![Page 1: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/1.jpg)
Chapter 3
How Cells Are Put Together
![Page 2: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/2.jpg)
The Plasma Membrane
• “Sheet” of molecules that encases all living cells• Fluid mosaic model
– A model for the plasma membrane– The PM is composed of proteins, lipids and
carbohydrates all of which are embedded in the phosholipid bilayer and may be exposed to the cell exterior/interior
– The PM is fluid; lipids that make up the plasma membrane can move laterally
![Page 3: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/3.jpg)
Phospholipid
![Page 4: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/4.jpg)
Phospholipid Bilayer
![Page 5: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/5.jpg)
Proteins Embedded in Lipid Bilayer
![Page 6: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/6.jpg)
Fig. 4.7Nonpolar regions of the lipid bilayer lock proteins into membranes
![Page 7: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/7.jpg)
Eukaryotic Cell
![Page 8: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/8.jpg)
Plant Cell
![Page 9: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/9.jpg)
The Nucleus
• Spherical structure ensheathed in the nuclear envelope (a double-layered membrane)
• Fx = Command center of the cell!!– 1. Directs protein synthesis– 2. Directs cell reproduction– 3. Stores genetic information (DNA)– 4. Site where DNA is converted to RNA
![Page 10: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/10.jpg)
Nuclear Envelope
• Membrane that surrounds the nucleus
• Contains “openings” through which RNA (once it’s converted from DNA) exits
![Page 11: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/11.jpg)
The NucleusAnimal
Plant
![Page 12: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/12.jpg)
The Endomembrane System
• Route through which material is passed within the cell
• Main components include:– Nuclear envelope– Endoplasmic Reticulum– Golgi Complex– Vesicles– Cell membrane
![Page 13: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/13.jpg)
Endoplasmic Reticulum• An extensive system of internal membranes that form channels and
interconnections; also vesicles• ER surface: cell makes proteins to be exported here• 2 types: Rough ER Smooth ER
•Heavily studded with ribosomes
•Fx = sites of protein synthesis
•RNA is converted to a polypeptide chain
•Surface ribosomes are scarce
•Rather, surface is embedded w/ enzymes that aid in manufacturing carbs and lipids
![Page 14: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/14.jpg)
Endoplasmic ReticulumAnimal
Plant
![Page 15: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/15.jpg)
Golgi Complex
• Sacs of flattened vesicles (“pancake-like”)
• Receives polypeptide chain from ER where it is modified (i.e. carb addition) and packaged into secretory vesicles
• Fx = packages protein for export from the cell
![Page 16: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/16.jpg)
Golgi ComplexAnimal
Plant
![Page 17: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/17.jpg)
Lysosomes
• Spherical organelles that arise from Golgi
• Contain digestive enzymes that break down macromolecules
• “Recycling centers” of the cell: they digest intracellular matter
![Page 18: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/18.jpg)
Fig. 4.15The Endomembrane System
![Page 19: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/19.jpg)
Additional Organelles
• Mitochondria
• Chloroplasts
![Page 20: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/20.jpg)
Mitochondria
• Rod-shaped organelles that derived from a bacterium that invaded a host cell
• The powerhouse of the cell!• Only organelle other than the nucleus to house DNA
– Mitochondrial DNA (mtDNA) has unique genes in their DNA that are lacking in nuclear DNA
• Place where oxidative phosphorylation occurs– Energy (ATP) is extracted from food through a series of
chemical reactions
• Two-membrane structure: – Outer– Inner: forms folds (cristae) which encompass the matrix
![Page 21: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/21.jpg)
Mitochondria
Animal
Plant
![Page 22: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/22.jpg)
Chloroplast
• Unique to plants• Organelle in which photosynthesis occurs• Plant cells can contain one to several hundred• Two-membrane structure (outer and inner
membranes)• Larger size than mitochondria and more
complex inner membrane organization – Thylakoids: fused inner membranes that form stacks
in which photosynthesis occurs
![Page 23: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/23.jpg)
Chloroplast
Plant
![Page 24: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/24.jpg)
The Cytoskeleton
• Dense fiber structure• Fx: 1. Provide support to cellular structure
2. Anchors organelles to fixed locations• Composed of dynamic protein fibers that are embedded
to membrane proteins embedded in the PM– Microfilaments– Microtubules– Intermediate Filaments
![Page 25: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/25.jpg)
Cytoskeletal Proteins
![Page 26: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/26.jpg)
The Cytoskeleton, continued
Microfilaments• Fine, thread-like protein fibers• Composed of the contractile
protein actin, the most abundant cellular protein!!!
• Prevent excessive stretching of cells
• Form and dissolve readily ≡ major role in determining cell shape
• Roles in cellular movement include gliding and contraction (when in combination with myosin) http://www.biology.arizona.edu/cell_bio/tutorials/cytoskeleton/page1.html
![Page 27: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/27.jpg)
The Cytoskeleton, continued
Microtubules• Composed of tubulin protein• Assembled by centrioles
– Located near the nuclear envelope in the cytoplasm at right angles to each other
• “Conveyor belts” of the cell• They move vesicles and
organelles (i.e. mitochondria) as well as chromosomes
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/M/Microtubule.gif
![Page 28: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/28.jpg)
Centrioles
![Page 29: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/29.jpg)
The Cytoskeleton, continued
Intermediate Filaments• Filamentous fibers• ‘Intermediate’ in size • Ubiquitous throughout the body• Bundles of IFs are found in
characteristic ‘plaques’ that form in AD in brain
• Includes keratin
http://www.cytoskeleton.com/aif.htm
![Page 30: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/30.jpg)
Fig. 4.23
Central
Vacuole
Plant
![Page 31: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/31.jpg)
Central Vacuole
• Storage center
• Contains large amounts of water, ions, sugars and pigments
• Increases surface-to-volume ratio outside the vacuole – Applies pressure to plasma membrane– Plasma membrane expands → ↑ surface area
• ↑ surface area → MORE EFFICIENCY!!
![Page 32: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/32.jpg)
Is there anything outside the plasma membrane??
![Page 33: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/33.jpg)
Cell WallPlants
![Page 34: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/34.jpg)
Cell Wall
• Present in plants and fungi – NOT ANIMAL CELLS• Composed of cellulose (polysaccharide)• Primary walls are laid while plant is growing • Individual cells are held together by the middle lamella• Secondary walls are present in some plants
– Inside the Primary walls of fully expanded, grown cells• Located OUTSIDE the plasma membrane• Fx: maintain cell shape
protectionprevents excessive water uptake
![Page 35: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/35.jpg)
Fig. 4.25
Extracellular Matrix
Animal cell
![Page 36: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/36.jpg)
Extracellular Matrix
• Present in ANIMAL cells• Mixture of glycoproteins, collagen, elastin, proteoglycans• Fx: serves as a protective layer for the cell
helps coordinate cell behavior• Attached to the plasma membrane by fibronectin
– Glycoprotein – Bind to integrins in the plasma membrane
![Page 37: Chapter 3 How Cells Are Put Together. The Plasma Membrane “Sheet” of molecules that encases all living cells Fluid mosaic model –A model for the plasma](https://reader035.vdocument.in/reader035/viewer/2022062716/56649dd05503460f94ac5357/html5/thumbnails/37.jpg)
Everyday Science
• Forensic Science uses mitochondrial DNA testing• mtDNA is maternally inherited• Why use mtDNA vs. nuclear DNA?
– mtDNA is more abundant – in every mitochondria in the cell
– nuclear DNA may degrade more easily as there is only one copy
• What is the drawback of mtDNA testing?• Relatives from the same mother can’t be excluded