Rate Of Cellular Respiration Biology Essay

Published:

This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.

In the lab the relative volume of O2 consumed by germinating and non-germinating peas at room temperature and 10ËšC was determined. The central purpose was to find the affect of germination and temperature on the rate of cellular respiration. The results indicated that the respirometers that contained germinated peas had a greater rate of cellular respiration compared to those with non-germinating and showed that cellular respiration was faster at 10ËšC. The experiment demonstrated the affect of environmental factors on cellular respiration.

Introduction

The general questions for the lab involve the affect of environmental factors such as temperature and germination of seeds on cellular respiration. The experiment was performed to discover the affects of temperature and germination on the pea, Pisum Savitum during respiration. The hypothesis predicted says the rate of cellular respiration would be greater in germinating peas verses in non-germinating peas because the dormancy of the non- germinating seeds would result in less oxygen consumed. The prediction for the affect of temperature on cellular respiration says that hotter the temperature, the faster the rate of consumption because as the temperature increases the molecules will move more slowly causing the interactions to be more frequent producing more CO2

Cellular Respiration is a key way that a cell gains energy. Organic compounds release energy in cellular respiration using O2. This takes place in the mitochondria of a cell. Energy of food molecules is freed and made into ATP. Fats, Proteins, and Carbohydrates are all sources of fuels. Glycolysis, the Krebs Cycle, and oxidative phosphorylation are the three metabolic processes that make up cellular respiration. When O2 is not present, respiration occurs in only glycolysis and fermentation. In glycolysis, glucose breaks into two pyruvates producing two ATP molecules and two NADH molecules. Next is the Krebs cycle where a bundle of chemical energy is produced. The pyruvate is transferred into the mitochondria where it loses carbon dioxide forming acetyl-CoA. This molecule is oxidized to carbon dioxide releasing chemical energy and staying in the form of FADH2, NADH, and ATP. Then the energy stored in NAD+ and FAD is released. The released energy is ATP. In cells lacking oxygen, pyruvate is oxidized by fermentation after glycolysis. Fermentation regenerates NAD+ by oxidizing the NADH produced in glycolysis. About 36-38 molecules of ATP are generated by glucose in aerobic respiration compared to only two in anaerobic respiration. Cells control reaction rates in response to changes in metabolic needs. When their products are sufficient in supply anabolic pathways are shut off. Feedback inhibition is the most common mechanism. Glycolysis and the Krebs cycle are controlled by regulating enzyme activity at certain points. The third step of glycolysis is a key point in catabolism which is catalyzed by a key enzyme called phosphofructokanse. As its concentration rises, it slows down glycolysis. As the rate of glycolysis slows the Krebs cycle also slows since the supply of acetyl-CoA is reduced. ADP and AMP are allosteric activators for phosphofructokinase so when their concentrations (relative to ATP) the enzyme speeds up glycolysis which speeds up the Krebs cycle.

This experiment involved seeds that were living but also dormant. A seed is dormant if it is in a state where it is prevented from germinating in all conditions. The non-germinating seeds we used were dormant. Germination begins when warmth and moisture conditions are favorable. Most seeds contain a plant embryo and an initial food supply which are protected by a seed coat. Environmental condition ns such as gases, temperature, light, and mechanical restrictions which are usually favorable for germination do not germinate a dormant seed. In the experiment, germination will begin when the seeds are soaked. The enzymes begin to use to stored food supply to make ATP which increases the rate of cellular respiration. The complete oxidation of glucose is shown in the equation by this equation: C6H12O6  6CO2 +6H2O +686 kilocalories of energy/mole of glucose oxidized. . Oxygen is required for this energy releasing process to occur. Cellular respiration can be determined by the consumption of O2, the production of CO2, and the release of energy during cellular respiration. In this experiment, the relative volume of O2 consumed by germinating and non germinating peas will be measured.

The apparatus used in the experiment can be explained by gas laws. PV=nRT is the general gas law. P stands for the pressure of the gas. V stands for the volume of the gas. N stands for the number of molecules of gas. R stands for the gas constant. T is the temperature of the gas (K). The law suggests four concepts about gases. The first law states that if the pressure and temperature are kept constant, then the volume of the gas is directly proportional to the number of molecules of the gas. The second states that the pressure and molecules of gas are proportionate if the temperature and volume are unchanged. The third states if the amount of gas molecules and the temperature remain constant, then the pressure is inversely relative to the volume. The fourth is if the temperature changes and gas molecules are kept constant, then either the pressure, volume, or both will change in direct proportion to the temperature. Both gases and fluids flow from areas of high pressure to regions of low pressure. In the experiment, potassium hydroxide will remove the CO2 formed during cellular respiration. This will form solid potassium carbonate (K2CO3) shown by CO2 + 2KOH  K2CO3 +H2O. Because CO2 is removed, the change in the volume of gas in the respirometers will be directly related to the amount of oxygen consumed. In the experiment apparatus, if H2O temperature and volume remain constant, the water will move toward the region with lower pressure. Oxygen is consumed during respiration. Its volume is reduced, because the CO2 produced is being converted to a solid. The net result is decrease in gas volume within the tube and a related decrease in pressure in the tube. The vial with glass beads alone will show any changes in volume due to pressure, atmospheric, or temperature changes. A respirometer measures the rate of exchange of either carbon dioxide or oxygen. It is used to determine the rate of respiration for a living organism.

Materials and methods

Materials

100 mL graduated cylinder

20 dried peas

20 germinating peas

Glass beads

Six vials with fastened stoppers and pipettes

Nonabsorbent cotton

15% KOH

-Carolina Biological Potassium Hydroxide 15% 150 mL for KOH 2006

Absorbent cotton

Ice

Ice pack

Thermometer

Tap water

Piece of paper

Timer

weights

scale

-Item No: SC2020

-Capacity: 200 X 0.01g

-Power: +6 to 12 VDC 70m A max

-Battery req: 1 av alkaline

Dry Peas, 1 lb.-

manufacturer: Carolina Biological

model # 158863

AP Biology Lab 5: Cellular Respiration Lab Activity

manufacturer: Ward's Natural Science

model # 36 V 7104

Methods

Begin by setting up a 10ËšC bath to allow time for the temperature of the water to adjust. Add ice and an ice pack to attain a temperature of 10ËšC. Then fill 50mL of water into a 100mL graduated cylinder. Put 20 germinating peas in the cylinder and measure how much water was displaced. The quantity of H2O moved should equal the peas' volume. Record the volume of the 20 peas. Then remove the peas and place them on to a paper towel. Fill the graduate cylinder with 50 mL. Drop 20 non-germinating. Put in glass beads until a volume equal to the germinating peas' volume is reached. Take out the peas and put them on to a paper towel. Then fill the graduated cylinder with fifty mL of H2O. Drop glass beads until a volume equal to the volume of the germinating peas is reached. Then take out these peas and put them on a paper towel. Then put together three respirometers. Get three vials attached with a pipette and stopper. For each vial, put a tiny piece of cotton and put five drops or until moistened onto cotton of 15% KOH. On the top of each KOH-soaked absorbent cotton, place a small wad of nonabsorbent cotton. Then, place the first three sets of beads into the first thee vials. Place in the fitted stopper. Put a weighted collar on every end of the vial. Then place the first three vials into the 10ËšC water bath. Make sure that the pipettes did not touch the H2O for the seven minute equilibration. After seven minutes, submerge the three respirometers into the baths, covering them complete with water. Place a sheet of paper underneath to make the amount of water entering the pipette easier to see and measure. Position the pipettes to ensure they can be read clearly. Let the respirometers equilibrate for three additional minutes and then record the initial position of H2O in every pipette. Check the temperature in both baths and record them. In 5 minute intervals up to 20 minutes take measurements of the water's position in each pipette and record the data.

(College Board, 2001)

Respirometer Setup

Respirometer

Temperature

Contents

1

Room

Germinating seeds

2

Room

Dry seeds and beads

3

Room

Beads

4

10 ËšC

Germinating seeds

5

10ËšC

Dry seeds and beads

6

10ËšC

Beads

Table 1

Equations and calculations

Difference = initial reading at time 0 - reading at time X

<>Corrected difference= (Initial pea seed reading at time 0 - pea seed reading at time X) - (initial bead reading at time 0 - bead reading at time X)

Rate of O2 consumption of germinating and non-germinating peas (during experiment at both temperatures)= <>Y/<>X

Averages= Group 1 Data + Group 2 Data + Group 3 Data + Group 4 Data/4

Results

Group Data 10ËšC

Temp (CËš)

Time (min)

Beads alone

Germinating Peas

Dry Peas and Beads

Reading at time x

Diff

Reading at time x

Diff

Corrected Diff

Reading at time x

Diff

Corrected Diff

12

0

.79

-

.71

-

-

.88

-

-

11

5

.76

.03

.66

.05

.02

.85

.03

-.001

11

10

.75

.04

.63

.08

.04

.85

.03

-.01

11

15

.75

.04

.61

.1

.06

.85

.05

-.01

12

20

.75

.04

Table 2.59

.12

.08

.85

.03

-.01

Graph 1

Class Data Group 1 for 10ËšC

Time

(min.)

Temp.

(CËš)

Beads

Germinating

Non-Germ

With Beads

Read. X

Diff.

Read. X

Diff

Corrected Diff

Read. X

Diff

Corrected Diff.

Group 1

0

12

0.81

-

0.72

-

-

0.71

-

-

5

11

0.74

.07

0.63

.09

.07

0.65

.06

-.01

10

11

0.72

.09

0.57

.15

.06

0.67

.04

-.05

15

11.5

0.72

.09

0.54

.18

.09

0.71

.0

-.09

20

11.5

0.72

.09

0.53

.19

.1

0.69

.02

-.07

Table 3

Class Data Group Two 10ËšC

Time

(min)

Temp

(CËš)

Beads

Germinating

Non-Germ With Beads

Read. X

Diff.

Read. X

Diff

Corr.

Diff.

Read. X

Diff

Corrected Diff.

Group 2

0

10

0.88

-

0.85

-

-

0.87

-

-

5

10

0.88

0.00

0.80

.05

.05

0.85

.02

.02

10

10

0.86

.02

0.70

.15

.13

0.83

.04

.02

15

11

0.90

-.02

0.69

.16

.18

0.85

.02

.04

20

11

0.95

-.07

0.65

.2

.27

0.8

.07

.14

Table 4

Class Data Group Three 10ËšC

Time

(min)

Temp

(CËš)

Beads

Germinating

Non- Germ With Beads

Beads

Diff

Read. X

Diff

Corr.

Diff.

Read. X

Diff

Corr.

Diff.

Group 3

0

13.5

0.80

-

0.75

-

-

0.78

-

-

5

13.5

0.79

.01

0.685

.065

.055

0.75

.03

.02

10

13.5

0.783

.017

0.66

.09

.073

0.745

.035

.018

15

13.5

0.785

.015

0.65

.1

.085

0.75

.03

.015

20

13.5

0.79

.01

0.646

.104

.094

0.75

.03

.02

Table 5

Class Data Group Four 10ËšC

Time

(Min)

Temp

(CËš)

Beads

Germinating

Non- Germ With Beads

Read. X

Diff.

Read. X

Diff

Corr.

Diff.

Read. X

Diff

Corr.

Diff.

Group 4

0

12

0.79

-

0.71

-

-

0.88

-

-

5

11

0.76

.03

0.66

.05

.02

0.85

.03

0

10

11

0.75

.04

0.63

.08

.04

0.85

.03

-.01

15

11

0.75

.04

0.61

.1

.06

0.85

.03

-.01

20

12

0.75

.04

0.59

.12

.08

0.85

.03

-.01

Table 6

Class Data Group 1 Room Temperature

Time

Temp

(CËš)

Beads

Germinating

Non-Germ With Beads

Read.

x

Diff.

Read

Diff.

Corr.

Diff.

Read. X

Diff

Corr.

Diff.

Group 1

0

24

0.87

-

0.83

-

-

0.82

-

-

5

24

0.85

.02

0.78

.05

.03

0.78

.04

.02

10

23

0.84

.03

0.73

.1

.07

0.76

.06

.03

15

23

0.84

.03

0.68

.15

.12

0.75

.07

.04

20

23

0.83

.04

0.65

.18

.14

0.74

.08

.04

Table 7

Class Data Group 2 Room Temperature

Time

(min.)

Temp.

(ËšC)

Beads

Diff

Germinating

Non-Germ With Beads

Read.

X

Diff.

Read. X

Diff

Corr. Diff.

Read. X

Diff

Corr. Diff.

Group 2

0

24

0.90

-

0.9

-

-

0.88

-

-

5

24

0.88

.02

0.86

.04

.02

0.88

0.00

-.02

10

24

0.87

.03

0.83

.07

.04

0.87

.01

-.02

15

24

0.86

.04

0.8

.1

.06

0.87

.01

-.03

20

24

0.85

.05

0.77

.13

.08

0.86

.02

-.03

Table 8

Class Data Group 3 Room Temperature

Time

(min.)

Temp

(CËš)

Beads

Germinating

Non- Germ With Beads

Read. X

Diff.

Read. X

Diff

Corr. Diff.

Read

Diff

Corr. Diff.

Group 3

0

23

0.89

-

0.86

-

-

0.88

-

-

5

23

0.88

.01

0.82

.04

.03

0.87

.01

0.0

10

23

0.86

.03

0.78

.08

.05

0.84

.04

.01

15

23

0.85

.04

0.74

.12

.08

0.82

.06

.02

20

23

0.83

.06

0.68

.18

.12

0.8

.08

.02

Table 9

Class Data Group 4 Room Temperature

Time

(min)

Temp.

(CËš)

Beads

Germinating

Non- Germ With Beads

Read. X

Diff.

Diff

Corr. Diff.

Read. X

Diff.

Corr. Diff.

Group 4

0

21

0.85

-

0.81

-

-

0.84

-

-

5

21

0.84

.01

0.77

.04

.03

0.83

.01

0.0

10

21

0.83

.02

0.72

.09

.07

0.81

.03

.01

15

21

0.83

.02

0.68

.13

.11

0.81

.03

.01

20

21

0.83

.02

0.67

.14

.12

0.80

.04

.02

Table 10

Class Average Germinating Peas 10C

Time (min.)

Temperature (c )

Corrected Difference (mL)

Germinating Peas

10C

0

11.88

-

5

11.38

.049

10

11.38

.076

15

11.75

.104

20

12

.136

Table 11

Class Average Germinating Peas Room Temperature

Time

Temperature

Corrected difference (mL)

Non-Germinating Peas

10C

0

11.88

-

5

11.38

.0075

10

11.38

-.0055

15

11.75

-.01125

20

12

.02

Table 12

Class Average Germinating Peas Room Temperature

Time

Temperature

Corrected Difference (mL)

Germinating Peas

Room Temperature

0

23

-

5

23

.0275

10

22.75

.0575

15

22.75

.0925

20

22.75

.12

Table 13

Class Average Non-Germinating Peas Room Temperature

Time

Temperature

Corrected Difference (mL)

Non-germinating Peas with beads

Room temperature

0

23

0

5

23

.0.0075

10

22.75

.01

15

22.75

.01

20

22.75

.0125

Table 14

Graph 3

Rate of Cellular Respiration

Condition

Calculations

Rate (mL O2 per minute)

Germinating peas at10ËšC

.136/20

.0068

Germinating peas at room temperature

.12/20

.006

Dry peas at10ËšC

.02/20

.001

Dry peas at room Temperature

.0125/20

6.25E-4

Table 15

The results showed a general trend of increase in the concentrated difference of the peas. Most of the results accurately showed the affect of germination and temperature on cellular respiration. The rate of the Germinating Peas was the quickest. The group data for the non-germinating peas was not accurate because the amount of oxygen was reduced (Graph 1). However; the group data for the germinating peas showed a linear trend of increase. Because the temperatures varied we corrected the differences in volume that were due to temperature instability rather than the rate of respiration by finding the corrected difference. Corrected difference was found by subtracting the change in the transition of H2O into the vial with glass beads from the experimental vials, held at the equal temperature. Therefore our results showed an accurate affect of temperature.

Conclusion

The Results supported the hypothesis predicting the affect of germination on the rate of respiration. The respirometers with germinating seeds had a faster rate of cellular respiration in both room and 10ËšC temperature compared to the respirometers containing non-germinating seeds (Table 15). The non-germinating peas took in less O2 compared to those germinated which can be seen by Graph 1 and 2, causing cellular respiration to occur more slowly. This happened because germinated seeds need more oxygen to continue to survive and grow even though germinated and non- germinated seeds are both alive. In the lab, the carbon dioxide made by cellular respiration was removed by Potassium Hydroxide which created Potassium Carbohydrate. The difference in the volume of gases in the respirometers was proportional to the quantity of oxygen consumed due to the oxygen being removed. What was predicted of the affect on temperature on respiration did not occur. The rate of respiration was not higher at room temperature compared to at 10ËšC. This may be due to the peas being adapted to harvesting. Peas are a cool weathering crop, so they do not harvest best at hotter temperatures. The peas therefore are adapted to cooler temperature accounting for the rate of cellular respiration being higher in 10ËšC.

There were possible errors that may have occurred in the experiment. Any of the respirometers could have leaked due to the seals not being completely air tight causing gas to escape. The amount of cotton in each vial was an estimate which could have affected the transformation of CO2 into a solid. The peas came in contact with the KOH which may have affected the transformation of CO2 into a solid. Moving the vials and putting your hands in the water could have caused contamination. The timing for the five minute timer intervals and equilibration period may have had errors affection the amount of oxygen consumed. Improvements in the lab could be made by taping the respirometers onto the bath to prevent movement. Also by having more ice and also crushing the ice instead of using cubes to help keep the water temperature more constant. Some extensions for the lab could be to measure the rate of cellular respiration with different types of peas. Also the affect of other environmental factors such as light intensity and pH could be tested. This lab effectively showed affect of temperature and germination on cellular respiration using the pea, Pisum Sativum.

Writing Services

Essay Writing
Service

Find out how the very best essay writing service can help you accomplish more and achieve higher marks today.

Assignment Writing Service

From complicated assignments to tricky tasks, our experts can tackle virtually any question thrown at them.

Dissertation Writing Service

A dissertation (also known as a thesis or research project) is probably the most important piece of work for any student! From full dissertations to individual chapters, we’re on hand to support you.

Coursework Writing Service

Our expert qualified writers can help you get your coursework right first time, every time.

Dissertation Proposal Service

The first step to completing a dissertation is to create a proposal that talks about what you wish to do. Our experts can design suitable methodologies - perfect to help you get started with a dissertation.

Report Writing
Service

Reports for any audience. Perfectly structured, professionally written, and tailored to suit your exact requirements.

Essay Skeleton Answer Service

If you’re just looking for some help to get started on an essay, our outline service provides you with a perfect essay plan.

Marking & Proofreading Service

Not sure if your work is hitting the mark? Struggling to get feedback from your lecturer? Our premium marking service was created just for you - get the feedback you deserve now.

Exam Revision
Service

Exams can be one of the most stressful experiences you’ll ever have! Revision is key, and we’re here to help. With custom created revision notes and exam answers, you’ll never feel underprepared again.