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.