How plant absorb sunlight
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The document discusses sunlight and its roles and effects. It provides the following key points: 1. Sunlight is a form of electromagnetic radiation that provides light and heat. It is essential for photosynthesis in plants and vitamin D production in humans. 2. Plants absorb specific wavelengths of sunlight, mainly blue and red, using chlorophyll pigments like chlorophyll a and b. This energy drives photosynthesis. 3. Direct sunlight can cause skin cancer and aging in humans if exposed excessively due to the ultraviolet radiation. It is important to protect skin from sun exposure.
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Photosynthesis notes
This document provides an overview of photosynthesis including:
1. The history and key discoveries in photosynthesis research from ancient times to the 1950s when the Calvin cycle was discovered.
2. The significance of photosynthesis including that it is the source of food and fuel, drives other biological processes, and provides organic substances used by organisms.
3. Details on photosynthetically active radiation including that visible light drives photosynthesis, the properties of light waves, and that chlorophylls and carotenoids are the main light-absorbing pigments.
Biological basis of proton and high let beam
1) The document discusses the biological effects of different types of radiation sources used in radiotherapy, including protons, electrons, neutrons, alpha particles, and heavy ions like carbon ions.
2) High linear energy transfer (LET) radiations like alpha particles and heavy ions produce denser ionization tracks that result in more severe biological damage compared to low LET radiations like X-rays and gamma rays.
3) The relative biological effectiveness (RBE) of a radiation, which represents its biological damage per unit dose, increases with higher LET but decreases at very high LETs due to cellular overkill. Oxygen enhancement ratios also decrease at higher LETs.
RBE
This document discusses the concept of relative biological effectiveness (RBE), which compares the biological effects of different types of ionizing radiation. It defines RBE as the ratio of doses of radiation (such as x-rays versus neutrons) required to produce the same biological effect. Higher RBE values indicate radiation that causes greater biological damage. The document explains that RBE depends on factors like radiation dose, number of fractions, and biological endpoint. It also discusses how RBE varies with linear energy transfer (LET), being highest around 100 keV/μm, and how RBE and oxygen enhancement ratio are inversely related and peak around the same LET value.
Chap1 physics and chemistry of radiation absorption
from the book "Radiobiology for the Radiologist, 7th Ed by E.J Hall"
I'll delete the file immediately, if it is illegal to upload the file.
LET RBE OER
It contains some basic concept of radiobiology like linear energy transfer , relative biologic effectiveness and oxygen enhancement ratio and their interrelationship
Let rbe oer
X-rays and neutrons interact differently with biological material based on their ionizing ability. X-rays produce sparse ionization while neutrons produce more dense ionization. Linear energy transfer (LET) quantifies the energy deposited over track length and is used to compare radiation types. Higher LET radiation like alpha particles are more biologically effective due to producing denser ionization over shorter tracks. The relative biological effectiveness (RBE) of radiation depends on factors like dose, fractions, and biological system and is calculated as the ratio of doses needed for equal effect compared to a reference radiation like x-rays. RBE increases with increasing LET up to 100keV/μm then decreases with further increases in LET. Oxygen enhancement ratio (
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Photosynthesis notes
This document provides an overview of photosynthesis including:
1. The history and key discoveries in photosynthesis research from ancient times to the 1950s when the Calvin cycle was discovered.
2. The significance of photosynthesis including that it is the source of food and fuel, drives other biological processes, and provides organic substances used by organisms.
3. Details on photosynthetically active radiation including that visible light drives photosynthesis, the properties of light waves, and that chlorophylls and carotenoids are the main light-absorbing pigments.
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2) High linear energy transfer (LET) radiations like alpha particles and heavy ions produce denser ionization tracks that result in more severe biological damage compared to low LET radiations like X-rays and gamma rays.
3) The relative biological effectiveness (RBE) of a radiation, which represents its biological damage per unit dose, increases with higher LET but decreases at very high LETs due to cellular overkill. Oxygen enhancement ratios also decrease at higher LETs.
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from the book "Radiobiology for the Radiologist, 7th Ed by E.J Hall"
I'll delete the file immediately, if it is illegal to upload the file.
LET RBE OER
It contains some basic concept of radiobiology like linear energy transfer , relative biologic effectiveness and oxygen enhancement ratio and their interrelationship
Let rbe oer
X-rays and neutrons interact differently with biological material based on their ionizing ability. X-rays produce sparse ionization while neutrons produce more dense ionization. Linear energy transfer (LET) quantifies the energy deposited over track length and is used to compare radiation types. Higher LET radiation like alpha particles are more biologically effective due to producing denser ionization over shorter tracks. The relative biological effectiveness (RBE) of radiation depends on factors like dose, fractions, and biological system and is calculated as the ratio of doses needed for equal effect compared to a reference radiation like x-rays. RBE increases with increasing LET up to 100keV/μm then decreases with further increases in LET. Oxygen enhancement ratio (
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2. Factors like linear energy transfer (LET), relative biological effectiveness (RBE), fractionation, and oxygenation level impact radiation response. High LET radiation like alpha particles is more effective due to dense ionization.
3. The oxygen enhancement ratio (OER) compares radiation doses needed under hypoxic vs aerated conditions. It is typically 2.5-3.0 for X-rays but 1 for high
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Slideshow is from the University of Michigan Medical
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View additional course materials on Open.Michigan: openmi.ch/med-M2Hematology
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1. Radiobiology is the study of the effects of ionizing radiation on living things. When radiation passes through living matter, it loses energy by interacting with atoms and molecules, causing ionization and excitation that can alter living cells.
2. The biological effects of radiation occur on different time scales - physical interactions are instantaneous, chemical changes occur within milliseconds, and biological effects can take hours to years to present.
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1) Radiation is naturally present and comes from space, ground, and within our bodies. Biological effects depend on factors like radiation type, dose, and exposed tissues.
2) Acute radiation exposure can cause acute radiation syndrome with prodromal, latent, and manifest illness stages depending on dose. Bone marrow, gastrointestinal, and cardiovascular syndromes can occur.
3) Radiation damages DNA directly or indirectly through water radiolysis. Cells may be delayed, die, mutate, or develop genomic instability and cancer. Bystander effects can also occur.
Oer , rbe & let
1) The document discusses various factors that affect radiation response, including linear energy transfer (LET), relative biological effectiveness (RBE), oxygen effect, and cell cycle phase.
2) It provides details on oxygen enhancement ratio (OER), describing how it ranges from 2.5-3.0 for x-rays and varies according to cell cycle phase and radiation type (higher for x-rays and neutrons vs. alpha particles).
3) LET is discussed in relation to radiation type (low for x-rays, medium for neutrons, high for alpha particles) and how it impacts ionization density and biological damage. An optimal LET of around 100 keV/μm is described.
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1. The document discusses various strategies to overcome tumor hypoxia, including improving oxygen delivery to tumors, using hypoxic cell radiosensitizers, and hypoxia-activated cytotoxic drugs.
2. It provides examples of compounds that have shown promise in improving tumor oxygenation, such as motexafin gadolinium, as well as hypoxia-activated cytotoxic drugs like tirapazamine.
3. Hypoxia-selective gene therapy is also discussed as a potential strategy to selectively kill hypoxic tumor cells.
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This document discusses key radiation biology concepts including oxygen enhancement ratio (OER), linear energy transfer (LET), and relative biological effectiveness (RBE). It provides the following key points:
- OER is the ratio of radiation doses needed to produce the same effect under hypoxic vs aerated conditions. OER is typically 2-3 for low-LET radiation like X-rays since oxygen "fixes" free radical damage.
- LET measures the average energy deposited by ionizing radiation per unit distance traveled. It increases from low-LET X-rays to high-LET alpha particles.
- RBE compares the biological effectiveness of different radiations, defined as the ratio of standard radiation doses (e.g
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Basics of radiobiology
Radiobiology is the study of the effects of ionizing radiation on living things. The biological effects are manifestations of energy absorption within a living system and can result in ionization or excitation. Ionizing radiation includes electromagnetic radiation like x-rays and gamma rays as well as particulate radiation like electrons, protons, alpha particles, and neutrons. The effects depend on factors like linear energy transfer, dose, and oxygen presence and can include direct damage to DNA or indirect damage through radical production. Cell survival curves are used to study radiation effects at the cellular level and depend on radiation type, dose, and biological factors like cell cycle stage and repair processes.
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Linear energy transfer
Linear Energy Transfer (LET) refers to the energy deposited by ionizing radiation per unit distance traveled through a material. High LET radiation like neutrons and alpha particles deposit energy densely along their tracks, while low LET radiation like x-rays and gamma rays deposit energy sparsely. High LET radiation is more destructive to biological tissue due to localized DNA damage. The relative biological effectiveness (RBE) of radiation, defined as the ratio of doses needed to produce an equal biological effect, increases with LET up to around 100 keV/μm, where DNA damage is maximized. The oxygen enhancement ratio, which quantifies radiation damage under hypoxic versus oxygenated conditions, decreases with increasing LET and reaches unity for LETs over 200 keV
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Slideshow is from the University of Michigan Medical
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View additional course materials on Open.Michigan: openmi.ch/med-M2Hematology
Ionizing Radiation
Deep Shah presented on ionizing radiation. Ionizing radiation has enough energy to remove electrons from atoms, ionizing them. There are three main types of radioactive decay - alpha, beta, and gamma. Alpha particles emit helium nuclei, beta particles emit electrons or positrons, and gamma rays are electromagnetic radiation. X-rays are a form of electromagnetic radiation similar to gamma rays but are emitted by electrons rather than the nucleus. While ionizing radiation can be hazardous, it has important medical uses such as radiation therapy to treat cancer.
BIOLOGICAL BASIS OF RADIOTHERAPY
1. Radiobiology is the study of the effects of ionizing radiation on living things. When radiation passes through living matter, it loses energy by interacting with atoms and molecules, causing ionization and excitation that can alter living cells.
2. The biological effects of radiation occur on different time scales - physical interactions are instantaneous, chemical changes occur within milliseconds, and biological effects can take hours to years to present.
3. Radiation can directly damage DNA through ionization, but the probability is low since DNA is a small target within cells. More likely, radiation interacts with water in cells, producing free radicals that can diffuse and indirectly damage critical targets like DNA through chemical reactions.
LET & RBE and Radioprotectors
Linear Energy Transfer (LET) refers to the amount of energy deposited by ionizing radiation per unit distance traveled. High LET radiation like alpha particles and neutrons deposit large amounts of energy over short distances, while low LET radiation like x-rays deposit energy sparsely over longer tracks. High LET radiation is more biologically destructive due to dense localized DNA damage. Relative Biological Effectiveness (RBE) compares the biological effects of different radiations, with higher RBE indicating greater effectiveness. RBE increases with LET up to around 100 keV/μm due to optimal DNA double-strand break formation, then decreases at higher LET. Sulfhydryl compounds like cysteamine are effective radioprotectors by scavenging free radicals
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1) Radiation is naturally present and comes from space, ground, and within our bodies. Biological effects depend on factors like radiation type, dose, and exposed tissues.
2) Acute radiation exposure can cause acute radiation syndrome with prodromal, latent, and manifest illness stages depending on dose. Bone marrow, gastrointestinal, and cardiovascular syndromes can occur.
3) Radiation damages DNA directly or indirectly through water radiolysis. Cells may be delayed, die, mutate, or develop genomic instability and cancer. Bystander effects can also occur.
Oer , rbe & let
1) The document discusses various factors that affect radiation response, including linear energy transfer (LET), relative biological effectiveness (RBE), oxygen effect, and cell cycle phase.
2) It provides details on oxygen enhancement ratio (OER), describing how it ranges from 2.5-3.0 for x-rays and varies according to cell cycle phase and radiation type (higher for x-rays and neutrons vs. alpha particles).
3) LET is discussed in relation to radiation type (low for x-rays, medium for neutrons, high for alpha particles) and how it impacts ionization density and biological damage. An optimal LET of around 100 keV/μm is described.
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1. The document discusses various strategies to overcome tumor hypoxia, including improving oxygen delivery to tumors, using hypoxic cell radiosensitizers, and hypoxia-activated cytotoxic drugs.
2. It provides examples of compounds that have shown promise in improving tumor oxygenation, such as motexafin gadolinium, as well as hypoxia-activated cytotoxic drugs like tirapazamine.
3. Hypoxia-selective gene therapy is also discussed as a potential strategy to selectively kill hypoxic tumor cells.
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Oer, let and rbe
This document discusses key radiation biology concepts including oxygen enhancement ratio (OER), linear energy transfer (LET), and relative biological effectiveness (RBE). It provides the following key points:
- OER is the ratio of radiation doses needed to produce the same effect under hypoxic vs aerated conditions. OER is typically 2-3 for low-LET radiation like X-rays since oxygen "fixes" free radical damage.
- LET measures the average energy deposited by ionizing radiation per unit distance traveled. It increases from low-LET X-rays to high-LET alpha particles.
- RBE compares the biological effectiveness of different radiations, defined as the ratio of standard radiation doses (e.g
Biological effects of radiation
The document discusses the biological effects of radiation. It defines biological effects of radiation as the harmful effects caused to living beings due to exposure to radiation. It describes two main mechanisms of radiation damage: direct and indirect effects. Direct effects occur when radiation directly interacts with DNA, while indirect effects occur when free radicals produced by radiation interact with DNA. It also covers topics like dose measurement, different types of radiation effects on cells, risks of low dose radiation, and factors that influence radiation sensitivity.
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The document discusses radiation hazards in orthopedic trauma care, including definitions of different types of radiation, how x-rays are produced, measurements of radiation exposure, effects of radiation like cancer and genetic mutations, and methods for radiation protection. Radiation can cause both stochastic effects like cancer that depend on probability as well as deterministic effects above a threshold that increase in severity with dose. Protecting patients and medical staff requires understanding radiation measurements, injuries, and factors that determine biological impacts.
Basics of radiobiology
Radiobiology is the study of the effects of ionizing radiation on living things. The biological effects are manifestations of energy absorption within a living system and can result in ionization or excitation. Ionizing radiation includes electromagnetic radiation like x-rays and gamma rays as well as particulate radiation like electrons, protons, alpha particles, and neutrons. The effects depend on factors like linear energy transfer, dose, and oxygen presence and can include direct damage to DNA or indirect damage through radical production. Cell survival curves are used to study radiation effects at the cellular level and depend on radiation type, dose, and biological factors like cell cycle stage and repair processes.
Radiation hazards
Radiation is energy transmitted through space or matter in the form of waves or particles. It includes visible light, ultraviolet light from the sun, and radio/TV signals. Nuclear radiation comes from unstable atoms undergoing radioactive decay, emitting particles like alpha and beta or electromagnetic waves like gamma rays. Exposure to ionizing radiation can damage living tissue. Natural sources of radiation include cosmic rays, radioactive elements in the earth's crust like radon, and some food/drink. Medical procedures and occupational exposures also contribute. In materials, radiation can cause impurities from nuclear reactions, ionization by charged particles, and displacement of atoms from their normal positions in the crystal structure.
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This document discusses ionizing and non-ionizing radiation. It defines ionizing radiation as radiation capable of producing ions through direct or indirect interaction with matter, while non-ionizing radiation does not have a wavelength sufficient for ionization. The document discusses the different types of ionizing radiation including electromagnetic radiation like x-rays and gamma rays, and corpuscular radiation like alpha particles, beta particles, neutrons, and protons. It also discusses the mechanisms of radiation damage, relative biological damage of different types of radiation, sources of background radiation exposure, and medical uses and effects of ionizing radiation.
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Solar radiation in rice ppt
Solar radiation provides the energy for key plant physiological processes like photosynthesis. It consists of visible light, infrared, and ultraviolet wavelengths. The quality, intensity, and duration of light impact plant growth. Different plant species have varying responses to light intensities, with some being short day or long day plants. Solar radiation is measured using pyranometers and provides energy for evaporation, heating soils and air, and driving photosynthesis in plants.
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Photosynthesis.pptx
This document provides information about the process of photosynthesis. It defines key terms like autotroph, heterotroph, chloroplasts, thylakoids, grana, and stroma. It describes how chloroplasts absorb light energy and contain the pigments chlorophyll and carotenoids that capture light for photosynthesis. The light reactions of photosynthesis occur in the thylakoid membranes of chloroplasts and utilize two photosystems. The energy captured from sunlight is used to convert carbon dioxide and water into oxygen and energy-rich organic compounds like glucose.
Chloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic cells that are the site of photosynthesis. They contain chlorophyll and have a double membrane structure, with stacks of internal membranes called thylakoids that are the site of the light-dependent reactions of photosynthesis. During photosynthesis, chloroplasts capture energy from sunlight and use it to convert carbon dioxide and water into oxygen and energy-rich molecules like glucose through a two-stage process of light-dependent and light-independent reactions.
Photosynthesis
Photosynthesis,Importance of Photosynthesis ,Structural feature of leaf advantage for photosynthesis,Leaf anatomy of C3 and C4 plants: etc.
Photosynthesis Notes
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce oxygen and energy in the form of glucose. It takes place in chloroplasts through two stages - the light reactions where light energy is captured to make ATP and NADPH, and the Calvin cycle where carbon is incorporated into organic compounds using the energy from the light reactions. Photosynthesis is essential as it provides the primary source of energy for nearly all life on Earth and removes carbon dioxide from the atmosphere.
Photosynthesis
Photosynthesis involves two main stages - the light-dependent reactions and the light-independent Calvin cycle. In the light-dependent reactions, chlorophyll uses light energy to convert water and carbon dioxide into oxygen and energy carriers (ATP and NADPH). In the Calvin cycle, the energy carriers are used to convert the energy from the light reactions into glucose through a series of reduction reactions.
Photosynthesis
Photosynthesis involves two main stages - the light-dependent reactions and the light-independent Calvin cycle. In the light-dependent reactions, chlorophyll uses light energy to convert water and carbon dioxide into oxygen and energy carriers (ATP and NADPH). In the Calvin cycle, the energy carriers are used to convert the energy from the light reactions into glucose through a series of reduction reactions.
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Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in the chloroplasts of plant cells, using chlorophyll and releasing oxygen and water as byproducts. The energy from sunlight is captured and used to convert carbon dioxide and water into oxygen and energy-storing organic molecules like glucose, providing nutrients and oxygen for all living things.
Photosynthesis
The document summarizes photosynthesis, including:
1) Photosynthesis uses light energy, water, carbon dioxide to produce glucose and oxygen through two phases - the light reactions and dark reactions.
2) The light reactions use light to produce ATP and NADPH using chlorophyll and a series of electron carriers in the thylakoid membranes.
3) The dark reactions use ATP and NADPH to fix carbon from carbon dioxide into glucose through the Calvin cycle in the chloroplast stroma.
photosynthesis in Plants its importance and site
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water, and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in the chloroplasts and involves two stages - the light-dependent reactions where light energy is captured to form ATP and NADPH, and the light-independent reactions where carbon dioxide is incorporated into organic compounds to form carbohydrates such as glucose. Many factors can influence the rate of photosynthesis including light intensity, temperature, carbon dioxide levels, and water availability. Photosynthesis is essential for life as it provides energy and organic compounds for all organisms on Earth.
Light and temperature, light and temperature as ecological factors
The document discusses light and temperature, defining light and its importance for plants. It covers light quality, types of light including ultraviolet, visible and infrared radiation. It describes units of light measurement and methods. It discusses diurnal and seasonal variations in light and temperature and the eco-physiological responses of plants, including effects on photosynthesis, transpiration, seed germination, photoperiodism, reproduction, growth, and plant structure.
Photosynthesis
The document provides information about photosynthesis including:
1. Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar.
2. The primary product of photosynthesis is glucose, which is the source of carbohydrates like cellulose, starches, etc. Photosynthesis also produces oxygen, fats, proteins, and water soluble sugars.
3. Photosynthesis takes place in the chloroplasts of plant leaves. The chloroplasts contain chlorophyll and other pigments that absorb sunlight to drive a series of reactions that produce ATP and NADPH.
Unit 6 photosynthesis
Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. It occurs in the chloroplasts of plant cells, using chlorophyll and takes place in two stages - the light-dependent reaction which converts light energy to chemical energy in the form of ATP and NADPH, and the light-independent Calvin cycle which uses this energy to convert carbon dioxide into sugars like glucose. Photosynthesis is essential for life as it provides food and oxygen and removes carbon dioxide from the atmosphere.
Energy-Saving Lamps & Health
Currently, conventional incandescent lamps are in the process of being replaced with more energy-efficient lamps, mainly compact fluorescent lamps (CFLs). Fluorescent light has been used for many years in overhead fluorescent tubes without causing any problems. Nevertheless, certain “light sensitive” citizens’ associations have voiced concerns about compact fluorescent lamps.
Do these energy-saving lamps aggravate the symptoms in patients with certain diseases?
Light reaction in photosynthesis
The document discusses photosynthesis and how it harvests sunlight using pigments like chlorophyll. It describes how:
1) Photosynthesis uses energy from sunlight to convert carbon dioxide and water into oxygen and carbohydrates like glucose, providing energy for plants and all life.
2) Light is absorbed by photosynthetic pigments in the chloroplast and its energy is transferred to the reaction center where the chemical reactions of photosynthesis take place.
3) Experiments by Emerson and Arnold showed that many chlorophyll molecules work together as a photosynthetic unit, with around 250-300 chlorophyll molecules transferring energy to each reaction center.
Solar radiation distribution in plant canopies and rue
This document discusses various aspects of solar radiation distribution and interception in plant canopies and its impact on radiation use efficiency (RUE). It explains that solar radiation provides the energy for photosynthesis and plant growth. Only a portion of the total solar radiation, called photosynthetically active radiation (PAR) between 400-700nm, is utilized by plants. The ability of plant canopies to intercept incoming solar radiation depends on factors like leaf area, leaf angle, and canopy architecture. Light interception efficiency can be estimated using methods like the triangular and circular methods. Radiation interception influences photosynthesis, biomass production, and crop yields. The document also discusses concepts like albedo, light extinction in canop
Photosynthesis.pptx
The document discusses microbial photosynthesis and the process of photosynthesis in plants. It begins by explaining that the sun is the main source of energy for life on Earth and provides details about its composition and layers. It then describes how photosynthesis uses light energy from the sun to convert carbon dioxide and water into glucose and oxygen through two stages - the light-dependent reactions and the Calvin cycle. The light reactions generate ATP and NADPH using energy from sunlight, while the Calvin cycle uses these products to incorporate carbon from carbon dioxide into organic molecules to form glucose.
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Light and temperature, light and temperature as ecological factors
Light and temperature, light and temperature as ecological factors
Solar radiation distribution in plant canopies and rue
Solar radiation distribution in plant canopies and rue
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Complete data logger. i will survive!
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- 22. Mg N N N N CH 3 CHO CH2 CH CHO O CH2 CH2 C=O CH CH2 Chlorophyll a Chlorophyll c Chlorophyll d Chlorophyll b pheophytin I II III IV
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