Chapter 7.3 and 7.4
Cell Transport
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http://www.tsicontainers.com/images/Shipping%20Port.jpg
Chapter Mystery?
Chapter 4 Vocab1. Active transport-
transport across the cell membrane that requires energy
2. Passive transport-movement across the cell membrane that does not require energy.
3. Concentration gradient-difference of concentration across a space
4. Osmosis 5. Diffusion
6. Facilitated Diffusion7. Aquaporin8. Endocytosis9. Exocytosis10.receptor protein- a protein
on the cell membrane that receives a signal molecule.
11. Hypertonic12. Hypotonic13. Isotonic
Main Function of the Cell Membrane • Membranes are selectively permeable so they
control what moves in and out of the cell– Based on size and polarity
The Cell Membrane
http://micro.magnet.fsu.edu/cells/plasmamembrane/images/plasmamembranefigure1.jpg
The Phospholipid bilayer
• Every single cell exists in a liquid environment
• Bilayer made of phospholipids– Hydrophilic
Heads-love water (polar)
– Hydrophobic tails- hate water (non polar)
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/lipos.gif
What are polar and nonpolar molecules?
http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/chemistry/chemis4.gif
So what moves in and out?
Size Polarity
In Small molecules Non-polar and some small polar molecules
Out Large molecules Polar
http://www.youtube.com/watch?v=s0p1ztrbXPY&feature=BFa&list=PLAF7748B8E2D52AC3&lf=results_video
Passive Transport: Requires NO Energy
• Every cell exists in a liquid environment.
• Every cell must maintain homeostasis
• Cells must regulate transport across the cell membrane
http://www.google.com/imgres?q=passive+transport&um=1&hl=en&rlz=1T4ADSA_enUS428US430&biw=1366&bih=507&tbm=isch&tbnid=K_YR1U3sz3K5vM:&imgrefurl=http://www.absoluteastronomy.com/topics/Passive_transport&docid=0VcILTJKWB-yLM&imgurl=http://image.absoluteastronomy.com/images/encyclopediaimages/s/sc/scheme_simple_diffusion_in_cell_membrane-en.svg.png&w=626&h=399&ei=OT-bTpi1IeTg0QH_xYDLBA&zoom=1&iact=hc&vpx=401&vpy=201&dur=5444&hovh=179&hovw=281&tx=143&ty=89&sig=107888942202169124570&page=2&tbnh=113&tbnw=177&start=13&ndsp=12&ved=1t:429,r:1,s:13
Concentration Gradients: the differences in concentration across a
space.
http://brainchemist.wordpress.com/2011/01/21/diffusion-mri-ch-1-introduction-to-diffusion-magnetic-resonance/
Equilibrium
• B. equal concentrations across a space.
http://academic.kellogg.cc.mi.us/herbrandsonc/bio111/images/water/water.3.jpg
Diffusion: the movement from an area of high concentration to an
area of low concentration.• 1) a difference in
concentration exists across the cell membrane
• 2) diffusion occurs down the gradient.
http://www.biologycorner.com/resources/diffusion-animated.gif
Cell membrane is selectively permeable• A. repels non
polar molecules and ions.
• B. polar molecules and very small molecules can diffuse across the cell membrane.
http://www.geosciences.unl.edu/~dbennett/images/Cell_membrane.gif
Ion Channel: a polar pore through which ions can pass into
a cell.• A. some molecules
cannot pass directly through the cell membrane.
• B. Ion channels- allows polar molecules, (like ions) pass into the cell.
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_06/4_20B.GIF
Facilitated Diffusion: Sugars and amino acids
• A. carrier proteins -bind to substances outside the cell and carry it inside.
• B. Amino acids and Sugars
• C. Down the concentration gradient.
• D. NO ENERGY REQUIRED
http://images.google.com/imgres?imgurl=http://www.aber.ac.uk/gwydd-cym/graffeg/biolgell/cludiant/sianel.gif&imgrefurl=http://www.aber.ac.uk/gwydd-cym/cellbiol/transport/index.htm&h=161&w=157&sz=16&hl=en&start=4&tbnid=ZvBWMBrJP6UWrM:&tbnh=98&tbnw=96&prev=/images%3Fq%3Dmembrane%2Bproteins%2Banimation%26svnum%3D10%26hl%3Den%26lr%3D
Osmosis: the diffusion of water through a selectively permeable
membrane.• A. uses a
concentration gradient• B. passive transport• C. Aquaporins-water
channel proteins• D. This is a type of
facilitated diffusion
http://www.bigbrandwaterfilter.com/water_filter_images/waterdrop_embossed.gif
Hypertonic solutions• 2. Water moves out of
the cell-causes cell to shrink, called a Hypertonic solution
Hypotonic Solutions
• 3. Water moves into the cell-causes cell to swell and burst, called a hypotonic solution
http://www.biologycorner.com/resources/hypotonic.gif
Isotonic solutions
• 4. No net movement- cell remains the same, called a Isotonic solution.
http://www.biologycorner.com/resources/isotonic.gif
How to Deal with osmotic pressure? • A. contractile
vacuole-a water pump found in paramecium
• B. cell walls- keeps central vacuole from over expanding.
• Large organisms cells are bathed in blood or isotonic solutions
http://science.kennesaw.edu/biophys/biodiversity/protista/pictures/paramecium.gif
http://imcurious.wikispaces.com/Midterm+Exam+2010+Review+P2
Review Questions• 1. What is a concentration gradient?
• 2. Describe the movement of molecules during diffusion.
• 3. Can polar molecules pass through the cell membrane? Why or why not?
• What is a aquaporin?
• 5. What is the difference between a hypotonic, hypertonic and an isotonic solution.
• 6. What is passive transport?
Label the following cells as Isotonic, hypotonic, or hypertonic
Image from www.ndpteachers.org/perit/biology_image_galle...
Active Transport: Requires ATP• A Requires ATP
– 1. Carrier proteins-act as pumps
– 2. Against the concentration gradient.
• B. Sodium-Potassium Pump– 1. Sodium ions-more
on outside of cell– 2. Potassium ions-
more on inside of cell
http://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/ATPpumA.gif
How do you get Big Molecules across the cell membrane?
Answer: Endocytosis and Exocytosis
Endocytosis: too large to pass through the cell membrane.
• A. polysaccharides and proteins
• B. use a vesicle• C. cell forms a pouch
around the substance.• D. phagocytosis-
engulfing prey.
http://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/RectmAnA.gif
http://www.youtube.com/watch?v=aWItglvTiLc&feature=related
Endocytosis
Exocytosis
http://www.sirinet.net/~jgjohnso/exocytosis.jpg
Exocytosis
• A. the movement out of the cell using a vesicle.
• B. the vesicle fuses with the cell membrane.
• C. golgi body-proteins modified here are released from the cell using exocytosis
http://www.stanford.edu/group/Urchin/GIFS/exocyt.gif
Review Question• 7. What is active transport?
• 8. How does a sodium-potassium pump work?
• 9. What are the similarities and differences between endocytosis and exocytosis?
• 10. What is the function of a receptor protein?
How do multicellular organism maintain homeostasis?
• Cell specialization- in order for cells to be effective, they must work together.
http://www.ptei.org/interior.php?pageID=42
Teamwork
Levels of Organization in multicellular organisms
http://www2.lbsdk12.com/science/Anatomy/levelsoforganization.jpg
Levels of Organization• Cells- group of ORGANELLES working
together to perform a particular function.
• Tissue- a group of cells working together to perform a particular function.
• Organ- a group of tissues working together to perform a particular function.
• Organ system- a group of organs working together to perform a particular function.
• Organism- all organ systems working together to maintain homeostasis
How do you send a text message to a cell?
http://www.biologycorner.com/APbiology/cellular/(notes)cell_membrane.html
Answer: Membrane Receptor Proteins Receive Information
• 1. Cells release signal molecules that carry info (hormones).
• 2. Receptor proteins-binds to specific receptor molecules
• 3. They can speed up or slow down cell activities.