BIOKIMIA FOTOSINTESIS REAKSI TERANG
Summary
TLDRThis script delves into the intricacies of photosynthesis, focusing on the light-dependent reactions within the two photosystems. It explains how chlorophyll in photosystem II absorbs light, leading to the excitation of electrons and the process of photolysis, which splits water into hydrogen and oxygen. The script also discusses the role of plastoquinone and the electron transport chain, culminating in the production of ATP and NADPH, essential for the Calvin cycle. Additionally, it touches on the light-independent reactions, emphasizing the cyclic process of photosynthetic phosphorylation and its significance in bacteria.
Takeaways
- 🌱 The script discusses the process of photosynthesis, specifically highlighting the light-dependent (non-cyclic) and light-independent (cyclic) reactions.
- 🔬 Photosystem I and Photosystem II are two key components of the light-dependent reaction, each containing chlorophyll and accessory pigments within the plant's thylakoid membranes.
- 🌟 Chlorophyll in Photosystem II absorbs light at a wavelength of 680 nm, known as P680, while Photosystem I uses chlorophyll that absorbs light at 700 nm, known as P700.
- 💡 The light energy is absorbed by chlorophyll P680 in Photosystem II, initiating the process of photolysis, which involves the splitting of water molecules using solar energy.
- 🚀 Electrons from the reaction center of Photosystem II are transferred through a protein chain to the Cytochrome b6f complex, part of the electron transport chain.
- 💧 The splitting of water molecules (photolysis) produces hydrogen ions, electrons, and oxygen, with oxygen being released as a byproduct of photosynthesis.
- 🔄 The electrons lost from Photosystem II are replaced through the process of photolysis, maintaining the flow of electrons in the electron transport chain.
- 🌀 The proton gradient created by the movement of hydrogen ions is used to generate ATP through a process known as chemiosmosis.
- 🔁 The cyclic photophosphorylation reaction, part of the light-independent reaction, occurs only in Photosystem I and uses ATP to produce NADPH.
- 🌿 The light-independent reactions, also known as the Calvin cycle, do not require water or produce oxygen as a byproduct, focusing on the synthesis of glucose using ATP and NADPH.
- 🔄 The cyclic reaction is dominant in bacteria and is characterized by the continuous recycling of electrons from Photosystem I back to the Calvin cycle.
Q & A
What is photosynthesis and why is it important?
-Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll pigments. It is crucial as it converts light energy into chemical energy, producing oxygen and organic compounds that serve as the primary source of energy for most living organisms.
What are photosystems and what role do they play in photosynthesis?
-Photosystems are complex protein structures containing chlorophyll and accessory pigments found in the thylakoid membranes of plant cells. They are responsible for the conversion of light energy into chemical energy during photosynthesis.
What is the difference between Photosystem I and Photosystem II?
-Photosystem I and Photosystem II are two distinct photosystems involved in photosynthesis. Photosystem II absorbs light at a wavelength of 680 nm and is involved in the water-splitting process, while Photosystem I absorbs light at a wavelength of 700 nm and is involved in the production of NADPH.
What is the role of chlorophyll in photosynthesis?
-Chlorophyll is a pigment that plays a central role in photosynthesis by absorbing light energy, particularly in the form of photons. It is present in both photosystems and initiates the light-dependent reactions of photosynthesis.
What is the significance of the reaction center in Photosystem II?
-The reaction center in Photosystem II is where the absorbed light energy is used to excite electrons from chlorophyll molecules. These excited electrons are then transferred to the primary electron acceptor, initiating the electron transport chain.
Can you explain the process of photolysis in photosynthesis?
-Photolysis is the process where water molecules are split into hydrogen ions, electrons, and oxygen using the energy from sunlight. This occurs in Photosystem II and is a part of the light-dependent reactions of photosynthesis.
What is the role of plastoquinone in the electron transport chain?
-Plastoquinone, also known as PQ, is an electron carrier in the electron transport chain. It receives electrons from the reaction center of Photosystem II and transports them to the cytochrome b6f complex.
What is the significance of the proton gradient in ATP synthesis?
-The proton gradient is essential for ATP synthesis in photosynthesis. It is created by the movement of protons across the thylakoid membrane, which drives the enzyme ATP synthase to produce ATP from ADP and inorganic phosphate.
What is cyclic photophosphorylation and how does it differ from non-cyclic photophosphorylation?
-Cyclic photophosphorylation is a process that occurs only in Photosystem I, where the electrons excited by light energy are transferred back to the same photosystem without the involvement of water splitting or the production of oxygen. Non-cyclic photophosphorylation involves both photosystems and results in the production of both ATP and NADPH.
What is the role of ferredoxin-NADP+ reductase in photosynthesis?
-Ferredoxin-NADP+ reductase (FNR) is an enzyme that catalyzes the reduction of NADP+ to NADPH using electrons provided by ferredoxin. This reaction is a crucial step in the light-dependent reactions of photosynthesis.
How does the Calvin cycle relate to the light-dependent reactions of photosynthesis?
-The Calvin cycle is the light-independent set of reactions in photosynthesis that uses the ATP and NADPH produced in the light-dependent reactions to fix carbon dioxide into organic molecules, such as glucose.
Outlines
🌱 Photosynthesis Process Overview
This paragraph introduces the concept of photosynthesis, focusing on the light-dependent reactions. It explains the role of photosystems I and II, the absorption of light by chlorophyll, and the process of electron transfer. The paragraph details the initial capture of light energy by chlorophyll p680 in photosystem II, leading to the excitation of electrons and their transfer to the primary acceptor. It also touches on the process of photolysis, where water molecules are split using solar energy, releasing oxygen, electrons, and protons. The electrons are then passed through a series of carriers, including plastoquinone, to generate ATP and NADPH, which are essential for the synthesis of glucose in the Calvin cycle.
🔁 The Light-Dependent Reaction Cycle
The second paragraph delves deeper into the cyclic process of light-dependent reactions in photosynthesis. It discusses the cyclic electron transport chain that occurs within photosystem I, which only involves photosystem I unlike the non-cyclic reactions. The paragraph explains how light energy excites electrons in chlorophyll p700, leading to their transfer to the primary acceptor and the subsequent generation of ATP and NADPH. The process is cyclic, as electrons are eventually returned to photosystem I, and no water is consumed, nor oxygen is released as a byproduct. This cycle is dominant in bacteria and is crucial for the production of energy in the form of ATP for the dark reactions of photosynthesis.
Mindmap
Keywords
💡Photosynthesis
💡Photosystems
💡Chlorophyll
💡Light-Dependent Reactions
💡Electron Transport Chain
💡Plastquinone (PQ)
💡Cyclic Photophosphorylation
💡ATP Synthase
💡Ferredoxin (FB)
💡NADPH
💡Chemiosmosis
💡Cyclic Reaction
💡Non-Cyclic Reaction
Highlights
Explanation of light-dependent and light-independent photosynthesis reactions.
Introduction to the two photosystems: Photosystem I and Photosystem II.
Photosystem I contains chlorophyll and accessory pigments that absorb light.
Photosystem II is responsible for the initial capture of light energy by chlorophyll p680.
Light energy absorbed by chlorophyll p680 is transferred to the primary acceptor.
Electrons are excited and transferred through a protein chain to the plastoquinone pool.
The process of photolysis uses light energy to split water molecules.
Oxygen is released as a byproduct of the photosynthesis process.
The proton gradient across the thylakoid membrane is used to generate ATP.
Electrons from Photosystem II are transferred to Photosystem I via plastoquinone.
Ferredoxin and NADP+ combine to form NADPH, a key molecule in the light reactions.
Cyclic photophosphorylation is a process that occurs within Photosystem I alone.
Cyclic photophosphorylation does not require water and does not produce oxygen.
The light reactions produce ATP and NADPH, which are used in the Calvin cycle.
The cyclic electron transport chain is a key component of the light reactions.
The role of the light reactions in providing energy for the dark reactions of photosynthesis.
The significance of the proton gradient and chemiosmosis in ATP production.
The cyclic nature of the light reactions in plants, as opposed to the non-cyclic reactions.
The dominance of cyclic photophosphorylation in certain bacteria.
Transcripts
hai hai
Hai reaksi terang fotosintesis reaksi
terang nonsiklik fotosintesis baik
mahasiswaku kali ini ibu akan
menjelaskan perlahan kalian amati
terlebih dahulu gambar reaksi terang
nonsiklik fotosintesis yang sudah Ibu
beri apabila kalian amati ada dua
fotosistem fotosistem pertama dan putus
sistem kedua Apakah kalian tahu apa yang
dimaksud dengan fotosistem i
foto-foto sistem adalah Kompleks protein
yang terdapat mengandung klorofil dan
pigmen asesoris pada tilakoid sel
tumbuhan jadi proses ini terjadinya
detail akui tumbuhan klorofil dan pigmen
itu adalah sumber protein kompleks yang
amat penting dan bertanggungjawab
terhadap konversi energi
Hai pegang klorofil pada fotosintesis
pertama itu mampu menyerap cahaya hingga
lebar pita bentuknya seperti gelombang
wavelength 766 meter sehingga dikenal
sebagai
Hai YouTubers sedangkan klorofil pada
fotosintesis kedua mampu menyerap cahaya
dengan panjang pita w680 Nano sehingga
disebut molekul p680 kalau kalian amati
di sini ada p680 pada fotosistem kedua
dan p700 pada fotosistem pertama kita
mulai terlebih dahulu fotosistem
Ayo kita bahas perlahan foton atau
energi cahaya ini menabrak permukaan
pada daun foton energi cahaya ini akan
diserap dengan klorofil p680 pada
fotosintesis kedua jadi kita masih
berada di fotosistem kedua ya Nah energi
yang dihasilkan cahaya matahari akan
masuk dalam satu molekul p680 yang
sampai ke aseptor primer
Hai atau sampai ke pusat reaksi dari
fotosintesis sistem kedua atau yang kita
kenal sebagai reaction center atau RC
lalu RC ABS atau pusat reaksi fotosistem
kedua ini akan terdapat sepasang molekul
klorofil p680 elektron jadi disini
kalian kalau amati ada elektron-elektron
nya itu bersifat tidak stabil karena
ketidakstabilan itu akhirnya mereka
terlepas lalu dilepas lagi satu elektron
PRC kemudian elektronik to akan dibawa
rantai protein ya menuju peking ini
Hai menuju Kompleks sitokrom B
the carrier elektron atau pembawa PQ ini
dinamakan plastokuinon makanya disingkat
Hai plastokuinon tersebut akan membawa
elektron-elektron dari reaksi Pusat atau
RCT di pada fotosistem kedua menuju
Kompleks sitokrom menuju ke kompleks
sitokrom terjadi di sini Pemecahan
molekul air yang menggunakan bantuan
energi cahaya matahari lalu dengan
menggunakan bantuan matahari tersebut
disebut sebagai proses fotolisis
n**** dengan kehilangan elektron dari PS
2 tadi akan ditutupi dengan adanya
fotolisis ini yang akan memecah air
maupun hidrogen elektron dan oksigen
Hai setelah hasil pemecahan oksigen
oksigen maaf dan ion hidrogen tersebut
ke lumen tilakoid oksigen tersebut akan
dibuang sebagai hasil fotosintesis
Hai dengan menggunakan PST di
plastokuinon ya berada di stroma diantar
dilepas ke lumen menyebabkan konsentrasi
ion hidrogen the gradient atau gradien
Proton dibawalah ATP kalau kalian lihat
pada angka nomor 4 ini aliran energi
yang menyediakan energi untuk sintesis
games metik KTP ini sitokrom kemudian
membawa elektron PS tadi epc atau
plastosianin tadi di bawah ke fotosistem
pertama dibawa ke
foto-foto sistem
Hai kemudian elektron-elektron yang ada
ya naik dibawa oleh ferek Design and add
ya atau FB ya disingkat FB di sini ada
rantai transport electron lalu FB atau
ferediksi nenad ini bergabung dengan
hidrogen untuk membentuk nadph ennard
reduktase membentuk nadph2
Hai dilanjutkan reaksi siklik reaksi
terang siklik ini akan hanya menggunakan
fotosistem
Hai bukan seperti pada reaksi nonsiklik
yang sebelumnya yang terjadi pada kedua
fotosistem yaitu fotosistem 1 dan
fotosistem 2 jadi reaksi siklik ini
hanya terjadi fotosistem 1 dan
Hai reaksi lain di dalam rangkaian
fotosintesis ya salah satunya
[Musik]
fosforilasi siklik sesuai dengan namanya
reaksi ini hanya berputar dari awal
kemudian Kembali ke awal reaksi lagi
jadi seperti siklus siklik
Noah bukan seperti pada reaksi nonsiklik
ya tadi Kalau reaksi nonsiklik kan ada
dua fotosistem nih Nah kalau pada
fosforilasi siklik energi matahari yaitu
berupa foton kalau kalian amati di sini
matahari itu perupa foton menabrak suatu
membran tilakoid
Hai dan mengenai fotosistem pertama yang
memiliki klorofil tipe p700 sesuai
friend gelombang tadi dan hal ini akan
membuat elektron itu tereksitasi
Hai semuanya jadi adanya tingkat energi
yang naik hingga akhirnya terlepas yaitu
sebanyak masing-masing dua elektron
terlepas lalu kemudian elektronik itu
dimuat oleh PC atau pasti kuinon lalu
oleh sitokrom yang kemudian pastu sianin
dikembalikan lagi ke klorofil jadi ada
tetap pada rantai transpor elektron di
dalamnya tadikan WTS Ini mengandung
postur keinginan atau PC sedangkan it's
mendapatkan ATP menjadi sitokrom jadi
disini plastosianin akan dikembalikan
lagi ke klorofil
hai lalu rangkaian perpindahan elektron
itu disebut rantai transport electron
kekuatan motif Proton ayam menghasilkan
ion H + ini membuat spa jam gradien
konsentrasi membran hingga menjadi ATP
atau energi yang dinamakan chemiosmosis
ngarep proses tersebut berulang ketika
alectrona kembali lagi ke fotosistem
pertama reaksi siklik dalam reaksi
terang tumbuhan ini tidak butuh air
Hai atau fotolisis juga tidak
menghasilkan energi buangan seperti
oksigen
Hai reaksi siklik hanya akan
menghasilkan ATP atau energi yang
digunakan dalam reaksi gelap
fotosintesis maupun siklus
Hai namun fosforilasi siklik nih dominan
pada bakteri
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