Imidazoleglycerol-phosphate dehydratase is an enzyme in the histine biosynthesis pathway. It catalyzes the E1 dehydration of D-erthyro-imidazole-glycerol phosphate to imidazole acetol-phosphate. This is a rare example of a biological E1 reaction, as most biological elimination reactions occur through E1cB instead. In this reaction, D-erthyro-imidazole-glycerol phosphate is first protonated to form a good leaving group. Then, the leaving group is ejected to form the resonance-stabilized carbocation below. Draw curved arrows forming the most stable resonance structure to explain why this reaction goes through an E1 mechanism.

Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. a physical change doesn’t break the bonds between atoms of a substance or form new ones. compounds can be broken down by a chemical change. a chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. what simple substance would a compound break into? the basic elements that make it up! for example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. which of the following is an example of a chemical change? a separating water into different glasses b breaking frozen ice cubes with a hammer c running an electric current through water d boiling water to evaporate it on a stove

Match the type of adaptation to the correct example, structural adaptation functional adaptation behavioral adaptation example type of adaptation elephants live in herds to protect their young leaves of a rain forest plant species have a pointed tip that enables rainwater to drain off easily. camels have nostrils that they can close snakes produce venom to kill prey and defend themselves. earthworms coil when touched, as part of a defense mechanism. human skin darkens with increased exposure to sunlight.

Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the correct position in the answer box. release your mouse button when the item is place. if you change your mind, drag the item to the trashcan. click the trashcan to clear all your answers. label the following topographic map. click on a label below the map to select it, and then click on the appropriate box on the map to place the label. (increments for contour lines is 50 ft).