6. Inner Workings of a Cell – soundtracked Inner Workings Harvard – extended narrated version First click on the first link then try and call out what organelles you are looking at aloud! (do this in a private place otherwise you will look like a nutcase) Then click on the second one to see if you were right Then try this link for professor MegaCell Game… Organelles Game Organelles Revision – use your powerpoints we made in class to revise. Then…
7. Mitochondria : Where respiration happens. Energy is generated in a chemical reaction between glucose and oxygen Nucleus: Contains DNA in big bundles called chromosomes . These carry your genes which control your characteristics Ribosomes: Your nucleus sends DNA messages to these instructing them what to build . They make proteins (including enzymes )
15. Diffusion Diffusion is when something travels from an area of high concentration to an area of low concentration. For example, consider the scent from a hamburger. Oxygen passes into cells by diffusion I took this slide from a GCSE powerpoint. For you at AS – remember only Small or Non-Polar (hydrophobic ) molecules can pass through the phospholipid bilayer The “scent particles” from this hamburger are in high concentration here: Eventually they will “diffuse” out into this area of low concentration:
17. Osmosis Osmosis is the net movement of water from an area of its high concentration to an area of its low concentration across a partially-permeable membrane. Shuffle these around to get the definition – I’ve done the first one for you Remember : At AS level we talk about WATER POTENTIAL in terms of Ψ (psi) Maximum Ψ = 0 (pure water) Low Ψ = -500KPa (v. salty water) Note negative values
20. When a carrier or channel just isn’t big enough… BULK TRANSPORT
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22. The Cell Cycle Mitosis is the division of a nucleus The cell cycle describes the life cycle of a cell (duh) Mitosis is the birth of a new cell (stricly speaking mitosis and cytokinesis ) After this the cell must grow (G1) Then it decides whether to head towards division again (a checkpoint) Then DNA is copied ( S phase – part of interphase) Then it grows again and the centriole is copied ( G2 ) before it can do mitosis again
23. Mitosis In case your wondering – blue stuff is chromosomes (hoescht stain) and green stuff is GFP modified microtubules (spindle and cytoskeleton) 1.Interphase: DNA Copied 2. Prophase – chromosomes condensing 3. Metaphase – chromosomes line up on equator 4. Anaphase – chromosomes move to opposite poles 5. Telophase: chromosomes reach poles 5. Cytokinesis (not part of mitosis) = cell division A cell – start here AMAZING VIDS: Watch the chromosomes wiggle about Synchronised mitosis in a maggot ( urgh !)
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25. Stem Cells and differentiation How does an embryo go from all the same cell to about 210 cell types in an adult person?? Watch this zebrafish do it speeded up (you don’t need to know the annotations)