Swamp Talk: Okefenokee Toastmasters Club Newsletter, October 2014
Cells The Smallest Unit of Life - Okefenokee...
Transcript of Cells The Smallest Unit of Life - Okefenokee...
CellsThe Smallest Unit of Life
Organization• All cells have DNA, ribosomes, a plasma
membrane, and cytoplasm
• Cells make up tissues, tissues make up organs, and organs make up organ systems
Can We See Cells Without A Microscope?
• They are not doing much metabolically
• They are mostly nutrient warehouses
Surface To Volume Ratio• Surface area is squared but volume is cubed
• Growing volume increases faster than surface area
• The cell has to be small enough to transport materials through the cell from the plasma
membrane
• If growth increases four times, then the volume increases 64 units, (4X4x4) ,but the surface area only increases 16 units, (4X4)
• The cell membrane would have to service 4X as much cytoplasm
• Cells Respond To Stimuli
• Receptor molecules detect stimuli and activate to trigger necessary changes
Cells Maintain Homeostasis
Cells Grow And Reproduce
Cells Pass On Their Traits
Prokaryotes• Archaebacteria and Eubacteria
• Most metabolically diverse forms of life on Earth
• They are alike in outward appearance and size
Prokaryotic Cell Structure• Prokaryotic cells DNA is located in the
nucleoid
• They have a circular chromosome and plasmids with only a few genes
Prokaryotic Cell Structure• Cell walls are permeable to dissolved substances crossing to and from the cell
membrane
• Many have a thick, jellylike capsule for attachment
Archaebacteria• Are adapted to extreme environments
• Are more closely related to Eukaryotic cells
• 2 main shapes: Coccus –, Bacillus – rod ( but can be triangular and square)
Methanogens• Anaerobic bacteria that helps break down
peat in the swamp and vegetation in cow’s intestines
• Produce methane with its distinctive odor
Halophiles
• Salt loving bacteria
Thermophiles• Heat loving bacteria
Eubacteria• 3 shapes : Cocci - round, Bacilli – rod,
Spirilla - spiral
Eubacteria
Eukaryotic Cells• All cells synthesize, store, break down, and transport diverse substances but Eukaryotic
cells compartmentalize those operations
Eukaryotic Cells• Have a nucleus and membrane bound
organelles
• Organelles interact to keep the cell functioning properly
Plasma Membrane• Plasma membrane encloses/sustains
microenvironment for cell activities
• Separates cell activities that might be incompatible
Plasma Membrane• Controls the types and amounts of
substances entering and leaving
• Phospholipid bilayer – polar heads and non polar tails with proteins attached and
embedded
• Fluid mosaic model
Cytoplasm• Semifluid substances between the plasma
membrane an nucleus
• Contains structural components for cell tasks
Nucleus• Double nuclear membrane with pores
• Outer membrane merges with ER and controls movement to and from the
cytoplasm
• Inner membrane has fibrous proteins that anchor the DNA and helps keep them organized and makes copying easier
Nucleus• The grainy substances are chromatin which
is a collection of DNA and proteins
• A chromosome is a double stranded DNA molecule and its associated proteins whether it is dispersed or condensed
Nucleolus• Dense proteins/ copies of genes coding for
rRNA
• 1 large and 1 small subunit join after they move out of the pores into the cytoplasm to
make an intact ribosome during protein synthesis
Ribosomes• Site of protein synthesis
Endoplasmic Reticulum• Demo – folding
• A flattened, folded channel where proteins are modified and lipids are assembled and
sent to and fuse with the Golgi Bodies/Apparatus
Endoplasmic Reticulum• Rough E.R. – contain fixed ribosomes and are
sites for translation
• Smooth E.R. - no ribosomes – makes lipid that become part of the cell membrane –takes part in fatty acid breakdown and
degrades some toxins
Golgi Bodies• Membrane channels fold back on themselves
like a stack of pancakes
• Removes some protein, adds sugars chains to proteins and lipids, packages them in vesicles
to be sent where needed
Lysosomes• Contain diverse enzymes that can digest
almost all biological molecules
• The enzymes are activated when they fuse with another vesicle and digest it
• It is how tadpole lose their tail
Mitochondrion• Site of Aerobic Respiration, produces ATP
• Double membrane, inner highly folded
• Has own DNA and can divide on their own
Chloroplasts
• Site of Photosynthesis
• A double membrane encloses a semifluid interior called the stroma
Chloroplasts• In the stroma, a 3rd membrane folds to resemble a stack of flattened disks called
grana(pl)
• Chlorophyll and other pigments are located in the thylakoid membrane
Central Vacuoles• Can take up to 50-90% of a plant cells
interior
• Fluid filled – stores A.A. ,sugars, ions, toxic waste
• Expands during growth
• Responsible for turgor pressure
Cell Wall• Physical protection and support for plants,
give plant cells shape
• Porous – allows water and solutes to move into and out of plasma membrane
Cytoskeleton
• System of protein filaments that extend between the nucleus and plasma membrane
• It reinforces, organizes, and transports materials throughout the cell
• High concentration to low concentration
• No energy required
Passive Transport
Active Transport• Going from a high concentration to a low
concentration…against the gradient
• Requires energy…ATP
• Acknowledgements• https://health.howstuffworks.com/medicine/modern-technology/can-use-microbes-to-
fight-disease.htm• https://www.google.com/url?sa=i&source=images&cd=&ved=2ahUKEwjF1LjZv9vcAhVK3FM
KHWupCvIQjxx6BAgBEAI&url=http%3A%2F%2Fwildlife.ohiodnr.gov%2Fspecies-and-habitats%2Fspecies-guide-index%2Famphibians%2Famerican-toad&psig=AOvVaw1Hh5N6vutQXBeGNhKyJ5sX&ust=1533750397743549
• http://www.assignmentpoint.com/science/biology/types-of-cells-in-human-body-and-functions.html
• http://phytophactor.fieldofscience.com/2012/01/new-semester-new-course-unprepared.html
• http://discovermagazine.com/2014/nov/20-trial-and-error• https://askabiologist.asu.edu/cell-division• https://www.pinterest.com/pin/288863763578125688/?lp=true• https://www.sciencetopia.net/biology/prokaryotic-cell-structure• http://astarbiology.com/ib/1-2-prokaryotic-cells/• http://www.betterhealthfacts.com/2017/02/good-bacteria-vs-bad-bacteria.html• https://longitudeprize.org/blog-post/10-most-dangerous-antibiotic-resistant-bacteria• https://edu.glogster.com/glog/eukaryotic-cell-animal-cell/22knap4sxa8?=glogpedia-source• https://biologydictionary.net/eukaryotic-cell/• https://www.mrsec.psu.edu/content/model-membrane• http://discovermagazine.com/galleries/2015/jan-feb/science-beautiful• https://nigerianscholars.com/tutorials/biology-109/fluid-mosaic-model-2/
• https://brainly.in/question/4081298• https://courses.lumenlearning.com/wm-biology1/chapter/reading-nucleus/• https://www.quora.com/What-function-do-ribosomes-serve-in-polypeptide-synthesis• https://ajweinmann.wordpress.com/endoplasmic-reticulum/• https://twitter.com/golgi_body667• http://www.biology4kids.com/files/cell_lysosome.html• https://www.medicalnewstoday.com/articles/320875.php• https://www.quora.com/What-are-chloroplasts-and-why-do-they-move• https://infograph.venngage.com/p/155855/central-vacuole• https://www.gettyimages.ca/photos/cytoskeleton?sort=mostpopular&mediatype=photogra
phy&phrase=cytoskeleton• https://www.gettyimages.ca/photos/cytoskeleton?sort=mostpopular&mediatype=photogra
phy&phrase=cytoskeleton• https://byjus.com/biology/active-transport/• https://slideplayer.com/slide/8648458/• https://clinicalgate.com/nuclear-structure-and-dynamics/• https://www.haikudeck.com/cell-parts-and-functions--science-and-technology-presentation-
9f63S3zqEM• https://www.quora.com/What-does-a-chloroplast-look-like• https://www.ru.ac.za/emu/temimages/theplantcell/• https://www.plantscience4u.com/2014/05/function-of-eyespot-stigma-in-
algae.html#.W227IM5Kipo• https://www.cell.com/cell-metabolism/issue?pii=S1550-4131(13)X0010-5