#13 Biochemistry Lecture (Lipids and Membranes) from Kevin Ahern's BB 350
Sign in to YouTube
Sign in to YouTube
Sign in to YouTube
Published on Apr 24, 2013
1. Contact me at email@example.com / Friend me on Facebook (kevin.g.ahern)
2. Download my free biochemistry book at http://biochem.science.oregonstate.ed...
3. Take my free iTunes U course at https://itunes.apple.com/us/course/bi...
4. Check out my free book for pre-meds at http://biochem.science.oregonstate.ed...
5. Course video channel at http://www.youtube.com/user/oharow/vi...
6. Check out all of my free workshops at http://www.youtube.com/playlist?list=...
7. Check out my Metabolic Melodies at http://www.davincipress.com/metabmelo...
8. My courses can be taken for credit (wherever you live) via OSU's ecampus. For details, see http://ecampus.oregonstate.edu/soc/ec...
9. Course materials at http://oregonstate.edu/instruct/bb350
1. Steroids are compounds with ring structures that are made from cholesterol. Steroids include sex hormones (androgens, estrogens, etc.) and in animals are derived from cholesterol. Cholesterol is an important constituent of animal membranes, giving them integrity.
2. Glycerophospholipids and sphingolipids form lipid bilayers, not micelles.
3. Cellular membranes are sensitive to temperature. The higher the temperature, the more fluid the membrane. The fluidity of a membrane is related to the fatty acids in it. Membranes with shorter and more unsaturated fatty acids are fluid at lower temperatures than membranes with longer and more saturated fatty acids.
4. Cholesterol "fits" into the non-polar portion of the lipid bilayer.
5. In addition to lipids, membranes also contain proteins. Integral membrane proteins project through both sides of the lipid bilayer. Associated membrane proteins are found near, but not attached to the lipid bilayer. Peripheral membrane proteins stick through one side of the lipid bilayer. Anchored membrane proteins are attached to a molecule that is embedded in the lipid bilayer. Embedded proteins are completely embedded in the non-polar portion of the lipid bilayer.
6. Animals live in widely varying environmental conditions. Fish, for example life in an environment that is cooler than most land animals. Their membranes have more polyunsaturated fatty acids than our cells do, for example.
7. Double bonds cause 'bends' in the non-polar portion of a membrane lipid.
8. Carbohydrates (sugar compounds) have links to components in a lipid bilayer in an orientation-specific direction - all carbohydrates are located on the portion of the lipid bilayer that is on the outside of the cell. This is because carbohydrates serve as identity markers for cells. These identity markers function in the body's rejection of transplanted organs.
9. Liposomes are artificial membranes that allow researchers to move materials across biological lipid bilayers.
10. Vitamin D is involved in calcium and phosphate metabolism in the body. It is derived from cholesterol and its activation requires UV light.
11. Vitamin E is a cellular antioxidant and probably protects membrane lipids from oxidation by reactive oxygen species.
12. Vitamin K is involved in the blood coagulation process.
13. Vitamin A is involved in vision and a form of vitamin A is also involved in cellular differentiation.
14. Materials have to cross the cellular membrane in order for cells to live. Nutrients must be brought into the cell and waste products must be exported. Crossing the lipid bilayer is a problem for most molecules. Only oxygen, carbon dioxide, carbon monoxide and water readily diffuse across the lipid bilayer.
15. Mechanisms for moving materials across the lipid bilayer are Passive (diffusion) or Active (energy required). The driving force for a passive mechanism is concentration driven.
16. Active transport mechanisms require energy to move compounds across a membrane because they are taking materials against concentration gradients (low to high).
17. The sodium-potassium pump is an active transport system that transports sodium from inside the cell to outside of it. The sodium-potassium pump also transports potassium from outside the cell to the inside. Since both of these movements involve taking a substance from a lower concentration and moving it to a higher concentration, energy is required and this mechanism is an active transport mechanism. It uses ATP.
18. A secondary transport system is an active transport system that uses a high concentration of a molecule outside the cell to "carry" a molecule with it across a membrane and against a concentration gradient. An example is the lactose transport system which uses a proton gradient to carry lactose against a concentration gradient.
19. An example of a receptor that internalizes a compound is the LDL receptor, which binds to LDLs (cholesterol-containing complexes in the blood) and brings them inside of the cell.
Standard YouTube License
- 49:59 #17 Biochemistry Lecture DNA Replication III & Transcription) from Kevin Ahern's BB 350 Broadbandby Kevin Ahern1,121 views
- 49:08 #25 Biochemistry Lecture (Carbohydrates and Glycolysis) from Kevin Ahern's BB 350by Kevin Ahern1,116 views
- 45:36 #12 Biochemistry Lecture (Enymzes and Lipids) from Kevin Ahern's BB 350by Kevin Ahern1,072 views
- 48:39 #10 Biochemistry Lecture (Enzyme Regulation) from Kevin Ahern's BB 350by Kevin Ahern1,350 views
- 45:41 #4 Biochemistry Lecture (Amino Acids) from Kevin Ahern's BB 350by Kevin Ahern2,628 views
- 41:10 #30 Biochemistry Lecture (Electron Transport and Respiration) from Kevin Ahern's BB 350by Kevin Ahern726 views
- 48:02 #22 Biochemistry Lecture (Viruses, Cancer and Oncogenes) from Kevin Ahern's BB 350by Kevin Ahern679 views
- 12 videos Play all Kevin Ahern's Lipids and Membranes Lecturesby oharow
- 41:58 #14 BB 350 Membranes III / Nucleic Acids I - Kevin Ahern's Biochemistry Onlineby Kevin Ahern2,147 views
- 49:00 #13 BB 350 Membranes II - Kevin Ahern's Biochemistry Onlineby Kevin Ahern1,846 views
- 47:11 #35 Biochemistry Lecture (Nitrogen and Amino Acid Metabolism) from Kevin Ahern's BB 350by Kevin Ahern2,246 views
- 44:30 #29 Biochemistry Lecture (Citric Acid Cycle) from Kevin Ahern's BB 350by Kevin Ahern1,007 views
- 48:29 #19 Biochemistry Lecture (Translation) from Kevin Ahern's BB 350by Kevin Ahern847 views
- 51:17 #15 Biochemistry Lecture (DNA Structure and Replication) from Kevin Ahern's BB 350by Kevin Ahern1,858 views
- 47:27 #8 Biochemistry Lecture (Gels/Enzymes) from Kevin Ahern's BB 350by Kevin Ahern1,165 views
- 49:49 #32 Biochemistry Nerve Transmission/Mitochondria Lecture for Kevin Ahern's BB 451/551by Kevin Ahern4,017 views
- 49:20 #5 Biochemistry Lecture (Protein Structure) from Kevin Ahern's BB 350by Kevin Ahern3,253 views
- 48:58 #04 Biochemistry Protein Primary/Secondary Structure Lecture for Kevin Ahern's BB 450/550by Kevin Ahern22,443 views
- 14:47 Introduction to Biochemistry Lecture by Kevin Ahern, Part 1 of 4by Kevin Ahern38,756 views
- 49:43 17. Kevin Ahern's Biochemistry - Carbohydrates IIby Kevin Ahern824 views