TOPICS ON CELLS
Essential Biology Learning Guides/Electronic Packet (homework, review)
1.1 learning guide Introduction (Cell Theory)
1.2 learning guide Prokaryotic & Eukaryotic Ultrastructure
1.3 learning guide Membrane Structure
1.4 learning guide Membrane Transport
1.5 learning guide Origin of Cells - SL only!
1.6 learning guide Cell Division
1.2 learning guide Prokaryotic & Eukaryotic Ultrastructure
1.3 learning guide Membrane Structure
1.4 learning guide Membrane Transport
1.5 learning guide Origin of Cells - SL only!
1.6 learning guide Cell Division
Support/Resource material for unit (homework, class discussion)
Topic 1.1 slides (C Paine) Allott & Mindorff text pp. 1-16
Topic 1.2 slides (C Paine) Allott & Mindorff text pp. 16-25
Topic 1.3 slides (C Paine) Allott & Mindorff text pp. 25-33
Topic 1.4 slides (C Paine) Allott & Mindorff text pp. 33-45
Topic 1.5 slides (C Paine) Allott & Mindorff text pp. 45-51 SL only!
Topic 1.6 slides (C Paine) Allott & Mindorff text pp 51-60
Topic 1.2 slides (C Paine) Allott & Mindorff text pp. 16-25
Topic 1.3 slides (C Paine) Allott & Mindorff text pp. 25-33
Topic 1.4 slides (C Paine) Allott & Mindorff text pp. 33-45
Topic 1.5 slides (C Paine) Allott & Mindorff text pp. 45-51 SL only!
Topic 1.6 slides (C Paine) Allott & Mindorff text pp 51-60
CELL THEORY (TOPIC 1.1)
The following video is a very nice treatment of the history of science behind the Cell Theory. Below is an outline for taking notes while viewing.
Active Listening Questions to accompany the video
Exceptions to the Cell Theory...see multinucleate cells in slide presentation and this video on subcellular particles - virues, viroids & prions...and the diseases they cause.
Click to link below to the lab activity on SA/volume ratio
Emergent Properties - what a beautiful example:
right: Stem Cells - where do they come from? EuroStemCell video
left: Stem Cells - overview - what are they good for? Susan Lim, TED talk (INK conference, 2010, India)
left: Stem Cells - overview - what are they good for? Susan Lim, TED talk (INK conference, 2010, India)
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Stem Cells - Real example, heart cells beating in petri dish
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CELL STRUCTURE AND FUNCTION (TOPICS 1.2)
1. Try this: Cells - Fact or Fiction?
2. And for a nice organizer for Topic 1.2 - Cell Part Chart.
3. A GREAT site for reviewing parts of all cells - Cells alive.com
2. And for a nice organizer for Topic 1.2 - Cell Part Chart.
3. A GREAT site for reviewing parts of all cells - Cells alive.com
4. A bit of clarification on prokaryotic cell structure...
- Although you may still find references to them, including the current IB Bio materials/tests, mesosomes are generally considered artifacts of electron microscope processing and probably serve no function in living cells.
- The term "envelope" includes the plasma membrane directly around the cytoplasm and the cell wall, if present.
- Bacterial cell walls can be quite varied - generally made of peptidoglycan (protein and carbohydrate), they can be (a) thick and external, or (b) thin and surrounded by a lipoprotein (lipid/protein) external membrane. Different variations on this wall structure reflect adaptations to the great diversity of bacterial habitats.
- Another optional outer structure is a secreted coating of slime, known as a capsule, which may help bacterial in attaching to their environment or to each other.
- Projections coming off of the cell are also varied, including flagella (long and functioning for movement), pili (short, thick and functioning for connecting to other cells) and fimbria (short and thin and functioning for attachment and absorption of nutrients)
5. TOK moment - alternate ways of thinking about cells...
British artist, Luke Jerrum has created pieces using structural data for various disease causing bacteria, viruses and micro-organisms. In this interview, he discusses the balance between beauty and repulsion, as well as the importance of visual images in understanding an otherwise invisible world.
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Plasmodium, a parasitic protozoan
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BIOLOGICAL MEMBRANES STRUCTURE AND TRANSPORT (TOPIC 1.3 & 1.4)
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First, a bit of chemistry...
A triglyceride, a type of fat (or lipid)
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Fatty Acid - part of what makes up fats (lipids)
Detail of the carbon bonds in the hydrocarbon tail of fatty acids
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Ways that fatty acids can arrange themselves - in nature (bilayer and liposomes) or in soaps (micelles)
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Modeling Membranes with Soap Bubbles - Lab Link
(http://chemistry.about.com/od/cleanerchemistry/a/how-soap-cleans.htm)
Soaps are sodium or potassium fatty acids salts, produced from the hydrolysis of fats. Each soap molecule has a long hydrocarbon chain, sometimes called its 'tail', with a carboxylate 'head'. In water, the sodium or potassium ions float free, leaving a negatively-charged head.
Soap is an excellent cleanser because it is capable of dispersing one liquid into another liquid. This means that while oil (which attracts dirt) doesn't naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed.
The organic part of a natural soap is a negatively-charged, polar molecule. Its hydrophilic (water-loving) carboxylate group (-CO2) interacts with water molecules via ion-dipole interactions and hydrogen bonding. The hydrophobic (water-fearing) part of a soap molecule, its long, nonpolar hydrocarbon chain, does not interact with water molecules. The hydrocarbon chains are attracted to each other by dispersion forces and cluster together, forming structures called micelles. In these micelles, the carboxylate groups form a negatively-charged spherical surface, with the hydrocarbon chains inside the sphere. Because they are negatively charged, soap micelles repel each other and remain dispersed in water.
Grease and oil are nonpolar and insoluble in water. When soap and soiling oils are mixed, the nonpolar hydrocarbon portion of the micelles break up the nonpolar oil molecules. A different type of micelle then forms, with nonpolar soiling molecules in the center. Thus, grease and oil and the 'dirt' attached to them are caught inside the micelle and can be rinsed away.
(http://chemistry.about.com/od/cleanerchemistry/a/how-soap-cleans.htm)
Soaps are sodium or potassium fatty acids salts, produced from the hydrolysis of fats. Each soap molecule has a long hydrocarbon chain, sometimes called its 'tail', with a carboxylate 'head'. In water, the sodium or potassium ions float free, leaving a negatively-charged head.
Soap is an excellent cleanser because it is capable of dispersing one liquid into another liquid. This means that while oil (which attracts dirt) doesn't naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed.
The organic part of a natural soap is a negatively-charged, polar molecule. Its hydrophilic (water-loving) carboxylate group (-CO2) interacts with water molecules via ion-dipole interactions and hydrogen bonding. The hydrophobic (water-fearing) part of a soap molecule, its long, nonpolar hydrocarbon chain, does not interact with water molecules. The hydrocarbon chains are attracted to each other by dispersion forces and cluster together, forming structures called micelles. In these micelles, the carboxylate groups form a negatively-charged spherical surface, with the hydrocarbon chains inside the sphere. Because they are negatively charged, soap micelles repel each other and remain dispersed in water.
Grease and oil are nonpolar and insoluble in water. When soap and soiling oils are mixed, the nonpolar hydrocarbon portion of the micelles break up the nonpolar oil molecules. A different type of micelle then forms, with nonpolar soiling molecules in the center. Thus, grease and oil and the 'dirt' attached to them are caught inside the micelle and can be rinsed away.
FLUID MOSIAC MODEL - PHOSPHOLIPID BILAYER AROUND ALL CELLS
Here's a (mostly) unlabeled fluid mosaic model image with which to test yourself:
Here's a (mostly) unlabeled fluid mosaic model image with which to test yourself:
Video review of types of transport across the plasma membrane
Nice animation of phospholipid micelles (aggregates of the PL's with hydrophillic phosphates exposed and hydrophobic fatty acids on inside) fusing to make bilayer and eventually a membrane as it would surround cell cytoplasm. (J Szostak, MGH/HHMI)
2004 Nature Publishing Group Pietzsch, J. Mind the membrane. Horizon
Symposia: Living Frontier, 1-4 (2004). This is a very useful source of "Scitable" images from a highly respected publisher, Nature Publishing Group. Definitely check it out for citations for lab reports.
Symposia: Living Frontier, 1-4 (2004). This is a very useful source of "Scitable" images from a highly respected publisher, Nature Publishing Group. Definitely check it out for citations for lab reports.
Stick with this video demonstration...it gives an updated version of water transport across a membrane and a very nice animation showing both animal and plant cells and how they respond to being in high (hypertonic) or low (hypotonic) solute conditions.
Prezi on Topic 1.4 (previously 2.4) - try it for review
Cell Division - Mitosis and Cancer
Quirky but informative animation...especially good in the emphasis on the cell cycle as a whole. (don't worry - starts with black screen)
Questions to consider:
1. Differentiate between cell cycle and mitosis
2. How does the cell (both nucleus and cytoplasm) prepare for mitosis?
3. Cancer can be thought of as mitosis gone awry - research two type of genes that cause cancer - p. 68, Biozone workbook.
4. Normal cells stop dividing after 50 cell cycles or so (more on the mechanism for this later when we get to DNA/chromosome structure). Some cells stop in a more programmed way - programmed cell death. Is this a good or a bad thing - research on p. 71, Biozone book. Research other tissues that utilize PCD (also called apoptosis) on the internet. Contrast apoptosis with necrosis.
Questions to consider:
1. Differentiate between cell cycle and mitosis
2. How does the cell (both nucleus and cytoplasm) prepare for mitosis?
3. Cancer can be thought of as mitosis gone awry - research two type of genes that cause cancer - p. 68, Biozone workbook.
4. Normal cells stop dividing after 50 cell cycles or so (more on the mechanism for this later when we get to DNA/chromosome structure). Some cells stop in a more programmed way - programmed cell death. Is this a good or a bad thing - research on p. 71, Biozone book. Research other tissues that utilize PCD (also called apoptosis) on the internet. Contrast apoptosis with necrosis.
David Agus TED talks, New Strategy in the War on Cancer (2010). Questions to accompany the video.
And...the 3 years later appearance on Daily Show...
And...the 3 years later appearance on Daily Show...
or...from the bioengineer's perspective (perhaps the most impacting presentation)
Cell Division Data Collection: Cancer Cell Cams!
Click on this image to go to a REAL time cell cam image of human melanoma cells growing in culture. Images are uploaded every ten minutes throughout the day. Compare this to the Bacteria Cam on the same site. Bacteria replicate so rapidly that these images are uploaded every minute!