Chapter 10: Photosynthesis – Flashcards

The oxygen released during photosynthesis comes from the splitting of water during the light-dependent reaction. 3. Remember, the electrons lost from the reaction center in photosystem II must be replaced. The splitting of water serves to replace these lost electrons.

chloroplasts "capture" sunlight energy in two ways. Light ''excites'' electrons in pigment molecules, and light provides the energy to split water molecules, providing more electrons as well as hydrogen ions. Light Energy to Chemical Energy

photophosphorylation

This is the light independent portion of the photosynthetic process. ATP from photosystem II provides energy and NADPH from PS I provides a source of hydrogens and high-energy electrons needed to bind the hydrogen to carbon. In the Calvin Cycle three molecules each containing 5 carbons (Ribulose bisphosphate) are joined to 3 carbon dioxide molecules to produce 6 molecules of 3-phosphoglycerate. This reaction is catalyzed by the enzyme rubisco. A series of reactions consumes 6 ATP and 6 NADPH to produce 6 glyceraldehyde 3-phosphate molecules. One of these is used ultimately to produces glucose, the other five are turned back into the original ribulose bisphosphate at a cost of a further 3 ATP molecules.

pine tree....An autotroph[?] ("self-feeding", from the Greek autos "self" and trophe "nourishing") or producer, is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) from simple substances present in its surroundings, generally using energy from light (photosynthesis) or inorganic chemical reactions (chemosynthesis).

In general outline and in effect, photosynthesis is the opposite of cellular respiration, in which glucose and other compounds are oxidized to produce carbon dioxide and water, and to release chemical energy (an exothermic reaction) to drive the organism's metabolism.

Light-dependent reactions 1. Capture energy from sunlight 2. Use the energy and H20 to make ATP and NADPH Light-independent reactions 3. Use ATP and NADPH to make sugars from CO2

The Calvin cycle is the last step in photosynthesis. The purpose of the Calvin Cycle is to take the energy from photosystem I and fix carbon. Carbon fixation means building organic molecules by adding carbon onto a chain. In order to do this, you have to start with an organic molecule, a starter molecule.

Green pigments found in chloroplast, that absorb light during photosynthesis. absorbs in blue and red regions of visable spectrum

Light Is a type of energy electromagnetic radiation Acts both particle-like and wave-like *Wavelength*The greater the energy, the larger the frequency and the shorter (smaller) the wavelength. Given the relationship between wavelength and frequency — the higher the frequency, the shorter the wavelength — it follows that short wavelengths are more energetic than long wavelengths. wave or partical.... photon energy packet

The light-harvesting complex (or antenna complex) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants, which transfer light energy to one chlorophyll a molecule at the reaction center of a photosystem series of chlorophyll

When a chlorophyll molecule is excited in the reaction center, its excited electron is transferred to an electron acceptor. Electromagnetic energy is transformed into chemical energy.

pheophytin

Photosystem II produces A proton gradient that drives the synthesis of ATP Photosystem I yields Reducing power in the form of NADPH Several groups of bacteria have just one of the two photosystems The cyanobacteria, algae, and plants have both

take light excited electrons used to create hydrogen gradient to create ATP

thylakoid membranes ( in the chloroplast)

thylakoid

thylakoid

via a proton gradient across thylakoid membarane

hydrogen protons to make ATP

chloraphyll

one has alihide and methal group

chloraphylle a and b die off left with caratanoids

aborb reflect or transmitt

Stabilize free radicals Protect chlorophylls from damage

produce floresence or undergo resenence

blue and red

*NADPH*functions as a reducing agent similar to NADH produced in cellular resperation. Some of the energy released from these redox reactions is also used to make ATP.*Plastoquinone* In photosystem 2 PQ transports electrons between molecles like that of ubiquinone in the ETC of cellular resperation. PQ delivers electrons from Photo.2 to the thylakoid.*Plastocyanin* forms a physical link between photosystem 2 and 1 and shuttles electrons between Photo. 1 and the cytochrome complex.

H20 in the thylakoid membrane

energy is used to make ATP. NAPD in 2

Function. The gas exchange that occurs when stomata are open facilitates photosynthesis. Photosynthesis is the process by which plants convert sunlight into usable energy. During photosynthesis, carbon dioxide is taken in from the atmosphere through the stomata and oxygen is released as a waste product.