Summary 8.2

• Sunlight is a type of electromagnetic energy


• these energys travel in waves


• A wavelength is the distance between two adjacent waves


• The electromagnetic spectrum is the range of different types of electromagnetic energies
  


• These types of electromagnetic energy include gamma rays, x-rays, UV, infrared and others.


• Visible light is the smallest fraction of the electromagnetic spectrum


• visible light consists of wavelengths from 400 nanometers to 700 nanometers


• Shorter wavelengths contain more energy


• people burned by the sun's UV rays people can develop skin cancer


• Colors are caused by chemical compounds known as pigments


• Pigments cannot absorb the same color of light.


• Paper chromatography is a method to observe pigments inside a leaf


• Photosystem is the membrane of the thylakoid


• Photosystems are like mini solar panels that absorb energy


• in the light reactions stage, two photosystems are used


• The first photosystem is used to split water molecules and producing oxygen as a waste but also release hydrogen ions.


• The second photosystem is a NADPH producing photosystem and is done by transferring excited electrons and hydrogen ions to NADP+.

Vocab:

-wavelength: the distance between two adjacent waves.

-electromagnetic spectrum: the range of electromagnetic energy.

-pigment: chemical compounds that decide the color of a substance.

-paper chromatography: a laboratory technique that is used to observe the pigments inside a leaf.

-photosystem: molecules that consists of clusters of chlorophyll a & b and carotenoids.

Concept Check:

1. A leaf is green because of its pigments and pigments are the chemical compounds in substances that decide what different colors they would have.

2. When a chlorophyll a molecule absorbs light they turn a electron from ground state to excited state and causes the electron to jump from molecule to molecule until it gets turned into ATP or NADPH through the primary electron acceptor.

3. Other than oxygen, ATP and NADPH is produced at the end of the light reactions stage.

4. Light reactions always take place inside the thylakoid which is inside the chloroplast.

The light reaction system.

Electromagnetic Spectrum