Photosynthesis BIOLOGY- CH 8

Distinguish between how rubisco acts to make RuBP and how it oxidizes RuBP.

Rubisco has 2 enzymatic activities: carboxylation and photorespiration Carboxylation- addition of CO2 to RuBP --CO2 + RuBP (w help of rubisco enzyme) so it fixes carbon to make photosynthetic products *Photorespiration- adds O2 to RuBP, oxidizing it

Stroma

Semiliquid that is surrounding thylakoid membranes

Describe carbon fixation.

builds carbohydrates using energy and reduction potential energy: ATP from light dependent rxns, cyclic and noncyclic photophosphorylation, drives endergonic rxn reduction potential: NADPH from photosystem 1, source of protons and energetic electrons

Describe the structure of the chloroplast.

thylakoid membrane: internal membrane that contains chlorophyll and other pigments, which clustered into photosystems grana: stacks of flattened sacs of thylakoid membrane stroma lamella: connect grana stroma: semiliquid surrounding thylakoid membranes

Contrast the function of reaction center and antenna chlorophyll molecules.

-antenna complex gathers photons from sunlight and feed the captured light energy to the reaction center chlorophylls -reaction center passes excited electrons out of the photosystem

Demonstrate how six CO2 molecules can be used to make one glucose.

1. carbon fixation: RuBP+CO2-->PGA 2. reduction: Pga is r4educed to G3P 3. regeneration of RuBP: PGA is used to regenerate RuBP ***6 turns incorporate enough Carbon for 1 glucose***

Compare the function of carbon fixation in the C3, C4, and CAM pathways.

C3: uses calvin cycle to fix carbon C4: incorporates the CO2 into a 4 C molecule of malate in mesophyll cells, allows efficient carbon fixation by the calvin cycle CAM: initially fix CO2 using PEP carboxylase to produce oxaloacetate. when stroma are closed at night, the organic acids are decarboxylated to yield high levels of CO2, driving the calvin cycle and minimizing photorespiration

Explain the reaction for photosynthesis.

CO2 and water react with sunlight to create glucose (energy for the plant), excess water, and oxygen

Antenna Complex

Captures photons from sunlight and channels them to the reaction center chlorophylls. Also called light-harvesting complex.

Stroma Lamella

Connects Grana

Oxygenic

Creating Oxygen

Photosynthesis is carried out by_____________.

Cyanobacteria 7 Groups of Algae All Land Plants (chloroplasts)

Thylakoid Membrane

Internal Membrane Contains chlorophyll and other photosynthetic pigments Pigments clustered into photosystems.

Describe experiments that support our understanding of photosynthesis.

Jan Baptista van Helmont: demonstrated the substance of the plant was not produced only from the soil Joseph Priestly: living vegetation adds something to the air Jan Ingenhousz: proposed plants carry out a process that uses sunlight to split CO2 into C and O2

Grana

Stacks of flattened sacs of thylakoid membrane

Carbon Fixation

Taking an inorganic carbon and turning it into an organic form of carbon.

Discuss how pigments are important to photosynthesis.

absorb light energy from the sun. when pigments absorb light energy, it puts it in the visible range.

Differentiate between the light-dependent and light-independent reactions.

light dependent require light to function, light independent do not

Describe the nature of photosystems.

light is captured by photosystems of two components, antenna complex and reaction center

Energy for all life on Earth ultimately comes from ______________.

photosynthesis

Compare the function of the two photosystems in green plants.

photosystem 1 (P700) functions like sulfur bacteria photosystem 2 (p680) generate an oxidation potential high enough to oxidize water

Explain how the light reactions generate ATP and NADPH

photosystem 1 transfers e- to NADP+ producing NADPH. cyclic photophosphorylation generates ATP via electron transport chemiosmosis

Relate the absorption spectrum of a pigment to its color.

range and efficiency of photons molecule is capable of absorbing