Laboratory report for BIO PDF

Preview

Summary

Lab results for assignments. homework and study notes....

Description

Laboratory Report

LABORATORY REPORT Activity: Name: Instructor: Date:

Enzyme Activity Tenique Johnson Elizabeth Kraske 07.23.2021

Predictions 1. Sucrase will have the greatest activity at pH 3 2. Sucrase will have the greatest activity at 40 °C (104 °F)

3. Sucrase activity increases with increasing sucrose concentration until a plateau is reached

Materials and Methods Effect of pH on Enzyme Activity 1. Dependent Variable amount of product (glucose and fructose) produced

2. Independent Variable pH

3. Controlled Variables temperature, amount of substrate (sucrose) present, sucrase + sucrose incubation time

Effect of Temperature on Enzyme Activity 1. Dependent Variable amount of product (glucose and fructose) produced

2. Independent Variable temperature

3. Controlled Variables pH, amount of substrate (sucrose) present, sucrase + sucrose incubation time

Effect of Substrate Concentration on Enzyme Activity 1. Dependent Variable amount of product (glucose and fructose) produced

2. Independent Variable amount of substrate (sucrose) present

3. Controlled Variables temperature, pH, sucrase + sucrose incubation time

4. Describe what is measured as an indicator of sucrase activity and why this is an indicator of sucrase activity. The amount of glucose and fructose formed will be an indicator of sucrase activity. This is an absolute indicator of sucrase activity because the amount of the activity.

Laboratory Report/ Tenique Johnson/ Enzyme Activity/ Elizabeth Kraske/ 07.23.2021/ Page [1] of [4]

Laboratory Report

5. Explain why denatured sucrase was used as a control. Denatured sucrase was used as a control to check the presence and activity of experimental sucrase and also to confirm that the changes in experimental set up is due to sucrase activity.

6. Addition of DNS at the end of the incubation period stopped the reaction by denaturing sucrase. Explain why it is important to denature sucrase before measuring product concentration. It is important to denature sucrase before measuring product concentration to stop the continuous enzyme activity and product formation.

Results Table 4: Effect of pH on Sucrase Activity ph 3 0.193 0.169 0.165 0.176

1 2 3 average

ph 4 0.340 0.337 0.328 0.335

ph 5 0.671 0.636 0.631 0.646

Optical Density ph 6 0.961 0.932 0.957 0.950

ph 7 0.801 0.822 0.784 0.802

ph 8 0.421 0.421 0.431 0.424

ph 9 0.184 0.179 0.157 0.173

Effect of pH on Sucrase Activity Glucose (O.D. units) 1 0.8 0.6 0.4 0.2 0 3

4

5

6

7

8

9

pH

1. State the optimum pH for sucrase activity and describe how sucrase activity changes at more acidic and more alkaline pH values. The optical density corresponds to amount of glucose released from sucrose as a result of sucrase activity. Higher the optical density, higher will be the sucrase activity.

2. Was the rate of increase of sucrase activity higher at a pH of 8.5 or a pH of 5.5? The enzyme activity will be higher at pH 5.5 than at pH 8.5. This is because pH 5.5 is much closer to the optimal pH of sucrase than pH 8.5.

Table 5: Effect of Temperature on Sucrase Activity 10 °C (50 °F) 0.008 0.007 0.010 0.008

1 2 3 average

20 °C (68 °F) 0.289 0.300 0.267 0.285

30 °C (86 °F) 0.792 0.762 0.796 0.783

Optical Density 40 °C (104 °F) 0.922 0.939 0.964 0.942

Effect of Temperature on Sucrase Activity Glucose (O.D. units) 1 0.8 0.6 0.4 0.2 0 10

20

30

40

50

60

70

t, °C

Laboratory Report/ Tenique Johnson/ Enzyme Activity/ Elizabeth Kraske/ 07.23.2021/ Page [2] of [4]

50 °C (122 °F) 0.934 0.910 0.940 0.928

60 °C (140 °F) 0.846 0.806 0.812 0.821

70 °C (158 °F) 0.618 0.644 0.618 0.627

Laboratory Report

3. State the optimum temperature for sucrase activity and describe how sucrase activity changes at lower and higher temperatures. This means higher the Sucrase activity, higher will be the glucose concentration. The glucose concentration in terms of OD indicates Sucrase activity. 4. Was sucrase activity higher at 25 °C or 55 °C? Sucrase activity was higher at 55 degree Celsius than at 25 degree Celsius because higher the glucose concentration, higher is the Sucrase activity.

Table 6: Effect of Sucrose Concentration on Sucrase Activity

1 2 3 average

35 g/L 0.988 1.002 1.014 1.000

30 g/L 0.996 1.000 0.987 0.994

25 g/L 0.944 0.943 0.945 0.944

Optical Density 20 g/L 15 g/L 0.900 0.850 0.903 0.858 0.891 0.864 0.898 0.857

10 g/L 0.750 0.778 0.759 0.762

5 g/L 0.492 0.490 0.511 0.498

0 g/L 0.001 0.000 0.003 0.001

Effect of Sucrose Concentration on Sucrase Activity Glucose (O.D. units) 1 0.8 0.6 0.4 0.2 0 0

5

10

15

20

25

30

35

final sucrose concentration, g/l

5. State how sucrase activity changes with increasing sucrose concentration. In the first stages sucrase activity is directly proportional to sucrose concentration. When sucrose concentration reaches a particular level of 30g/l sucrase activity becomes constant. No increase. 6. Was the rate of increase of sucrase activity greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l? Rate of increase of sucrase activity is greater when sucrose concentration went from 2.5-7.5g/l than from 22.5-27.5g/l.

pH Along the GI Tract Organ

mouth

stomach

pH

6.35 - 6.85

1-3

duodenum (first section of small intestine) 6

jejuneum (second ileum (third section section of of small intestine) small intestine) 7.5 7.5

colon

7.5 - 8

Discussion 1. Referring to the table above, specifically state where in the intestine sucrase is likely most active. In the intestine sucrase activity is more in the duodenum. Because the ph in duodenum is 6.optimum ph(ph at which maximum enzyme activity present) of sucrase is approximately 6 (range-4.5-7.0)

2. Compare optimal temperature for sucrase activity to body temperature. Optimal temperature for sucrase is 40 C or 104 Farenheit. Our body temperature is about 98.6 farenheit or 37C.sucrase have no optimal activity at body temperature. 3. How would a slight fever affect sucrase activity? A slight fever increases body temperature slightly so that it reaches near the optimal temperature of sucrase. This increases sucrase activity.

4. Explain how pH of intestine and temperature of body together affect enzyme activity.

Laboratory Report/ Tenique Johnson/ Enzyme Activity/ Elizabeth Kraske/ 07.23.2021/ Page [3] of [4]

Laboratory Report

Enzymes are most active at their optimum ph and temperature conditions. The body temperature is normally optimal for almost all enzymes with slight variations as in case of sucrase. Intestines has 3 regions with different ph which allows a particular enzyme to act at any one of the 3 regions. 5. Explain how increasing amount of sucrose in food affects sucrase activity. Increasing amount of sucrose in food increases sucrase activity but only up to a particular level of sucrose concentration as seen in the above graph. After that if sucrose concentration is increased it does not affect sucrase activity. 6. In the results section you were asked if rate of increase of sucrase activity was greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l. Explain why the rate of increase was greater for this range. At first stages when ph went from 2.5 to 7.5 g/l rate of increase of sucrase activity was greater. But when it went from 22.5 to 27.5 g/l increase in sucrase activity was lower. This is because when sucrose concentration was low more sucrase enzyme molecules are available for action. When sucrose concentration increased these enzymes got occupied and availability of free enzymes was low. Almost all enzymes got saturated with sucrose.

7. In this experiment, if the sucrose concentration were increased to 70 g/l would you expect sucrase activity to be significantly higher than the activity at 35 g/l. Explain your answer. If sucrose concentration is tremendously increased from 30g/l to 70 g/l overall sucrase activity will be increased. But not much increase will be noted as enzymes will be saturated. There will also be increase in glucose and fructose. 8. Restate your predictions that were correct and give the data from your experiment that supports them. Restate your predictions that were not correct and correct them, giving the data from your experiment that supports the corrections. I predicted that the ph 7 would have greater activity than ph 6. I believed this in the beginning since it was a higher number, it would have been more activity. I now know that ph 6 has greater activity after further research.

Application 1. Myosin ATPase is an enzyme that is involved in muscle contraction. Athletes do warm-up exercises prior to athletic performance. Explain why warm-up exercises increase myosin-ATPase activity. Warm-up exercises loosens the muscles and increase blood flow to muscles and lessens chance of injury. It also activates myosin ATPase so that myosin heads are activated and increase muscle contraction. Describe how increasing myosin-ATPase activity affects muscle contraction. Increasing myosin ATPase activity increases myosin head activation. This causes more binding of myosin heads to actins. More stronger binding results in increased force of contraction and increase performance of athletes.

2. 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. Optimum ph of salivary amylase is about 6.7 - 7.0.ph of mouth is 6.7-7.3.so salivary amylase is active in the mouth. When it reaches the stomach, ph lowers below 5.0 and salivary amylase becomes inactive. It cannot act at the acidic ph of the stomach.

Laboratory Report/ Tenique Johnson/ Enzyme Activity/ Elizabeth Kraske/ 07.23.2021/ Page [4] of [4]...