Bio 20 Unit 1 Lesson 1 Assignment Enzymes (2)

Unit 1 Lesson 1 Assignment Total /27 Before completing this assignment please read Chapter 6 (pages 200 to 216) of your textbook. Also read the information on the Moodle website for Unit 1 Lesson 1. 1. At high temperatures, the rate of enzyme action decreases because the increased heat changes the pH of the system alters the active site of the enzyme neutralizes the acids and bases in the system increases the concentration of the enzyme 2. Enzymes influence chemical reactions in living systems by providing the substrate required for the reaction to occur affecting the rate at which reactions occur absorbing water released when polymers are formed combining with excess hydrogen to form gaseous wastes 3. Which group of organic compounds includes the enzymes? proteins starches carbohydrates lipids 4. The "lock and key hypothesis" attempts to explain the mechanism of protein denaturation ATP formation sharing of electrons enzyme specificity 5. Any substance that is acted upon by an enzyme is called a(n) coenzyme substrate vitamin polypeptide 6. Vitamins are essential to the survival of organisms because vitamins most function as substrates nucleic acids coenzymes nucleotides 7. A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation? Starch molecules are too large to be hydrolyzed. Enzyme molecules are specific in their actions. Egg white acts as a coenzyme for hydrolysis. Starch is composed of amino acids. 8.  The effect of temperature on the relative rate of action of an enzyme is represented in the graph below.   The optimum temperature for the action of this enzyme is approximately  15º C  22º C  37º C  50º C 9.  The fact that amylase in the human small intestine works best at normal body temperature suggests that  amylase is denatured at temperatures below 37º C  amylase can function only in the small intestine  the lock-and-key model of enzyme action does not apply to amylase  the optimum temperature for amylase is 37ºC 10. An essential amino acid is one which is required for cell respiration one which is produced by the organism one which must be obtained in the diet one which is found in muscle tissue Written Response 1. Using an example, explain feedback inhibition as it applies to enzymes. 2. Using your knowledge of enzyme structure and function, explain why a prolonged period of high fever is dangerous to humans. 3. List three different factors which influence the rate of enzyme activity and specifically explain each factor’s influence on enzyme activity. 4. How do enzymes reduce the energy of activation of biochemical reactions. 5. What is a cofactor? What role do cofactors play in enzyme activity? 6. Explain competitive inhibition. 7. Compare exergonic and endergonic reactions.