CELL & MOLECULAR BIOLOGY (EDUSCI14) Quiz - PDF

CELL & MOLECULAR BIOLOGY (EDUSCI14) cytoskeleton cytoskeleton microtubules & microfilaments BANLOR & LEON CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton...

CELL & MOLECULAR BIOLOGY (EDUSCI14) cytoskeleton cytoskeleton microtubules & microfilaments BANLOR & LEON CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton It is estimated that the cell is made up of 70% Water Together with a fluid membrane, why doesn’t it COLLAPSE? CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton WHAT IS THE CYTOSKELETON? A network of filamentous proteins throughout the cytoplasm Provides physical support to the cell Polymers of different proteins Not fixed; Can disassemble & reassemble CYTO + SKELETON = CELL’S SKELETON CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton consists of Microtubules & Different Microfilaments CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton MICROTUBULES MICROTUBULES CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton MICROTUBULES ARE POLYMERS OF TUBULIN. Forms a helical, rope-like structure that is hollow in the middle. Composed of α- and β-tubulin dimers. Has multiple roles in the cell Microtubules are CILIA CENTRIOLES the component of different structures in a cell. FLAGELLA MITOTIC SPINDLES CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton MICROFILAMENTS CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton Also known as Actin Filaments Thinnest (6-7 nm) Consist of two intertwined strand made of globular proteins Flexible Strong Can act alone or in co-ordination with microtubules Located beneath of plasma membrane CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton GLOBULAR-ACTIN (G-ACTIN) FILAMENTOUS ACTIN (F-ACTIN) monomeric form of actin protein polymerized form of actin globular shaped protein G-Actin is soluble in aqueous helical structure with two solution strands of G-Actin monomers consists: twisted around each other. single polypeptide chain binding site for ATP (adenosine triphosphate) ). CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton Muscle Contraction Cell Migration Cytoplasmic Streaming Cell Division CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton MUSCLE CONTRACTION Muscle contraction is the process by which muscles tighten, shorten, or lengthen to produce movement. This complex process involves the interaction of proteins within muscle cells. Microfilaments, composed of actin, interact with myosin to generate the force necessary for muscle contraction. CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton CELL MIGRATION Cell migration is a fundamental biological process where cells move from one location to another. This movement is crucial for various biological processes Microfilaments enable cells to change shape and move, as seen in processes like cell crawling and white blood cell migration CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton CYTOPLASMIC STREAMING also called cyclosis, is the flow or movement of cytoplasm within the cell to transport and deliver metabolites, nutrients, and some cell organelle to other parts within the cell Microfilaments facilitate the movement of cytoplasm and organelles within plant cells. CELL & MOLECULAR BIOLOGY (EDUSCI14) PAIR NO.5 | cytoskeleton CELL DIVISION Cell division is the process by which new cells are formed for growth, repair, and replacement in the body. During cytokinesis, microfilaments form a contractile ring that divides the cell into two daughter cells. Mitochondria/ Mitocondrion It is the power plant of the cell. Structures: 1. Outer Membrane 2. Inner Membrane 3. Inter membrane Space 4. Cristae 5. Mitochondria Matrix Mitochondrion’s Membrane 1. Outer Membrane 2. InterMembrane Space 3. Inner Membrane 1. Outer Membrane A phospholipid bilayer membrane that separates the inside of mitochondria from the rest of the cell (permeable) This outer portion includes proteins called Porins and Translocase of Outer Membrane (TOM) which form channels that allow proteins to cross. 1. Outer Membrane The voltage-dependent anion channel porin/VDAC allows transfer of metabolites across the outer membrane. The translocase of the outer membrane, also termed TOM complex, forms the entry gate for the precursor proteins. The import of carrier proteins is particularly important for mitochondrial metabolism. 2. Inner Membrane a highly specialized structural membrane. The inner membrane of mitochondria is covered by numerous large protein complexes involved in cellular respiration. Electron Transport Chain/ Oxidative Phosphorylation 2. Inner Membrane 3. Inter membrane Space This is the area between the inner and outer membranes. inter-membrane space which is used by mitochondria to store hydrogen ions for use of their charge and potential energy 4. Cristae These are the folds of the inner membrane. They increase the surface area of the membrane, therefore increasing the space available for chemical reactions.  5. Mitochondria Matrix The mitochondria matrix is the innermost part of the mitochondria. It is a gel-like component of the mitochondria. Contains mitochondrial DNA, ribosomes, and enzymes for the Krebs cycle, fatty acid oxidation, and other metabolic processes. Functions : Energy Production Mitochondria uses the Cellular respiration to provide energy to the cell Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP. Functions : Energy Production Mitochondria uses the Cellular respiration to provide energy to the cell Cellular respiration is a metabolic pathway that breaks down glucose and produces ATP.  CELLULAR RESPIRATION MITOCHONDRION Group 7: Unica Fadri Jude Paano Cellular Respiration * Cell respiration is the process where cells break down glucose to release energy for the cell to use. *Is the biochemical process by which cells convert glucose into energy (ATP) with the help of oxygen. It is essential for all living organisms to provide energy for various cellular activities. Two Types of Cellular Respiration AEROBIC RESPIRATION occurs in the cytoplasm and mitochondria of cells. a chemical process that uses oxygen to break down glucose and other nutrients to produce energy for cells ANAEROBIC RESPIRATION a biological process that produces cellular energy without oxygen. It's a common metabolic process for prokaryotes, which can survive in environments without oxygen.  Stages of Cellular Respiration GLYCOLYSIS PYRUVATE OXIDATION KREBS CYCLE (CITRIC ACID CYCLE) ELECTRON TRANSPORT CHAIN (ETC) AND OXIDATIVE PHOSPHORYLATION Aerobic Respiration GLYCOLYSIS Process of breaking down glucose (sugar) to produce energy for cellular processes. It produces energy in the form of ATP(adenosine triphosphate) and NADH (nicotinamide adenine dinucleotide) Glycolysis Equation In words, the equation is written as: Glucose + Adenosine diphosphate + Phosphate + Nicotinamide adenine dinucleotide ↓ Pyruvate + Water + Adenosine triphosphate + Nicotinamide adenine dinucleotide + Hydrogen ions Aerobic Respiration PYRUVATE OXIDATION THE TRANSITION STEP This step take place in the matrix, the innermost compartment of mitochondria. Converts pyruvate ( 3 carbon molecule) into acetyl CoA ( 2 carbon molecule) producing an NADH and releasing one carbon dioxide molecule in the process. Aerobic Respiration KREBS CYCLE (CITRIC ACID CYCLE) discovered by Hans Krebs in 1937, at Cambridge University in Great Britain (Holmes, 1993). Is a series of reactions catalyzed by eight enzymes in mitochondria. Its function is to catalyze removal of electrons from nutrients and to transfer them to NAD+ and FAD, producing NADH plus H+, and FADH2, respectively. Key Products: 2 ATP, 6 NADH, 2 FADH₂, and 4 CO₂ molecules (per glucose). Location: Mitochondrial matrix.  Aerobic Respiration 1. Formation of Citrate 2. Conversion of citrate to Isocitrate 3. Isocitrate to a- ketoglutarate 4. a-ketoglutarate to Succinyl - CoA 5. Succinyl - CoA to Succinate 6. Oxidation of Succinate to Fumarate 7. Hydration of Fumarate to Malate 8. Regeneration of Oxaloacetate  Mitochondria Cytosol NADH Glucose NADH Krebs Electron Cycle Transport Pyruvic Acid FADH2 Glycolysis ATP ATP ATP STEP 1: FORMATION OF CITRATE STEP 5: FORMATION OF SUCCINATE REACTANTS: ACETYL-COA (2-CARBON MOLECULE) COMBINES WITH REACTION: SUCCINYL-COA IS CONVERTED TO SUCCINATE (4- OXALOACETATE (4-CARBON MOLECULE). CARBON MOLECULE). ENZYME: CITRATE SYNTHASE. ENERGY PRODUCED: THIS STEP GENERATES GTP (WHICH CAN BE PRODUCT: THIS REACTION FORMS CITRATE (A 6-CARBON MOLECULE), CONVERTED TO ATP). THE STARTING MOLECULE OF THE CYCLE. ENZYME: SUCCINYL-COA SYNTHETASE. STEP 2: CONVERSION OF CITRATE TO ISOCITRATE STEP 6: OXIDATION OF SUCCINATE REACTION: CITRATE IS REARRANGED INTO ISOCITRATE (STILL A 6- REACTION: SUCCINATE IS OXIDIZED TO FUMARATE (4-CARBON CARBON MOLECULE). MOLECULE). ENZYME: ACONITASE. BY-PRODUCTS: ONE MOLECULE OF FADH₂ IS GENERATED. THIS STEP PREPARES CITRATE FOR OXIDATION IN THE NEXT STEP. ENZYME: SUCCINATE DEHYDROGENASE. STEP 3: OXIDATION OF ISOCITRATE STEP 7: CONVERSION OF FUMARATE TO MALATE REACTION: ISOCITRATE IS OXIDIZED TO FORM Α-KETOGLUTARATE (5- REACTION: FUMARATE IS HYDRATED (WATER IS ADDED) TO FORM CARBON MOLECULE). MALATE (4-CARBON MOLECULE). BY-PRODUCTS: ENZYME: FUMARASE. ONE MOLECULE OF CO₂ IS RELEASED. ONE MOLECULE OF NADH IS GENERATED. STEP 8: REGENERATION OF OXALOACETATE ENZYME: ISOCITRATE DEHYDROGENASE. REACTION: MALATE IS OXIDIZED TO REGENERATE OXALOACETATE. BY-PRODUCTS: ONE MOLECULE OF NADH IS GENERATED. STEP 4: FORMATION OF SUCCINYL-COA ENZYME: MALATE DEHYDROGENASE. REACTION: Α-KETOGLUTARATE IS OXIDIZED AND COMBINED WITH COA, FORMING SUCCINYL-COA (4-CARBON MOLECULE). CYCLE RESTART BY-PRODUCTS: ONE MOLECULE OF CO₂ IS RELEASED. THE REGENERATED OXALOACETATE IS READY TO COMBINE WITH A ONE MOLECULE OF NADH IS GENERATED. NEW ACETYL-COA MOLECULE, RESTARTING THE CYCLE. ENZYME: Α-KETOGLUTARATE DEHYDROGENASE.  ELECTRON TRANSPORT CHAIN AND OXIDATIVE PHOSPHORYLATION Process: Electrons from NADH and FADH₂ pass through protein complexes in the inner mitochondrial membrane, generating a proton (H⁺) gradient. ATP Production: The flow of protons back into the matrix through ATP synthase drives the production of ATP. Oxygen's Role: Oxygen accepts electrons at the end of the chain and combines with protons to form water. Key Products: 32–34 ATP molecules, 6 H₂O molecules. Location: Inner mitochondrial membrane. ATP Yield in Total Anaerobic Respiration (Fermentation) Glycolysis: 2 ATP (net gain). Lactic Acid Fermentation: In animals, when Krebs Cycle: 2 ATP. oxygen is limited, pyruvate is converted to ETC and Oxidative Phosphorylation: 32–34 ATP. lactic acid, generating 2 ATP. Total ATP Produced: 36–38 ATP per molecule of glucose. Alcoholic Fermentation: In yeast and some plants, pyruvate is converted to ethanol and CO₂, producing 2 ATP. Importance of Cellular Respiration Energy Source: ATP is used for muscle contraction, Key Terms to Highlight: protein synthesis, cell division, and other essential ATP (Adenosine Triphosphate) activities. NADH and FADH₂ (electron carriers) Carbon Dioxide and Oxygen: Helps maintain Acetyl-CoA balance between oxygen consumption and carbon Oxygen (O₂) and Carbon Dioxide (CO₂) dioxide production in living organisms. Pyruvate Regulation: Cells regulate the rate of cellular respiration based on energy demand. CHLOROPLAST Nature’s solar powerhouses Chloroplast specialized organelles in plant and algal cells responsible for photosynthesis and other metabolic activities. double membrane structure not fixed within the cell  Outer membrane Parts of Chloroplast Inner membrane regulates the passage labyrinth of complexity of molecules forming thylakoids Granum Genome sunlight absorption surface area contains genes for photosynthesis Stroma Ribosomes Thylakoids fluid-filled space envelops the thylakoids; synthesize proteins stacked flattened sacs second phase of needed for photosynthesis chloroplast functions Chloroplast adorned with pigments and chlorophyll. Chlorophyll - absorbs light Carotenoids - provide protection against excessive light and oxidative stress  Significance of Chloroplast Generate oxygen Power the food chain Help regulate our planet’s climate by absorbing carbon dioxide PHOTOSYNTHESIS Light, energy and life  The word comes from Greek: Photosynthesis PHOTO: LIGHT SYNTHESIS: COMPOSITION  Photosynthesis It is a chemical process that involves the conversion of inorganic matter into organic matter through the energy provided by sunlight. 6CO 2 + 6H2 O C 6 H12 O 6 + 6O 2 CARBON DIOXIDE WATER GLUCOSE OXYGEN This formula of photosynthesis explains that the reactants, which are six carbon dioxide molecules and six water molecules, get converted into six molecules of oxygen and sugar molecules using the light energy captured by chlorophyll.  light reaction THE LIGHT REACTIONS OCCUR WITHIN THE THYLAKOID OF THE CHLOROPLAST. SPECIAL PIGMENTS ABSORB LIGHT ENERGY AND TRANSFER IT TO HIGH ENERGY ELECTRONS EVENTUALLY PRODUCING ATP AND THE ELECTRON CARRIER NADPH. THE LIGHT REACTIONS USE TWO PHOTOSYSTEMS, CALLED PHOTOSYSTEM 1 AND PHOTOSYSTEM 2, WHICH ARE BOTH EMBEDDED IN THE THYLAKOID MEMBRANE. note: These photosystems are named in the order they were discovered not for the order in which they participate in the photosynthetic process. The light reaction actually begins in photosystem 2.  light reaction THE FIRST THING THAT HAPPENS IS THAT THE PHOTOSYSTEM 2 RECEIVES PHOTOS, OR LIGHT ENERGY. THIS LIGHT ENERGY IS TRANSFERRED TO A CHLOROPHYLL REACTION CENTER CAUSING ELECTRONS IN THE REACTION CENTER TO BECOME ENERGIZED. THESE ELECTRONS BECOME SO ENERGIZED THAT THEY ESCAPE PHOTOSYSTEM 2 AND MOVE TO A NEARBY ELECTRON ACCEPTOR MOLECULE, LOCATED IN THE ELECTRON TRANSPORT CHAIN.  light reaction MEANWHILE, TO REPLACE THE ELECTRONS LEAVING PHOTOSYSTEM 2, WATER IS SPLIT, RELEASING OXYGEN, TWO HYDROGEN IONS AND TWO ELECTRONS. THE FIRST SET OF ELECTRONS CONTINUES TO MOVE DOWN THE ELECTRON TRANSPORT CHAIN, RELEASING STORED ENERGY AS IT MOVES. THIS ENERGY IS USED TO CREATE A HYDROGEN ION GRADIENT.  light reaction A PROTEIN IN THE ELECTRON TRANSPORT CHAIN PUMPS HYDROGEN IONS FROM THE STROMA INTO THE THYLAKOID SPACE. THIS CREATES A HIGH CONCENTRATION OF IONS IN THE THYLAKOID SPACE, RELATIVE TO THE LOW CONCENTRATION OF IONS IN THE STROMA. THIS GRADIENT CONTAINS A LARGE AMOUNT OF POTENTIAL ENERGY WHICH IS USED BY AN ENZYME CALLED ATP SYNTHASE.  light reaction THE HYDROGEN IONS FLOW DOWN THEIR CONCENTRATION GRADIENT, THROUGH A CHANNEL IN THE ATP SYNTHASE, RELEASING ENERGY IN THE PROCESS. ATP SYNTHASE USES THIS ENERGY TO ADD A PHOSPHATE TO ADP FORMING ATP. THE LIGHT REACTION PRODUCE BOTH ATP AND NADPH. AS PHOTOSYSTEM 1 ABSORBS ADDITIONAL LIGHT ENERGY, THE ELECTRONS AGAIN BECOME ENERGIZED, ESCAPING PHOTOSYSTEM 1 AND MOVING DOWN THE SECOND ELECTRON TRANSPORT CHAIN.  light reaction ELECTRONS FROM THE ELECTRON TRANSPORT CHAIN ADJACENT TO PHOTOSYSTEM 2, REPLACE THOSE IN PHOTOSYSTEM 1. AND AGAIN, WATER IS SPLIT TO REPLACE THE ELECTRONS THAT HAVE MOVED FROM PHOTOSYSTEM 2. AT THE END OF THIS ELECTRON TRANSPORT CHAIN THE ENERGIZED ELECTRONS AND A HYDROGEN MOLECULE ARE USED TO REDUCE NADP TO NADPH.  light reaction TOGETHER, THE ATP AND NADPH FORMED DURING THE LIGHT REACTIONS, ARE USED BY THE CALVIN CYCLE REACTIONS. THE IMPORTANT THING TO REMEMBER IS THAT PLANT NEEDS BOTH LIGHT AND WATER TO SURVIVE. WITHOUT THESE INGREDIENTS, THE LIGHT REACTIONS WOULD SHUT DOWN STALLING PHOTOSYNTHESIS AND CAUSING THE PLANT TO DIE.  calvin cycle THE ULTIMATE GOAL OF THE LIGHT-INDEPENDENT REACTIONS (OR CALVIN CYCLE) IS TO ASSEMBLE A MOLECULE OF GLUCOSE. THIS IS THE PART OF PHOTOSYNTHESIS THAT REQUIRES THE CO2 THE PLANT GETS FROM THE AIR. STEPS OF PHOTOSYNTHESIS Light capture: The very first step of the process of photosynthesis is the absorption of light by chlorophylls. These chlorophylls are connected with proteins in the thylakoids sack of chloroplasts. Moreover, the absorbed light converts itself into energy, and then it is used for eliminating the electrons from the water, which is an electron donor to form oxygen. Then, these eliminated electrons pass to a major electron acceptor. Transfer of electron After the transfer of electrons to the electron acceptors, they get transferred to the final electron acceptor, an NADP positive. They are transferred by the process known as the chain of electron transfer, in which the molecules exist in the thylakoid membrane. STEPS IN PHOTOSYNTHESIS Production of ATP When electrons are transferred to the final acceptor, it moves out to the stroma of the plant from the thylakoid lumen by the complex process of F0F1. This results in the production of ATP, which is the most important source of energy in a plant’s biological process. This ATP production is solely utilized during synthesis and is dependent on light. Carbon fixation The formed NADP and ATP produce the energy. The process of reducing carbon occurs by the electrons into the six-carbon molecules. All the above three steps are known as light reactions, while this carbon fixation is light-independent, and thus, they are called dark reactions. This process is also known as the Calvin Cycle. Graphic summary Graphic summary Importance Vital energy source: Photosynthesis converts sunlight into chemical energy, nourishing plants and initiating food webs on Earth. Oxygen production: Photosynthetic organisms release oxygen as a byproduct, sustaining the respiration of most living beings and enriching the atmosphere with this gas. Climate regulation: Photosynthesis absorbs carbon dioxide, aiding in climate change control and maintaining the balance of the greenhouse effect.