the tour of the cell
DESCRIPTION
The Tour of the Cell. Chapter 6. The Fundamental Units of Life. All living things composed of cells Cell structure correlated to cell function All cells descend from existing cells. Microscopy. Light microscope = visible light through specimen magnified by lenses Up to 1000X. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/1.jpg)
The Tour of the Cell
Chapter 6
![Page 2: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/2.jpg)
The Fundamental Units of Life
• All living things composed of cells• Cell structure correlated to cell function• All cells descend from existing cells
![Page 3: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/3.jpg)
Microscopy
• Light microscope = visible light through specimen magnified by lenses– Up to 1000X
![Page 4: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/4.jpg)
• Electron microscopes (EMs)
• Scanning EM (SEM) focus beam of electrons onto surface 3-D image
• Transmission EM (TEM) • focus beam of electrons through specimen • internal structures
![Page 5: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/5.jpg)
• Gills of fish yeast
• HIV
![Page 6: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/6.jpg)
![Page 7: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/7.jpg)
Cell Fractionation
centrifugeseparates cell
components
![Page 8: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/8.jpg)
Homogenization
Homogenate
Differential centrifugation
Tissuecells
TECHNIQUE
![Page 9: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/9.jpg)
Supernatant poured into next tube
TECHNIQUE (cont.)
Homogenate
Pellet
Supernatant
1000 g 10 min
20,000g 20 min
80,000g 60 min
150,000g 3 hr
Nuclei, debris mitochondria membranes ribosomes
![Page 10: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/10.jpg)
• Prokaryotic cells= Archaea and Bacteria• No nucleus, no membrane-bounded organelles• DNA in nucleoid region
0.5 µm
![Page 11: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/11.jpg)
Eukaryotic cells = Plants, Animals, Fungi, Protista•DNA in nucleus•Organelles•Membrane bounded
•Cytoplasm = fluid + organelles•Cytosol = fluid
![Page 12: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/12.jpg)
Featured scientist: Robert Hooke 1635-1703
![Page 13: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/13.jpg)
Best CLM of its time!Micrographia was a best seller
![Page 14: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/14.jpg)
The famous slide:
. . . I could exceedingly plainly perceive it to be all perforated and porous, much like a Honey-comb, but that the pores of it were not regular. . . . these pores, or cells, . . . were indeed the first microscopical pores I ever saw, and perhaps, that were ever seen, for I had not met with any Writer or Person, that had made any mention of them before this. . .
![Page 15: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/15.jpg)
1. The plasma membrane = selective barrier allows passage of oxygen, nutrients, waste etc
• Composed of phospholipid bilayer
Features of cells
![Page 16: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/16.jpg)
2. Surface to Volume ratio high
•Small cells have greater surface area relative to volume
•Larger organisms do not have larger cells than smaller organisms
Human Rat
![Page 17: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/17.jpg)
![Page 18: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/18.jpg)
![Page 19: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/19.jpg)
The Eukaryotic Cell
![Page 20: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/20.jpg)
![Page 21: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/21.jpg)
1. The Nucleus
Hela cells
![Page 22: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/22.jpg)
A. Nuclear envelope (NE)
–Double membrane; each a bilayer–Pores regulate entry and exit of molecules
from nucleus
![Page 23: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/23.jpg)
![Page 24: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/24.jpg)
Nuclear lamina fibrous proteins maintain shape of nucleus
Lamin A and lamin B can bind histones – may have role in chromosome organization
![Page 25: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/25.jpg)
B. Chromatin = DNA + proteins
•Chromosomes = strands of chromatin
![Page 26: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/26.jpg)
C. Nucleolus –Assembles ribosomes
![Page 27: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/27.jpg)
• D. Nucleoplasm– Viscous fluid of nucleus
![Page 28: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/28.jpg)
2. Ribosomes: Protein Factories
• Assemble amino acids into polypeptides– cytosol (free ribosomes)– RER/NE (bound ribosomes)
![Page 29: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/29.jpg)
3. The Endomembrane System
• Components– Nuclear envelope– Endoplasmic reticulum (ER)– Golgi apparatus– Lysosomes– Vacuoles– *Plasma membrane
![Page 30: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/30.jpg)
A. The Endoplasmic Reticulum
• >half of total membrane• continuous with nuclear envelope– Smooth ER – lacks ribosomes
1.Synthesizes lipids2.Metabolizes carbohydrates3.Detoxifies poison4.Stores calcium
![Page 31: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/31.jpg)
• Rough ER (RER)
– Ribosomes assemble proteins thread through ER lumen transport vesicles
– Membrane factory
![Page 32: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/32.jpg)
![Page 33: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/33.jpg)
B. The Golgi Apparatus
• flattened membranous sacs called cisternae• cis and trans face
trans face(“shipping” side of Golgi apparatus)
![Page 34: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/34.jpg)
• Functions of the Golgi apparatus:– Modifies proteins from ER– Sorts and packages protein into transport vesicles
Golgi makes polysaccharides in plants
![Page 35: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/35.jpg)
Smooth ER
Nucleus
Rough ER
Plasma membrane
cis Golgi
trans Golgi
Where do the vesicles go?
![Page 36: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/36.jpg)
• Virtual cell
Note: Ribosome, RER, vesicle, Golgi
![Page 37: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/37.jpg)
C. Lysosomes
• membranous sac of enzymes that digest macromolecules
• What do they do?recycle cell components (autophagy)get rid of phagocytosed invadersform food vacuoles
How do they work?
![Page 38: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/38.jpg)
phagocytosis A cell engulfs another cell to form a food vacuole– lysosome fuses with food vacuole and digests
molecules
![Page 39: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/39.jpg)
D. Vacuoles– Food vacuoles formed by phagocytosis– Contractile vacuoles
• freshwater protists• store or/and pump excess water out of cells
![Page 40: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/40.jpg)
– Central vacuoles• found in many plant cells• hold organic compounds and water
![Page 41: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/41.jpg)
4. Mitochondria
• cellular respiration generates ATP (energy)• contain mtDNA• all eukaryotic cells have mt– Some have 1, some 1000sOuter
membrane
Cristae
![Page 42: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/42.jpg)
mitochondrion
![Page 43: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/43.jpg)
Mitochondria
• outer membrane and inner membrane fold into cristae– large surface area for enzymes that synthesize ATP
![Page 44: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/44.jpg)
5. Chloroplasts (plastid)• found in plants and algae• sites of photosynthesis– green pigment chlorophyll, enzymes, other
molecules
![Page 45: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/45.jpg)
6. Peroxisomes
• detoxify
catalase2 H2O2 2H2O + O2
(toxic)
![Page 46: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/46.jpg)
• Bioflix Tour of animal cell – the big picture• Note:– Sticky extracellular matrix– Plasma membrane– Cytoskeleton – Mitochondria- ATP, surface area– Nucleus and nuclear envelope with pores– DNA and protein wrappings, code for protein– Ribosome builds protein– Endomembrane system = RER and SER + Golgi
![Page 47: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/47.jpg)
7. Cytoskeleton
• Network of protein fibers organize structures and activities in cell
• Anchors organelles• Maintains cell shape
![Page 48: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/48.jpg)
Cytoskeleton
• interacts with motor proteins to transport cargo or for movement
![Page 49: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/49.jpg)
![Page 50: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/50.jpg)
10 µm
Column of tubulin dimers
Tubulin dimer
25 nm
![Page 51: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/51.jpg)
Actin subunit
10 µm
7 nm
![Page 52: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/52.jpg)
5 µm
Keratin proteinsFibrous subunit
(keratinscoiled together)
8–12 nm
![Page 53: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/53.jpg)
• Vesicles in a plant cell• Golgi sorting and packaging
![Page 54: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/54.jpg)
8. Centrosomes and Centrioles
• Centrosome– microtubule-
organizing center
Centrosome
Microtubule
Centrioles0.25 µm
Longitudinal section of one centriole
Cross sectionof the other centriole
![Page 55: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/55.jpg)
– centrioles • animal cells only• centrosome has pair • each with 9 triplets of microtubules arranged in a ring
centrosome
![Page 56: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/56.jpg)
9. Cilia and Flagella
• Locomotor appendages of some cells
• Movement pattern controlled by microtubules
• Example: paramecium, algae
![Page 57: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/57.jpg)
10. Extracellular materials
• Cells secrete materials external to plasma membrane
![Page 58: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/58.jpg)
• Harvard life of a cell – 3 min.• Can you find –
– Cell membrane– Cytoskeleton– Microtubule polymerization and depolymerization– A motor protein walking along the cytoskeleton– Lysosomes and mt– A centriole– Nuclear pores with mRNA leaving nucleus– RER– Ribosomes making proteins– Vesicles budding with cis face of Golgi– Proteins leaving the cell
![Page 59: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/59.jpg)
A. Cell Walls of PlantsAlso, prokaryotes, fungi, some protists
• protects, maintains shape, prevents excessive uptake of water
• cellulose fibers + polysaccharides and protein
![Page 60: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/60.jpg)
• Layers of cell wall
– Primary wall: thin – Middle lamella: between primary walls of adjacent
cells– Secondary wall (some cells): between plasma
membrane and primary cell wall
![Page 61: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/61.jpg)
• Plasmodesmata -channels between adjacent plant cells for water, nutrients…..
![Page 62: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/62.jpg)
B. Extracellular Matrix (ECM) of Animal Cells
• No cell walls • Functions :
Support, Adhesion, Movement, Regulation
• Structure– Glycoproteins: bind to receptor proteins in membrane
called integrins• Integrins “glue cytoskeleton to ECM
![Page 63: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/63.jpg)
Collagen
Fibronectin
Plasma membrane
Proteoglycan complex
Integrins
CYTOPLASM
Micro-filaments
EXTRACELLULAR FLUID
![Page 64: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/64.jpg)
Collagen in the ECM Collagen, fibronectin and laminin of cartilage
![Page 65: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/65.jpg)
C. Intercellular Junctions
• Function – Adherance, communication through direct physical contact
• 4 Types:– Plasmodesmata- plant cells– Tight junctions– Desmosomes– Gap junctions
![Page 66: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/66.jpg)
• Tight junction seals against fluid and ions
![Page 67: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/67.jpg)
• Desmosome in cells that experiencemechanical stress (skin)
![Page 68: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/68.jpg)
• Gap junction connects cytoplasm to allow small molecules, ions to pass from cell to cell – connexin protein
![Page 69: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/69.jpg)
Tight junction
0.5 µm
1 µm
Desmosome
Gap junction
Extracellularmatrix 0.1
µm
Plasma membranesof adjacent cellsSpacebetweencells
Gapjunctions
Desmosome
Tight junction
![Page 70: The Tour of the Cell](https://reader035.vdocuments.us/reader035/viewer/2022062501/56815da9550346895dcbda41/html5/thumbnails/70.jpg)
The Cell: Living Unit Greater Than Sum of Its Parts
• integration of structures and organelles to function
• example, a macrophage’s ability to destroy bacteria involves coordinating cytoskeleton, lysosomes, and plasma membrane
5 µ m