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Questions and Answers
Which statement best describes the function of the plasma membrane?
What is the primary role of the Rough Endoplasmic Reticulum?
What is the main structural component of microtubules?
Which organelle is responsible for detoxifying waste products in the cell?
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Which statement accurately reflects the role of the nucleus in a cell?
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What is the primary role of creatine phosphate during muscle contraction?
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What is produced during the glycolysis process apart from ATP?
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Which component of the extracellular matrix is primarily responsible for tensile strength?
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How does the electron transport chain generate ATP?
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Which type of cell junction is characterized as impermeable?
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What is the primary function of desmosomes?
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What happens to pyruvate when oxygen is limited or unavailable?
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What is the composition of the plasma membrane primarily made of?
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Which type of fibers allows cells to stretch and recoil?
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What is the total ATP yield from one complete turn of the citric acid cycle?
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Study Notes
Principles of Cell Theory
- Cell is the fundamental unit of life.
- Functionality is determined by cellular structure.
- All cells share similarities in structure and function.
Cell Structures & Functions
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Plasma Membrane:
- Thin lipid bilayer with embedded proteins.
- Provides selective permeability to regulate substances entering and exiting the cell.
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Nucleus:
- Houses DNA and is surrounded by a double membrane.
- Acts as a blueprint for cell replication and directs protein synthesis.
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Endoplasmic Reticulum (ER):
- Consists of folded membranes to increase surface area.
- Rough ER: Contains ribosomes, mainly for protein production.
- Smooth ER: Involved in lipid production.
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Golgi Complex:
- Stacked, flattened sacs for modifying, packaging, and distributing proteins.
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Lysosomes:
- Small membranes that break down foreign molecules using hydrolytic enzymes.
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Peroxisomes:
- Detoxify waste utilizing oxidative enzymes.
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Centrioles:
- Pair of cylindrical structures that form microtubules for cell division and the formation of cilia and flagella.
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Mitochondria:
- ATP production site with an inner membrane folded into cristae, providing a large surface area for reactions.
- Matrix is the inner cavity of mitochondria.
Cytoskeleton
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Microtubules:
- Hollow tubes composed of tubulin, maintain cell shape and movement, and position organelles.
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Microfilaments:
- Small chains of actin; integral in muscle contraction.
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Intermediate Filaments:
- Provide stiffness and resistance to stress, made up of irregular threadlike proteins like keratin.
Cytosol
- Gel-like substance within the cell.
- Contains enzymes for metabolism and nutrient storage.
Cellular Metabolism
- ATP produced from creatine phosphate (CP) for rapid energy during stress (like muscle contraction).
- Anaerobic glycolysis converts pyruvate to lactate when oxygen is unavailable.
Respiration Process
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Glycolysis:
- Breakdown of glucose in the cytosol yielding 2 pyruvate, 2 ATP, and 2 NADH.
- McArdle disease: Deficiency in enzyme converting glycogen to glucose.
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Pyruvate Decarboxylation:
- Converts pyruvates into 2 Acetyl-CoA, with release of 2 CO2 and production of 2 NADH.
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Citric Acid Cycle:
- Acetyl-CoA joins oxaloacetate to form citrate in 8 steps, yielding 2 ATP, 6 NADH, 2 FADH2, and 4 CO2.
- Hydrogen removal contributes to the electron transport chain.
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Electron Transport Chain (ETC):
- Electrons pass through protein complexes, pumping hydrogen ions to create a gradient.
- ATP synthesis occurs as hydrogen returns through ATP synthase and electrons are combined with oxygen to form water.
- Produces approximately 32 ATP.
Plasma Membrane
- Acts as a barrier between intracellular and extracellular fluids.
- Composed of lipids (50%) and proteins (50%), utilizing a fluid mosaic model for flexibility.
Cell-Cell Adhesion
- Cells adhere through cell adhesion molecules (CAM), enhancing intercellular connections but not providing the strongest bond.
Extracellular Matrix (ECM)
- Gel-like mixture contains interstitial fluid and fibrous proteins produced by fibroblasts.
- Collagen: Provides tensile strength, most abundant ECM protein.
- Elastin: Offers elasticity and resilience, crucial for stretchable tissues like lungs.
- Fibronectin: Promotes adhesion and stability among cells.
Specialized Cell Junctions
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Desmosomes:
- Strong adhesion structures linking cells via the ECM, composed of cadherins and filaments.
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Tight Junctions:
- Form impermeable barriers between cells, often found in epithelial tissues.
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Gap Junctions:
- Protein tunnels (connexons) that allow communication and transport between adjacent cells.
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Description
Test your knowledge on the fundamental principles of cell theory and the various cell structures. This quiz covers essential concepts such as the plasma membrane, nucleus, and endoplasmic reticulum, highlighting their functions and significance. Enhance your understanding of the basic unit of life!
