General Biology 1, 2nd Quarter PDF

**ATP and Energy Metabolism** - ATP (Adenosine Triphosphate) is the primary energy currency of the cell, providing energy for various cellular processes. - ATP is composed of adenine, a five-carbon sugar (ribose), and three phosphate groups. **ATP-ADP Cycle and Energy Transfer** -...

**ATP and Energy Metabolism** - ATP (Adenosine Triphosphate) is the primary energy currency of the cell, providing energy for various cellular processes. - ATP is composed of adenine, a five-carbon sugar (ribose), and three phosphate groups. **ATP-ADP Cycle and Energy Transfer** - ATP plays a crucial role in linking exergonic (energy-releasing) and endergonic (energy-requiring) reactions, allowing energy to be transferred between them. - During exergonic reactions, ATP is generated, and during endergonic reactions, ATP is broken down to ADP (Adenosine Diphosphate). **ADP and Energy Metabolism** - ADP is the primary recipient of energy from the breakdown of ATP, allowing it to be recycled back into ATP. - The primary role of ADP is to accept energy from the breakdown of ATP, which can then be used to drive endergonic reactions. **Cellular Respiration and Energy Production** - The primary source of energy used by living organisms is the breakdown of glucose and other nutrients through cellular respiration. - Cellular respiration is the process by which organisms use oxygen to turn fuel into chemical energy, producing ATP as a byproduct. **Types of Respiration and Energy Production** - Anaerobic respiration is a type of respiration that can break down sugars to generate energy in the absence of oxygen. - The energy required for endergonic reactions is called activation energy. **ATP Synthesis and Phosphorylation** - The process of combining ADP with a phosphate molecule to make ATP is called phosphorylation. - The energy released from breaking a molecular bond in ATP comes from the energy stored in the phosphate bonds. - ATP provides the premier energy molecule in living cells, powering various cellular processes. **The ATP-ADP Cycle** - ATP (adenosine triphosphate) is the primary energy currency of cells. - The ATP-ADP cycle describes the continuous conversion of ATP to ADP (adenosine diphosphate) and back again. - ATP releases energy when a phosphate group is removed, converting it to ADP. - This energy is used to power cellular processes. - ADP can then be re-phosphorylated to ATP using energy from various sources, like cellular respiration or photosynthesis. **Photosynthesis: Light-Dependent Reactions** - Chlorophyll and other pigments absorb light energy. - This energy is used to excite electrons in the pigments. - The excited electrons move through an electron transport chain, generating ATP and NADPH. - Water is split, releasing oxygen as a byproduct. **Photosynthesis: Products of the Light-Dependent Reactions** - ATP (adenosine triphosphate) is a primary energy carrier used in the Calvin Cycle. - NADPH (nicotinamide adenine dinucleotide phosphate) is a reducing agent used in the Calvin Cycle. - Oxygen is a byproduct released into the atmosphere. **The Calvin Cycle** - The Calvin cycle is the light-independent stage of photosynthesis. - It uses the energy from ATP and the reducing power of NADPH to convert carbon dioxide into sugar. **Discoverers of the Calvin Cycle** - Melvin Calvin and his team at the University of California, Berkeley, discovered the Calvin cycle. **Alternative Names for the Calvin Cycle** - The Calvin cycle is also known as the Calvin-Benson cycle or the C3 cycle. **Function of the Calvin Cycle** - The Calvin cycle is the main process by which plants fix carbon dioxide into organic compounds, specifically glucose. **G3P, a Product of the Calvin Cycle** - G3P (glyceraldehyde 3-phosphate) is a three-carbon sugar that is produced in the Calvin Cycle. - It is used to synthesize other sugars and organic molecules. **Carbon Fixation** - The process of incorporating CO2 into an organic material is called carbon fixation. **RuBisCo** - Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) is an enzyme responsible for attaching CO2 to a five-carbon sugar molecule (ribulose bisphosphate) in the Calvin Cycle. **Six-Carbon Sugar: Fate after Carbon Fixation** - The resulting six-carbon sugar, an unstable intermediate, quickly breaks down into two molecules of 3-phosphoglycerate (3-PGA). **NADPH Role in the Calvin Cycle** - NADPH provides electrons to reduce 3-PGA into G3P, which is then used to synthesize glucose and other organic molecules. **G3P Fate: The Calvin Cycle** - Most of the G3P molecules produced by the Calvin Cycle are used to regenerate the five-carbon sugar (ribulose bisphosphate) to continue the cycle. - A small portion of G3P is used to create glucose and other organic molecules, for plant growth and energy storage. **ADP and NADP+: Fate after the Calvin Cycle** - ADP and NADP+ formed during the Calvin Cycle return to the light-dependent reactions to be re-energized. - This replenishes the energy carriers needed for continued carbon fixation. **Rubisco Function** - Rubisco is the most abundant enzyme on Earth and is essential for the Calvin Cycle. - It has a dual role in fixing CO2 and oxygen. - However, its affinity to oxygen can be a limiting factor in plant growth. **Product of Carbon Fixation** - The initial product of carbon fixation is an unstable six-carbon sugar that breaks down into two molecules of 3-phosphoglycerate (3-PGA). **Cellular Respiration Overview** - Cellular respiration produces ATP by breaking down organic compounds. - Both autotrophs (organisms that produce their own food) and heterotrophs (organisms that consume others for food) undergo cellular respiration. **Photosynthesis Relationship** - Photosynthesis converts light energy to chemical energy in autotrophs. - The products of photosynthesis serve as reactants in cellular respiration, highlighting their interdependence. **Breakdown of Organic Compounds** - The breakdown of organic compounds releases energy, which is primarily used to produce ATP. - Major products of cellular respiration include carbon dioxide (CO2), water (H2O), and ATP. **Stages of Cellular Respiration** - Two primary stages are glycolysis and aerobic respiration. - Glycolysis occurs in the cytosol and converts one glucose molecule into two molecules of pyruvic acid, yielding 2 ATP and 2 NADH. **Glycolysis Steps** - Step one: ATP donates phosphate groups to glucose, forming glucose-6-phosphate. - Step two: The 6-carbon molecule splits into two 3-carbon molecules called G3P. - Step three: G3P loses electrons and gains phosphate, transforming NAD+ into NADH. - Step four: Phosphates are removed, generating pyruvic acid and producing ATP from ADP. **Anaerobic vs Aerobic Conditions** - In the absence of oxygen, pyruvic acid undergoes fermentation, while in oxygen\'s presence, it enters aerobic respiration. - Anaerobic fermentation regenerates NAD+ but does not produce ATP; common pathways include lactic acid fermentation and alcoholic fermentation. **Fermentation Types** - Lactic acid fermentation converts pyruvic acid to lactic acid and occurs in muscle cells under strenuous exercise. - Alcoholic fermentation, utilized by plant cells and unicellular organisms, converts pyruvic acid into ethyl alcohol and releases CO2. **Krebs Cycle and Electron Transport Chain** - Aerobic respiration involves the Krebs cycle and the electron transport chain (ETC). - The Krebs cycle breaks down acetyl CoA and takes place in the mitochondria, producing CO2, hydrogen atoms, and ATP. **Final Electron Acceptors and Energy Yield** - The final electron acceptor in the ETC is oxygen, which plays a crucial role in cellular energy production. - Aerobic respiration generates approximately 20 times more ATP compared to glycolysis. **Energy Efficiency** - The efficiency of glycolysis is measured as the energy required to create ATP over the energy released by glucose oxidation. - The overall efficiency of cellular respiration is calculated similarly, conveying how effectively glucose is converted into usable energy. **Phases of Cellular Respiration** - Three main phases are glycolysis, the Krebs Cycle, and the electron transport chain. **Location of Processes** - Glycolysis occurs in the cytoplasm. - The Krebs Cycle takes place in the mitochondrial matrix. - The electron transport chain is located in the inner membrane of mitochondria. **ATP Production** - Glycolysis yields a net gain of 2 ATP. - The Krebs Cycle also produces 2 ATP. - The electron transport chain generates 34 ATP, making it the most productive phase. **Byproducts of Cellular Respiration** - Carbon dioxide is produced during the Krebs Cycle. - Water is formed in the electron transport chain. **Substrates in Cellular Respiration** - Glucose serves as the substrate in glycolysis. - Oxygen acts as a substrate in the electron transport chain. **NADH and FADH2** - Each NADH can produce about 3 ATP in the electron transport chain. - Each FADH2 yields approximately 2 ATP during the process. **Enzyme Deficiency Impact** - Missing or defective enzymes at any step of cellular respiration will halt processes beyond that point. **Anaerobic Conditions** - In the absence of oxygen, pyruvic acid accepts high-energy electrons from NADH. **Fermentation Reactions** - Yeast fermentation reaction: Glucose converts to ethyl alcohol, carbon dioxide, 2 ATP, and heat. - Lactic acid fermentation reaction: Glucose converts to lactic acid, 2 ATP, and heat.