* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 4 A Tour of the Cell
Survey
Document related concepts
Tissue engineering wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Cell growth wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Cell encapsulation wikipedia , lookup
Extracellular matrix wikipedia , lookup
Signal transduction wikipedia , lookup
Cell nucleus wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell membrane wikipedia , lookup
Cytokinesis wikipedia , lookup
Transcript
Chapter 4 A Tour of the Cell PowerPoint Lectures for Campbell Biology: Concepts & Connections, Seventh Edition Reece, Taylor, Simon, and Dickey © 2012 Pearson Education, Inc. Lecture by Edward J. Zalisko Plans: Day 1) Notes: 4.1-4.4/ HW Packet, Assign project and talk about cell cake Day 2) Cards Day 3) Cards Day 4) Review cards Day 5) Card Matching Game Day 6) Quiz Day 7) Cell Cake Day 8) test Do Now: What is life? Describe the characteristics of all living things. 1) Nutrition 2) Respiration 3) Regulation 4) Reproduction 5) Synthesis 6) Transport 7) Excretion 8) Growth Introduction Cells are the simplest collection of matter that can live. Cells were first observed by Robert Hooke in 1665. Working with more refined lenses, Antoni van Leeuwenhoek later described – blood, – sperm, and – organisms living in pond water. © 2012 Pearson Education, Inc. Introduction Since the days of Hooke and Leeuwenhoek, improved microscopes have vastly expanded our view of the cell. © 2012 Pearson Education, Inc. Figure 4.0_1 Chapter 4: Big Ideas Introduction to the Cell The Endomembrane System The Nucleus and Ribosomes Energy-Converting Organelles The Cytoskeleton and Cell Surfaces Figure 4.0_2 INTRODUCTION TO THE CELL © 2012 Pearson Education, Inc. 1)LIGHT MICROSCOPE Common? Maximum Magnification? Magnification: Resolution: The most frequently used Light passes through a specimen, then through glass lenses, and finally light is projected into the viewer’s eye. – Magnified up to 1,000 times Magnification is the increase in the apparent size of an object. Resolution is a measure of the clarity of an image. In other words, it is the ability of an instrument to show two close objects as separate. Limited detail © 2012 Pearson Education, Inc. Figure 4.1A Figure 4.1B 10 m 100 mm (10 cm) Length of some nerve and muscle cells Chicken egg 10 mm (1 cm) Unaided eye Human height 1m Frog egg 10 µm 1 µm 100 nm Most plant and animal cells Nucleus Most bacteria Mitochondrion Smallest bacteria Viruses Ribosome 10 nm Proteins Lipids 1 nm 0.1 nm Small molecules Atoms Electron microscope 100 µm Paramecium Human egg Light microscope 1 mm 2) ELECTRON MICROSCOPE (EM) How it works? Maximum magnification? limitiation? © 2012 Pearson Education, Inc. 1950s, scientists started using them to view the ultrastructure of cells. – Instead of light, EM uses a beam of electrons. Electron microscopes can – resolve biological structures as small as 2 nanometers and – magnify up to 100,000 times. – Specimen must be dead © 2012 Pearson Education, Inc. Figure 4.1E 3) Scanning Electron Microscope (SEM) What can you study? How does it work? Scanning electron microscopes (SEM) study the detailed architecture of cell surfaces. – An electron beam to scan the surface which is usually coated in gold, – beam excites electrons on the surface – an image is translated Figure 4.1C 4) Transmission Electron Microscope (TEM) What is it used for? How does it work? Transmission electron microscopes (TEM) study the details of internal cell structure. – Aims an electron beam through a thin section – Section is stained with heavy metals – Electrons that scatter create an image – Uses electromagnets instead of lenses to bend pathway of electron, magnifying specimen . © 2012 Pearson Education, Inc. Figure 4.1D 5) CELL THEORY/ SIZE What is the cell theory? Why are cells small? In the 1800s, these studies led to cell theory, which states that – all living things are composed of cells and – all cells come from other cells. Cell size must – be large enough to house DNA, proteins, and structures needed to survive and reproduce, but – remain small enough to allow for a surface-to-volume ratio that will allow adequate exchange with the environment. Figure 4.2A 1 3 1 3 Total volume Total surface area Surface-tovolume ratio 27 units3 27 units3 54 units2 162 units2 2 6 6) PLASMA MEMBRANE (CELL MEMBRANE) What is the cell membrane like? Where are the proteins? How does it control the traffic of molecules across it? What things pass over easily? What things need help? How are they helped? The plasma membrane forms a flexible boundary between the living cell and its surroundings. Phospholipids form a two-layer sheet called a phospholipid bilayer in which – hydrophilic heads face outward, exposed to water, and – hydrophobic tails point inward, shielded from water. Membrane proteins are – attached to the membrane surface or – embedded in the phospholipid bilayer. Some proteins form channels or tunnels that allow ions and other hydrophilic/polar molecules through O2 and CO2 are nonpolar and pass right over Other proteins serve as pumps, using energy to actively transport molecules into or out of the cell. © 2012 Pearson Education, Inc. Figure 4.2B Outside cell Hydrophilic heads Hydrophobic region of a protein Hydrophobic tails Phospholipid Hydrophilic region of a protein Inside cell Channel protein Proteins 7) PROKARYOTIC CELL Types of organisms? Common with eukaryotic cells? Different? What do they have on the outside? Attach to other things? Move? What do they lack? Bacteria and archaea – Prokaryotic and eukaryotic cells have – a plasma membrane – chromosomes, ribosomes and cytoplasm The DNA is coiled into a region called the nucleoid, but no membrane surrounds DNA The surface of prokaryotic cells may – be surrounded by a complex cell wall, – have a capsule surrounding the cell wall, – have short projections that help attach to other cells or the substrate, – have longer projections called flagella (swim) – no true membrane bound organelles. © 2012 Pearson Education, Inc. Figure 4.3 Fimbriae Ribosomes Nucleoid Plasma membrane Cell wall Bacterial chromosome A typical rod-shaped bacterium Capsule Flagella A TEM of the bacterium Bacillus coagulans Figure 4.3_1 Fimbriae Ribosome Nucleoid Plasma membrane Cell wall Bacterial chromosome A typical rod-shaped bacterium Capsule Flagella Figure 4.3_2 Ribosome Nucleoid Plasma membrane Cell wall Capsule A TEM of the bacterium Bacillus coagulans 8) EUKARYOTIC CELL What does it have that is missing in prokaryotes? What are the four functions? How are they achieved? membrane-bound nucleus and number of other organelles. The structures/organelles perform four basic functions. 1. The nucleus and ribosomes are involved in the genetic control of the cell. 2. The endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and peroxisomes are involved in the manufacture, distribution, and breakdown of molecules. 3. Mitochondria in all cells and chloroplasts in plant cells are involved in energy processing. 4. Structural support, movement, and communication between cells are functions of the cytoskeleton, plasma membrane, and cell wall. © 2012 Pearson Education, Inc. 9) Plant and Animal Cell What does an animal cell have that is missing in a plant? What does a plant have that is missing in an animal? What are the chemical reactions in the cell called? What are the little organs called? Organelles: are the small structures with specific functions Cellular metabolism: the many chemical activities of cells, occurs within organelles Animals only: Lysosomes and centrioles Plant only: a rigid cell wall, chloroplasts, and a central vacuole. © 2012 Pearson Education, Inc. Figure 4.4A Rough Smooth endoplasmic endoplasmic reticulum reticulum NUCLEUS: Nuclear envelope Chromatin Nucleolus NOT IN MOST PLANT CELLS: Centriole Lysosome Peroxisome Ribosomes Golgi apparatus CYTOSKELETON: Microtubule Intermediate filament Microfilament Mitochondrion Plasma membrane Figure 4.4B NUCLEUS: Nuclear envelope Chromatin Nucleolus Golgi apparatus NOT IN ANIMAL CELLS: Central vacuole Chloroplast Cell wall Plasmodesma Mitochondrion Peroxisome Plasma membrane Cell wall of adjacent cell Rough endoplasmic reticulum Ribosomes Smooth endoplasmic reticulum CYTOSKELETON: Microtubule Intermediate filament Microfilament THE NUCLEUS AND RIBOSOMES © 2012 Pearson Education, Inc. 10) NUCLEUS Function? What is inside? How is it kept separate? What organelle is inside? Function? - contains most of the cell’s DNA and – controls the cell’s activities by directing protein synthesis by making messenger RNA (mRNA). DNA is associated with many proteins in structures called chromosomes. (46 for humans) / unorganized chromatin The nuclear envelope – is a double membrane – has pores that allow material in and out The nuclear envelope is attached to cellular membranes called the endoplasmic reticulum. The nucleolus is – a prominent structure in the nucleus – the site of ribosomal RNA (rRNA) synthesis © 2012 Pearson Education, Inc. Figure 4.5 Two membranes of nuclear envelope Chromatin Nucleolus Pore Endoplasmic reticulum Ribosomes Nucleus 11) RIBOSOMES What do they do? What are they made up of? Who makes them? Where are they found? Ribosomes are involved in the cell’s protein synthesis. – Ribosomes are synthesized from rRNA produced in the nucleolus. – Cells that must synthesize large amounts of protein have a large number of ribosomes. – Free ribosomes are – suspended in the cytoplasm – make proteins that function in cytoplasm. – Bound ribosomes are – attached to the endoplasmic reticulum (ER) – associated with proteins packed in organelles or exported © 2012 Pearson Education, Inc. Figure 4.6 Ribosomes ER Cytoplasm Endoplasmic reticulum (ER) Free ribosomes Bound ribosomes Colorized TEM showing ER and ribosomes mRNA Protein Diagram of a ribosome THE ENDOMEMBRANE SYSTEM © 2012 Pearson Education, Inc. Many of the membranes within a eukaryotic cell are part of the endomembrane system Some are physically connected and some are related by the transfer of membrane segments by tiny vesicles (sacs made of membrane). Many of these organelles work together in the – synthesis, – storage, and – export of molecules. The endomembrane system includes – the nuclear envelope, endoplasmic reticulum (ER), Golgi apparatus, lysosomes, vacuoles, and the plasma membrane. © 2012 Pearson Education, Inc. 12) Rough Endoplasmic Reticulum What does it do? What does it have on it? Steps: Has ribosomes attached Rough ER makes – additional membrane – ER ribosomes synthesize, modify, and package proteins to be transported to other organelles or secreted by cell – Steps 1. Polypeptide synthesized by ribosomes according to mRNA, as it enters it takes on its 3D shape 2. Short sugars(address) added creating a glycoprotein 3. Packaged into a vesicle 4. Off to the Golgi © 2012 Pearson Education, Inc. Figure 4.8B Transport vesicle buds off 4 Secretory protein inside transport vesicle mRNA Ribosome 3 Sugar chain 1 2 Polypeptide Glycoprotein Rough ER 13) Smooth Endoplasmic Reticulum 3 functions? 1. Produces enzymes important in the synthesis of lipids, oils, phospholipids, and steroids. 2. Other enzymes help process drugs, alcohol, and other potentially harmful substances. 3. Some smooth ER helps store calcium ions. © 2012 Pearson Education, Inc. Figure 4.8A Nuclear envelope Smooth ER Ribosomes Rough ER Figure 4.8A_1 Smooth ER Ribosome Rough ER 14) Golgi Apparatus Function? Steps? Serves as a molecular warehouse and finishing factory for products (proteins) manufactured by the ER. 1. Products travel in transport vesicles from the ER to the Golgi apparatus. 2. One side of the Golgi apparatus functions as a receiving dock for the product and the other as a shipping dock. 3. Products are modified by enzymes as they go from one side of the Golgi apparatus to the other and travel in vesicles to other sites. – Change sugars, add molecular tags like P to help sort proteins © 2012 Pearson Education, Inc. Figure 4.9 “Receiving” side of Golgi apparatus Golgi apparatus 1 Transport vesicle from ER 2 Transport vesicle from the Golgi 3 4 4 “Shipping” side of Golgi apparatus Golgi apparatus 15) Lysosome What is it? How is it created? Steps? Membranous sac containing digestive enzymes. – The enzymes and membrane are produced by the ER and transferred to the Golgi apparatus for processing. – Safely isolate these potent enzymes Digests food particles engulfed by a cell 1. A food vacuole binds with a lysosome. 2. The enzymes in the lysosome digest the food. 3. The nutrients are then released into the cell. Remove or recycle damaged parts of a cell. © 2012 Pearson Education, Inc. Figure 4.10A_s1 Digestive enzymes Lysosome Plasma membrane Figure 4.10A_s2 Digestive enzymes Lysosome Food vacuole Plasma membrane Figure 4.10A_s3 Digestive enzymes Lysosome Food vacuole Plasma membrane Figure 4.10A_s4 Digestive enzymes Lysosome Digestion Food vacuole Plasma membrane Figure 4.10B_s1 Lysosome Vesicle containing damaged mitochondrion Figure 4.10B_s2 Lysosome Vesicle containing damaged mitochondrion Figure 4.10B_s3 Lysosome Digestion Vesicle containing damaged mitochondrion 16)VACUOLES Functions in protists Functions in plants: Variety of functions. – Food vacuole – Some fresh water protists have contractile vacuoles that help to eliminate extra water – In plants, vacuoles may – have digestive functions, – contain pigments, or – contain poisons that protect the plant – Large central vacuole © 2012 Pearson Education, Inc. Figure 4.11A Contractile vacuoles Nucleus Figure 4.11B Central vacuole Chloroplast Nucleus 17)PEROXISOME Did it come from the EMS? What does it do? Do not originate from EM system Break down fatty acids to be used as fuel In your liver, they detox alcohol – an enzyme adds H to oxygen to make H2O2 or hydrogen peroxide – Other enzymes then convert this toxic substance into a water 4.12 A review of the structures involved in manufacturing and breakdown The following figure summarizes the relationships among the major organelles of the endomembrane system. © 2012 Pearson Education, Inc. Figure 4.12 Nucleus Nuclear membrane Rough ER Transport vesicle from Golgi to plasma membrane Smooth ER Transport vesicle from ER to Golgi Golgi apparatus Lysosome Vacuole Plasma membrane ENERGY-CONVERTING ORGANELLES © 2012 Pearson Education, Inc. 18)MITOCHONDRIA What do they do? How? Compartments. Carries out cellular respiration Converts chemical energy in foods to chemical energy in ATP (adenosine triphosphate). 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, – many enzymes that catalyze some of the reactions of cellular respiration. © 2012 Pearson Education, Inc. Figure 4.13 Mitochondrion Outer membrane Intermembrane space Inner membrane Cristae Matrix 19) CHLOROPLAST Process? Compartments? Photosynthesizing organelles Photosynthesis is the conversion of light energy from the sun to the chemical energy of sugar molecules. Compartments. – Between the outer and inner membrane is a thin intermembrane space. – Inside the inner membrane is – a thick fluid called stroma that contains the chloroplast DNA, ribosomes, and many enzymes and – a network of interconnected sacs called thylakoids. – In some regions, thylakoids are stacked like poker chips. Each stack is called a granum, where green chlorophyll molecules trap solar energy. © 2012 Pearson Education, Inc. Figure 4.14 Inner and outer membranes Granum Chloroplast Stroma Thylakoid 20)Endosymbiont Theory What is it? What organelles is it about? Why is this thought to be true? Mitochondria and chloroplasts have – DNA and – ribosomes. The structure of this DNA and these ribosomes is very similar to that found in prokaryotic cells. The endosymbiont theory proposes that – mitochondria and chloroplasts were formerly small prokaryotes and they began living within larger cells. © 2012 Pearson Education, Inc. Figure 4.15 Mitochondrion Nucleus Endoplasmic reticulum Some cells Engulfing of oxygenusing prokaryote Engulfing of photosynthetic prokaryote Chloroplast Host cell Mitochondrion Host cell THE CYTOSKELETON AND CELL SURFACES © 2012 Pearson Education, Inc. 21)CYTOSKELETON Function: 3 types: Functions? A network of protein fibers, which functions in structural support and motility. Motility and cellular regulation result when the cytoskeleton interacts with proteins called motor proteins. The cytoskeleton is composed of three kinds of fibers. 1. Microfilaments (actin filaments) support the cell’s shape and are involved in motility. 2. Intermediate filaments reinforce cell shape and anchor organelles. 3. Microtubules (made of tubulin) give the cell rigidity and act as tracks for organelle movement. © 2012 Pearson Education, Inc. Figure 4.16 Nucleus Nucleus Actin subunit 7 nm Microfilament Fibrous subunits Tubulin subunits 10 nm 25 nm Intermediate filament Microtubule 22)Cilia and Flagella Function in multicellular organisms Function in single celled eukaryotes (protists) and prokaryotes Structure multicellular organisms – Cells that sweep mucus out of our lungs have cilia and animal sperm are flagellated Protists and Prokaryotes A flagellum, longer than cilia, propels a cell by an undulating, whiplike motion. Cilia work more like the oars of a crew boat. Structure Both are made of microtubules wrapped in an extension of the plasma membrane. A ring of nine microtubule doublets surrounds a central pair of microtubules. This arrangement is – called the 9 + 2 pattern – anchored in a basal body with nine microtubule triplets arranged in a ring. Cilia and flagella move by bending motor proteins called dynein feet. © 2012 Pearson Education, Inc. Figure 4.17A Cilia Figure 4.17B Flagellum Figure 4.17C Outer microtubule doublet Central microtubules Radial spoke Dynein proteins Plasma membrane Figure 4.17C_1 Outer microtubule doublet Central microtubules Radial spoke Dynein proteins 4.18 CONNECTION: Problems with sperm motility may be environmental or genetic In developed countries over the last 50 years, there has been a decline in sperm quality. The causes of this decline may be – environmental chemicals or – genetic disorders that interfere with the movement of sperm and cilia. Primary ciliary dyskinesia (PCD) is a rare disease characterized by recurrent infections of the respiratory tract and immotile sperm. © 2012 Pearson Education, Inc. Figure 4.18 23)Extracellular Matrix Function: Components: Most Abundant? Integrin functions Animal cells synthesize and secrete an elaborate extracellular matrix (ECM) that – helps hold cells together in tissues and – protects and supports the plasma membrane. The ECM may attach to a cell through glycoproteins that then bind to membrane proteins called integrins. Integrins span the plasma membrane and connect to microfilaments of the cytoskeleton. © 2012 Pearson Education, Inc. Figure 4.19 Glycoprotein complex with long polysaccharide EXTRACELLULAR FLUID Collagen fiber Connecting glycoprotein Integrin Plasma membrane CYTOPLASM Microfilaments of cytoskelton 24) Animal Cell Junctions: Functions: 3 Types described Adjacent cells communicate, interact, and adhere through specialized junctions between them. – Tight junctions prevent leakage of extracellular fluid across a layer of epithelial cells. – Anchoring junctions fasten cells together into sheets. – Gap junctions are channels that allow molecules to flow between cells. © 2012 Pearson Education, Inc. Figure 4.20 Tight junctions prevent fluid from moving between cells Tight junction Anchoring junction Gap junction Plasma membranes of adjacent cells Extracellular matrix 25) Plasmodesmata Type of cells Function A plant cell has a rigid cell wall that – protects and provides skeletal support that helps keep the plant upright against gravity and – is primarily composed of cellulose. Plant cells have cell junctions called plasmodesmata that serve in communication between cells. © 2012 Pearson Education, Inc. Figure 4.21 Plant cell walls Vacuole Plasmodesmata Primary cell wall Secondary cell wall Plasma membrane Cytoplasm 4.22 Review: Eukaryotic cell structures can be grouped on the basis of four basic functions Eukaryotic cell structures can be grouped on the basis of four functions: 1. genetic control, 2. manufacturing, distribution, and breakdown, 3. energy processing, and 4. structural support, movement, and communication between cells. © 2012 Pearson Education, Inc. Table 4.22 Table 4.22_1 Table 4.22_2 You should now be able to 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. © 2012 Pearson Education, Inc. You should now be able to 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. © 2012 Pearson Education, Inc. You should now be able to 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. © 2012 Pearson Education, Inc. You should now be able to 14. Relate the structures of plant cell walls and plasmodesmata to their functions. 15. Describe the four functional categories of organelles in eukaryotic cells. © 2012 Pearson Education, Inc. Figure 4.UN02 Figure 4.UN03 a. l. b. c. k. j. i. h. d. g. e. f.