The difference between wavelengths relates to the amount of energy carried by them. The sun emits energy in the form of electromagnetic radiation.
This radiation exists at different wavelengths, each of which has its own characteristic energy. All electromagnetic radiation, including visible light, is characterized by its wavelength. Each type of electromagnetic radiation travels at a particular wavelength. The longer the wavelength, the less energy it carries. Short, tight waves carry the most energy. This may seem illogical, but think of it in terms of a piece of moving heavy rope. It takes little effort by a person to move a rope in long, wide waves.
To make a rope move in short, tight waves, a person would need to apply significantly more energy. The electromagnetic spectrum Figure shows several types of electromagnetic radiation originating from the sun, including X-rays and ultraviolet UV rays.
The higher-energy waves can penetrate tissues and damage cells and DNA, which explains why both X-rays and UV rays can be harmful to living organisms. Absorption of Light Light energy initiates the process of photosynthesis when pigments absorb specific wavelengths of visible light.
Plants use these compounds in all of their metabolic processes; plants do not need to consume other organisms for food because they build all the molecules they need.
Unlike plants, animals need to consume other organisms to consume the molecules they need for their metabolic processes. The Process of Photosynthesis During photosynthesis, molecules in leaves capture sunlight and energize electrons, which are then stored in the covalent bonds of carbohydrate molecules. That energy within those covalent bonds will be released when they are broken during cell respiration.
How long lasting and stable are those covalent bonds? The energy extracted today by the burning of coal and petroleum products represents sunlight energy captured and stored by photosynthesis almost million years ago. Plants, algae, and a group of bacteria called cyanobacteria are the only organisms capable of performing photosynthesis. Photosynthetic and Chemosynthetic Organisms: Photoautotrophs, including a plants, b algae, and c cyanobacteria, synthesize their organic compounds via photosynthesis using sunlight as an energy source.
Cyanobacteria and planktonic algae can grow over enormous areas in water, at times completely covering the surface. In a d deep sea vent, chemoautotrophs, such as these e thermophilic bacteria, capture energy from inorganic compounds to produce organic compounds. The ecosystem surrounding the vents has a diverse array of animals, such as tubeworms, crustaceans, and octopi that derive energy from the bacteria.
Those carbohydrates are the energy source that heterotrophs use to power the synthesis of ATP via respiration. When a top predator, such as a wolf, preys on a deer, the wolf is at the end of an energy path that went from nuclear reactions on the surface of the sun, to light, to photosynthesis, to vegetation, to deer, and finally to wolf.
Main Structures and Summary of Photosynthesis In multicellular autotrophs, the main cellular structures that allow photosynthesis to take place include chloroplasts, thylakoids, and chlorophyll. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll.
Chlorophyll absorbs certain portions of the visible spectrum and captures energy from sunlight. Key Terms chloroplast: An organelle found in the cells of green plants and photosynthetic algae where photosynthesis takes place.
Overview of Photosynthesis Photosynthesis is a multi-step process that requires sunlight, carbon dioxide, and water as substrates. These sugar molecules contain covalent bonds that store energy.
Organisms break down these molecules to release energy for use in cellular work. Photosynthesis: Photosynthesis uses solar energy, carbon dioxide, and water to produce energy-storing carbohydrates. Oxygen is generated as a waste product of photosynthesis.
The energy from sunlight drives the reaction of carbon dioxide and water molecules to produce sugar and oxygen, as seen in the chemical equation for photosynthesis. Though the equation looks simple, it is carried out through many complex steps. Before learning the details of how photoautotrophs convert light energy into chemical energy, it is important to become familiar with the structures involved.
Chemical equation for photosynthesis: The basic equation for photosynthesis is deceptively simple. In reality, the process includes many steps involving intermediate reactants and products. Light-dependent and light-independent reactions are two successive reactions that occur during photosynthesis. Light energy is harnessed in Photosystems I and II, both of which are present in the thylakoid membranes of chloroplasts.
In light-independent reactions the Calvin cycle , carbohydrate molecules are assembled from carbon dioxide using the chemical energy harvested during the light-dependent reactions. Key Terms photosystem: Either of two biochemical systems active in chloroplasts that are part of photosynthesis.
Photosynthesis takes place in two sequential stages: The light-dependent reactions; The light-independent reactions, or Calvin Cycle.
Light-Dependent Reactions Just as the name implies, light-dependent reactions require sunlight. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and converted into stored chemical energy, in the form of the electron carrier molecule NADPH nicotinamide adenine dinucleotide phosphate and the energy currency molecule ATP adenosine triphosphate.
Not all photosynthetic organisms have full access to sunlight. The oxygen molecules produced as byproducts find their way to the surrounding environment.
You might ask, "What the heck happened, Shmoop? Light-Independent Reactions In the light-independent reactions or Calvin cycle, the energized electrons from the light-dependent reactions provide the energy to form carbohydrates from carbon dioxide molecules. And we mean a lot. Glucose, the primary energy source in cells, is made from two three-carbon GA3P molecules. The light-dependent reactions release oxygen from the hydrolysis of water as a byproduct. Chloroplasts contain disc-shaped structures called thylakoids, which contain the pigment chlorophyll.
Admit it. This potential energy is harvested and stored as chemical energy in ATP through chemiosmosis, the movement of hydrogen ions down their electrochemical gradient through the transmembrane enzyme ATP synthase, just as in the mitochondrion.
Oxygen is generated as a waste product of photosynthesis. RuBisCo is actually a poor enzyme. To make matters worse, RuBisCo is also capable of catalyzing another less-than-beneficial reaction. Plants, algae, and cyanobacteria, known as photoautotrophs, are the only organisms capable of performing photosynthesis. The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem. NEXT The light reactions, or the light-dependent reactions, are up first.
This potential energy is harvested and stored as chemical energy in ATP through chemiosmosis, the movement of hydrogen ions down their electrochemical gradient through the transmembrane enzyme ATP synthase, just as in the mitochondrion. Key Terms photosystem: Either of two biochemical systems active in chloroplasts that are part of photosynthesis. Our good buddy carbon dioxide CO2 provides an excellent source of carbon for making carbohydrates. What's that? In light-independent reactions the Calvin cycle , carbohydrate molecules are assembled from carbon dioxide using the chemical energy harvested during the light-dependent reactions.
But where does the stored energy in food originate? Light-Dependent Reactions Just as the name implies, light-dependent reactions require sunlight. This reaction is called photorespiration, and it occurs when the concentration of CO2 drops too low relative to the concentration of O2 in the cell. Therefore, a single wave is measured from two consecutive points, such as from crest to crest or from trough to trough Figure. It takes little effort by a person to move a rope in long, wide waves. In the light-dependent reactions, energy from sunlight is absorbed by chlorophyll and converted into stored chemical energy, in the form of the electron carrier molecule NADPH nicotinamide adenine dinucleotide phosphate and the energy currency molecule ATP adenosine triphosphate.
You might ask, "What the heck happened, Shmoop?
The first is called photosystem II, which was named for the order of its discovery rather than for the order of the function. Carnivores eat other animals and herbivores eat plants. Admit it.
After the energy is transferred, the energy carrier molecules return to the light-dependent reactions to obtain more energized electrons. In the Calvin cycle, which takes place in the stroma, the chemical energy derived from the light-dependent reactions drives both the capture of carbon in carbon dioxide molecules and the subsequent assembly of sugar molecules. It is the only biological process that captures energy from outer space sunlight and converts it into chemical energy in the form of G3P Glyceraldehyde 3-phosphate which in turn can be made into sugars and other molecular compounds. This process is called photomorphogenesis.