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Unit A: Cells

0. Unit A: Cells. A Tour of the Cell. By the end of this unit you should be able to: Recognize and explain the function of each organelle Look at micrographs/diagrams/pictures and correctly ID each organelle Write/work with/explain the balanced chemical equation for cellular respiration

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Unit A: Cells

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  1. 0 Unit A: Cells A Tour of the Cell

  2. By the end of this unit you should be able to: • Recognize and explain the function of each organelle • Look at micrographs/diagrams/pictures and correctly ID each organelle • Write/work with/explain the balanced chemical equation for cellular respiration • Relate the role of an organelle to a specific part of the body • Explain how the endomembrane system functions to compartmentalize the cell and move materials through it Standards

  3. Big Picture – in case you did not know!!! Life = Cells Cells=prokaryotic (bacteria) OR eukaryotic (all other) How do you recognize???? Cell Intro

  4. Cells EVERYWHERE!!! Staphylococcus aureus Human Red Blood Cells Escherichia coli Apoptosis in a Leukemia Cell – Cell Suicide

  5. How big is a cell???? • How many cells in your body??? • 50 million million (50 trillion) cells – stretched end to end they would stretch around the Earth 47 times – if you could count one cell per second it would take you 2600 years !!! • Inner Life of Cell Cells Everywhere!!!

  6. What cells can you see??? Hummingbird Egg – 0.02 ounces Beluga sturgeon Eggs - $700 per ounce Human Egg – Thousands of dollars per egg -25G’s

  7. 10 m Human height 1 m Length of somenerve andmuscle cells 100 mm(10 cm) Unaided eye Chicken egg 10 mm(1 cm) Frog egg 1 mm 100 m Light microscope Most plant andanimal cells 10 m Nucleus Most bacteria Mitochondrion 1 m Mycoplasmas(smallest bacteria) 100 nm Electron microscope Viruses Ribosome 10 nm Proteins Lipids 1 nm Small molecules Atoms 0.1 nm • Cells vary in size and shape • Most cells are microscopic What cells can you see???

  8. 10 m 30 m 30 m 10 m Surface areaof one large cube 5,400m2 Total surface areaof 27 small cubes 16,200m2 • The microscopic size of most cells ensures a sufficient sur face area • Across which nutrients and wastes can move to service the cell volume • A small cell has a greater ratio of sur face area to volume than a large cell of the same shape Surface area to volume ratio

  9. Prokaryotic cell Nucleoidregion Colorized TEM 15,000  Nucleus Eukaryotic cell Organelles Recall: there are two kinds of cells • Prokaryotic and eukaryotic, which is which and how do you know? Prokaryotic cells are structurally simpler than eukaryotic cells A. B.

  10. Prokaryoticflagella Ribosomes Capsule Cell wall Plasmamembrane Nucleoid region (DNA) Pili • Prokaryotic cells are small, relatively simple cells • That do not have a membrane-bound nucleus • You should recall all the “bits” from Gr 11 microbiology (bacteria) Prokaryotic Cells

  11. Eukaryotic cells are partitioned into functional compartments (organelles) • All other forms of life (anything not bacteria) are composed of more complex eukaryotic cells • Distinguished by the presence of a true nucleus • Membranes form the boundaries of and within many eukaryotic cells • Compartmentalizing the interior of the cell into organelles and facilitating a variety of metabolic activities Eukaryotic Cells

  12. Smooth endoplasmicreticulum Nucleus Roughendoplasmicreticulum Flagellum Not in mostplant cells Lysosome Ribosomes Centriole Golgiapparatus Peroxisome Microtubule Plasma membrane Intermediatefilament Cytoskeleton Mitochondrion Microfilament • There are two types of Eukaryotic cells: animal and plant • A typical animal cell contains a variety of membranous organelles Types of Eukaryotic Cells

  13. Roughendoplasmicreticulum Nucleus Ribosomes Smoothendoplasmicreticulum Golgiapparatus Microtubule Centralvacuole Intermediatefilament Cytoskeleton Not inanimalcells Microfilament Chloroplast Cell wall Mitochondrion Peroxisome Plasma membrane • A typical plant cell has some structures that an animal cell lacks • Such as chloroplasts, a rigid cell wall and a central vacuole Types of Eukaryotic Cells

  14. Plant Cell Animal Cell Centrioles Plant and Animal Differences:The 4 C’s! Cell wall Chloroplasts Central Vacuole

  15. All other organelles found here • Defined by cell membrane & envelope • Cytoskeleton – maintains cell’s shape Cytoplasm

  16. Nucleus Chromatin Two membranesof nuclearenvelope Nucleolus Pore Roughendoplasmicreticulum Ribosomes • The nucleus is the cell’s genetic control center • Its the largest organelle which is separated from the cytoplasm by the nuclear envelope • The nucleus is the cellular control center • It contains the cell’s DNA, which directs cellular activities The Nucleus

  17. i) Nuclear Envelope – 2 membranes with pores ii) Chromatin – thread like Becomes chromosomes* (condensed) during cell division *Contains genetic material (DNA): Meaningful parts = genes Made of - DNA & proteins iii) Nucleolus – dark center Makes rRNA (ribosomal RNA) NuclearStructure

  18. Many cell organelles are connected through the endomembrane system • a collection of membranous organelles that manufactures and distributes cell products • Nucleus, RER, SER, Golgi, Vesicles, Vacuoles Endomembrane System

  19. Smooth ER Rough ER Nuclearenvelope Ribosomes Rough ER Smooth ER TEM 45,000 • Smooth endoplasmic reticulum (SER) has a variety of functions • Synthesizes lipids • Processes toxins and drugs in liver cells • Stores and releases calcium ions in muscle cells SER

  20. Rough endoplasmic reticulum (RER) makes membrane and proteins • Ribosomes on the surface of the RER • Produce proteins that are secreted, inserted into RER membranes, or transported in vesicles to other organelles • 4 stages of protein synthesis??? RER And Ribosomes

  21. ER – interconnected membrane, tubular canals,begin at nuclear envelope RER • Studded with ribosomes • Synthesize proteins for export (use outside of the cell) • Ex - insulin SER • NO ribosomes • Synthesize lipids • (ex. Male testes – make testosterone – a lipid steroid – so lots of SER) • Help liver in detox. process ER Comparison

  22. Free Floating • Make proteins for cell use (internal) Embedded in RER • Make proteins for export out of cell (external) 2 Types of Ribosomes

  23. Golgi apparatus “Receiving” side ofGolgi apparatus Golgiapparatus Transportvesiclefrom ER TEM 130,000 New vesicleforming Transportvesicle fromthe Golgi “Shipping” sideof Golgi apparatus The Golgi apparatus finishes, sorts, and ships cell products • Stacks of membranous sacs receive and modify ER products then ships them to other organelles or the cell surface Golgi Apparatus

  24. Rough ER 1 Transport vesicle(containing inactivehydrolytic enzymes) Golgiapparatus Plasmamembrane Lysosomeengulfingdamagedorganelle 2 Engulfmentof particle Lysosomes 3 5 4 Foodvacuole Digestion Lysosomes are digestive compartments within a cell • Sacs of hydrolytic enzymes that function in hydrolysis (digestion) within a cell • Double membrane bound and made by GA • Function in autodigestion EX: tadpole tail, finger webbing Lysosomes “Food” lysosomes clip

  25. Lysosome containingtwo damaged organelles Lysosome Mitochondrion fragment TEM 42,500 Peroxisome fragment Nucleus TEM 8,500 • Lysosomes in white blood cells • Destroy bacteria that have been ingested • Lysosomes also recycle damaged organelles • Abnormal lysosomes can cause fatal diseases (Lysosomal storage diseases) which interfere with various cellular functions Lysosomes

  26. Nucleus Nucleus Chloroplast Centralvacuole Colorized TEM 8,700 Contractilevacuoles LM 650 • Vacuoles function in the general maintenance of the cell • Plant cells contain a large central vacuole which has lysosomal and storage functionsas well as support functions • Some protists have contractile vacuoles that pump out excess water Vacuoles

  27. Transport vesicle fromGolgi to plasma membrane Transport vesiclefrom ER to Golgi Rough ER Plasmamembrane Nucleus Vacuole Lysosome Nuclear envelope Smooth ER Golgi apparatus • The various organelles of the endomembrane system are interconnected structurally and functionally A review of the endomembrane system

  28. Chloroplast Stroma Inner and outermembranes TEM 9,750 Granum Intermembranespace • Chloroplasts convert solar energy to chemical energy • Chloroplasts, found in plants and some protists, convert solar energy to chemical energy in sugars (glucose) • Contains chlorophyll ENERGY-CONVERTING ORGANELLES

  29. Mitochondrion Outermembrane Intermembranespace Innermembrane TEM 44,880 Cristae Matrix • Mitochondria harvest chemical energy from food • Mitochondria carry out cellular respiration which uses the chemical energy in food (glucose) to make ATP for cellular work • OXYGEN + GLUCOSE ---- CARBON DIOXIDE + ATP + WATER • Double membrane bound, has own DNA ENERGY-CONVERTING ORGANELLES

  30. Tubulin subunit Actin subunit Fibrous subunits 25 nm 10 nm 7 nm Microtubule Microfilament Intermediate filament The cell’s internal skeleton helps organize its structure and activities • A network of protein fibers make up the cytoskeleton. • Microfilaments of actin • Enable cells to change shape and move • Intermediate filaments • Reinforce the cell and anchor certain organelles • Microtubules give the cell rigidity • And provide anchors for organelles and act as tracks for organelle movement Cytoskeleton

  31. Flagellum Electron micrographsof cross sections: Outer microtubuledoublet Centralmicrotubules TEM 206,500 Radial spoke Dynein arms Flagellum Plasmamembrane Colorized SEM 4,100 LM 600 TEM 206,500 Basal body(structurally identical to centriole) Basal body Figure 4.17A Figure 4.17B Cilia and flagella move when microtubules bend • Eukaryotic cilia and flagella are locomotor appendages that protrude from certain cells • Clusters of microtubules drive the whipping action of these organelles Cilia and Flagella Figure 4.17C

  32. Walls of two adjacent plant cells Vacuole Plasmodesmata Layers of one plant cell wall Cytoplasm Plasma membrane Cell surfaces protect, support, and join cells • Cells interact with their environments and each other via their surfaces. • Plant cells • Are supported by rigid cell walls made largely of cellulose • Connect by plasmodesmata, which are connecting channels CELL SURFACES AND JUNCTIONS

  33. Tight junctions Anchoring junction Gap junctions Extracellular matrix Space between cells Plasma membranes of adjacent cells Animal cells • Animal cells are embedded in an extracellular matrix which binds cells together in tissues • Tight junctions can bind cells together into leak-proof sheets • Anchoring junctions link animal cells into strong tissues • Gap junctions allow substances to flow from cell to cell CELL SURFACES AND JUNCTIONS

  34. Eukaryotic organelles comprise four functional categories • Eukar yotic organelles fall into four functional groups • Manufacturing • Breakdown • Energy processing • Suppor t, movement, and communication between cells FUNCTIONAL CATEGORIES OF ORGANELLES Table 4.19

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