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Friday, November 9, 2018

Photosynthesis

Author: Mohamad Ismail Bin Ahmad Loti, 2018402598 (Photosynthesis)

Photosynthesis can be defined as a process by which involves the synthesis of carbohydrate from carbon dioxide and water, using sunlight as the source of energy and the green pigment chlorophyll for trapping the light.

The process of reducing carbon dioxide into carbohydrate requires abundant of energy in the form of ATP and large quantity of chemical reductant. Chloroplast is the important organelle for the production of ATP and chemical reductant. Chloroplast consists of chlorophyll that are important for photochemical during photosynthesis.

HOW PHOTOSYNTHESIS OCCUR:

The photosynthesis is two stage process, each with multiple reaction. These two stages of photosynthesis are known as the light reaction and dark reaction. Photosynthesis proceeds by light-dependent reaction then follow up by light-independent reaction. First of all, the light dependent reaction is the unique feature of photosynthesis in which light energy converts to chemical energy. The light reactions use solar energy to make ATP and NADPH, which function as chemical energy and reducing power, respectively in the Calvin cycle.

The process of light dependent reaction is:

· Light absorption in PSII. Energy is passed from pigment to pigment until it reaches the reaction center when light is absorbed by the pigments in photosystem II. There, energy is transferred to P680, boosting an electron to a high energy level. The high-energy electron is passed to an acceptor molecule and replaced with an electron from water. O₂is release by splitting water.

· ATP synthesis. The high-energy electron travels down an electron transport chain, losing energy as it goes. H+ ions are being pump by some of the released energy drives from the stroma into the thylakoid interior, building a gradient. H⁺ions from the splitting of water also add to the gradient.) As H⁺ ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as chemiosmosis.

· Light absorption in PSI. At photosystem I, the electron arrives and joins the P700 special pair of chlorophylls in the reaction center. When pigments absorb light energy and passed it inward to the reaction center, the electron in P700 is boosted to a very high energy level and transferred to an acceptor molecule. The special pair's missing electron is replaced by a new electron from PSII (arriving via the electron transport chain).

· NADPH formation. The high-energy electron travels down a short second leg of the electron transport chain. The electron is passed to NADP+ to make NADPH at the end of the chain.

Next of the reaction are the light independent reaction. Light independent reaction also known as dark reaction. The light independent reaction take place in the stroma of the chloroplast. It does not require light and use the energy (ATP) and reducing power (NADPH) produced by the light-dependent reactions to reduce carbon dioxide. The process of light independent reaction:

Image result for dark reaction photosynthesis

· Carbon fixation.: Five-carbon acceptor molecule, ribulose-1,5-bisphosphate (RuBP) combines with CO₂. This step makes a six-carbon compound that splits into two molecules of a three-carbon compound, 3-phosphoglyceric acid (3-PGA). This reaction is catalyzed by the enzyme RuBP carboxylase/oxygenase, or rubisco.

· Reduction. ATP and NADPH are used to convert the 3-PGA molecules into molecules of a three-carbon sugar, glyceraldehyde-3-phosphate (G3P) in the second stage. This stage gets its name because NADPH donates electrons to, or reduces, a three-carbon intermediate to make G3P.

· Regeneration. Some G3P molecules go to make glucose, while others must be recycled to regenerate the RuBP acceptor. Regeneration requires ATP and involves a complex network of reactions.

In conclusion, Photosynthesis process only happen in photoautotrophs organisms as they do not depend on other organisms to sustain themselves. Photosynthesis is importing to the environment as it releases oxygen while absorbing carbon dioxide. Without photosynthesis, organisms will die as it need oxygen to survive. Furthermore, the increase of the temperature due to abundant of the carbon dioxide if there is a lack of photoautotrophs organisms that do the photosynthesis process.

References:

-Light dependent reaction, Retrieved November 8, 2018
from https://www.khanacademy.org/
science/biology/photosynthesis-in-plants/

the-light-dependent-reactions-of-photosynthesis/a/light-dependent-reactions

- The Calvin Cycle, Retrieved November 8, 2018
from https://www.khanacademy.org/
science/biology/photosynthesis-in-plants/
the-calvin-cycle-reactions/a/calvin-cycle

-Photosynthesis, Retrieved November 8, 2018 from https://www.quora.com/

Why-are-photosynthesis-and-transpiration-complementary-to-one-another

- Kamaludin A.R., Kamariah .H, Mahanom. J, Nor A.A.Z. (2012). College Biology IPTA PUBLICATIONS SDN.BHD.

- Energy IV - Photosynthesis (Light-dependent Reactions), Retrieved November 8, 2018 from https://wikispaces.psu.edu/

pages/viewpage.action?pageId=97552145

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Friday, November 9, 2018

Author: Mohamad Ismail Bin Ahmad Loti, 2018402598 (Photosynthesis)

The process of reducing carbon dioxide into carbohydrate requires abundant of energy in the form of ATP and large quantity of chemical reductant. Chloroplast is the important organelle for the production of ATP and chemical reductant. Chloroplast consists of chlorophyll that are important for photochemical during photosynthesis.

HOW PHOTOSYNTHESIS OCCUR:

The photosynthesis is two stage process, each with multiple reaction. These two stages of photosynthesis are known as the light reaction and dark reaction. Photosynthesis proceeds by light-dependent reaction then follow up by light-independent reaction. First of all, the light dependent reaction is the unique feature of photosynthesis in which light energy converts to chemical energy. The light reactions use solar energy to make ATP and NADPH, which function as chemical energy and reducing power, respectively in the Calvin cycle.

The process of light dependent reaction is:

· Light absorption in PSII. Energy is passed from pigment to pigment until it reaches the reaction center when light is absorbed by the pigments in photosystem II. There, energy is transferred to P680, boosting an electron to a high energy level. The high-energy electron is passed to an acceptor molecule and replaced with an electron from water. O₂is release by splitting water.

· ATP synthesis. The high-energy electron travels down an electron transport chain, losing energy as it goes. H+ ions are being pump by some of the released energy drives from the stroma into the thylakoid interior, building a gradient. H⁺ions from the splitting of water also add to the gradient.) As H⁺ ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as chemiosmosis.

· Light absorption in PSI. At photosystem I, the electron arrives and joins the P700 special pair of chlorophylls in the reaction center. When pigments absorb light energy and passed it inward to the reaction center, the electron in P700 is boosted to a very high energy level and transferred to an acceptor molecule. The special pair's missing electron is replaced by a new electron from PSII (arriving via the electron transport chain).

· NADPH formation. The high-energy electron travels down a short second leg of the electron transport chain. The electron is passed to NADP+ to make NADPH at the end of the chain.

Next of the reaction are the light independent reaction. Light independent reaction also known as dark reaction. The light independent reaction take place in the stroma of the chloroplast. It does not require light and use the energy (ATP) and reducing power (NADPH) produced by the light-dependent reactions to reduce carbon dioxide. The process of light independent reaction:

· Carbon fixation.: Five-carbon acceptor molecule, ribulose-1,5-bisphosphate (RuBP) combines with CO₂. This step makes a six-carbon compound that splits into two molecules of a three-carbon compound, 3-phosphoglyceric acid (3-PGA). This reaction is catalyzed by the enzyme RuBP carboxylase/oxygenase, or rubisco.

· Reduction. ATP and NADPH are used to convert the 3-PGA molecules into molecules of a three-carbon sugar, glyceraldehyde-3-phosphate (G3P) in the second stage. This stage gets its name because NADPH donates electrons to, or reduces, a three-carbon intermediate to make G3P.

· Regeneration. Some G3P molecules go to make glucose, while others must be recycled to regenerate the RuBP acceptor. Regeneration requires ATP and involves a complex network of reactions.

In conclusion, Photosynthesis process only happen in photoautotrophs organisms as they do not depend on other organisms to sustain themselves. Photosynthesis is importing to the environment as it releases oxygen while absorbing carbon dioxide. Without photosynthesis, organisms will die as it need oxygen to survive. Furthermore, the increase of the temperature due to abundant of the carbon dioxide if there is a lack of photoautotrophs organisms that do the photosynthesis process.

References:

-Light dependent reaction, Retrieved November 8, 2018
from https://www.khanacademy.org/
science/biology/photosynthesis-in-plants/

the-light-dependent-reactions-of-photosynthesis/a/light-dependent-reactions

- The Calvin Cycle, Retrieved November 8, 2018
from https://www.khanacademy.org/
science/biology/photosynthesis-in-plants/
the-calvin-cycle-reactions/a/calvin-cycle

-Photosynthesis, Retrieved November 8, 2018 from https://www.quora.com/

Why-are-photosynthesis-and-transpiration-complementary-to-one-another

- Kamaludin A.R., Kamariah .H, Mahanom. J, Nor A.A.Z. (2012). College Biology IPTA PUBLICATIONS SDN.BHD.

- Energy IV - Photosynthesis (Light-dependent Reactions), Retrieved November 8, 2018 from https://wikispaces.psu.edu/

pages/viewpage.action?pageId=97552145

OLD | NEW

What is Plant Physiology?

Plants have many different uses.

But how do plants develop from seeds, and how do they grow?

This is where plant physiology comes into play.

Plant physiology is a study of the plant way of life, which include various aspects of the plant lifestyle and survival including: metabolism, water relations, mineral nutrition, development, movement, irritability (response to the environment), organization, growth, and transport processes.

Father of plant physiology: Stephan hales.

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If you truly love nature, you'll find beauty everywhere
-Van Gogh