Name: photosystem ii and water splitting
Uploaded: 2019-03-11T09:21:12.000Z
Duration: 1 min 22 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Environmental Science

Earth’s Systems

HS-ESS2-6

Photosystem II

在光系统II，一个多蛋白质复合物中， 光子被吸收，并且它们的能量 通过许多结合了色素分子 (例如叶绿素a和b 和类胡萝卜素的捕光蛋白。
 这种主动吸收产生的能量 转移到反应中心的 一对叶绿素a分子P680上。
 在这里，两个叶绿素专门 在称为光响应 的过程中氧化，向初级电 子受体分子放出激发的电子。
 然后通过将水分成 两个氢离子和一个氧原子 来取代缺失的电子，释放两个电子， 这两个电子一个接一个地供给反应中心。
 现在电子已准备好通过电子， 传输链到达光系统I. 氧原子可以与来自水中的另一氧 结合，形成逃逸到大气中的气体， 类囊体内的氢离子积聚 形成浓度梯度， 高浓度区域的氢通过 称为ATP合成酶的 专用半透性蛋白质通道， 在基质中进入低浓度区域。
 这个过程被称为化学渗透 并产生能量，使ATP合成 酶将第三个磷酸基团 连接到ADP上以形成能量产物ATP。

<ol>
	<li>Sasi、Shina、Jelli Venkatesh、Rawya Fatohllah Daneshi 和 Mayank Anand Gururani。"光系统 II 外源蛋白及其在高等植物非生物胁迫耐受性中的假定作用。"植物 7，第 4 期（2018 年 12 月）:100。</li>
	<li>山本安司。"光系统 II 的质量控制:避免和容忍光和热应力的机制与类囊体的膜流动性密切相关。"植物科学前沿 7 （2016）。</li>
</ol>

光系统ii

光系统II是一种嵌入类囊体膜内的多蛋白复合物，在那里它可以获得光能。叶绿素分子在光系统II的反应中心向特定的一对叶绿素a分子传递能量。在这里，叶绿素a分子失去一个电子（氧化），把它转移到一个初级电子受体。提供的电子通过电子传递链进入光系统I。分裂一个水分子释放一个氧原子、两个质子（H+）和两个电子。这些电子取代了反应中心两个叶绿素a分子的电子。氧原子立即与另一个氧原子发生反应，生成被释放到大气中的O2。质子聚集并在类囊体膜上形成浓度梯度，这一过程称为化学渗透，驱动ATP合成。

<h4>光系统II中的光收集</h4>
 
多蛋白复合物光系统ii通过其结合色素叶绿素a和b以及类胡萝卜素来获取光子和传递能量。类胡萝卜素具有保护作用，因为它们有助于耗散吸收的大量能量，否则可能损害植物组织。
 
能量从一个叶绿素分子传递到另一个叶绿素分子，直到到达一个叫做反应中心的区域的一对特殊的叶绿素a分子。反应中心也被称为P680，因为它吸收680波长的光。能量足够强，可以从叶绿素A分子中分解电子（氧化）。自由电子转移到一个初级电子受体分子上，这个过程叫做光作用。反应中心叶绿素的电子被水分子分裂释放的两个电子之一所取代。
 
<h4>质子梯度与ATP生成</h4>
 
光系统II中水的分裂也产生一个氧原子，它与第二个氧原子结合。由此产生的O2逃逸到大气中。这种反应还使两个质子 ( H+)形成浓度梯度，为一种叫做ATP合酶的特殊的半透膜蛋白通道提供能量。质子从类囊体中的高浓度通过通道移动到基质中的低浓度区域的过程称为化学渗透。化学渗透产生能量，使ATP合酶将第三个磷酸基团附着到ADP上，形成能量分子ATP。

光系统II

多蛋白复合体光系统II（PS II）捕获光子，并将其结合的色素吸收的能量传递至反应中心，……

Education

教育

JoVE Core

Biology

生物学

Cellular Processes

细胞结构与功能

Photosynthesis

光合作用

KEY TERMS AND CONCEPTS

关键术语与概念

photosystem ii and water splitting

Photosystem II is a multi-protein complex that captures light energy and begins the flow of electrons in photosynthesis. It uses bound pigments to harvest photons and send that energy to its reaction center. From there, the energy continues through the electron transport chain and on to photosystem I.

The pigments in photosystem II include chlorophyll a, chlorophyll b, and carotenoids. They are arranged in two parts of the photosystem: the antenna complex and the reaction center. The antenna complex absorbs light and funnels that energy to the special chlorophyll pair in the reaction center.

Carotenoids also have a protective role. They help dissipate excess absorbed energy and reduce damage to plant tissue. In the reaction center, also called P680, a photon excites an electron in chlorophyll. The high-energy electron is released and passed to the primary electron acceptor.

P680 then replaces the lost electron by taking low-energy electrons from water splitting. Splitting one H2O molecule releases two electrons, two hydrogen atoms, and one oxygen atom. Two oxygen atoms from two H2O molecules join to form oxygen gas, which is released into the environment. The hydrogen ions also help build the proton gradient across the thylakoid membrane. That gradient is essential for ATP synthesis in the chloroplast.

Photosystem II and Water Splitting

what is photosynthesis?

Photosynthesis in Chloroplasts and Leaves

Photosynthesis happens in plants and in some bacteria. It is the process that captures carbon dioxide and solar energy to make glucose. Glucose stores chemical energy as carbohydrates. The overall biochemical equation is 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2. Photosynthesis also releases oxygen into the atmosphere and helps maintain Earth’s atmospheric oxygen content. Photosynthetic reactions take place in chloroplasts, which are specialized membrane-enclosed parts of the plant cell.

light as energy

How Plant Pigments Capture Light

Photosynthesis uses light energy from the sun, which is a form of electromagnetic radiation. The full range of possible wavelengths is called the electromagnetic spectrum. Light is made of photons, which are small packets of energy. Photons act like waves and are described by frequency, wavelength, and amplitude. Waves with higher frequencies carry more energy and have shorter wavelengths. Waves with lower frequencies carry less energy and have longer wavelengths. For most organisms,...

anatomy of chloroplasts

Chloroplasts and Photosynthesis in Plant Cells

Chloroplasts are the organelles where photosynthesis takes place in green algae and plants. They are also found in green stems and unripe fruit. In plants, mesophyll cells in the leaf contain the highest density of chloroplasts. Each chloroplast has a double membrane. The outer membrane faces the plant cell cytoplasm on one side and the chloroplast intermembrane space on the other. The inner membrane separates that narrow space from the stroma, which is the watery interior of the chloroplast.

photosystem ii

Photosystem II is a multi-protein complex that captures light energy and begins the flow of electrons in photosynthesis. It uses bound pigments to harvest photons and send that energy to its reaction center. From there, the energy continues through the electron transport chain and on to photosystem I. The pigments in photosystem II include chlorophyll a, chlorophyll b, and carotenoids. They are arranged in two parts of the photosystem: the antenna complex and the reaction center. The antenna...

photosystem i

Photosystem I and NADPH Formation

Photosystem I helps convert light energy into NADPH during photosynthesis. It works with photosystem II in the thylakoid membrane of the chloroplast, but it uses a different electron supplier and a different electron acceptor. Electrons excited in photosystem II move to photosystem I through an electron transport chain. That chain includes plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As the electrons travel between the two photosystems, they lose energy and must be...

the calvin cycle

Carbon Fixation in Photosynthesis

Photosynthesis uses light energy to turn carbon dioxide into carbohydrates. It also releases oxygen as a by-product. These products help support most food webs and make aerobic life possible. Photosynthesis has two main stages, and they happen in different parts of the chloroplast. The light-dependent reactions take place in the thylakoid membranes. Chlorophyll absorbs light energy there and helps split water molecules. This releases O2 and makes ATP and NADPH. The light-independent reactions...

c4 pathway and cam

Plant Carbon Fixation in Hot Climates

Plant carbon fixation in hot climates can follow the C4 pathway or the CAM pathway. These alternative pathways help some plants reduce energy loss from photorespiration. Photorespiration happens when oxygen levels are high and rubisco, the enzyme in the Calvin cycle, binds O2 instead of CO2. When that happens, photosynthesis slows and energy is used up. The C4 pathway is used by plants such as corn and sugarcane. In mesophyll cells, CO2 first joins with PEP, or phosphoenolpyruvate, through the...

key terms and concepts

Learn how photosystem II captures light, excites P680, splits water, releases oxygen, and helps build the proton gradient needed for ATP synthesis.

Photosystem II and Water Splitting | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

JoVE Core系列通过300多节动画视频课简明易懂地讲解生物学中的关键概念，以及150余段视频展示科学家在现代实验室开展实际研究实验，让生物学变得平易近人。

Virginia  Standards of Learning

HIgh School

Life Science

LS.4

LS.4.a

Next Generation Science Standards

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-5

Texas Essential Knowledge and Skills

BIO.11

BIO.11.A

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

ecosystems-interactions-energy-and-dynamics

Ecosystems: Interactions, Energy, and Dynamics

B-LS2-5.

new-york-state-science-learning-standards

New York State Science Learning Standards

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

HS-LS1-5.

Georgia Standards of Excellence

9-12

SB1.e

myJoVE Corporation

determining-spatial-orientation-rock-layers-with-brunton

Determining Spatial Orientation of Rock Layers with the Brunton Compass

Source: Laboratory of Alan Lester - University of Colorado Boulder
Most rock units exhibit some form of planar surfaces or linear features. Examples ...

using-topographic-maps-to-generate-topographic-profiles

Using Topographic Maps to Generate Topographic Profiles

Source: Laboratory of Alan Lester - University of Colorado Boulder
Topographic maps are &#34;plan-view&#34; representations of Earth&#39;s ...

exploring-effects-atmospheric-forcings-on-evaporation-experimental

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

Earth’s systems, being dynamic and interacting, include feedback effects that can increase or decrease the original changes.

HS-ESS2-2

What is Weather?

Overview

Weather refers to the current state of atmospheric conditions at a specific time and place. Weather is temporary and is influenced by the ...

What is Climate?

Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, &#8220;Climate is what you expect. ...

Global Climate Change

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global ...

The geological record shows that changes to global and regional climate can be caused by interactions among changes in the sun’s energy output or Earth’s orbit, tectonic events, hydrosphere circulation, volcanic activity, glaciers, vegetation, and human activities. These changes can occur on a variety of time scales from sudden (e.g., volcanic ash clouds) to intermediate (ice ages) to very long-term tectonic cycles.

HS-ESS2-4

Making a Geologic Cross Section

Source: Laboratory of Alan Lester - University of Colorado Boulder
Geologic maps were first made and utilized in Europe, in the mid-to-late 18th century. ...

physical-properties-of-minerals-i-crystals-and-cleavage

Physical Properties Of Minerals I: Crystals and Cleavage

Source: Laboratory of Alan Lester - University of Colorado Boulder
The physical properties of minerals comprise various measurable and discernible ...

physical-properties-of-minerals-ii-polymineralic-analysis

Physical Properties Of Minerals II: Polymineralic Analysis

Source: Laboratory of Alan Lester - University of Colorado Boulder
The physical properties of minerals include various measurable and discernible ...

Igneous Volcanic Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
Igneous rocks are the products of cooling and crystallization of magma. Volcanic rocks ...

Igneous Intrusive Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
Igneous rocks are products of the cooling and crystallization of high temperature ...

The abundance of liquid water on Earth’s surface and its unique combination of physical and chemical properties are central to the planet’s dynamics. These properties include water’s exceptional capacity to absorb, store, and release large amounts of energy, transmit sunlight, expand upon freezing, dissolve and transport materials, and lower the viscosities and melting points of rocks.

HS-ESS2-5

The foundation for Earth’s global climate systems is the electromagnetic radiation from the sun, as well as its reflection, absorption, storage, and redistribution among the atmosphere, hydrosphere, and land systems, and this energy’s re-radiation into space.

What is Photosynthesis?

Photosynthesis is a multipart, biochemical process that occurs in plants as well as in some bacteria. It captures carbon dioxide and solar energy to ...

Light as Energy

The energy required to carry out photosynthesis is light&#8212; typically electromagnetic radiation from the sun. The range of all possible wavelengths is ...

Anatomy of Chloroplasts

Green algae and plants, including green stems and unripe fruit, harbor chloroplasts&mdash;the vital organelles where photosynthesis takes place. In ...

The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ...

Photosystem I

Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these ...

The Calvin Cycle

Overview

Oxygenic photosynthesis converts approximately 200 billion tons of carbon dioxide (CO2) annually to organic compounds and produces approximately ...

C4 Pathway and CAM

Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative ...

Measuring Tropospheric Ozone

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Ozone is a form of elemental oxygen (O3), a molecule of three oxygen atoms ...

determination-of-nox-in-automobile-exhaust-using-uv-vis-spectroscopy

Determination Of NOx in Automobile Exhaust Using UV-VIS Spectroscopy

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
In the troposphere, ozone is naturally formed when sunlight splits nitrogen ...

carbon-and-nitrogen-analysis-of-environmental-samples

Carbon and Nitrogen Analysis of Environmental Samples

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Elemental Analysis is a method used to determine elemental composition of a ...

Gradual atmospheric changes were due to plants and other organisms that captured carbon dioxide and released oxygen.

What are Biogeochemical Cycles?

The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited ...

Cyclical changes in the shape of Earth’s orbit around the sun, together with changes in the tilt of the planet’s axis of rotation, both occurring over hundreds of thousands of years, have altered the intensity and distribution of sunlight falling on Earth. These phenomena cause a cycle of ice ages and other gradual climate changes.

Photosystem II and Water Splitting

Description

Transcript

Tags

More videos by Standards