Chapter 4: Cellular Metabolism and Reproduction PDF

***[Chapter 4:Cellular Metabolism and Reproduction: Mitosis and Meiosis]*** Let\'s break down these complex biological processes into simpler terms, defining key vocabulary along the way. **I. Metabolism: The Body\'s Chemical Factory** Imagine your body as a complex factory. Metabolism is the ove...

***[Chapter 4:Cellular Metabolism and Reproduction: Mitosis and Meiosis]*** Let\'s break down these complex biological processes into simpler terms, defining key vocabulary along the way. **I. Metabolism: The Body\'s Chemical Factory** Imagine your body as a complex factory. Metabolism is the overall term for all the processes happening inside, like: - **Catabolism (Breaking Down):** Like dismantling a complex machine into its individual parts to reuse them or get energy. This is how your body breaks down food into smaller molecules and releases energy. - **Anabolism (Building Up):** Like using those parts to build new things. This is how your body uses energy to build complex molecules like proteins and tissues. **II. Glycolysis: The First Step in Energy Production** Glycolysis is like the first step in a factory\'s energy production line. It happens in the cytoplasm (the factory floor). 1. **Glucose (Sugar) Input:** Starts with glucose, a 6-carbon sugar, the main fuel for your cells. 2. **Splitting Glucose:** Glucose is split in half, creating two 3-carbon molecules (like cutting a 6-slice pizza into two 3-slice halves). 3. **Energy Carriers:** Some \"energy carrier\" molecules (NADH) are created, like trucks that will transport energy to the next stage. 4. **ATP Production:** A small amount of ATP (the cell\'s energy currency, like money) is produced directly. 5. **Pyruvate Output:** The final product is pyruvate, a 3-carbon molecule. - **Key terms:** - **Phosphorylation:** Adding a phosphate group to a molecule, often used to activate it. - **NADH:** An energy carrier molecule. - **ATP:** The cell\'s energy currency. - **Pyruvate:** A 3-carbon molecule, the end product of glycolysis. **III. Krebs Citric Acid Cycle: Refining the Fuel** The Krebs cycle is like the second stage of the energy production line, happening in the mitochondria (the factory\'s power plant). 1. **Pyruvate to Acetyl CoA:** Pyruvate is converted to Acetyl CoA, a smaller molecule that can enter the cycle. 2. **Cycle of Reactions:** Acetyl CoA goes through a series of chemical reactions. 3. **More Energy Carriers:** More \"energy carrier\" molecules (NADH and FADH2) are produced. 4. **CO2 Released:** Carbon dioxide (CO2) is released as a byproduct (like smoke coming out of the factory). 5. **Small ATP Production:** A small amount of ATP is produced directly. - **Key terms:** - **Mitochondria:** The cell\'s power plants. - **Acetyl CoA:** A molecule that enters the Krebs cycle. - **FADH2:** Another energy carrier molecule. **IV. Electron Transport System (ETS): The Power Generator** The ETS is the final stage, also in the mitochondria. It\'s like the generator in the power plant. 1. **Energy Carriers Deliver:** NADH and FADH2 deliver their \"energy\" (electrons) to the ETS. 2. **Electron Transfer:** Electrons are passed along a chain of molecules, releasing energy. 3. **Proton Gradient:** This energy is used to pump protons, creating a \"proton gradient\" (like water building up behind a dam). 4. **ATP Synthase:** Protons flow back across the membrane through an enzyme called ATP synthase (like water turning a turbine). 5. **ATP Production:** ATP synthase uses this energy to produce a lot of ATP. 6. **Oxygen\'s Role:** Oxygen is the final electron acceptor, combining with electrons and protons to form water. - **Key terms:** - **Electron Transport System:** A series of protein complexes that transfer electrons. - **ATP Synthase:** An enzyme that produces ATP. - **Proton Gradient:** A difference in proton concentration across a membrane. **V. Glycolysis vs. Anaerobic ATP Production vs. Fermentation** - **Glycolysis:** The first step in energy production, whether oxygen is present or not. - **Anaerobic ATP Production (in muscles):** If there\'s no oxygen (e.g., during intense exercise), your muscles can still make a little ATP by converting pyruvate to lactate. This is less efficient and leads to muscle fatigue. - **Fermentation:** Other anaerobic pathways used by some organisms (like yeast). For example, yeast converts pyruvate to alcohol and CO2 during alcohol fermentation. The main goal is to regenerate molecules needed for glycolysis to continue. **VI. Other Energy Sources** Your body can also use other food sources for energy: - **Carbohydrates:** Other sugars can be converted to glucose. - **Fats:** Broken down into fatty acids, which can be used to produce Acetyl CoA. - **Proteins:** Broken down into amino acids, which can also be used for energy production. **VII. DNA: The Genetic Blueprint** - **Discoverers:** James Watson and Francis Crick figured out the structure of DNA. - **Structure:** DNA is like a twisted ladder (double helix). The \"rungs\" of the ladder are made of pairs of nitrogenous bases. - **Base Pairs:** - Adenine (A) always pairs with Thymine (T). - Guanine (G) always pairs with Cytosine (C). **VIII. Cell Cycle: The Life of a Cell** The cell cycle is like the life cycle of a cell, from its \"birth\" to its division. - **Interphase:** The cell grows and prepares for division. - G1 phase: Growth and preparation. - S phase: DNA is copied (replicated). - G2 phase: More growth and preparation. - **M phase (Mitotic phase):** The cell divides. - Mitosis: The nucleus divides. - Cytokinesis: The cytoplasm divides. **IX. Mitosis: Cell Division for Growth and Repair** Mitosis is how one cell divides into two identical cells. It\'s important for growth and repair. **X. Meiosis: Creating Sex Cells** Meiosis is a special type of cell division that creates sex cells (sperm and eggs). It reduces the number of chromosomes by half, so that when sperm and egg combine, the resulting cell has the correct number of chromosomes. Meiosis also introduces genetic variation, making offspring different from their parents. **[Vocabulary:]** **A** - **Acetaldehyde:** A two-carbon aldehyde produced during alcohol fermentation. - **Acetic acid:** A two-carbon acid, a product of some fermentation processes. - **Acetyl-CoA:** A molecule that carries acetyl groups (2 carbons) from glycolysis to the Krebs cycle. - **Adenine:** A purine base found in DNA and RNA. - **Aerobic:** Requiring oxygen. - **Alpha-ketoglutaric acid:** A five-carbon molecule involved in the Krebs cycle. - **Anabolism:** The building up of complex molecules from simpler ones, requiring energy. - **Anaerobic respiration:** ATP production without oxygen, less efficient than aerobic respiration. - **Anaphase:** The stage of mitosis where sister chromatids separate and move to opposite poles. - **Anaphase I:** The stage of meiosis I where homologous chromosomes separate and move to opposite poles. - **Anaphase II:** The stage of meiosis II where sister chromatids separate and move to opposite poles. - **Aster:** A star-shaped structure formed by microtubules during cell division. **C** - **Calories:** Units of energy, often used to measure the energy content of food. - **Carcinogens:** Substances that can cause cancer. - **Carcinomas:** Cancers that originate in epithelial tissues. - **Catabolism:** The breakdown of complex molecules into simpler ones, releasing energy. - **Cell cycle:** The series of events that take place in a cell leading to its division and duplication. - **Cell plate:** A structure that forms between dividing plant cells during cytokinesis. - **Cellular respiration/metabolism:** The set of metabolic processes by which cells generate energy (ATP) through oxidation of nutrients. - **Centromere:** The region of a chromosome where sister chromatids are joined. - **Chiasmata:** The points where homologous chromosomes cross over during meiosis. - **Chromatids:** Two identical copies of a chromosome, joined at the centromere. - **Chromatin:** The complex of DNA and proteins that makes up chromosomes. - **Citric acid:** A six-carbon molecule formed in the Krebs cycle. - **Cleavage furrow:** A constriction that forms during cytokinesis in animal cells, eventually pinching the cell in two. - **Clones:** Genetically identical individuals or cells. - **Co-enzyme A:** A coenzyme that carries acetyl groups in cellular respiration. - **Crossing-over:** The exchange of genetic material between homologous chromosomes during meiosis I. - **Cytochrome system:** A series of electron carriers in the electron transport system. - **Cytokinesis:** The division of the cytoplasm following mitosis or meiosis. - **Cytosine:** A pyrimidine base found in DNA and RNA. **D** - **Diploid:** Having two sets of chromosomes (2n). - **DNA (deoxyribonucleic acid):** The molecule that carries genetic information. - **Down syndrome:** A genetic disorder caused by an extra copy of chromosome 21. **E** - **Electron transfer/transport system:** A series of protein complexes that transfer electrons, releasing energy used to generate ATP. - **Ethyl alcohol:** A two-carbon alcohol produced during some types of fermentation. **F** - **Fermentation:** Anaerobic pathways that generate ATP by glycolysis alone, regenerating NAD+ for continued glycolysis. - **Flavin adenine dinucleotide (FAD):** An electron carrier that accepts and donates electrons in the Krebs cycle and electron transport chain, becoming FADH2. **G** - **Gametogenesis:** The process of forming gametes (sperm and egg). - **Gene:** A segment of DNA that codes for a specific protein. - **Glucose:** A six-carbon sugar, a primary source of energy for cells. - **Glycolysis:** The breakdown of glucose into two molecules of pyruvate. - **Guanine:** A purine base found in DNA and RNA. **H** - **Haploid:** Having one set of chromosomes (n). **I** - **Interphase:** The phase of the cell cycle between cell divisions, consisting of G1, S, and G2 phases. **K** - **Kinetochore:** A protein structure on a centromere to which spindle fibers attach during cell division. - **Klinefelter's syndrome:** A genetic disorder in males with an extra X chromosome (XXY). - **Krebs citric acid cycle:** A series of reactions in the mitochondrial matrix that oxidize acetyl CoA, producing ATP, NADH, FADH2, and CO2. **L** - **Lactic acid:** A three-carbon acid produced during anaerobic respiration in muscle cells. **M** - **Malic acid:** A four-carbon molecule involved in the Krebs cycle. - **Meiosis:** A type of cell division that produces gametes with half the number of chromosomes as the parent cell. - **Metabolism:** The sum of all chemical reactions that occur within a living organism. - **Metaphase:** The stage of mitosis where chromosomes line up along the metaphase plate. - **Metaphase I:** The stage of meiosis I where homologous chromosome pairs line up along the metaphase plate. - **Metaphase II:** The stage of meiosis II where chromosomes line up along the metaphase plate. - **Metastases:** The spread of cancer cells from the original site to other parts of the body. - **Metastasize:** To spread to other parts of the body (cancer). - **Mitosis:** The division of the nucleus into two identical daughter nuclei. - **Mutation:** A change in the DNA sequence. **N** - **Nicotinamide adenine dinucleotide (NAD):** An electron carrier that accepts and donates electrons in cellular respiration, becoming NADH. - **Nucleic acid:** A polymer of nucleotides (DNA or RNA). - **Nucleotides:** The building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base. **O** - **Oogenesis:** The process of forming eggs (ova). - **Oxaloacetic acid:** A four-carbon molecule involved in the Krebs cycle. **P** - **Phosphoglyceraldehyde (PGAL):** A three-carbon molecule produced during glycolysis. - **Phosphoglyceric acid (PGA):** A three-carbon molecule produced during glycolysis. - **Phosphorylation:** The addition of a phosphate group to a molecule. - **Polar bodies:** Small, nonfunctional cells produced during oogenesis. - **Prophase:** The first stage of mitosis, during which chromosomes condense. - **Prophase I:** The first stage of meiosis I, during which homologous chromosomes pair up and crossing over occurs. - **Prophase II:** The first stage of meiosis II, during which chromosomes condense again. - **Purines:** Double-ringed nitrogenous bases (adenine and guanine). - **Pyrimidines:** Single-ringed nitrogenous bases (cytosine, thymine, and uracil). - **Pyruvic acid:** A three-carbon molecule, the end product of glycolysis. **Q** - **Quinone:** A molecule involved in electron transport. **S** - **Sarcomas:** Cancers that originate in connective tissues. - **Spermatogenesis:** The process of forming sperm. - **Spindle fibers:** Microtubules that attach to chromosomes during cell division and help move them. - **Succinic acid:** A four-carbon molecule involved in the Krebs cycle. - **Synapsis:** The pairing of homologous chromosomes during prophase I of meiosis. **T** - **Tay-Sachs disease:** A genetic disorder caused by a mutation in a gene that codes for an enzyme needed to break down certain lipids in the brain. - **Telophase:** The final stage of mitosis, during which the nuclear envelope reforms. - **Telophase I:** The final stage of meiosis I, during which the nuclear envelope reforms. - **Telophase II:** The final stage of meiosis II, during which the nuclear envelope reforms. - **Tetrad:** A group of four chromatids (two homologous chromosomes) during meiosis I. - **Thymine:** A pyrimidine base found in DNA. - **Tubulin:** A protein that forms microtubules, including spindle fibers. - **Tumor:** A mass of abnormal cells. **Z** - **Zygote/fertilized egg:** A diploid cell formed by the fusion of sperm and egg.