Campbell Biology: Concepts & Connections Chapter 4 Lecture Notes PDF

Campbell Biology: Concepts & Connections Tenth Edition Chapter 4 A Tour of the Cell Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Introduction Improved microscopes and techniques have vastly expanded our view of t...

Campbell Biology: Concepts & Connections Tenth Edition Chapter 4 A Tour of the Cell Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Introduction Improved microscopes and techniques have vastly expanded our view of the cell. – In 1665, Hooke used a crude microscope to examine a piece of bark from an oak tree. Hooke compared the structures he saw to “little rooms”—cellulae in Latin—and the term “cell” stuck. – A few decades later Leeuwenhoek used more refined microscope to view numerous subjects, including blood, sperm, and pond water. In this chapter, we will explore the cellular basis of life. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.0_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Introduction to the Cell Copyright © 2020 Pearson Education, Inc. All Rights Reserved. The Discovery of the Cell 1. Early Microscopes Robert Hooke- Used simple microscope to look at a slice of cork- “cells” Anton van Leeuwenhoek- Observed tiny living things in pond water-animalcules 2. The Cell Theory Mathias Schleiden- Concluded all plants are made of cells Theodor Schwann- Stated all animals are made of cells Rudolf Virchow- Concluded new cells come from existing cells Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.1 Microscopes Reveal the World of the Cell (1 of 2) The light microscope can display living cells. The greater magnification and resolution of scanning and transmission electron microscopes reveal the ultrastructure of cells. – Magnification is the increase in an object’s image size compared with its actual size. – Resolution is a measure of the clarity of an image. In other words, it is the ability of an instrument to show two nearby objects as separate. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.1 Microscopes Reveal the World of the Cell (2 of 2) In the mid-1800s, early studies of cells led to cell theory, which states that – all living things are composed of cells and – all cells come from other cells. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.1e_3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.2 The Small Size of Cells Relates to the Need to Exchange Materials Across the Plasma Membrane (1 of 2) The microscopic size of most cells provides a large surface-to-volume ratio. The plasma membrane is a phospholipid bilayer with embedded proteins. – Some proteins form channels (tunnels) that shield ions and other hydrophilic molecules as they pass through the hydrophobic center of the membrane. – Other proteins serve as pumps, using energy to actively transport molecules into or out of the cell. SA/V ratio video Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.2 The Small Size of Cells Relates to the Need to Exchange Materials Across the Plasma Membrane (2 of 2) Checkpoint question To convince yourself that a small cell has a greater surface area relative to volume than a large cell, compare the surface-to-volume ratios of the large cube and one of the small cubes in Figure 4.2A. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.2b Proteins aid movement across the membrane for large polar molecules small nonpolar molecules can cross the membrane on their own. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.3 Prokaryotic Cells Are Structurally Simpler Than Eukaryotic Cells All cells have a plasma membrane, DNA, ribosomes, and cytosol. Bacteria and Archaea consist of prokaryotic cells. All other forms of life are placed in domain Eukarya and have eukaryotic cells. Eukaryotic cells are distinguished by having – a membrane-enclosed nucleus and – many membrane-enclosed organelles that perform specific functions. Prokaryotic cells are smaller and simpler in structure. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.3 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.4 Eukaryotic Cells Are Partitioned into Functional Compartments (1 of 2) Membrane-enclosed organelles compartmentalize a cell’s activities. The organelles and other structures of eukaryotic cells can be organized into four basic functional groups: 1. The nucleus and ribosomes carry out the genetic control of the cell. 2. Organelles involved in the manufacture, distribution, and breakdown of molecules include the endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.4 Eukaryotic Cells Are Partitioned into Functional Compartments (2 of 2) 3. Mitochondria in all cells and chloroplasts in plant cells function in energy processing. 4. Structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall. Checkpoint question Identify the structures in the plant cell that are not present in the animal cell. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.4a Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.4b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Plant and animal cell lab Onion cells and Cheek cells at low magnification and at high magnification under the microscope Copyright © 2020 Pearson Education, Inc. All Rights Reserved. The Nucleus and Ribosomes Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.5 The Nucleus Contains the Cell’s Genetic Instructions The nucleus houses the cell’s DNA, which directs protein synthesis via messenger RNA. Subunits of ribosomes are assembled in the nucleolus. Checkpoint question Describe the processes that occur in the nucleus. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.5 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.6 Ribosomes Make Proteins for Use in the Cell and Export Ribosomes – are composed of ribosomal RNA and proteins and – synthesize proteins according to directions from DNA. Cells that make a lot of proteins have a large number of ribosomes. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.6 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. The Endomembrane System Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.7 Many Organelles Are Connected in the Endomembrane System Many of the membranes within a eukaryotic cell are part of the endomembrane system. Many of these organelles interact in the – synthesis, – distribution, – storage, and – export of molecules. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  4.8 The Endoplasmic Reticulum is a Biosynthetic Workshop The E R is a membranous network of tubes and sacs. – Smooth E R synthesizes lipids and processes toxins. – Rough E R produces membranes, and ribosomes on its surface make membrane and secretory proteins. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.8b Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.9 The Golgi Apparatus Modifies, Sorts, and Ships Cell Products (1 of 2) The Golgi apparatus consists of stacks of sacs in which products of the ER are processed and then sent to other organelles or to the cell surface. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.10 Lysosomes Are Digestive Compartments Within a Cell (1 of 2) – Mitochondria in all cells and chloroplasts in plant cells function in energy processing. – Structural support, movement, and communication between cells are the functions of the cytoskeleton, plasma membrane, and plant cell wall. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.10 Lysosomes Are Digestive Compartments Within a Cell Lysosomes house enzymes that break down ingested substances and damaged organelles. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.11 Vacuoles Function in the General Maintenance of the Cell Vacuoles are large vesicles that have a variety of functions. – Some protists have contractile vacuoles. – Plant cells contain a large central vacuole that stores molecules and wastes and facilitates growth. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.12 A Review of the Structures Involved in Manufacturing and Breakdown (1 of 3) The organelles of the endomembrane system are interconnected structurally and functionally. Figure 4.12 summarizes the relationships among the major organelles of the endomembrane system. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.12 A Review of the Structures Involved in Manufacturing and Breakdown (2 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.12 A Review of the Structures Involved in Manufacturing and Breakdown (3 of 3) Peroxisomes are metabolic compartments that do not originate from the endomembrane system. Peroxisomes break down organic molecules by the process of oxidation to produce hydrogen peroxide. This is then quickly converted to oxygen and water. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Energy-Converting Organelles Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  4.13 Mitochondria Harvest Chemical Energy from Food Mitochondria are organelles that carry out cellular respiration in nearly all eukaryotic cells. Mitochondria have two internal compartments. 1. The intermembrane space is the narrow region between the inner and outer membranes. 2. The mitochondrial matrix contains the mitochondrial DNA, ribosomes, and many enzymes that catalyze some of the reactions of cellular respiration. Checkpoint question What is cellular respiration? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.14 Chloroplasts Convert Solar Energy to Chemical Energy (1 of 2) Photosynthesis is the conversion of light energy from the sun to the chemical energy of sugar molecules. Chloroplasts are the photosynthesizing organelles of plants and algae. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.15 Evolution Connection: Mitochondria and Chloroplasts Evolved by Endosymbiosis The endosymbiont theory states that mitochondria and chloroplasts were formerly small prokaryotes that began living within larger cells. Evidence: -similar size as bacteria -have their own DNA -not synthesized in cells Copyright © 2020 Pearson Education, Inc. All Rights Reserved. The Cytoskeleton and Cell Surfaces Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  4.16 The Cell’s Internal Skeleton Helps Organize Its Structure and Activities (1 of 2) The cytoskeleton includes microfilaments, intermediate filaments, and microtubules. Their functions include – maintenance of cell shape, – anchorage and movement of organelles, – amoeboid movement, and – muscle contraction. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.17 Scientific Thinking: Scientists Discovered the Cytoskeleton Using the Tools of Biochemistry and Microscopy (1 of 2) In the 1940s, biochemists first isolated and identified the proteins actin and myosin from muscle cells. In 1954, scientists, using newly developed techniques of microscopy, established how filaments of actin and myosin interact in muscle contraction. In the next decade, researchers identified actin filaments in all types of cells. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  4.17 Scientific Thinking: Scientists Discovered the Cytoskeleton Using the Tools of Biochemistry and Microscopy Researchers then tagged actin proteins with fluorescent molecules and injected them into living cells. This technique enabled scientists to visualize the dynamic behavior of cytoskeletal proteins in living cells. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.18 Cilia and Flagella Move When Microtubules Bend (1 of 2) Eukaryotic cilia and flagella are locomotor appendages made of microtubules in a “9 + 2” arrangement. – Flagella, longer than cilia, propel a cell by an undulating, whiplike motion. Cilia work more like the coordinated oars of a rowing team. – Though different in length and beating pattern, cilia and flagella have a common structure and mechanism of movement. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.18 Cilia and Flagella Move When Microtubules Bend Checkpoint question Primary ciliary dyskinesia (PCD), also known as immotile cilia syndrome, is a fairly rare disease in which cilia and flagella are lacking motor proteins. PCD is characterized by recurrent respiratory tract infections and immotile sperm. How would you explain these seemingly unrelated symptoms? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.18c Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Video: Dynein arms animation https://www.youtube.com/watch?v=9 nZYlyFGm50 Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  4.19 The Extracellular Matrix of Animal Cells Functions in Support and Regulation Animal cells synthesize and secrete an elaborate extracellular matrix (E C M), which -binds tissue cells together, -supports the plasma membrane, and -communicates with the cytoskeleton. The E C M may attach to the cell through other glycoproteins that then bind to membrane proteins called integrins. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.20 3 Types of Cell Junctions Are Found in Animal Tissues Neighboring cells often adhere, interact, and communicate through specialized junctions between them. – Tight junctions bind cells to form leakproof sheets. – Anchoring junctions rivet cells into strong tissues. – Gap junctions allow ions and small molecules to flow from cell to cell. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.21 Cell Walls Enclose and Support Plant Cells A plant cell, but not an animal cell, has a rigid cell wall that – protects and provides skeletal support that helps keep the plant upright on land and – is primarily composed of cellulose. Plant cells have cell junctions called plasmodesmata that allow plant tissues to share water, nourishment, and chemical messages. Checkpoint question Which animal cell junction is analogous to a plasmodesma? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.21 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. 4.22 Review: Eukaryotic Cell Structures Can Be Grouped on the Basis of Four Main Functions (1 of 2) Eukaryotic cell structures can be grouped on the basis of four functions: 1. genetic control, 2. manufacturing, distribution, and breakdown of materials, 3. energy processing, and 4. structural support, movement, and intercellular communication. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 4.22 Eukaryotic Cell Structures and Their Functions (1 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 4.22 Eukaryotic Cell Structures and Their Functions (2 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 4.22 Eukaryotic Cell Structures and Their Functions (3 of 3) Copyright © 2020 Pearson Education, Inc. All Rights Reserved. You Should Now Be Able to (1 of 4) 1. Describe the importance of microscopes in understanding cell structure and function. 2. Describe the two parts of cell theory. 3. Distinguish between the structures of prokaryotic and eukaryotic cells. 4. Explain how cell size is limited. 5. Describe the structure and functions of cell membranes. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. You Should Now Be Able to (2 of 4) 6. Explain why compartmentalization is important in eukaryotic cells. 7. Compare the structures of plant and animal cells. Note the function of each cell part. 8. Compare the structures and functions of chloroplasts and mitochondria. 9. Describe the evidence that suggests that mitochondria and chloroplasts evolved by endosymbiosis. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  You Should Now Be Able to (3 of 4) 10. Compare the structures and functions of microfilaments, intermediate filaments, and microtubules. 11. Relate the structure of cilia and flagella to their functions. 12. Relate the structure of the extracellular matrix to its functions. 13. Compare the structures and functions of tight junctions, anchoring junctions, and gap junctions. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.  You Should Now Be Able to (4 of 4) 14. Relate the structures of plant cell walls and plasmodesmata to their functions. 15. Describe the four functional categories of organelles in eukaryotic cells. Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Table 4.1 Metric Measurement Equivalents Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN01 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN02 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN03 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN04 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN04_1 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Figure 4.UN04_2 Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Checkpoint question Which type of microscope would you use to study (a) the changes in shape of a living human white blood cell; (b) the finest details of surface texture of a human hair; (c) the detailed structure of an organelle in a liver cell? Copyright © 2020 Pearson Education, Inc. All Rights Reserved. Copyright This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials. Copyright © 2020 Pearson Education, Inc. All Rights Reserved.