Lab 5: The Hill Reaction in Isolated Chloroplasts

Photosynthesis

Is the process by which plant convert light energy to chemical energy

6CO₂+12H₂O →(Light and chloroplasts) C₆H₁₂O₆ +6O₂ +6H₂O

The overall reaction of photosynthesis appears simple, but it involves many _.

Steps

The steps of photosynthesis are organized into two big stages known as what?

The light-dependent and light-independent reactions. 

The light-dependent reaction only occurs in the presence of what?

Light

The light-independent reaction can occur when?

Either in the dark or in the light

What happens during the light dependent reaction?

Light energy excites an electron in the chlorophyll molecule within a photosystem inside the thylakoid membrane of the chloroplast.

This electron enters nan electron transport chain (produces ATP) and travels to another photosystem, where it can be excited by another packet of light energy and transferred to NADP+, reducing that molecule to NADPH.

This NADPH and thehe previously mentioned ATP, will be used as energy in the light-independent reaction

During the light-dependent reaction what happens to a molecule of water?

A molecule of water is oxidized, releasing electrons, hydrogen ions, and molecular ions. 

The electrons released from water replace the electrons that are removed from the initial reaction

The oxidation of water, known as the hill reaction, cannot occur without light, water and intact functional chloroplasts.

The discovery of the Hill Reaction was pivotal in determining that the oxygen generated during photosynthesis came from the oxidation of water

How can we measure Hill Reaction in the laboratory?

By using DPIP (dichlorophenolindophenol) that can absorb free electrons so we can measure the changes based on absorbance

What is the goal of cell fractionation?

To isolate organelles or cells based on density

You can use this to study about it just like in this experiment

What is a supernatant?

The liquid that sits on top of a test tube or glass equipment after the centrifuge

What is a pellet?

It is the solid that collects at the bottom of the tube.