LABORATORY REPORT Activity: Recruitment and Isotonic and Isometric Contractions Name: Carolyn Chrzastowski Instructor: Professor Waite Date: 07.19.2015 Predictions When the arm goes from resting to flexing, the amplitude and frequency of sEMG spikes will increase During flexion, the amplitude and frequency of sEMG spikes will ___ during extension. be greater than Recruitment of motor units will be greatest when the load is 20 pounds Materials and Methods Comparison of motor unit activation during muscle tone and concentric and eccentric isotonic contractions Dependent Variable amplitude and frequency of sEMG spikes Independent Variable muscle movement Controlled Variables total number of motor units
Description and Theories A. Principles and Theories Used to Obtain our Result An conventional spring, when subjected the weight (w=mg) of an object at one of its terminations, will displace a certain distance, x, with an equal and opposite force, F, being created in the spring of which opposes the pull of the weight. This conventional spring will become significantly distorted if it is subjected to a large enough weight and the force, F, will only be able to return the spring to its original configuration once the burden is removed. The force that will restore the spring to its original configuration is directly proportional to the displacement that occurred. The following equation represents this relationship where k denotes the spring constant or stiffness of the spring, F=-kx Since x symbolizes the displacement or change in the length of the spring the above equation can now be surmised in the following manner, F=mg=-k∆l This new form makes it evident that a linear proportion exists between the plot of F as function of changing in length, ∆, thus confirming the spring does in fact obey Hooke’s Law.
Background: A reaction rate is the decrease in concentration of a reactant or the increase in concentration of a product with time. Thus, the units for the reaction rate are usually Molarity per second (M/s) – that is , the change in concentration (measured in molarity) divided by a time interval (seconds in this case) (Chemistry: The Central Science, P. 527). Rate is usually calculated by taking an average of the disappearance or appearance of a compound with respect to time. In this case it is calculated by the absorbance of the light. Reaction rate is affected by any catalysts present (which speed up the reaction usually with an intermediate step), temperature (increases the number of particles collisions), concentration (increases the number of collisions), and surface area (increases the space available for collisions).
The response diminishes as deviations from this optimal length increases. These results are consistent with an optimal length of overlap, with associated cross-bridging, between actin and myosin filaments in the sarcomere as suggested by sliding filament theory. Introduction According to the sliding filament theory, (1) and (2), striated muscle contracts when cross-bridges between overlapping myosin (thick) and actin (thin) filaments initiate many independent filament micro-slides which result in shrinkage of the structural unit of the muscle fiber called the sarcomere. Evidence for this sliding theory was first observed in the constancy of the length of the sarcomere’s A-band under length variations of the sarcomere. The A-band has a region where actin and myosin filaments overlap.
a. decreasing the temperature b. changing the concentration of A c. changing the concentration of B d. changing the concentration of C e. letting the reaction go on for a long time 4. The gas phase reaction A + B C has a reaction rate which is experimentally observed to follow the relationship rate = k[A]2[B]. If the concentration of A is tripled and the concentration of B is doubled, the reaction rate would be increased by a factor of ____. a. 6 b.
Explain the effect that the flow tube radius change had on flow rate. How well did the results compare with your prediction? The increase of flow tube radius increased the flow rate, as predicted. 3. Describe the effect that radius changes have on the laminar flow of a fluid.
Next we will chart the data and form two different plots. The first plot will be actual temperature as a function of time. The second chart will be excess temperature as a function of time. On the second chart I will place an exponential trendline showing the equation of the line. Using this equation I can determine the cooling time constant for the block of steel.
This is illustrated above, where the equilibrium price rises from P to P’ and the quantity from Q to Q’. (b) The substitution effect is closely related to the principle of substitution. (c) Answer (a) is incorrect because it causes an upward movement along the demand curve. Answers (b) and (d) cause the demand curve to shift to the left. (c) The distinction between an increase (or decrease) in demand and an increase (or decrease) in quantity demanded is vital.
This causes the rubber band to have an elastic limit which is caused when the molecules’ motion is stopped by these cross links. The disorder in the rubber band is described as its entropy, so when there is a high level of disorder of the molecules, there will be a high entropy level. When stretching occurs, the molecules line up and they uncoil from their original structures. This causes the molecules to become more ordered and so lowers the entropy. Heat is then given out when entropy decreases and therefore energy is lost.
State the optimum pH for sucrase activity and describe how sucrase activity changes at more acidic and more alkaline pH values. See Table 2: Effect of Temperature on Sucrase Activity See Graph, Effect of Temperature on Sucrase Activity 2. Was the rate of increase of sucrase activity higher at a pH of 8.5 or a pH of 5.5? 3. State the optimum temperature for sucrase activity and describe how sucrase activity changes at lower and higher temperatures.