1 phase: Cell grows and carries out normal functions. S phase: DNA is replicated. G2 phase: Organelles and molecules for division are produced. M phase (mitosis + cytokinesis): Cell divides into two identical daughter cells. 5. Name the 3 parts of interphase and describe what happens in each. • • • G1: Growth and normal activity. S: DNA replication. G2: Preparation for mitosis (organelles duplicated). 6. Name the phases of mitosis and describe what happens in each. • Prophase: Chromosomes condense, spindle forms, nuclear envelope breaks down. • Metaphase: Chromosomes line up in the center of the cell. • Anaphase: Sister chromatids separate to opposite sides. • Telophase: Two new nuclei form, chromosomes uncoil. • Cytokinesis: Cytoplasm divides, forming two identical cells. 8. Explain the role of centrioles and spindle fibers. • • Centrioles: Help organize spindle fibers during mitosis. Spindle fibers: Attach to centromeres and pull chromatids apart. 9. Explain how cancer can be caused by failure to regulate the cell cycle. • When cell cycle checkpoints fail, cells divide uncontrollably, forming tumors (cancer). • 10. Identify the types of cells that undergo mitosis. • Body (somatic) cells — like skin, muscle, and bone cells. 11. Contrast the cells produced as the result of mitosis and meiosis. • • Mitosis: Produces 2 identical diploid cells. Meiosis: Produces 4 genetically different haploid cells.