NTC Lecture 1.pdf - Biochemistry Lecture 1 Anisha Mehreja...

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Biochemistry Lecture 1 Anisha Mehreja Midterm exam 40% (40-45 Multiple Choice questions) Date: Wednesday, Feb 14thMNI, Jeanne Timmins Amphitheater Final Exam 60% (80-90 Multiple Choice questions; 25% of the questions will be based on topics covered prior to midterm) Date: April 17-30, 2018 TAs: Jun Tian à[email protected] Lisa Liu à[email protected] Frida Blackwell à[email protected] Plasma Membrane -Made up from phospholipids. There is a phosphate group with two free fatty acids. -Outer and inner layer form the phospholipid bilayer. -Amphipathic molecules arranged in a bilayer have both hydrophobic and hydrophilic parts.§These molecules allow you to form small globules of fat in the gut, cells or blood streams. The lipid molecule will be in contact with the hydrophobic tails whereas; the hydrophilic heads will be in contact with the ECF solution. -Humans are water based organisms, molecules inside of us are dissolved in water. Outside of our cells (ECF- most cells ISF with exception to blood cells in plasma) are water based solutions. oIn the inside of the cell contains cytoplasm, a water-based solution. oThe phosphate heads on the outside and inside are in direct contact with that solution and are, hydrophilic (ionic, highly polar). oThe interior with fatty acid tails is a region which is hydrophobic(non-polar). Semi-permeable membrane -Permeable to water and some molecules. The only molecule that can easily penetrate through the hydrophobic, non-polar region are lipids. Non-protein steroid molecules fall under lipids, and can therefore also easily pass through the membrane as well. -Simple diffusion- movement of molecules across membranes from a higher to lower concentration gradient. -Facilitated diffusion- does not require energy but needs a certain molecule to pass. -Osmosis – movement of H2O across the membrane. Recall that Water can move freely -Active transport- requires energy Semi-permeable around the cell
Plasma Membrane and Proteins -Proteins within are not rigid and can move around. -In some cases, certain ligands or molecules can bind to a specific receptor and complex of other protein will form. This structure will cause a signal to be transduced to form channels so that molecules can move in. -Plasma membrane proteins: peripheral proteins are connected to the exterior of the membrane. Integral proteins are embedded in the membrane. Transmembrane proteins span the plasma membrane (across). -Six types of Integral Membrane Proteins:Do not focus on memorizing them. Know that one end of an integral protein has an amine group, and the other has a carboxyl group. If the protein is running through the lipid bilayer, the amino acids within that specific protein molecule must be non-polar, hydrophobic.

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