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Lab Assignment Weight: This assignment is worth 10% of your final course grade. Total marks: /100 (50 marks for Part 1; 50 marks for Part 2) Instructions This assignment has two parts. Part 1 add... resses a number of the virtual labs on the PowerPhys website, which you can access through WileyPLUS. For Part 1, you will need to interpret some of the values you will obtain from the simulated experiments of the virtual labs, and you will also need to record your answers to the short-answer questions in this document related to the simulated activities of the virtual labs. Part 2 addresses the home laboratory activities. For the activities in Part 2, you will need the materials provided in the Home Lab Kit that you borrowed from Athabasca University. In this document, you will need to record and interpret some of the results you will obtain from the home lab activities, and you will also need to answer questions related to the activities and their results. Follow carefully the instructions in the Lab Manual for each activity. Type your answers to all the questions in this document. When you have completed this Lab Assignment, submit it for grading via the appropriate Assignment Drop Box on the course home page. Part 1: Virtual Lab Activities For this part of the assignment, you will need access to the PowerPhys website. Follow the general instructions and the instructions for each lab that are provided in the Lab Manual. Total marks: /50 Lab 1 (= Lab 1 in PowerPhys): Enzyme Activity Total marks: /6 1. What is the average obtained for the effect of pH 5 on sucrase activity? (1 mark) 2. State the optimum temperature for sucrase activity and describe how sucrase activity changes at lower and higher temperatures. (1 mark) The optimum temperature is 40 degrees Celsius. Acitivty increases from 10 degrees to 40 degrees where it plateau’s and begins decreasing at a smaller rate. A very large jump in activity occurs from 20-30 degrees Celsius. 3. What is the average sucrase activity obtained for a sucrose concentration of 15g/L? (1 mark) 4. How would a slight fever affect sucrase activity? (1 mark) A slight fever would increase the temperature. An increase in temperature would increase surcease activitiy. 5. Explain how an increasing amount of sucrose in food affects sucrase activity. (1 mark) Increasing the amount of sucrose in food affects sucrase activity by increasing it, as the fructose and glucose increase as well. Increasing sucrose in your food accelerates sucrase activity and elevates your blood sugar levels. 6. Salivary amylase, an enzyme in saliva that breaks down starch, has an optimal pH of 6.7–7.0. Explain why salivary amylase is active in the mouth but becomes inactive in the stomach. (1 mark) Salivary amylase is active in the mouth as it is breaking down enzymes and saliva. Amylase breaks down proteins in the saliva to starches to glucose. It’s average pH level is 6.5 to 7.0. Once the glucose makes it way to the stomach, the pH of 1 to 3 in the stomach is much lower and too acidic for the amylase to handle, so it becomes inactive. Lab 2 (= Lab 3 in PowerPhys): Recruitment and Isotonic and Isometric Contractions Total marks: /6 1. Did motor unit stimulation (reflected in amplitude and number of spikes per 0.2 sec time period) increase, decrease, or not change when biceps brachii went from concentric to eccentric contraction with a five-pound load? (1 mark) Motor unit stimulation decrease with amplitude – 0.43 to 0.32mV in an eccentric contraction with a five-pound load. Semg goes up and did not change or move from concentric to eccentric contraction with a five-pound load. 2. Based on changes in the amplitude and frequency of the EMG spikes, did motor unit activation increase, decrease, or stay the same with increasing muscle load? (1 mark) Motor activation increases because activated motor units are contracting with more frecuency. 3. Discuss the importance of muscle tone. (1 mark) Muscle tone is important because it allows humans to have posture and sit and stand straight. Smooth muscle tissue helps humans’ GI tracts work effectively. Muscle tone also helps blood vessels maintain an optimal blood pressure. 4. Discuss how increasing the number of motor units stimulated affects force. (1 mark) The motor unit frequency of firing rate of each individual motor unit increases with increasing muscular force until an optimal point is reached. 5. During forearm flexion, what type of contraction would the biceps brachii be exhibiting: concentric isotonic contraction, eccentric isotonic contraction, or isometric contraction. (1 mark) During forearm flexion, the biceps brachii would be exhibiting concentric isotonic contraction. In concentric isotonic contraction, the tension generated is great enough to overcome the resistance of the object to be moved; muscles get shortened pulling the tendon and causing movement; tension generated is not enough to overcome the reisstance offered by the object to be moved. 6. Flaccid muscles do not exhibit muscle tone. Explain how muscles become flaccid. (1 mark) ........................................................................CONTINUED...................................................................... [Show More]

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