SBI3UE Examination Notes
By: Gursangat Sidhu and Derek Meng Unit 1 - The Cell
Unit 2 - The Chemical Basis of Life Part 1 - Molecules of Life Part 2 - DNA Replication and Protein Synthesis Enzymes DNA Structure DNA Replication Protein Synthesis Overview Transcription Translation Mutations Part 3 - Cellular Respiration and Photosynthesis Unit 3 - Genetics
Unit 1 - The Cell
Cell Theory: Cell theory: refers to the idea that cells are the basic unit of structure in every living thing. It states that: ● New cells are formed from other existing cells, ● the cell is a fundamental unit of structure, ● function and organization in all living organisms.
Eukaryotic and Prokaryotic Cells
Prokaryotic ● ● ● ● ● ● Have pili No nucleus DNA in cytplasm Reproduce using binary fission No formal Organelles 70S Ribosomes
Eukaryotic ● ● ● ● ● ● No Pili Have Nucleus DNA in nucleus and code for proteins Divide using mitosis/meiosis Membrane bound organelles 80S Ribosomes
70S and 80S : A svedberg unit (symbol S, sometimes Sv) is a non-SI unit for sedimentation rate. The sedimentation rate is the rate at which particles of a given size and shape travel to the bottom of the tube under centrifugal force.
Binary fission in a prokaryote. 1: The bacterium before binary fission is when the DNA tightly coiled. 2: The DNA of the bacterium has replicated. 3: The DNA is pulled to the separate poles of the bacterium as it increases size to prepare for splitting. 4: The growth of a new cell wall begins to separate the bacterium. 5: The new cell wall fully develops, resulting in the complete split of the bacterium. 6: The new daughter cells have tightly coiled DNA, ribosomes, and plasmids.
Plant Cells ● ● ● ● ● Cell Wall Chloroplasts No flagellum (except algae) Have a large central vacuole No centrioles
Animal Cells ● ● ● ● ● No Cell Wall No Chloroplasts Can have flagellum Smaller Vacuole Have Centrioles
Phospholipids: A amphipatic molecule. ● Hydrophilic Head (Dissolves in Water) ● Hydrophobic Tails (Don’t Dissolve in Water)
Fluid Mosaic Model:
In this model, membrane proteins are dispersed and individually inserted into the phospholipid bilayer, with only the hydrophilic regions of the proteins be exposed in the water. This allows for the maximum surface area contact of the hydrophilic parts with the water, while providing a nonaqueous environment for the hydrophobic parts. In this model, the proteins are “floating” in the membrane, and they CAN move through the 5
phospholipid bilayer. Cell membranes have a fluid quality. Animal cells have cholesterol molecules which determine the fluidity.
Cholesterol can restrict the fluidity, which can increase the melting point (decreased fluidity). ● Saturated Fats are bad because the single carbon chain don’t make kinks. (decrease fluidity) ● Unsaturated and Polyunsaturated fats are good because the double carbon bonds make kinks. (increase fluidity) ● Trans fat are bad, because of how the geometric configuration ends up restricting the fluidity of the cell. Integral Proteins: transmembrane proteins with both hydrophobic and hydrophilic regions. ● Binding site for peripheral membrane proteins ● Act as a receptor for hormones ● Cell to Cell communication The combinations of glycoproteins and glycolipids provide each cell with a unique identity. Peripheral membrane: ● Takes messages from integral proteins further into cell Protein Channel: Controls the entry and removal of specific molecules from cell. Channels/ pumps allow for active and passive transport Cellular Transport: Passive Transport: Proteins contain channels. Materials move through the channel from high concentration into an area of low concentration. Active Transport: Proteins shuttle a substance from one side of the membrane to another by changing shape. This requires ATP to function. Facilitated Diffusion: In the membrane, a specific protein aids the...
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