ficio tecnia vegetal

Traducción del video: Reacción Luz fotosíntesis, ciclo de Calvin, [Animación 3D]
Traducido por: Edwin de Jesús Hernández Albores ing. Bioquímica 7 semestre
Documento a traducir:
In order for plants to grow, they need inputs of carbon-dioxide, water, and energy. The chemical process by which plants use these resources to manufacture glucose, the building blocks of plants, is calledphotosynthesis. In the process, oxygen gas is produced as a byproduct. The energy for photosynthesis originates in the sun and arrives at the earth as sunlight has both a wave and a particle nature. The particles, or photons, are the smallest units of light. Photons oscillate along a path, which is measured as wavelengths. The light emitted from the sun contains photons in a wide spectrum ofwavelengths, called the electromagnetic spectrum. Photosynthetic organisms use only a small portion of the electromagnetic spectrum, called visible light. Photosynthetic organisms contain pigments that facilitate the capture of wavelengths of light in the visible light range. The color of the pigment comes from the wavelengths of light reflected. Plants appear green because they reflect yellow and greenwavelengths of light. Read and blue wavelengths of light are absorbed by these pigments and provide energy that used for photosynthesis. Within eukaryotic photosynthetic organisms, also known as photoautotrophs, the chemical reactions of photosynthesis occur within plant cells in specialized structures known as chloroplasts. Photosynthesis consists of two sets of reactions- the light dependentreactions and the Calvin cycle. Within the chloroplast are small disk-like structures called thylakoids, which are surrounded by a fluid-filled space called the stroma. The reactions that synthesize glucose, the Calvin cycle-occur in the stroma. The light-dependent reactions occur in the thylakoid. It is here that conversion of light energy to chemical energy is initiated. In most photosyntheticorganisms, thylakoids contain pairs of photosystems, called photosystem I and photosystem II, that work in tandem to produce the energy that will later be used in the stroma to manufacture sugar. The photosystems of the thylakoid consist of a network of accessory pigment molecules and chlorophyll the molecules that absorb the photons of light. Within the pigment molecules, the absorbed light energyexcites electrons to higher state. Photosystems will channel the excitation energy gathered by the pigment molecules to a reaction center chlorophyll molecule which will then pass the electrons to series of proteins located on the thylakoid membrane. Photons of light strike photosystems I and II simultaneously. We will examine what happens with the photons striking photosystem II first. The energizedelectrons are passed from the reaction center of photosystem II to an electron transport chain. The electrons lost by Photosystem II are replaced by a process called photolysis, which involves the oxidation of a water molecule, producing free electrons and oxygen gas. While this oxygen gas is a byproduct of photosynthesis, it is an important input to the cellular respiration pathways. As electronspass through the electron transport chain, the energy from the electrons is used to pump hydrogen ions from the stroma to the thylakoid, creating a concentration gradient. This gradient power a protein called ATP synthase, which phosphorylates ADP to form ATP. The low-energy electrons leaving Photosystems II are shuttled to Photosystem I. Within photosystem I, low energy electrons are reenergizedand are passed through an electron transport chain where they are used to reduce the electron carrier NADP+ to NADPH. When the chloroplast is receiving a steady supply of photons, NADPH and ATP molecules are rapidly being provided to the metabolic pathways in the stroma. Therefore the ATP and NADPH formed during the light dependent reactions are used in the stroma to fuel the Calvin cycle...