Human Biology Sylvia S Mader Michael Windelspecht Chapter
Human Biology Sylvia S. Mader Michael Windelspecht Chapter 3 Cell Structure and Function Lecture Outline Part 4 Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. 1
3. 5 The Cytoskeleton, Cell Movement, and Cell Junctions What is the cytoskeleton? • A series of proteins that maintain cell shape, as well as anchors and/or moves organelles in the cell • Made of 3 types of fibers: large microtubules, thin ________, and medium-sized intermediate filaments 2
3. 5 The Cytoskeleton, Cell Movement, and Cell Junctions Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. What are cilia and flagella? Flagellum microtubules plasma membrane • Both are made of microtubules. a. cilia • Both are used in ______. sperm flagellum secretory cell • Cilia are about 20 shorter than flagella. b. flagellum Figure 3. 15 Structure and function of the cilia and flagella. c. (b): © Y. Nikas/Photo Researchers, Inc. ; (c): © David M. Phillips/Photo Researchers, Inc. 3
3. 5 The Cytoskeleton, Cell Movement, and Cell Junctions What are cell junctions? Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. • Junctions between the cells of human tissue that allow them to function in a coordinated manner filaments of • 3 main types cytoskeleton – _______ mechanically attach adjacent cells (common in skin cells). plasma membranes intercellular filaments intercellular space a. Adhesion junction Figure 3. 16 a Junctions between cells. 4
3. 5 The Cytoskeleton, Cell Movement, and Cell Junctions What are cell junctions? Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. – _______ are connections between the plasma membrane proteins of neighboring cells that produce a ______ barrier (common in digestive system and kidney where fluids must be contained to a specific area). Figure 3. 16 b Junctions between cells. plasma membranes tight junction proteins intercellular space b. Tight junction 5
3. 5 The Cytoskeleton, Cell Movement, and Cell Junctions What are cell junctions? Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. – ______ are communication portals between cells; channel proteins of the plasma membrane fuse, allowing easy movement between adjacent cells. plasma membranes membrane channels intercellular space c. Gap junction Figure 3. 16 c Junctions between cells. 6
3. 6 Mitochondria and Cellular Metabolism What do mitochondria do and what do they look like? Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. • Highly folded organelles in eukaryotic cells • Produce _______ in the form of ____ outer membrane intermembrane inner space membrane matrix 200 nm cristae • Thought to be derived from an engulfed prokaryotic cell Figure 3. 17 The structure of a mitochondrion. (top) : © Dr. Don W. Fawcett/Visuals Unlimited 7
3. 6 Mitochondria and Cellular Metabolism Enzymes are important for cellular respiration and many activities in the cell • Most enzymes are ____. • Enzymes are often named for the molecules that they work on, called ______. • Enzymes are _____ to what substrate they work on. • Enzymes have active sites where a substrate binds. • Enzymes are not used up in a reaction but instead are ______. • Some enzymes are aided by nonprotein molecules called coenzymes. 8
3. 6 Mitochondria and Cellular Metabolism How do enzymes work? Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. products product enzyme substrate enzyme–substrate complex substrates active site Degradation A substrate is broken down to smaller products. enzyme Figure 3. 18 Action of an enzyme–substrate complex active site Synthesis Substrates are combined to produce a larger product. enzyme 9
3. 6 Mitochondria and Cellular Metabolism What is cellular respiration? • Production of _____ in a cell • Includes 1. Glycolysis 2. Citric acid cycle (Krebs cycle) 3. Electron transport chain 10
3. 6 Mitochondria and Cellular Metabolism Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. Inside cell electrons transferred by NADH glucose electrons transferred by NADH Glycolysis glucose Citric acid cycle pyruvate Electron transport chain oxygen mitochondrion 2 ATP 32 ATP Outside cell Figure 3. 19 Production of ATP. 11
3. 6 Mitochondria and cellular metabolism Glycolysis – Occurs in the _____ – Breaks ____ into 2 pyruvate – NADH and 2 ATP molecules are made – Does not require _____ 12
3. 6 Mitochondria and Cellular Metabolism Citric acid cycle (Krebs cycle) – A cyclical pathway that occurs in the ______ – Produces NADH and 2 ATP – Releases carbon dioxide 13
3. 6 Mitochondria and Cellular Metabolism Electron transport chain • Series of molecules embedded in the mitochondrial membrane – NADH made in steps 1 and 2 carry electrons here – ______ are made depending on the cell – Requires _____ as the final electron acceptor in the chain 14
3. 6 Mitochondria and Cellular Metabolism What other molecules besides glucose can be used in cellular respiration? • Other carbohydrates • Proteins • Lipids 15
3. 6 Mitochondria and Cellular Metabolism How can a cell make ATP without oxygen? • Fermentation: – occurs in the ______. – does not require ____. – involves ______. – makes 2 ATP and lactate in human cells. – can give humans a burst of energy for a short time. 16
- Slides: 16