Fatty acid catabolism consists of: Activation and membrane transport of free fatty acids by binding to coenzyme A. Oxidation of the beta carbon to a carbonyl group.
Chloroplast and Thylakoid In photosynthetic bacteria, the proteins that gather light for photosynthesis are embedded in cell membranes. In its simplest form, this involves the membrane surrounding the cell itself.
A typical plant cell contains about 10 to chloroplasts. The chloroplast is enclosed by a membrane. This membrane is composed of a phospholipid inner membrane, a phospholipid outer membrane, and an intermembrane space.
Enclosed by the membrane is an aqueous fluid called the stroma. Embedded within the stroma are stacks of thylakoids granawhich are the site of photosynthesis. The thylakoids appear as flattened disks.
The thylakoid itself is enclosed by the thylakoid membrane, and within the enclosed volume is a lumen or thylakoid space. Embedded in the thylakoid membrane are integral and peripheral membrane protein complexes of the photosynthetic system.
Plants absorb light primarily using the pigment chlorophyll. The green part of the light spectrum is not absorbed but is reflected which is the reason that most plants have a green color.
Besides chlorophyll, plants also use pigments such as carotenes and xanthophylls. These pigments are embedded in plants and algae in complexes called antenna proteins. In such proteins, the pigments are arranged to work together. Such a combination of proteins is also called a light-harvesting complex.
Although all cells in the green parts of a plant have chloroplasts, the majority of those are found in specially adapted structures called leaves. Certain species adapted to conditions of strong sunlight and ariditysuch as many Euphorbia and cactus species, have their main photosynthetic organs in their stems.
The cells in the interior tissues of a leaf, called the mesophyllcan contain betweenandchloroplasts for every square millimeter of leaf.
The surface of the leaf is coated with a water-resistant waxy cuticle that protects the leaf from excessive evaporation of water and decreases the absorption of ultraviolet or blue light to reduce heating. The transparent epidermis layer allows light to pass through to the palisade mesophyll cells where most of the photosynthesis takes place.
Light-dependent reactions Main article: Light-dependent reactions In the light-dependent reactionsone molecule of the pigment chlorophyll absorbs one photon and loses one electron.
This electron is passed to a modified form of chlorophyll called pheophytinwhich passes the electron to a quinone molecule, starting the flow of electrons down an electron transport chain that leads to the ultimate reduction of NADP to NADPH.
In addition, this creates a proton gradient energy gradient across the chloroplast membranewhich is used by ATP synthase in the synthesis of ATP. The chlorophyll molecule ultimately regains the electron it lost when a water molecule is split in a process called photolysiswhich releases a dioxygen O2 molecule as a waste product.
The overall equation for the light-dependent reactions under the conditions of non-cyclic electron flow in green plants is: The photosynthetic action spectrum depends on the type of accessory pigments present. For example, in green plants, the action spectrum resembles the absorption spectrum for chlorophylls and carotenoids with absorption peaks in violet-blue and red light.
In red algae, the action spectrum is blue-green light, which allows these algae to use the blue end of the spectrum to grow in the deeper waters that filter out the longer wavelengths red light used by above ground green plants. The non-absorbed part of the light spectrum is what gives photosynthetic organisms their color e.
The light-dependent reactions are of two forms: In the non-cyclic reaction, the photons are captured in the light-harvesting antenna complexes of photosystem II by chlorophyll and other accessory pigments see diagram at right.
The absorption of a photon by the antenna complex frees an electron by a process called photoinduced charge separation. The antenna system is at the core of the chlorophyll molecule of the photosystem II reaction center. That freed electron is transferred to the primary electron-acceptor molecule, pheophytin.
The electron enters a chlorophyll molecule in Photosystem I. There it is further excited by the light absorbed by that photosystem.
The electron is then passed along a chain of electron acceptors to which it transfers some of its energy. The energy delivered to the electron acceptors is used to move hydrogen ions across the thylakoid membrane into the lumen.
The cyclic reaction takes place only at photosystem I. Once the electron is displaced from the photosystem, the electron is passed down the electron acceptor molecules and returns to photosystem I, from where it was emitted, hence the name cyclic reaction.
Water photolysis Main articles: Photodissociation and Oxygen evolution The NADPH is the main reducing agent produced by chloroplasts, which then goes on to provide a source of energetic electrons in other cellular reactions.Photosynthesis is the process whereby plants using light energy from the sun convert carbon dioxide and water to glucose sugar and oxygen gas through a series of reactions.
The overall equation for photosynthesis is. Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels.
Organic and inorganic chemistry are two of the main disciplines of chemistry. An organic chemist studies organic.
Chemosynthesis is at the heart of deep-sea communities, sustaining life in absolute darkness, where sunlight does not penetrate. All chemosynthetic organisms use the energy released by chemical reactions to make a . Learn chemosynthesis biology questions with free interactive flashcards. Choose from 91 different sets of chemosynthesis biology questions flashcards on Quizlet.
Equation for Photosynthesis. Water+Carbon Dioxide light Equation for Chemosynthesis. Carbon dioxide + water + hydrogen sulfide + sugar + sulfur compounds. Aerobic respiration equation.
Glucose + oxygen --> water + carbon dioxide + energy. Anaerobic respiration equation. Photosynthesis is the process by which plants, some bacteria, and some protistans use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the "fuel" used by all living things.