Photosynthesis Flashcards | Quizlet

However, these interactions can produce changes in electrical excitability.

temporarily stores energized electrons produced during the light ..

Recall from earlier tutorials, electrons are found in association with atoms, where they can participate in bond formation. Electrons have varying amounts of energy. In a non-illuminated pigment (one in the dark), critical electrons are usually found in a low energy state. However, the energy from an incoming photon can bump the electron into a higher energy state. If a photon of light resonates with a particular pigment, it has enough energy to raise a particular electron in the pigment to the next state. When this happens, light has been absorbed and energy has been transferred. Each photosystem has an electron acceptor that ultimately renews the energized electrons.

(1984) Influences of sinusoidal electric fields on excitability in rat hippocampal slice.

represents the flow of electrons during photosynthesis?

It is also possible that other uncontrolled factors, present only during excitation of the magnet coils, including mechanical vibrations, audible noise, and an increased ambient temperature, could have led to an altered pattern of brain electrical activity.

(1981) Influence of electric fields on the excitability of granule cells in guinea-pig hippocampal slices.

Remember that this process is happening inside the cell. Where do all of these electrons come from? You learned earlier that water is the source. Water molecules are split at the beginning of the first electron transport chain. This provides electrons that become energized in the photosystems, and protons that accumulate across the membrane.

It is this voltage-dependent permeability that gives the cells the property of being electrically excitable.


temporarily stores energized electrons produced during the ..

It is simply a series of redox reactions. There are two electron transport chains used in photosynthesis. They are energetically linked to one another, and electrons traverse through both.

correctly represents the flow of electrons during photosynthesis?


The peaks on this graph match the pigment peaks of the absorption spectrum
The matching peaks confirm that the pigments are directly related to photosynthesis
Reduction
Oxidation
Light Reactions

Chlorophyll in the thylakoids absorb solar energy and energize electrons
The energized electrons move down an elecron transport chain where the energy is captured and eventually used to make ATP & NADPH.

in the reaction center by the departure of light-energized electrons

Keep in mind, water is the source of the electrons. As shown in this figure, electrons are removed from water in photosystem II, and consequently, these electrons become energized into a more energetic state. Protons and oxygen are released as by-products of this reaction.
The electron transport chain of respiration occurs in the mitochondria, whereas the electron transport chains of photosynthesis are located in the chloroplasts. The thylakoid membrane is home to the many proteins involved.

Importance of Photosynthesis ..


Not the yellow or orange range.
Water
The roots of plants absorb water that travels through vascular tissue to the leaves.
Carbon dioxide in the air enters the leaf through small openings called stomata
Carbon Dioxide
The absorption spectrum shows the rate of photosynthesis.

these electrons become energized into a more ..

Free energy is released during redox reactions. In photosynthesis this energy is used for two things. First, hydrogen ions are moved across the membrane. The hydrogen ions really only consist of a single proton, and will be referred to that way throughout this tutorial. Remember that the electron loses some energy as it is passed along the electron transport chain because energy is required to pump the protons. The protons are moved into the thylakoid space where they accumulate; energy is required because these protons are being moved against a concentration gradient. (In other words, this is not passive diffusion.) The second use of free energy is reduction of an ultimate electron acceptor. At the end of the first electron transport chain, the electron is transferred to another molecule of chlorophyll. At the end of the second electron transport chain, the final acceptor of the electron is NADP+, which is reduced to NADPH.