BIOLOGY 207 1st Edition Lecture 5 Outline of Previous Lecture I. RespirationII. Cytoplasmic Membrane Outline of Current Lecture I. Cell Wall and MembraneII. Cell TransportationCurrent LectureCell Structure and Function ContinuedI. Cell Wall and Membranea. Gram negative bacteriai. Cell wall with thin peptidoglycan (bacteria specific feature that adds strength to the cell)ii. Outer membrane contains and endotoxin called Lipopolysaccarides (LPS)1. Extremely immunogenic; many people have reactions to this part of the bacteria2. Can cause fatal responses to humans and animals, including septic shockb. Gram positive bacteriai. Cell wall with thick layer of peptidoglycanii. More difficult to wash dye out, when testing the type of bacteria; makes it easier to tell if it is gram+ or gram-c. Three classes of transporters within the cell membranei. 1) Simple transport: driven by energy from PMFii. 2) Group translocation: chemical modification of substance transported, by a phosphate groupiii. 3) ABC transporter: periplasmic binding proteins involved; use energy from ATPiv. They are all very specific means of transportation; all have very specialized transport devicesd. What is transported across cell membranes?i. Essential elements that make up the structure and make up of a cell are takenin first through the membraneThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.1. C, O, N, H, P, Sii. Transition metals1. Readily oxidized/reduced substances 2. Helpful to enzymes, 1/3 of which have metal cofactors3. Offer mineral supplements e. Cell sizei. The significance of cells being so small has much to do with the surface-volume ratioii. The advantages: supporting greater nutrient exchange per unit; ability to grow faster1. Since microbes are limited to transportation by diffusion, having a high ration is important2. Transporters more readily transport nutrients to smaller cells3. Less energy is needed to excrete waste from the cell as compared to larger cells4. Ability to evolve and morph is higheriii. Cells have yet to evolve into bigger organisms because of this reason that the smaller they are, the more efficient and healthy they areiv. Cells in low nutrient areas have greater surface areas so as to have a greater place to intake whatever nutrients that they canII. Cell transporta. Bacteria, eukarya and archaea all have flagella of some formi. Flagella allow for movement within the environmentii. Called “archellon” in archaeaiii. The speed to which the flagella can move depends on the PMF; can make 300evolutions per second; speed is 60 cell lengths per second for bacteria making it relatively the fastest creatures knowniv. In the image above, the thin peptidoglycan reveals that this is a gram negative bacteriab. Fimbriae are similar to flagella, but smalleri. Involved in attachment to objects within the environmentc. Where do they go?i. Areas of higher nutrientii. Bacteria area able to sense their environments, thus moving to areas of higher gradients15–20 nmFilamentFlagellinLPMSHookOutermembrane(LPS)L RingP RingRodPeptidoglycanPeriplasmMS RingBasalbodyC RingCytoplasmicmembraneFli proteins(motor switch)Mot proteinMot protein45 nm+ + + + + + + +− − − − − − − −iii. Bacteria move in straight lines by rotating their flagella in counterclockwise circles (runs) or turn via random flagella movement (tumbles)iv. The strategy is to move to areas of higher gradients1. They “run” longer if they sense increased nutrients, then tumble if they sense that they are moving away2. They only have tumble with direction if they sense some attraction present; the image below shows no attraction present on the left (random movement), and attraction present on the right side (directed movement)Bundledflagella(CCW rotation)Tumble − flagellapushed apart(CW rotation)Flagella bundled(CCW