Glucose
As you have learned, glucose can be synthesized from water and carbon dioxide by a process known as photosynthesis. However, that's not the only way in which glucose can be created. It can also be synthesized from pyruvic acid and acetyl CoA by reversing the reactions that we studied earlier in the oxidation of glucose. Consequently, glucose can be made from such things as fats, carboxylic acids, and also amino acids by first converting them into acetyl CoA or pyruvic acid. (This diagram is also shown in Example 13 in your workbook.) In turn, glucose can be used as a starting material to make fats, carboxylic acids andamino acids, and other chemicals. Glucose can also be converted into a variety of other sugar molecules by doing such things as reorienting the location of hydroxyl groups, such as when it is converted into galactose, or by oxidizing one carbon and reducing another by shifting the locations of the hydrogen atoms, such as when it is converted into fructose. The bonding pattern of the hydrogens and hydroxyl groups around each carbon atom isvery important to the structure of carbohydrates. You should recall that a carbon atomwhich is bonded to four different groups is an asymmetric carbon atom. Glucose, with six carbon atoms, has four asymmetric carbon atoms (marked in this diagram with *). The arrangement of the OH's and H's on these atoms is very important. Structural formulas for sugar molecules are often written in this vertical arrangement with the aldehyde or the ketone group at or near the top. When written in this particular way, the position of the OH on the last asymmetric carbon atom will tell us whether we are dealing with a "D" sugar or an "L" sugar. "D" stands for dextro and "L" stands for levo. If the OH is on the right, then we are dealing wi Continue reading >>
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1a: Trees - The Carbon Storage Experts!
If the video does not load, you can view the video at this link Magnificent Giant Tree: Sequoia in a Snowstorm - YouTube With a partner, write down ideas of where you think the mass of the Giant Sequoia tree comes from as it grows and then create a class list of all possible ideas: What ideas about the source of the tree's mass are you more confident about? Why? Hint: Remember that mass is a measurement of matter, and matter is made of atoms. Next, watch Derek Muller of Veritasium ask people where they think a tree's mass comes from. As you watch, make note of the hypotheses suggested by people being interviewed and be prepared to compare your notes with the class. Trees, like all organisms, grow by adding mass (biomass) is the mass of living or once living material. . Carbon is the central ingredient in making that new biomass. Tree biomass is comprised of all parts of the tree; leaves, stems, branches, roots, tree trunks. The biomass of the woody tissue in the tree pictured on the right is made mostly of cellulose a long, fibrous carbohydrate (C6H12O6)n made by plants; wood and bark are made primarily out of cellulose. , a carbon compound. In a process called carbon fixation process by which photosynthetic organisms such as plants and algae turn inorganic carbon compounds (usually carbon dioxide) into organic carbon compounds (usually carbohydrate sugars). , plants transform CO2, an inorganic carbon compound a carbon compound that does not contain both carbon and hydrogen and tends to be simpler than organic compounds. Examples would include carbon dioxide (CO2) and carbonates (CaCO3). into organic carbon compounds contain carbon atoms bonded to hydrogen atoms and possibly other elements such as nitrogen or phosphorous; examples include proteins, carbohydrates, nucle Continue reading >>
Photosynthesis
Photosynthesis article provided by Encarta Encyclopedia 2000 INTRODUCTION Photosynthesis, process by which green plants and certain other organisms use the energy of light to convert carbon dioxide and water into the simple sugar glucose. In so doing, photosynthesis provides the basic energy source for virtually all organisms. An extremely important byproduct of photosynthesis is oxygen, on which most organisms depend. Photosynthesis occurs in green plants, seaweeds, algae, and certain bacteria. These organisms are veritable sugar factories, producing millions of new glucose molecules per second. Plants use much of this glucose, a carbohydrate, as an energy source to build leaves, flowers, fruits, and seeds. They also convert glucose to cellulose, the structural material used in their cell walls. Most plants produce more glucose than they use, however, and they store it in the form of starch and other carbohydrates in roots, stems, and leaves. The plants can then draw on these reserves for extra energy or building materials. Each year, photosynthesizing organisms produce about 170 billion metric tons of extra carbohydrates, about 30 metric tons for every person on earth. Photosynthesis has far-reaching implications. Like plants, humans and other animals depend on glucose as an energy source, but they are unable to produce it on their own and must rely ultimately on the glucose produced by plants. Moreover, the oxygen humans and other animals breathe is the oxygen released during photosynthesis. Humans are also dependent on ancient products of photosynthesis, known as fossil fuels, for supplying most of our modern industrial energy. These fossil fuels, including natural gas, coal, and petroleum, are composed of a complex mix of hydrocarbons, the remains of organisms that Continue reading >>
The Calvin Cycle | Biology I
By the end of this section, you will be able to: Explain how photosynthesis works in the energy cycle of all living organisms After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build food in the form of carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules comes from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules. Figure 1. Light-dependent reactions harness energy from the sun to produce ATP and NADPH. These energy-carrying molecules travel into the stroma where the Calvin cycle reactions take place. In plants, carbon dioxide (CO2) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplastthe site of the Calvin cycle reactions where sugar is synthesized. The reactions are named after the scientist who discovered them, and reference the fact that the reactions function as a cycle. Others call it the Calvin-Benson cycle to include the name of another scientist involved in its discovery (Figure 1). The Calvin cycle reactions (Figure 2) can be organized into three basic stages: fixation, reduction, and regeneration. In the stroma, in addition to CO2, two other chemicals are present to initiate the Calvin cycle: an enzyme abbreviated RuBisCO, and the molecule ribulose bisphosphate (RuBP). RuBP has five atoms of carbon and a phosphate group on each end. RuBisCO catalyzes a reaction between CO2 and RuBP, which forms a six-carbon compound that is immediately converted into t Continue reading >>
Photosynthesis Flashcards | Quizlet
What substance is needed to trap light energy from the sun? What gas is absorbed by plants during photosynthesis? What would happen to a green plant that received only green light? Plants are green because they do not absorb green light, but reflect or transmit it. So if a plant is kept in green light it will not be able to absorb it and will not be able to carry out photosynthesis. Where does energy in most food come from? A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption Because this pigment absorbs all the wavelengths of sunlight except green. Green is reflected back so our eyes could detect it; green has the lowest rate of photosynthesis (less absorption of photons), and when you see a color it is because it reflects that color, not absorbing it. The technique of separating and analyzing the components (colors) of a mixture of liquids or gases by selective adsorption Organism that goes through photosynthesis Green algae, Elodea, Diatoms (most Plantae) 6CO2 + 6H2O + sunlight ----> C6H12O6 + 6O2 (Carbon Dioxide + Water + Light ----> Glucose + Oxygen) What does sunlight do during the light reaction? The energy from light propels the electrons from a photosystem into a high-energy state What molecule do the hydrogen atoms that are found in glucose at the end of photosynthesis come from? What molecule do the carbon atoms that are found in glucose at the end of photosynthesis come from? What molecule do the oxygen atoms that are found in glucose at the end of photosynthesis come from? What is the difference between a heterotroph and an autotroph? What do autotrophs require? What do heterotrophs require? An autotroph (plant) makes its own food/energy (using sunlight in the process of photosynt Continue reading >>
We Breath O2 In And Co2 Out. Where Does The Carbon Atom Come From? - Quora
We breath O2 in and CO2 out. Where does the carbon atom come from? Updated Jun 17, 2015 Author has 4.7k answers and 6.7m answer views It comes from carbohydrates and other carbon containing molecules that are metabolized in our cells. These molecules can be of various types, mostly glucose or other sugars, and/or various fatty acids, though in some cases ketone "bodies" like acetone can contribute too. We are also quite capable of breaking down amino acids in the liver to produce glucose for metabolism, when a shortage exists. But basically the story is that carbon and hydrogen containing molecules are combined with oxygen from the air to produce CO2 and H20 and usable energy by a series of complicated and enzymatically catalysed reactions. Most of the energy comes from making the water molecules actually, since carbon dioxide is not as deeply bound a molecule. Since humans are incapable of using other energy sources like sunlight to fix carbon by photosynthesis using atmospheric CO2 as a basic source of carbon, which we need not only for metabolism but also for structural and functional components of our cells, we must ultimately replace all the carbon that we exhale in the form of CO2 by ingesting more carbon containing molecules. The end products of cellular respiration are H20 and CO2. 5.4k Views View Upvoters Not for Reproduction It comes from the glucose molecule (C6H12O6). The reason we breathe in oxygen in the first place is to react it with glucose from our food to produce energy for our cells. The reaction may be simplified as: glucose + oxygen -> carbon dioxide + water The water mostly gets exhaled as vapour in our breath, along with the CO2. 913 Views View Upvoters Not for Reproduction Quora User, Not just another brick in the wall Answered Jun 13, 2015 Aut Continue reading >>
How Are Respiration And Photosynthesis Related?
How are respiration and photosynthesis related? Question Date: 2002-09-07 Answer 1: During photosynthesis, a plant is able to convert solar energy into a chemical form. It does this by capturing light coming from the sun and, through a series of reactions, using its energy to help build a sugar molecule called glucose. Glucose is made of six carbon atoms, six oxygen atoms, and twelve hydrogen atoms. When the plant makes the glucose molecule, it gets the carbon and oxygen atoms it needs from carbon dioxide, which it takes from the air. Carbon dioxide doesn't have any hydrogen in it, though, so the plant must use another source for hydrogen. The source that it uses is water. There is a lot of water on the earth, and every water molecule is composed of two hydrogen atoms and one oxygen atom. In order to take the hydrogen it needs to build glucose molecules, the plant uses the energy from the sun to break the water molecule apart, taking electrons and hydrogen from it and releasing the oxygen into the air. The electrons it takes are put into an electron transport system, where they are used to produce energy molecules called ATP that are used to build the glucose molecule-- all made possible by the sun's energy. Thus, during photosynthesis a plant consumes water, carbon dioxide, and light energy, and produces glucose and oxygen. The sugar glucose is important because it is necessary for cellular respiration. During cellular respiration, the chemical energy in the glucose molecule is converted into a form that the plant can use for growth and reproduction. In the first step of respiration, called glycolysis, the glucose molecule is broken down into two smaller molecules called pyruvate, and a little energy is released in the form of ATP. This step in respiration does not req Continue reading >>
Chemistry For Biologists: Photosynthesis
Leaves and leaf structure | The structure of the chloroplast and photosynthetic membranes | Stages of photosynthesis | Non-cyclic phosphorylation (the Z scheme) | Chemiosmosis and ATP synthesis | Cyclic phosphorylation | The light-independent reactions | Summary of stages of photosynthesis | Factors affecting the rate of photosynthesis | Test your knowledge Photosynthesis is the process by which plants, some bacteria and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water. This glucose can be converted into pyruvate which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is also formed. Photosynthesis may be summarised by the word equation: The conversion of usable sunlight energy into chemical energy is associated with the action of the green pigment chlorophyll. Chlorophyll is a complex molecule. Several modifications of chlorophyll occur among plants and other photosynthetic organisms. All photosynthetic organisms have chlorophyll a. Accessory pigments absorb energy that chlorophyll a does not absorb. Accessory pigments include chlorophyll b (also c, d, and e in algae and protistans), xanthophylls, and carotenoids (such as beta-carotene). Chlorophyll a absorbs its energy from the violet-blue and reddish orange-red wavelengths, and little from the intermediate (green-yellow-orange) wavelengths. a lipid-soluble hydrocarbon tail (C20H39 -) a flat hydrophilic head with a magnesium ion at its centre; different chlorophylls have different side-groups on the head The tail and head are linked by an ester bond. Plants are the only photosynthetic organisms to have leaves (and not all plants have leaves). A leaf may be viewed as a solar collector crammed full of photosynthetic cells. The raw materials of photosynthe Continue reading >>
Biology Flashcards | Quizlet
Equation that shows how ADP is changed into ATP Which molecule stores more than 90 times the energy in ATP? How are these cell used How do animal cells store glucose for later? How do plants store glucose for later? 2. Strach - storage energy - storage energy 3. Glvogen- animals, stored sugar in animal cell. Liver plus muscle Jan van helmont, Jan ingenhousz, Joseph priestly, Melvin Calvin What was "wrong" about the van helmont's conclusion that when plants grow, their increase in mass comes from water Grew in mass size because the soil made the plant bigger, process of photosynthesis creating the plant to grow Write the chemical equation for photosynthesis What is a pigment? Why is the main pigment used by green plants to absorb energy? Molecule that absorbs light energy. Cloraphl- used blue and red light Which wavelength of light are the best absorbed by chlorophyll a & b? Which are reflected? How are carotene pigments different from chlorophyll? Fwy do plants have these other pigments besides chlorophyll? Why do plants look green Orange, yellow, some reds. To help the plant to get more light Be able to label the parts of a chloroplast and tell where the reactions for photosynthesis happen What is NADP? What does it do? How does it change into NADPH NADPH is an electron carrier molecule, carries exited electrons to the stroma used in the Calvin cycle. Ex: little kids energy Where does the H that ends up in NADPH ultimately come from Pick up from the water as it carries energized electrons Describe the 2 sets of reactions involved in photosynthesis Where are they located and what happens in each Lights absorbed, electrons get exited, heading to photosynthesis one. Join an electron carrier and makes NADP - goes to the light independent- stroma attached to NADP now makes Continue reading >>
8.4 The Two Parts Of Photosynthesis: The Calvin Cycle
8.4 The Two Parts of Photosynthesis: The Calvin Cycle After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build food in the form of carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules comes from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules. In plants, carbon dioxide (CO2) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplastthe site of the Calvin cycle reactions where sugar is synthesized. The reactions are named after the scientist who discovered them, and reference the fact that the reactions function as a cycle. Others call it the Calvin-Benson cycle to include the name of another scientist involved in its discovery (Figure 13). Figure 13 Light-dependent reactions harness energy from the sun to produce ATP and NADPH. These energy-carrying molecules travel into the stroma where the Calvin cycle reactions take place. The Calvin cycle reactions (Figure 14) can be organized into three basic stages: fixation, reduction, and regeneration. In the stroma, in addition to CO2, two other chemicals are present to initiate the Calvin cycle: an enzyme abbreviated RuBisCO, and the molecule ribulose bisphosphate (RuBP). RuBP has five atoms of carbon and a phosphate group on each end. RuBisCO catalyzes a reaction between CO2 and RuBP, which forms a six-carbon compound that is immediately converted into two three-carbon compounds. This process is called carbon fixation, bec Continue reading >>
The Calvin Cycle Synthesizes Hexoses From Carbon Dioxide And Water - Biochemistry - Ncbi Bookshelf
The enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco) comprises eight large subunits (one shown in red and the others in yellow) and eight small subunits (one shown in blue and the others in white). The active sites (more...) Rubisco requires a bound divalent metal ion for activity, usually magnesium ion. Like the zinc ion in the active site of carbonic anhydrase ( Section 9.2.1 ), this metal ion serves to activate a bound substrate molecule by stabilizing a negative charge. Interestingly, a CO2 molecule other than the substrate is required to complete the assembly of the Mg2+ binding site in rubisco. This CO2 molecule adds to the uncharged -amino group of lysine 201 to form a carbamate. This negatively charged adduct then binds the Mg2+ ion. The formation of the carbamate is facilitated by the enzyme rubisco activase, although it will also form spontaneously at a lower rate. The metal center plays a key role in binding ribulose 1,5-bisphosphate and activating it so that it will react with CO2 ( Figure 20.4 ). Ribulose 1,5-bisphosphate binds to Mg2+ through its keto group and an adjacent hydroxyl group. This complex is readily deprotonated to form an enediolate intermediate. This reactive species, analogous to the zinc-hydroxide species in carbonic anhydrase ( Section 9.2.2 ), couples with CO2, forming the new carbon-carbon bond. The resulting product is coordinated to the Mg2+ ion through three groups, including the newly formed carboxylate. A molecule of H2O is then added to this -ketoacid to form an intermediate that cleaves to form two molecules of 3-phosphoglycerate ( Figure 20.5 ). Formation of 3-Phosphoglycerate. The overall pathway for the conversion of ribulose 1,5 bisphosphate and CO2 into two molecules of 3-phosphoglycerate. Although the free Continue reading >>
The Carbon Cycle
Some features of this site are not compatible with your browser. Install Opera Mini to better experience this site. This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science. The time it takes carbon to move through the fast carbon cycle is measured in a lifespan. The fast carbon cycle is largely the movement of carbon through life forms on Earth, or the biosphere. Between 1015 and 1017 grams (1,000 to 100,000 million metric tons) of carbon move through the fast carbon cycle every year. Carbon plays an essential role in biology because of its ability to form many bondsup to four per atomin a seemingly endless variety of complex organic molecules. Many organic molecules contain carbon atoms that have formed strong bonds to other carbon atoms, combining into long chains and rings. Such carbon chains and rings are the basis of living cells. For instance, DNA is made of two intertwined molecules built around a carbon chain. The bonds in the long carbon chains contain a lot of energy. When the chains break apart, the stored energy is released. This energy makes carbon molecules an excellent source of fuel for all living things. During photosynthesis, plants absorb carbon dioxide and sunlight to create fuelglucose and other sugarsfor building plant structures. This process forms the foundation of the fast (biological) carbon cycle. (Illustration adapted from P.J. Sellers et al., 1992.) Plants and phytoplankton are the main components of the fast carbon cycle. Phytoplankton (microscopic organisms in the ocean) and plants take carbon dioxide from the atmosphere by absorbing it into their cells. Using energy from the Sun, both plants and plankton combine carbon dioxide (CO2) and water to form sugar Continue reading >>
Balanced Photosynthesis Equation
The balanced equation for photosynthesis helps us to understand the process of glucose synthesis by plants in a simplified form. Read this article to gain more information about this subject. The presence of chlorophyll and the ability to undergo photosynthesis are some attributes that distinguish plants from animals. Photosynthesis is defined as the chemical process, wherein carbon dioxide in the presence of water and radiant energy gets converted to glucose (chemical energy), giving out oxygen as byproducts. Green plants along with algae and some bacteria are grouped under photoautotrophs, meaning they can make their own food in the presence of light by photosynthesis. This conversion of light energy into chemical energy occurs in the pigment containing plastids called chloroplasts. The process that takes place in the chloroplasts for glucose production is put forth in the equation for photosynthesis. In the equation, the combining reactants and resulting products are expressed along with their respective numbers of molecules. Balanced Photosynthesis Chemical Equation Carbon dioxide, water, and radiant energy is present on the reactant side, whereas on the other side are the products of photosynthesis process, i.e., glucose and oxygen. Putting this in a simplified formula, the following equation represents this process. Step # 1: CO2 + H2O + Light energy C6H12O6 + O2 A chemical reaction is said to be balanced, when both sides of the photosynthesis equation (reactants and products) have the same number of molecules for each of the elements. Needless to mention, the above formula for photosynthesis is not balanced, as there is only one atom of carbon in the reactant side, while there are 6 carbon atoms in the product side. As you try to balance the above equation, put Continue reading >>
Photosynthesis
Photosynthesis is the process by which plants, some bacteria, and some protistansuse the energy from sunlight to produce sugar, which cellularrespiration converts into ATP ,the "fuel" used by all living things. The conversion of unusablesunlight energy into usable chemical energy, is associated with theactions of the green pigment chlorophyll .Most of the time, the photosynthetic process uses water and releasesthe oxygen that we absolutely must have to stay alive. Oh yes, weneed the food as well! We can write the overall reaction of this processas: Most of us don't speak chemicalese, so the abovechemical equation translates as: six molecules of water plus sixmolecules of carbon dioxide produce one molecule of sugar plus sixmolecules of oxygen Diagram of a typical plant, showing the inputs andoutputs of the photosynthetic process. Image from Purves etal., Life: The Science of Biology, 4th Edition, by SinauerAssociates ( www.sinauer.com ) andWH Freeman ( www.whfreeman.com ),used with permission. Plants are the only photosynthetic organisms tohave leaves (and not all plants have leaves). A leaf may be viewed as a solarcollector crammed full of photosynthetic cells. The raw materials of photosynthesis, water andcarbon dioxide, enter the cells of the leaf, and the products ofphotosynthesis, sugar and oxygen, leave the leaf. Cross section of a leaf, showing the anatomicalfeatures important to the study of photosynthesis: stoma, guard cell,mesophyll cells, and vein. Image from Purves et al., Life:The Science of Biology, 4th Edition, by Sinauer Associates( www.sinauer.com ) and WH Freeman( www.whfreeman.com ), used withpermission. Water enters the root and is transported up to theleaves through specialized plant cells known as xylem (pronounces zigh-lem). Land plants must guar Continue reading >>
5.3: The Calvin Cycle
Explain how photosynthesis works in the energy cycle of all living organisms After the energy from the sun is converted and packaged into ATP and NADPH, the cell has the fuel needed to build food in the form of carbohydrate molecules. The carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules comes from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules. In plants, carbon dioxide (CO2) enters the chloroplast through the stomata and diffuses into the stroma of the chloroplastthe site of the Calvin cycle reactions where sugar is synthesized. The reactions are named after the scientist who discovered them, and reference the fact that the reactions function as a cycle. Others call it the Calvin-Benson cycle to include the name of another scientist involved in its discovery ( Figure 5.14). Figure 5.14 Light-dependent reactions harness energy from the sun to produce ATP and NADPH. These energy-carrying molecules travel into the stroma where the Calvin cycle reactions take place. The Calvin cycle reactions ( Figure 5.15 ) can be organized into three basic stages: fixation, reduction, and regeneration. In the stroma, in addition to CO2, two other chemicals are present to initiate the Calvin cycle: an enzyme abbreviated RuBisCO, and the molecule ribulose bisphosphate (RuBP). RuBP has five atoms of carbon and a phosphate group on each end. RuBisCO catalyzes a reaction between CO2 and RuBP, which forms a six-carbon compound that is immediately converted into two three-carbon compounds. This proces Continue reading >>
