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Transcript of Chapter4 sections+8 13
- 1.
- Chapter 4 Cell Structure (Sections 4.8 - 4.13)
2.
- 4.8 The Endomembrane System
- Theendomembrane systemincludes rough and smoothendoplasmic reticulum( ER ),vesicles , andGolgi bodies
3. This system makes and modifies lipids and proteins; it also recycles and disposes of molecules and particles
- endomembrane system
-
- Series of interacting organelles (endoplasmic reticulum, Golgi bodies, vesicles) between nucleus and plasma membrane; produces lipids, proteins
4.
- The Endomembrane System
5.
- p. 62
- Stepped Art
- The Endomembrane System
- Makes lipids, breaks down carbohydrates and fats, inactivates toxins
- Smooth ER
- Finishes, sorts, ships lipids, enzymes, and proteins
- Golgi Body
- Modifies proteins made by ribosomes attached to it
- Rough ER
- Digests, recycles materials
- Lysosome
6.
- Endoplasmic Reticulum
- endoplasmic reticulum (ER)
-
- Organelle that is a continuous system of sacs and tubes
- 7. An extension of the nuclear envelope
8. Site where many new polypeptide chains are modified 9. Rough ER is studded with ribosomes thatmake polypeptides thatenter the ER as they are assembled 10. Smooth ER has no ribosomes: Enzymes assemble lipids that form cell membranes, and break down substances 11.
- A Variety of Vesicles
- Small, membrane-enclosed, saclikevesicles form in a variety of types, either on their own or by budding
12. Many vesicles transport substances from one organelle to another, including endocytic vesicles and exocytic vesicles 13. Other vesicles includeperoxisomes ,lysosomes , andvacuoles (includingcentral vacuoles ) 14.
- Key Terms
- vesicle
-
- Small, membrane-enclosed, saclike organelle; different kinds store, transport, or degrade their contents
- lysosome
-
- Enzyme-filled vesicle that functions in intracellular digestion
- peroxisome
-
- Enzyme-filled vesicle that breaks down amino acids, fatty acids, and toxic substances
15.
- Key Terms
- vacuole
-
- A fluid-filled organelle that isolates or disposes of waste, debris, or toxic materials
- central vacuole
-
- Fluid-filled vesicle in many plant cells
16.
- Golgi Bodies
- Enzymes in aGolgi bodyfinish proteins and lipids that are delivered by vesicles from the ER
- Golgi body
-
- Modifies polypeptides and lipids; a ttaches phosphate groups or oligosaccharides, and cuts certain polypeptides
- 17. Sorts and packages the finished products into vesiclesthat carry them to lysosomes or to the plasma membrane
18.
- Functions ofthe Endomembrane System
- Fig. 4.16.1,3, p. 62
- polypeptide
- ribosome attached to ER
- vesicle budding from ER
- RNA
- nucleus
- Vesicles Vesicles that bud from the rough ER carry some of the new proteins to Golgi bodies. Other proteins migrate through the interior of the rough ER, and end up in the smooth ER.
- 3
- Rough ER Some of the RNAin the cytoplasmis translated into polypeptide chains by ribosomes attached to the rough ER. The chains enter the rough ER, where they are modified into final form.
- 1
19.
- Functions ofthe Endomembrane System (cont.)
- Fig. 4.16.2,4,5, p. 62
- protein in smooth ER
- Smooth ERSome proteins from the rough ER are packaged into new vesicles and shipped to Golgi bodies. Others become enzymes of the smooth ER. These enzymes assemble lipids and inactivate toxins.
- 2
- Golgi bodyProteins arriving in vesicles from the ER are modified into final form and sorted. New vesicles carry them to the plasma membrane or to lysosomes.
- 4
- Plasma membraneA vesicles membrane fuses with the plasma membrane, so the contents of the vesicle are released to the exterior of the cell.
- 5
20.
- Animation: The Endomembrane System
21.
- 4.9 Mitochondria and Plastids
- Mitochondriamake ATP by breaking down organic compounds in the oxygen-requiring pathway of aerobic respiration
- Chloroplastsareplastids that produce sugars by photosynthesis
22.
- Function of Mitochondria
- mitochondrion
-
- Double-membraned organelle that produces ATP by aerobic respiration in eukaryotes
- During aerobic respiration, hydrogen ions accumulate between the two membranes
23. The buildup causes the ions to flow across the inner mitochondrial membrane, through membrane transport proteins that drive the formation of ATP 24.
- Mitochondrion
- Fig. 4.17a, p. 64
- inner compartment
- outer membrane
- outer compartment
- inner membrane
25.
- Fig. 4.17b, p. 64
- Mitochondrion
26.
- Fig. 4.17c, p. 64
- Energy powerhouse; produces many ATP by aerobic respiration
- Mitochondrion
27.
- Animation: Structure of a Mitochondrion
28.
- Origins of Mitochondria
- Theory of endosymbiosis: Mitochondria evolved from aerobic bacteria that took up permanent residence inside a host cell
-
- Resemble bacteria in size, form, and biochemistry
- 29. Have their own DNA, which is similar to bacterial DNA
30. Divide independently of the cell, and have their own ribosomes 31.
- Chloroplasts and Other Plastids
- plastid
-
- An organelle that functions in photosynthesis or storage,e.g.chloroplast, amyloplast
- chloroplast
-
- Organelle of photosynthesis in the cells of plants and many protists
32.
- Chloroplast Structure
- Two outer membranes enclose a semifluid interior (stroma) that contains enzymes and chloroplast DNA
33. In the stroma, a highly folded stack of membrane (grana/granum ) forms a single, continuous compartment 34. Photosynthesis takes place at the thylakoid membrane, which incorporates pigments such as chlorophylls, which are green 35.
- Photosynthesis
- Chlorophylls and other molecules in the thylakoid membrane use the energy in sunlight to synthesize ATP
36. ATP is used in the stroma to build carbohydrates from carbon dioxide and water 37.
- Chloroplasts
- Fig. 4.18a, p. 65
- ChloroplastSpecializes in photosynthesis
38.
- Fig. 4.18b, p. 65
- Mitochondrion
- ChloroplastSpecializes in photosynthesis
- Plant Cell
39.
- Chloroplast Structure
40.
- Fig. 4.18c, p. 65
- thylakoids(inner membrane system folded into flattened disks)
- two outer membranes
- stroma
41.
- Other Plastids
- Chromoplasts are plastids that make and store pigments other than chlorophylls
-
- Red, orange, and yellow pigments color many flowers, leaves, fruits, and roots
- Amyloplasts store starch grains
-
- Abundant in starch-storing cells of stems, tubers (underground stems), and seeds
42.
- 4.10 The Dynamic Cytoskeleton
- Acytoskeleton includesmicrotubules ,microfilaments , andintermediate filaments
- cytoskeleton
-
- Dynamic framework of protein filaments that support, organize, and move eukaryotic cells and their internal structures
43.
- Key Terms
- microtubule
-
- Cytoskeletal element involved in cellular movement; hollow filament of tubulin subunits
- microfilament
-
- Reinforcing cytoskeletal element; a fiber of actin subunits
- intermediate filament
-
- Cytoskeletal element that locks cells and tissues together
44.
- Microtubules
- Microtubules assemble, separate the cells duplicated chromosomes, then disassemble
45.
- Examples of Microtubules
- Microtubules (yellow) support and guide the growing ends of young nerve cells
46.
- Examples of Microfilaments
- Myosin and actin microfilaments interact in contraction of muscle cells
- cell cortex
-
- Reinforcing mesh of microfilaments under a plasma membrane
47.
- Examples of Intermediate Filaments
- The nuclear envelope is supported by an inner layer of intermediate filaments called lamins
48. Intermediate filaments connect to structures that lock cell membranes together in tissues 49.
- Fig. 4.19b, p. 66
- Microfilament
- Microtubule
- Intermediate filament
- one polypeptide chain
- actin subunit
- tubulin subunit
50.
- Animation: Cytoskeletal Components
51.
- Accessory Molecules
- Motor proteinsmove cell parts when energized by a phosphate-group transfer from ATP
- motor protein
-
- Energy-using protein that interacts with cytoskeletal elements to move the cells parts or the whole cell
52.
- Motor Proteins
- Kinesin ( tan)drags a pink vesicle along a microtubule
53.
- Animation: Motor Proteins
54.
- Motor Proteins
- Dynein interacts with arrays of microtubules to bring about movement of eukaryotic flagella and cilia
55.
- Flagella and Cilia
- A 9+2 array of microtubules extends lengthwise through a flagellum orcilium
56. The microtubules grow from a barrel-shapedcentriole , which remains below the finished array as abasal body 57.
- Key Terms
- cilium
-
- Short, movable structure that projects from the plasma membrane of some eukaryotic cells
- centriole
-
- Barrel-shaped organelle from which microtubules grow
- basal body
-
- Organelle that develops from a centriole
58.
- Flagella and Cilia
- 9+2 array: a ring of nine pairs of microtubules plus one pair at its core
59.
- Fig. 4.22a, p. 67
- pair of microtubules in a central sheath
- pair of microtubules
- dynein arms
- plasma membrane
- protein spokes
- ASketch and micrograph of one eukaryotic flagellum, cross-section. Like a cilium, it contains a 9+2 array: a ring of nine pairs of microtubules plus one pair at its core. Stabilizing spokes and linking elements that connect to the microtubules keep them aligned in this radial pattern.
60.
- Fig. 4.22b, p. 67
- BProjecting from each pair of microtubules in the outer ring are arms of dynein, a motor protein that has ATPase activity. Phosphate-group
- transfers from ATP cause the dynein arms to repeatedly bind the adjacent pair of microtubules, bend, and then disengage. The dynein arms walk along the microtubules. Their motion causes adjacent microtubule pairs to slide past one another
- CShort, sliding strokes occur in a coordinated sequence around the ring, down the length of each microtubule
- pair. The flagellum bends as the array inside bends:
- basal body, a microtubule organizing center that gives rise to the 9+2 array and then remains beneath it, inside the cytoplasm
- Flagellaand Cilia
61.
- Animation: Flagella Structure
62.
- False Feet
- Pseudopods move the cell and engulf prey
63. Motor proteins attached to microfilaments drag the plasma membrane 64.
- 4.11 Cell Surface Specializations
- Most cells of multicelled organisms are surrounded by a complex mixture of fibrous proteins and polysaccharides calledextracellular matrix,orECM
- extracellular matrix (ECM)
-
- Complex mixture of cell secretions
- 65. Supports cells and tissues
66. Has roles in cell signaling 67.
- ECM: Cuticle
- cuticle
-
- Secreted covering at a body surface
- 68. Chitin covering protects arthropods
69. Waxy coat protects plants exposed surfaces 70.
- Fig. 4.23, p. 68
- photosynthetic cell inside leaf
- thick, waxy cuticle atleaf surface
- cell of leaf epidermis
71.
- Animal ECM
- ECM in animals consists of various carbohydrates and proteins; it is the basis of tissue organization, and provides structural support
72. Example:Bone is mostly extracellular matrix composed of collagen, a fibrous protein, hardened by mineral deposits 73.
- Plant ECM
- Plant cell wall is a type of ECM:Pliableprimary wallsenclosesecondary wallsstrengthened withlignin
- primary wall
-
- The first cell wall of young plant cells
- secondary wall
-
- Lignin-reinforced wall inside the primary wall of a plant cell
- lignin
-
- Material that stiffens cell walls of vascular plants
74.
- Fig. 4.24a, p. 68
- APlant cell secretions form the middle lamella, a layer that cements adjoining cells together.
- BIn many plant tissues, cells also secrete materials that are deposited in layers on the inner surface of their primary wall. These layers strengthen the wall and maintain its shape. They remain after the cells die, and become part of pipelines that carry water through the plant.
- primary cell wall
- cytoplasm
- pipeline made of abutting cell walls
- primary cell wall
- secondary cell wall (added in layers)
- middle lamella
- plasma membrane
- PlantCell Walls
75.
- Animation: Plant Cell Walls
76.
- Plant Cell Junctions
- In plants, open channels calledplasmodesmata (plasmodesma)extend across cell walls, connecting the cytoplasm of adjoining cells
- plasmodesmata
-
- Cell junctions that connect the cytoplasm of adjacent plant cells
- 77. Allowwater, nutrients, and signaling molecules to flow quickly from cell to cell
78.
- Fig. 4.24c, p. 68
- middle lamella
- CPlasmodesmata are channels across the cell walls and the plasma membranes of living cells that are pressed against one another in tissues.
- middle lamella
- plasmodesma
- Plasmodesmata
79.
- Cell Junctions in Animals
- In animal tissues, cells are connected to their neighbors and to ECM bycell junctions
- cell junction
-
- Structure that connects a cell to another cell or to extracellular matrix
- 80. Cells send and receive ions, molecules, or signals through some junctions
81. Other kinds help cells recognize and stick to each other and to extracellular matrix 82.
- Types of Cell Junctions
- tight junctions
-
- Arrays of fibrous proteins; join epithelial cells and collectively prevent fluids from leaking between them
- adhering junction
-
- Cell junction that anchors cells to each other or to extracellular matrix
- gap junction
-
- Cell junction that forms a channel across the plasma membranes of adjoining animal cells
83.
- Fig. 4.25, p. 69
- adhering junction
- gap junction
- tight junctions
- free surface of epithelial tissue
- basement membrane (extracellular matrix)
- Types of Cell Junctions
84.
- Animation: Animal Cell Junctions
85.
- 4.12 Summary: Plant Cells
86.
- 4.12 Summary: Plant Cells
87.
- Fig. 4.26a, p. 70
- Energy powerhouse; produces many ATP by aerobic respiration
- Lysosome-like Vesicle Digests, recycles materials
- Golgi BodyFinishes, sorts, ships lipids, enzymes, and proteins
- Smooth ERMakes lipids, breaks down carbohydrates and fats, inactivates toxins
- Rough ERModifies proteins made by ribosomes attached to it
- Ribosomes(attached to rough ER and free in cytoplasm) Sites of protein synthesis
- NucleusKeeps DNA separated from cytoplasm; makes ribosome subunits; controls access to DNA
- nuclear envelope
- Central VacuoleIncreases cell surface area; stores metabolic wastes
- ATypical plant cell components
- Cell WallProtects, structurally supports cell
- Chloroplast Specializes in photosynthesis
- Plasma Membrane Selectively controls the kinds and amounts of substances moving into and out of cell; helps maintain cytoplasmic volume, composition
- microtubules
- microfilaments
- intermediate filaments(not shown)
- Plasmodesma Communication junction between adjoining cells
- CytoskeletonStructurally supports, imparts shape to cell; moves cell and its components
- Mitochondrion
- DNA in nucleoplasm
- nucleolus
88.
- Animation: Common Eukaryotic Organelles
89.
- Summary: Animal Cells
90.
- Fig. 4.26b, p. 70
- BTypical animal cell components.
- Plasma MembraneSelectively controls the kinds and amounts of substances moving into and out of cell; helps maintain cytoplasmic volume, composition
- microtubules
- CytoskeletonStructurally supports, imparts shape to cell; moves cell and its components
- Energy powerhouse; produces many ATP by aerobic respiration
- Mitochondrion
- Special centers that produce and organize microtubules
- Centrioles
- Golgi BodyFinishes, sorts, ships lipids, enzymes, and proteins
- Smooth ERMakes lipids, breaks down carbohydrates and fats, inactivates toxins
- Rough ERModifies proteins made by ribosomes attached to it
- Ribosomes(attached to rough ER and free in cytoplasm) Sites of protein synthesis
- Lysosome Digests, recycles materials
- NucleusKeeps DNA separated from cytoplasm; makes ribosome subunits; controls access to DNA
- nuclear envelope
- DNA in nucleoplasm
- nucleolus
- Intermediate filaments
- microfilaments
91.
- Summary: Cell Components
92.
- Key Concepts
- Eukaryotic Cells
-
- Cells of protists, plants, fungi, and animals are eukaryotic
- 93. They have a nucleus and other membrane-enclosed compartments
94. Cells differ in internal parts and surface specializations 95.
- 4.13 The Nature of Life
- Life is a property that emerges from cellular components, but a collection of those components in the right amounts and proportions is not necessarily alive
96. Characteristics of life:
-
- A set of properties unique to living things
- 97. Collectively, these properties characterize living things as different from nonliving things
98.
- Characteristics of Living Things
- They make and use organic molecules of life
99. They consist of one or more cells 100. They engage in self-sustaining biological processes such as metabolism and homeostasis 101. They change over their lifetime by growing, maturing, and aging 102. They use DNA as hereditary material 103. They have the collective capacity to change over successive generations by adapting to environmental pressures 104.
- Food for Thought (revisited)
- Meat, poultry, milk, and fruits sterilized by exposure to radiation are available in supermarkets
105. By law, irradiated foods must be marked with a special symbol:
- Foodssterilized with chemicals are not currently required to carry any disclosure