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Cellular Respiration and Photosynthesis

Page history last edited by Darrell Sharp 11 years, 11 months ago

 

8.1 Respiration

 

 

Mitochondrion micrograph from http://library.thinkquest.org/3564/gallery.html

 

 

 

 

 

 

 

 

    Overall Reaction

 

C6H12O6 + 6O2 --> 6CO2 + 6H2O

 

 36APD + 36Pi --> 36 ATP

 

 

    Cellular Respiration Lab

 

    Homework Questions 

 

    Click4Biology 

 

 

8.1.1 

State that oxidation involves the loss of electrons from an element, whereas reduction involves a gain of electrons; and that oxidation frequently involves gaining oxygen or losing hydrogen, whereas reduction frequently involves losing oxygen or gaining hydrogen.

 

 

Oxidation and reduction reactions are coupled together in respiration.

 

Oxidation Reactions

 

  • losing electrons
  • gaining oxygen
  • losing hydrogen
  • releasing energy 

 

Reduction Reactions

 

  • gaining electrons
  • losing oxygen
  • gaining hydrogen
  • gaining energy 

 

 

8.1.2 

Outline the process of glycolysis, including phosphorylation, lysis, oxidation and ATP formation.

 

Glycolysis

 

C-C-C-C-C-C + 2Pi

  I 

Phosphorylation

  I

P-C-C-C-C-C-C-P 

  I 

Lysis

  I 

2 P-C-C-C                 2ADP + 2Pi          NAD+ + H

  I                                    I                         I

Oxidation                 Reduction         Reduction

  I                                    I                         I

2 C-C-C                        2ATP               NADH + H+

 

Net production: 2 ATP

 

Glycolysis

 

1. Phosphorylation: 2 phosphates are added to glucose.

2. Lysis: breaking the hexose diphosphate into 2 triose phosphates. 

3. Oxidation: 2 triose phosphates are oxidized into 2 pyruvate.

4. ATP formation: coupled with the oxidation reaction above, reduction of ADP +Pi into ATP and reduction of NAD+ into NADH and H+.

 

1. C-C-C-C-C-C + 2Pi --> P-C-C-C-C-C-C-P

 

2. P-C-C-C-C-C-C-P -->2 P-C-C-C 

 

3. 2 P-C-C-C --> 2 C-C-C

 

4. 2ADP + 2Pi --> 2ATP

    NAD+ + H --> NADH + H+

 

Glycolysis Song with molecules and enzymes

Glycolysis Song with lyrics

 

 

8.1.3

Draw and label a diagram showing the structure of a mitochondrion as seen in electron micrographs.

 

Structures:

outer membrane

inner membrane

cristae

matrix

 

 

8.1.4

Explain aerobic respiration, including the link reaction, the Krebs cycle, the role of NADH + H+, the electron transport chain and the role of oxygen.

 

8.1.5

Explain oxidative phosphorylation in terms of chemiosmosis.

 

 

 

 

 

 

 

 

 

 

 

Link Reaction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Krebs Cycle

 

http://ict4us.com/r.kuijt/en_krebs.htm

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Oxidative phosphorylation - ATP synthesis

http://www.biologycorner.com/APbiology/cellular/(notes)cellular_respiration.html

 

 

 

 

 

Aerobic Respiration

 

Actors:

C-C-C = pyruvate: 3 carbon molecule

CoA = co-enzyme A, a large enzyme that breaks pyruvate

C-C-CoA = acetyl CoA, two carbons joined to the enzyme

CO2 = carbon dioxide

NAD+, FAD, ADP = low energy molecules

NADH, FADH2, ATP = high energy molecule

H+ = hydrogen ion/proton

O2 = molecular oxygen

e-  = electron

 

Transport:

Pyruvate is transported into the matrix of the mitochondrion.

 

Link reaction:

Pyruvate joins with co-enzyme A and is decarboxylated producing acetyl CoA and CO2.

This oxidation of pyruvate is coupled with the reduction of NAD+ into NADH and H+.

(CoA is an abbreviation, not a chemical formula)

 

 

C-C-C + CoA --> C-C-CoA + CO2

NAD+ + H --> NADH + H+

 

 

 

 

 

 

 

 

Krebs cycle

1. Acetyl CoA bonds with a four carbon molecule in the matrix to produce a six carbon molecule and co-enzyme A. 

2. The six carbon molecule is oxidized and decarboxylated to produce a five carbon molecule and a carbon dioxide.

This oxidation is coupled with the reduction of NAD+ into NADH and H+.

3. The five carbon molecule is oxidized and decarboxylated to produce a four carbon molecule and a carbon dioxide.

This oxidation is coupled with the reduction of NAD+ into NADH and H+.

4. The four carbon molecule is oxidized to reform the original four carbon molecule completing the cycle.

This oxidation is coupled with three reduction reactions: NAD+ into NADH and H+ ; FAD into FADH2 ; ADP + Pi into ATP.

 

1. C-C-CoA + C-C-C-C --> C-C-C-C-C-C + CoA

 

2. C-C-C-C-C-C --> C-C-C-C-C + CO2

    NAD+ + H --> NADH + H+

 

3. C-C-C-C-C --> C-C-C-C + CO2

    NAD+ + H --> NADH + H+ 

 

4. C-C-C-C --> C-C-C-C

    NAD+ + H --> NADH + H+

    FAD --> FADH2 

    ADP + Pi --> ATP

 

The products of the link reaction and the Krebs cycle from two pyruvate molecules are 6 carbon dioxide molecules and many high energy molecules (2ATP, 6NADH, and 2FADH2). 

 

Krebs Cycle Animation (aka Citric Acid Cycle)

Krebs Cycle Song (Karaoke)

 

 

Oxidative phosphorylation:  Electron Transport Chain Animation

The high energy molecules, NADH and FADH2, are oxidized (lose electrons) by proteins in the inner membrane. The proteins are reduced (gain electrons). A series of oxidation/reduction reactions occur in the inner membrane as the electrons are transported within the membrane; these reactions are coupled with the active pumping of hydrogen ions (H+) from the matrix to the intermembrane space. These proteins are called the electron transport chain. The electrons bond with molecular oxygen and hydrogen ions to form water at the end of the chain.

 

NADH --> NAD+ + e-  

FADH2 --> FAD + 2e-

O2 + 4H+ + 4e- --> 2H2O

 

 

The high concentration of hydrogen ions in the intermembrane space creates a concentration gradient. The movement of hydrogen ions across the inner membrane, from high to low concentration, is called chemiosmosis. The movement from the chemiosmosis gives kinetic energy (energy of motion) to ATP synthase, an enzyme complex. ATP synthase uses the energy to bond ADP and Pi into ATP.  ATP Synthase Animation



32ADP + 32Pi --> 32ATP

 

Net Production

2ATP (glycolysis) + 2ATP (Krebs cycle) + 32ATP (oxidative phosphorylation) = 36ATP

 

 

8.1.6

Explain the relationship between the structure of the mitochondrion and its function.

 

 

Structures

double membrane

cristae

matrix

intermembrane space

 

 

 

 

 

8.2 Photosynthesis

 

 

Chloroplast micrograph from http://library.thinkquest.org/3564/gallery.html

 

 

 

 

 

 

 

 

 

 

 

 

Overall Reaction

 

6CO2 + 6H2O --> C6H12O6 + 6O2

 

 

 

Photosynthesis Lab 

 

Homework Questions 

 

Click4Biology 

 

 

8.2.1

Draw and label a diagram showing the structure of a chloroplast as seen in electron micrographs. 

 

Structures

double membrane

thylakoid

grana

lumen

stroma

(starch granules)

 

 

8.2.2

State that photosynthesis consists of light-dependent and light-independent reactions.

 

 

The overall reaction is divided into two processes:

 

1. light-dependent reactions (needs light)

    - occurs in the thylakoid 

    - absorbs light energy

    - splits water

    - converts light energy into chemical energy

    - releases molecular oxygen 

 

2. light-independent reactions (does not need light)

    - occurs in the stroma 

    - uses chemical energy from the light-dependent reactions

    - converts carbon dioxide into organic compounds  such as glucose

 

 

8.2.3

Explain the light-dependent reactions.

Include the photoactivation of photosystem II, photolysis of water, electron transport, cyclic and non-cyclic photophosphorylation, photoactivation of photosystem I, and reduction of NADP+.

 

8.2.4

Explain photophosphorylation in terms of chemiosmosis.

 

 

Light-Dependent Reactions

 

  

http://www.biologycorner.com/

 

Notes

 

Step 2

Water is split to provide electrons for photosytem II.

 

Step 3

Hydrogen ions are pumped across the membrane into the thylakoid lumen by the electron transport chain.

 

Step 5

The diagram shows noncyclic photophosphorylation.

 

Not in the diargram

 

Step 6

In cyclic photophosphorylation, the electrons go back to the electron transport chain to pump hydrogen ions and do not produce NADPH. 

 

Step 7

Hydrogen ions diffuse through ATP synthase by chemiosmosis to produce ATP.

 

 

 

 

 

 

Light-Dependent Reactions

 

1. Photoactivation of Photosystem II

- Light energy excites chlorophylls' electrons in photosytsem II.

- Excited electrons are passed to an electron transport chain.

 

2. Photolysis of Water

- Water is split into molecular oxygen, hydrogen ions, and electrons

- Water's electrons replace chlorophylls' electrons.

 

3. Electron Transport

- Electrons move along an electron transport chain from photosystem II to photosystem I.

- Hydrogen ions are pumped from the stroma to the lumen of the thylakoid.

 

4. Photoactivation of Photosystem I

- Light energy excites chlorophylls' electrons in photosystem I.

 - The excited electrons can follow two different pathways: cyclic and noncyclic photophosphorylation (5A or 5B).

 

5A. Noncyclic Photophosphorylation

- The excited electrons of photosystem I are used to reduce NADP+ into NADPH + H+

 

5B. Cyclic Photophosphorylation

- This pathway occurs when NADPH concentration is very high.

- Excited electrons from photosystem I go back to the electron transport chain to pump more hydrogen ions across the membrane.

- The electrons return to photosystem I completing the cycle.

- This does not produce NADPH.

 

6. Photophosphorylation

- The electron transport chain produces a chemiosmotic gradient by pumping hydrogen ions into the thylakoid lumen. 

- Chemiosmosis of hydrogen ions through ATP synthase produces ATP (similar to the mitochondrion).

 

Note: The noncyclic pathway is more common in chloroplasts than the cyclic pathway. The cyclic pathway occurs in some bacteria and in chloroplasts when the NADPH concentration is already very high.

 

Light-Dependent Reactions Animation

 

Summary

 

 

8.2.5

Explain the light-independent reactions.

Include the roles of ribulose bisphosphate (RuBP) carboxylase, reduction of glycerate 3-phosphate (GP) to triose phosphate (TP), NADPH + H+, ATP, regeneration of RuBP, and subsequent synthesis of more complex carbohydrates.

 

 

 

 

 

 

 

 

 

 

 

 

Light-Independent Reactions

 

 

http://www.biotopics.co.uk/a2/light-independent_reactions.html

 

Light-Independent Reactions

 

Chemical energy (ATP and NADPH) from the light-dependent reactions is used to fix carbon dioxide into organic molecules.

 

 

In the stroma of the chloroplast...

 

The Calvin Cycle

 

1. Carbon Fixation: The enzyme ribulose bisphosphate carboxylase (Rubisco) bonds ribulose bisphosphate (RuBP), a five-carbon molecule, with carbon dioxide to make two three-carbon molecules called glycerate-3-phosphate (GP).

 

2. Oxidation-Reduction Reactions

Glycerate-3-phosphate (GP) is reduced to triose phosphate (TP) coupled with the oxidation of ATP and NADPH + H+ into ADP and NADP+.

 

3. Regeneration of RuBP

When six carbon dioxide molecules enter the Calvin cycle, twelve triose phosphates (TP) are produced. Ten TP molecules are used to make six ribulose bisphosphate (RuBP) molecules to continue the cycle. ATP energy is used to regenerate the RuBP.

 

4. Synthesis of Organic Molecules

    (Not part of the Calvin Cycle)

The remaining two triose phosphates (TP) are used to make a variety of organic molecules such as glucose, starch, lipids, and proteins.

 

 

1. Carbon fixation by Rubisco

  RuBP + carbon dixoide --(rubisco)--> 2 GP

 C-C-C-C-C + CO2 --> 2 C-C-C-P

 

2. Reduction of GP to TP and Oxidation of ATP and NADPH + H+

   2 GP --> 2 TP  :  2 C-C-C-P --> 2 C-C-C-P 

   ATP --> ADP + Pi

   NADPH + H+ --> NADP+ 

 

3. Regeneration of RuBP

  6CO2 + 6RuBP --> 12TP

   10TP --> 6RuBP

    6ATP --> 6ADP + 6Pi 

 

4. Synthesis

  2TP --> glucose

 2 C-C-C-P --> C-C-C-C-C-C

 

Calvin Cycle with Music

 

 

8.2.6

Explain the relationship between the structure of the chloroplast and its function.

 

 

Structures

double membrane

thylakoid

grana

lumen

stroma

 

 

8.2.7

Explain the relationship between the action spectrum and the absorption spectrum of photosynthetic pigments in green plants.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

http://www.bio.miami.edu/dana/226/226F08_10.html

 

Sunlight is made of a spectrum of different wavelengths of energy called the electromagnetic spectrum. A wavelength is a measurement of one kind of electromagnetic energy. Different wavelengths have different characteristics, such as color and amount of energy.

 

The Visible Spectrum

 

 

 

 

 

 

 

 

 

http://www.light-measurement.com/properties-and-concepts/

 

A pigment is a molecule that absorbs and reflects specific wavelengths of light. The absorption spectrum is the measurement of which wavelengths of light are absorbed by a pigment such as chlorophyll. Chlorophyll absorbs mostly blue and red light, and it reflects mostly green light.

 

http://www.bio.miami.edu/dana/226/226F08_10.html

 

Absorption spectra of other photosynthetic pigments. 

 

 

The action spectrum shows the rate of photosynthesis in different wavelengths of light. Photosynthesis is most active in blue and red light and least active in green light.

 

http://www.bio.miami.edu/dana/226/226F08_10.html

 

The absorption of blue and red light and the reflection of green light by chlorophyll corresponds to the high rate of photosynthesis in  blue and red light and the low rate in green light.

 

 

 

 

8.2.8

Explain the concept of limiting factors in photosynthesis, with reference to light intensity, temperature and concentration of carbon dioxide.

 

 

A limiting factor effects the maximum possible rate of a reaction.

In photosynthesis, light intensity, temperature, or carbon dixide concentration can be a limiting factor. 

 

With low light intensity and lots of carbon dixide and an optimum temperature, the light intensity will set the maximum rate.

 

With a low concentration of carbon dioxide, high light intensity, and optimum temperature, the carbon dioxide concentration is the limiting factor.

 

With a low temperature, high light intensity, and high carbon dixide concentration, the tremperature is the limiting factor.

 

 

 



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