Chapter 6: Photosynthesis

Primary Electron Acceptor

Accepts the electrons that the chlorophyll A molecules have lost in the reduction reaction in photosystem 2.

ADP

Adenosine diphosphate. Energy in which lacks the third phosphate

Accessory Pigment

Assists in capturing light energy. (Chlorophyll B and carotenoids). Enables plants in getting more energy by absorbing more light.

Calvin Cycle

Biochemical pathway that is the second step of photosynthesis. Produces organic compounds using the energy stored in ATP and NADPH during light reactions. Named after Melvin Calvin.

Photosystem

Cluster of pigment molecules

RuBP

Combination of CO2 and an enzyme to make this five carbon molecule in the Calvin Cycle first step.

Pigment

Compound which absorbs light. Absorbing colors subtracts them from the visible spectrum

ATP Synthase

Creates ATP by adding a phosphate group to ADP.

Photosynthesis

Creation of energy from light

Photosystem 2

First photosystem in the light reaction, electrons move into chlorophyll A and become "excited" then move to the primary electron acceptor. After they are moved across the ETC

Electron Transport Chain

First series of molecules in thylakoid membrane. Transfers electrons from one molecule to the next and the electrons lose their energy. This energy is used to move protons in the thylakoid. The ETC after photosystem 1 brings electrons to the edge of the thylakoid (by the stroma) and combine with NADP+ to make NADPH.

Carbon Fixation

Incorporation of carbon dioxide into organic compounds.

Light Reactions

Initial reaction of photosynthesis. Begins with absorption of light into the chloroplast. That light is absorbed by pigments and transferred to the thylakoid to continue the light reaction.

Photosystem 1

Light is also absorbed in here, where they move from another pair of chlorophyll A molecules to the primary electron acceptor. Electrons lost from chlorophyll A are replaced by the electrons from the ETC

Wavelength

Light waves, way of measuring light. 400 nm to 70o nm, violet to red.

NADP+

Organic molecule that accepts electrons during redox reactions. "Dump truck".

PGAL

Produced in step 2 of the Calvin Cycle. Each PGA molecule receives a phosphate from ATP. It then receives a proton from NADPH and releases a phosphate group.

Visible Spectrum

Ranging colors from red to violet, these are the colors we see from light

Chemiosmosis

Relies on concentration gradient of proteins across the thylakoid membrane. The movement of protons into the stroma of the chloroplast releases energy, which is used to manufacture ATP.

Biochemical Pathway

Series of reactions in which the product of one reaction is consumed in the next reaction.

Stromata

Small pores in the under surface of a leave where water escapes and CO2 enters and O2 leaves.

Stroma

Solution surrounding the thylakoids

PGA

Split half of RuBP in the Calvin Cycle 1st step

Granum

Stack of thylakoids

Chlorophyll

Type of pigment. Chlorophylls mostly reflect green colors because they are not absorbed. Chlorophyll A is directly involved in light reactions, while Chlorophyll B assists in capturing light energy.

Carotenoid

Yellow, orange, and brown accessory pigments