Metabolism and Cellular Respiration Overview
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Questions and Answers

What characterizes anabolic reactions in metabolism?

  • They produce ATP as a primary product.
  • They involve breaking bonds.
  • They require more time and energy. (correct)
  • They are typically exergonic.

    • In terms of Gibbs Free Energy, which statement is accurate?

  • Exergonic reactions move from low to high Gibbs Free Energy.
  • Low Gibbs Free Energy means there are more bonds in the molecules.
  • High Gibbs Free Energy indicates spontaneous reactions.
  • Endergonic reactions move from high to low Gibbs Free Energy. (correct)

    • What is the net gain of ATP during glycolysis?

  • 2 ATP produced with a net gain of 2 ATP.
  • 2 ATP produced with a net gain of 1 ATP.
  • 4 ATP produced with a net gain of 2 ATP. (correct)
  • 4 ATP produced with a net gain of 3 ATP.

    • Which process occurs in the mitochondria matrix?

    <p>Both B and C.</p> Signup and view all the answers

    What is a consequence of lactic acid fermentation?

    <p>Inability for some organs to function due to lactic acid buildup.</p> Signup and view all the answers

    What describes the role of activation energy in reactions?

    <p>It is essential for initiating a chemical reaction.</p> Signup and view all the answers

    Which statement is correct about oxidation and reduction in metabolic pathways?

    <p>Reduction is associated with catabolic reactions.</p> Signup and view all the answers

    What occurs during the phosphorylation of glucose in glycolysis?

    <p>Two phosphate groups are stripped from ATP.</p> Signup and view all the answers

    Which of the following correctly describes exergonic reactions?

    <p>They are characterized by a decrease in Gibbs Free Energy.</p> Signup and view all the answers

    Which compound is primarily produced in the Krebs cycle?

    <p>NADH.</p> Signup and view all the answers

    What is the main function of MHC proteins on host cells?

    <p>To display parts of degraded non-self proteins</p> Signup and view all the answers

    Which of the following cells is primarily responsible for the humoral immune response?

    <p>B cells</p> Signup and view all the answers

    How do natural killer cells determine whether to eliminate a host cell?

    <p>By analyzing MHC I molecules on the cell surface</p> Signup and view all the answers

    What is the role of Pattern-Recognition Receptors (PRRs) in the immune system?

    <p>To recognize Pathogen-Associated Molecular Patterns (PAMPs)</p> Signup and view all the answers

    Which statement correctly describes the differentiation of B and T cells?

    <p>Both come from the same type of stem cells but differentiate in different tissues</p> Signup and view all the answers

    Antibodies perform which of the following functions?

    <p>Bind to antigens and assist the complement system in pathogen destruction</p> Signup and view all the answers

    Which of the following accurately describes the function of neutrophils in the immune response?

    <p>They enhance inflammation through cytokine release</p> Signup and view all the answers

    What mechanism do antibodies utilize to aid in pathogen destruction?

    <p>Formation of immune complexes that trigger the complement system</p> Signup and view all the answers

    Which characteristic distinguishes cytotoxic T cells from helper T cells?

    <p>Cytotoxic T cells bind to MHC I molecules</p> Signup and view all the answers

    What is the role of the complement system in immune defense?

    <p>To bind to pathogens and facilitate their destruction</p> Signup and view all the answers

    What is the primary role of ligands in cellular communication?

    <p>To bind to receptors and initiate cellular responses</p> Signup and view all the answers

    Among the types of receptors, which one operates as dimers upon signal reception?

    <p>Receptor Tyrosine Kinases</p> Signup and view all the answers

    Which component primarily influences the amplification of a cellular response during signal transduction?

    <p>The number of relays in the cascade</p> Signup and view all the answers

    How do Ion Channel Receptors operate when a ligand is not present?

    <p>They are closed preventing ion passage</p> Signup and view all the answers

    What type of immune response is characterized by memory and speed upon re-exposure to a pathogen?

    <p>Adaptive immune response</p> Signup and view all the answers

    Which of the following is NOT a function of the innate immune system?

    <p>Retention of memory against past infections</p> Signup and view all the answers

    What is quorum sensing primarily associated with?

    <p>Single-celled organisms coordinating behavior</p> Signup and view all the answers

    Which of the following correctly describes the role of calcium ions in signal transduction?

    <p>They operate as non-protein relay messengers</p> Signup and view all the answers

    What distinguishes G Protein-Coupled Receptors from other types of receptors?

    <p>They involve the activation of a G protein upon ligand binding</p> Signup and view all the answers

    What is the purpose of cellular response in the signaling pathway?

    <p>To regulate cellular activities and responses</p> Signup and view all the answers

    What is the primary role of NADH in the Electron Transport Chain?

    <p>To deliver electrons to carrier proteins</p> Signup and view all the answers

    Which statement accurately describes the output of the chemiosmotic theory?

    <p>It results in the synthesis of ATP from ADP using energy from H+ ions</p> Signup and view all the answers

    What is the significance of the stomata in photosynthesis?

    <p>They release oxygen and take in carbon dioxide</p> Signup and view all the answers

    What process occurs in the thylakoids of chloroplasts during photosynthesis?

    <p>Light energy converts into chemical energy via ATP and NADPH production</p> Signup and view all the answers

    Which of the following is true about C4 plants?

    <p>They utilize a 4-carbon molecule for CO2 fixation in mesophyll cells</p> Signup and view all the answers

    What is the main purpose of breaking down glucose in cellular respiration?

    <p>To generate chemical energy in the form of ATP</p> Signup and view all the answers

    How does the Calvin Cycle primarily utilize ATP and NADPH?

    <p>To convert carbon dioxide into glucose precursors</p> Signup and view all the answers

    What happens to pyruvic acid after glycolysis when oxygen is present?

    <p>It enters the citric acid cycle as Acetyl-CoA</p> Signup and view all the answers

    What is the role of abscisic acid (ABA) in plants?

    <p>Regulates the opening and closing of stomata during water scarcity</p> Signup and view all the answers

    Which coenzyme is primarily involved in transferring electrons during metabolic reactions?

    <p>NAD</p> Signup and view all the answers

    What distinguishes endergonic reactions from exergonic reactions?

    <p>Endergonic reactions require a net input of energy, while exergonic reactions release energy.</p> Signup and view all the answers

    Which of the following best describes the function of phosphorylation in glycolysis?

    <p>To prevent glucose from diffusing back out of the cell.</p> Signup and view all the answers

    What is the primary outcome when glucose is processed in cellular respiration?

    <p>Conversion of chemical energy into ATP</p> Signup and view all the answers

    Which sequence correctly describes the flow of electrons in the Electron Transport Chain (ETC)?

    <p>Electrons → Carrier Proteins → Oxygen</p> Signup and view all the answers

    During pyruvate oxidation, which of the following is produced?

    <p>Acetyl-COA and CO2 per pyruvate.</p> Signup and view all the answers

    What physiological condition arises if the electron transport process is interrupted?

    <p>Cells become acidic and may die</p> Signup and view all the answers

    What role do redox reactions play in metabolism?

    <p>They couple energy-releasing and energy-consuming reactions.</p> Signup and view all the answers

    In CAM plants, when do stomata typically open?

    <p>At night to conserve moisture</p> Signup and view all the answers

    What characterizes the process of glycolysis?

    <p>It results in the formation of two molecules of pyruvic acid.</p> Signup and view all the answers

    What role does ribulose bisphosphate (RuBP) play in the Calvin Cycle?

    <p>It combines with CO2 to initiate the carbon fixation process</p> Signup and view all the answers

    Which statement is true about the Gibbs Free Energy in metabolic reactions?

    <p>Exergonic reactions have a negative change in Gibbs Free Energy.</p> Signup and view all the answers

    How are protons moved within the mitochondria during oxidative phosphorylation?

    <p>Using a concentration gradient established by the ETC</p> Signup and view all the answers

    What happens during lactic acid fermentation?

    <p>NADH donates its electrons to pyruvic acid to form lactic acid.</p> Signup and view all the answers

    Which of the following metabolic pathways occurs in the mitochondria?

    <p>Krebs Cycle.</p> Signup and view all the answers

    What is the purpose of light-dependent reactions in photosynthesis?

    <p>To split water and generate ATP and NADPH</p> Signup and view all the answers

    Which pathway do fats follow in cellular respiration?

    <p>Break down into glycerol and fatty acids for energy utilization</p> Signup and view all the answers

    What is the outcome of the cellular respiration process?

    <p>It transforms chemical energy from glucose into ATP.</p> Signup and view all the answers

    Which of the following distinguishes catabolic reactions from anabolic reactions?

    <p>Catabolic reactions release energy, while anabolic reactions require energy.</p> Signup and view all the answers

    What describes the role of chlorophyll in photosynthesis?

    <p>It captures photons to excite electrons</p> Signup and view all the answers

    What is the function of macrophages in the immune response?

    <p>They release cytokines after recognizing PAMPS.</p> Signup and view all the answers

    Which statement accurately describes the role of MHC proteins?

    <p>They display degraded non-self proteins on the host cell's surface.</p> Signup and view all the answers

    What do B cells primarily utilize in their immune function?

    <p>Antibodies to bind to and neutralize antigens.</p> Signup and view all the answers

    How do natural killer cells determine which host cells to eliminate?

    <p>By the absence of MHC I displaying a non-self flag.</p> Signup and view all the answers

    What characterizes the complement system's response to pathogens?

    <p>It is a set of proteins that coat pathogens and open their membranes.</p> Signup and view all the answers

    What defines the interaction of T cells with antigens?

    <p>T cells recognize antigens presented on MHC molecules.</p> Signup and view all the answers

    Which immune component is involved in the humoral immune response?

    <p>B cells.</p> Signup and view all the answers

    Which of the following mechanisms do antibodies NOT utilize to destroy pathogens?

    <p>Phagocytosis.</p> Signup and view all the answers

    What is the primary role of dendritic cells in the immune system?

    <p>To present antigens to T cells and activate adaptive immunity.</p> Signup and view all the answers

    What is the significance of Pathogen-Associated Molecular Patterns (PAMPs) in immune recognition?

    <p>They help leukocytes identify harmful pathogens.</p> Signup and view all the answers

    What is the primary role of G Protein-Coupled Receptors in cellular communication?

    <p>They bind ligands and activate G proteins to initiate a signaling cascade.</p> Signup and view all the answers

    Which statement best describes the process of quorum sensing in bacteria?

    <p>It enables bacteria to synchronize behavior based on cell population density.</p> Signup and view all the answers

    What characterizes the action of Receptor Tyrosine Kinases (RTKs) during signal reception?

    <p>They undergo dimerization after ligand binding.</p> Signup and view all the answers

    Which of the following accurately describes the initial step of signal transduction?

    <p>Receptors change shape, facilitating the relay of information through phosphorylation.</p> Signup and view all the answers

    How does the cellular response vary based on signal transduction pathways?

    <p>It can differ between cell types, even with the same initial signal.</p> Signup and view all the answers

    Which of the following statements about ion channel receptors is correct?

    <p>Their conformation is altered by ligand binding, enabling ion passage.</p> Signup and view all the answers

    What distinguishes the adaptive immune system from the innate immune system?

    <p>It has memory and can respond faster upon re-exposure to pathogens.</p> Signup and view all the answers

    In cellular signal regulation, what does altering transcription primarily affect?

    <p>The production of new proteins based on DNA usage.</p> Signup and view all the answers

    What role do calcium ions play in cellular signaling?

    <p>They function as secondary messengers in signal transduction.</p> Signup and view all the answers

    What is the main function of ligands in the context of cellular signaling?

    <p>To transmit information by binding to receptors.</p> Signup and view all the answers

    Study Notes

    Metabolism Overview

    • Chemical energy is transferred through anabolic and catabolic reactions.
      • Anabolic reactions use energy to build molecules (endergonic; harder).
      • Catabolic reactions release energy by breaking down molecules (exergonic; easier).
    • Energy coupling pairs catabolic and anabolic reactions for efficient energy transfer.
    • Redox reactions, another form of energy coupling, involve oxidation (losing electrons) and reduction (gaining electrons).
    • Gibbs Free Energy (G) measures the useful energy in a reaction, indicating the amount of chemical energy stored in molecules.
      • High G indicates more energy and more bonds.
      • Low G indicates less energy and fewer bonds.
      • Exergonic reactions release energy (high G to low G).
      • Endergonic reactions require energy (low G to high G).
    • Activation Energy (AE) is the energy needed to initiate a chemical reaction.

    Cellular Respiration

    • Chemical energy stored in bonds between atoms is released through cellular respiration.
    • ATP is the primary energy currency in cells, while ADP is a lower energy form.
    • Phosphorylation is the addition of a phosphate group (PO3) to a molecule.

    Glycolysis

    • Occurs in the cytoplasm of the cell.
    • Glucose breaks down into two pyruvate molecules (C6H12O6 → 2 C3H4O3).
    • Produces 4 ATP (2 net gain), 2 NADH, and 4 hydrogen ions.
    • Glucose phosphorylation prevents its diffusion out of the cell.

    Lactic Acid Pathway (Fermentation)

    • Occurs without oxygen.
    • NADH donates electrons to pyruvate, converting it to lactic acid.
    • Brain and heart cells cannot function on lactic acid.

    Pyruvate Oxidation

    • Happens in the matrix of the mitochondria.
    • Produces 0 ATP.
    • Pyruvate is converted into Acetyl-CoA, CO2, and NADH.

    Krebs Cycle (Citric Acid Cycle)

    • Occurs in the matrix of the mitochondria.
    • Produces NADH, FADH2, and 2 ATP.
    • Acetyl-CoA enters the cycle, releasing carbon dioxide and producing reduced electron carriers.

    Electron Transport Chain (Oxidative Phosphorylation Part 1)

    • NADH from glycolysis and the Krebs cycle delivers electrons to the Electron Transport Chain (ETC).
    • The ETC is a series of carrier proteins embedded in the mitochondrial membrane.
    • Electrons are passed down the ETC, releasing energy.
    • Protons (H+) are pumped from the matrix into the intermembrane space, creating a concentration gradient.

    Chemiosmotic Theory (Oxidative Phosphorylation Part 2)

    • The proton gradient drives ATP synthesis.
    • Protons flow back into the matrix through ATP synthase, generating energy.
    • This energy converts ADP into ATP.
    • Oxygen is the final electron acceptor, forming water.

    Photosynthesis Overview

    • Photosynthesis captures light energy and converts it into chemical energy stored in glucose.
    • Equation: 6 CO2 + 6 H2O → C6H12O6 + 6O2

    Light Reaction

    • Chlorophyll in thylakoid membranes captures light energy.
    • This energy splits water, producing oxygen, electrons, and protons (H+).
    • Electrons move through the ETC, pumping protons into the thylakoid lumen.
    • The proton gradient powers ATP synthase to produce ATP.
    • Electrons reduce NADP+ to NADPH.

    Calvin Cycle

    • Uses ATP and NADPH from the light reaction to create glucose.
    • Carbon fixation: Rubisco incorporates CO2 into RuBP, forming 3-phosphoglycerate.
    • Reduction: 3-phosphoglycerate is converted to G3P using ATP and NADPH.
    • Regeneration: RuBP is regenerated for further carbon fixation.

    Plant Structures & Processes

    • Chloroplasts are light-absorbing organelles where photosynthesis occurs.
    • Thylakoids are membrane-bound sacs within chloroplasts, containing chlorophyll and the ETC.
    • Stomata are tiny pores on leaves that allow for gas exchange (CO2, O2).

    Alternative Photosynthesis Pathways

    • C3 plants are the typical form, with stomata open during the day.
    • CAM plants adapt to arid conditions by opening stomata at night.
    • C4 plants thrive in hot, intense light by using PEP carboxylase to initially capture CO2, which is then transported to bundle sheath cells for the Calvin cycle.

    Coenzyme Roles

    • NAD (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) are coenzymes involved in redox reactions.
      • They accept and donate electrons, facilitating the transfer of energy.

    Cellular Communication Overview

    • Cells communicate using signaling molecules (ligands) that bind to receptors on target cells.
    • This communication triggers signal transduction pathways, leading to cellular responses.

    Bacteria Communication (Quorum Sensing)

    • Bacteria use quorum sensing to detect population density and coordinate group behavior.
    • This enables them to form biofilms and other organized structures.

    Yeasts Communication

    • Yeasts use cell signaling to distinguish between mating types.

    Communication Distance

    • Direct communication (gap junctions in animals, plasmodesmata in plants) allows for immediate cell-to-cell interactions.
    • Local communication involves signals that act on nearby cells.
    • Long-distance communication uses signals that travel throughout the body.

    Receptor Types

    • Membrane receptors are located in the cell membrane and bind to ligands outside the cell:
      • G Protein-Coupled Receptors (GPCRs): activate G proteins, triggering a signalling cascade.
      • Receptor Tyrosine Kinases (RTKs): phosphorylate themselves and other proteins, leading to a signalling cascade.
      • Ion Channel Receptors: open channels to allow ions across the membrane, changing the cell's electrical potential.
    • Intracellular receptors bind to ligands that can cross the cell membrane and are typically located in the cytoplasm or nucleus.

    Signal Transduction

    • Signal transduction relays information from the receptor to the cellular response machinery using a series of molecular interactions.
    • Protein relay molecules can be turned on or off by phosphorylation.
    • Non-protein relay molecules, such as cyclic AMP or calcium ions, act as messengers.

    Cellular Responses

    • Signal transduction regulates various cellular activities:
      • Regulating transcription: altering gene expression and protein production.
      • Regulating cytoplasmic activities: affecting protein function or other intracellular processes.

    Immune System Basics

    • Host organism: the organism infected by a pathogen.
    • Pathogen: disease-causing organism (bacteria, fungi, protozoa, viruses).
    • Not all microbes are pathogens; only those that cause disease.

    Innate Immune System

    • General defense system that recognizes and blocks pathogens without remembering them.
      • Barriers: physical (skin, mucus, etc.) and chemical (stomach acid, blood proteins)
      • Cells: macrophages, dendritic cells, neutrophils, NK cells
      • Defense mechanisms: complement system
      • Cleanup crews: macrophages and neutrophils

    Adaptive Immune System

    • Immune memory: able to recognize and fight specific pathogens.
      • Components: Antibodies, B cells, T cells

    Barriers

    • Physical barriers: skin, mucous membranes, urine, tears
    • Chemical barriers: stomach acid, blood proteins, antimicrobial factors in tears and mucus

    Recognition, Defense, Cleanup

    • Leukocytes (WBCs): white blood cells that defend the body against pathogens.
    • Phagocytes: leukocytes that engulf pathogens (macrophages, neutrophils, dendritic cells).
    • Pathogen-Associated Molecular Patterns (PAMPs): molecular patterns on pathogens recognized by the immune system.
    • Pattern-Recognition Receptors (PRRs): receptors on immune cells that recognize PAMPs.
    • MHC (Major Histocompatibility Complex) Proteins: display parts of "non-self" proteins on host cell surfaces to signal infection or cancer.
    • Natural Killer (NK) Cells: patrol for cells with "non-self" markers and kill them.
    • Complement System: 20 proteins that target pathogens by coating their surfaces and forming attack complexes that disrupt their membranes.

    B & T Cells

    • Both develop from stem cells in the bone marrow.
    • B cells mature in bone marrow, are covered in antibodies, and interact with antigens directly via antibodies and cytokine release.
    • T cells mature in the thymus, are covered in T-cell receptors, and interact with antigens indirectly by recognizing MHC proteins on infected cells.

    Antigens

    • Recognized by the adaptive immune system, stimulating an immune response.
    • Vaccines work by introducing antigens to the body, training it to recognize and fight them.

    Antibodies

    • Proteins produced by B cells that bind to and neutralize antigens.
    • Methods of pathogen destruction by antibodies:
      • Neutralization: blocking pathogen attachment to cells.
      • Opsonization: marking pathogens for phagocytosis.
      • Complement activation: triggering the complement system to attack pathogens.

    Chemical Energy Transfer

    • Anabolic Reactions build bonds, require energy (endergonic), and are typically slower.
    • Catabolic Reactions break bonds, release energy (exergonic), and are typically faster.
    • Energy Coupling pairs catabolic and anabolic reactions to transfer energy.
    • Redox Reactions are another form of energy coupling.
      • Oxidation is the loss of electrons (catabolic).
      • Reduction is the gain of electrons (anabolic).

    Gibbs Free Energy (G)

    • Measures the energy available for work in a reaction.
    • High G indicates more energy in molecules and more bonds.
    • Low G indicates less energy in molecules and fewer bonds.
    • High G to Low G = Exergonic, spontaneous.
    • Low G to High G = Endergonic, nonspontaneous.

    Activation Energy (AE)

    • Energy required to start a reaction.

    Cellular Respiration

    • Harvests chemical energy stored in bonds between atoms.
    • ATP (adenosine triphosphate) is the primary energy currency of cells.
    • ADP (adenosine diphosphate) is a lower energy form of ATP.
    • Phosphorylation is the addition of a phosphate group to a molecule.

    Glycolysis

    • Occurs in the cytoplasm.
    • Glucose is split into two pyruvic acid molecules (C6H12O6 → 2 C3H4O3).
    • Produces 4 ATP (net gain of 2 ATP).
    • NADH is produced by reducing NAD.
    • Lactic Acid Pathway (Fermentation) occurs when oxygen is limited.
      • NADH donates electrons to pyruvic acid, converting it to lactic acid.

    Pyruvate Oxidation

    • Occurs in the matrix of mitochondria.
    • No ATP is produced.
    • Pyruvic acid is converted to Acetyl-CoA.

    Krebs Cycle (Citric Acid Cycle)

    • Occurs in the matrix of mitochondria.
    • Produces NADH, FADH2, and 2 ATP.
    • CO2 is released as a byproduct.

    Electron Transport Chain (ETC)

    • NADH and FADH2 deliver electrons to electron carriers embedded in the mitochondrial membrane.
    • Proton Pump: During electron transport, protons (H+) are pumped into the intermembrane space.
    • Chemiosmotic Theory: The proton gradient drives the synthesis of ATP.
      • Movement of H+ through ATP synthase generates energy to convert ADP to ATP.
      • Oxygen is required as the final electron acceptor.

    Glucose Pathway Summary

    • Food → ATP
    • Aerobic process (requires oxygen).
    • Coupled exergonic and endergonic reaction (takes in and releases energy).
    • C6H12O6 + 6O2 → 6CO2 + 6H2O
    • Glucose from food enters the bloodstream, then enters cells via facilitated transport.
    • Glucose is phosphorylated to prevent diffusion.
    • Glucose is split into pyruvic acid.
    • Pyruvic acid enters mitochondria, converting to CO2 and NADH.
    • NADH releases electrons in the ETC, generating a proton gradient.
    • The proton gradient drives ATP synthesis through ATP synthase.
    • Oxygen is required to remove H+ from the mitochondria and forms water.
    • ATP Balance: Glycolysis and citric acid cycle yield 4 ATP, and the ETC yields 26-28 ATP.

    Food Pathways

    • Carbs: Glycolysis, citric acid cycle, ETC.
    • Fats: Split into glycerol and fatty acids. Glycerol enters glycolysis, fatty acids enter the citric acid cycle.
    • Proteins: Broken into amino acids, which enter the citric acid cycle.

    Photosynthesis (Simplified)

    • 6CO2 + 6H2O → C6H12O6 + 6O2

    Light Reaction

    • Chlorophyll in thylakoids converts light energy into ATP and NADPH.
    • Water is split, releasing electrons, H+, and O2.
    • Electrons enter the ETC, pumping protons into the thylakoid lumen.
    • Protons move through ATP synthase, generating ATP.
    • NADP+ is reduced to NADPH by H+.

    Calvin Cycle

    • Uses ATP and NADPH from the light reaction to produce glucose.
    • CO2 is incorporated into RuBP (a sugar) by Rubisco.
    • The resulting molecule is reduced to G3P (sugar precursor).
    • RuBP is regenerated for continuous cycling.

    Chloroplasts

    • Light-absorbing organelles that are the site of photosynthesis.
    • Contain thylakoids, where chlorophyll and electron transport occur.

    Stomata

    • Tiny pores on leaves that allow gas exchange and transpiration.
    • Opened and closed by guard cells.
    • Transpiration occurs when water is drawn up through xylem to the leaves.

    Abscisic Acid (ABA)

    • Used by plants to open and close stomata.
    • Released during water shortage and at night.

    Alternative Photosynthesis Pathways

    • C3 Plants: Typical plants with stomata open during the day.
    • CAM Plants: Adapted to dry conditions, with stomata open at night.
    • C4 Plants: Adapted to hot conditions, with stomata partially closed during intense sunlight.

    NAD/FAD/NADP

    • NAD (nicotinamide adenine dinucleotide): Coenzyme derived from niacin, works with dehydrogenases.
    • FAD (flavin adenine dinucleotide): Coenzyme derived from riboflavin, works with dehydrogenases.

    Cellular Communication

    • Ligands: Chemicals used by cells to send signals.
    • Receptors: Molecules that bind ligands, triggering cellular responses.

    Steps of Cell Communication

    • Signal Reception: Ligand binds to receptor.
    • Signal Transduction: Relay molecules amplify and transmit the signal.
    • Cellular Response: Changes in cellular activity.

    Bacteria Communication

    • Quorum Sensing: Bacteria detect cell density and coordinate group behavior.

    Yeast Communication

    • Mating Types: Yeasts use signaling to identify mating partners (α and a).

    Communication Distance Variations

    • Directly Connected: Gap junctions (animal cells), plasmodesmata (plant cells).
    • Brief Contact: Cells come into contact briefly.
    • Local: Nearby cells.
    • Long Distance: Signals travel far distances.

    Receptor Locations

    • Cytoplasm: Internal receptors.
    • Cell membrane: Membrane receptors.

    Cellular Communication (In-Depth)

    Signal Reception

    • Ligand binding: Ligands bind to receptors, causing conformational changes.
    • Specificity: Ligands and receptors are complementary.
    • Membrane Receptor Types:
      • G Protein-Coupled Receptors (GPCRs): Alpha helices with binding sites.
        • Ligand → Receptor → G protein → Enzyme
      • Receptor Tyrosine Kinases (RTKs): Monomers that dimerize upon ligand binding.
      • Ion Channel Receptors: Open channels in response to ligand binding.

    Signal Transduction

    • Relay Molecules: Proteins and small non-protein molecules/ions.
    • Protein Relay Molecules: Activated/deactivated by phosphorylation.
    • Non-Protein Relay Molecules: Act directly as messengers.

    Cellular Response

    • Regulating Transcription: Altering gene expression.
    • Regulating Cytoplasmic Activities: Affecting existing proteins.

    Immune System Basics

    • Host: Organism infected with pathogens.
    • Pathogens: Disease-causing organisms (bacteria, viruses, fungi, protozoa).
    • Innate Immune System: General defense, recognizes and blocks pathogens but doesn't remember them.
    • Adaptive Immune System: Specific defense, remembers pathogens and mounts a faster, more powerful response.

    Barriers

    • Physical Barriers: Skin, mucous membranes, tears, urination, blood-brain barrier.
    • Chemical Barriers: Stomach acid, blood proteins, microbicidal factors in tears and mucous.

    Recognition, Defense, Cleanup

    • Leukocytes: White blood cells.
    • Phagocytes: Leukocytes that engulf pathogens.
      • Macrophages: Release cytokines.
      • Dendritic Cells: Release cytokines.
      • Neutrophils:
    • Pathogen-Associated Molecular Patterns (PAMPS): Unique patterns on pathogen surfaces.
    • Pattern-Recognition Receptors (PRRs): Receptors on leukocytes that recognize PAMPS.

    MHC Proteins

    • Display fragments of "non-self" proteins on the host cell surface.
    • Act as "wash me" flags, signaling infection or cancer.

    Natural Killer Cells

    • Patrol the body and kill cells displaying non-self MHC I proteins.

    Complement System

    • A set of proteins that bind to pathogens, triggering their destruction.

    B & T Cells

    • Develop from stem cells in bone marrow.
    • B Cells: Mature in bone marrow, express antibodies, and are humoral.
      • Humoral immune response: B cells directly interact with antigens, releasing antibodies and cytokines.
    • T Cells: Mature in thymus, express T-cell receptors, and are cell-mediated.
      • Cell-mediated immune response: T cells indirectly interact with antigens on MHC I or II, activating other immune cells.
      • Cytotoxic T cells: Kill infected cells.
      • Helper T cells: Activate natural killer cells and phagocytes.

    Antigens

    • Macromolecule that the adaptive immune system can recognize.

    Antibodies

    • Proteins produced by B cells that bind to antigens.
    • Neutralization: Prevent pathogens from infecting cells.
    • Opsonization: Tag pathogens for destruction by phagocytes.
    • Complement Activation: Trigger complement system activation.

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    Description

    This quiz covers the fundamental concepts of metabolism, including anabolic and catabolic reactions, energy coupling, and the role of Gibbs Free Energy in chemical reactions. It also explores cellular respiration and the transfer of chemical energy. Test your understanding of these essential biochemical processes.

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