Embedded Files
This section includes the IB topic 2.9
This section includes the IB topic 2.9
- Photosynthetic pigments and chromatography
- Wavelengths of light
- Chlorophyll and light absorption
- Absorption spectra
- Oxygen production and effects of photosynthesis on the Earth
- Production of carbohydrates
- Limiting factors
- Experimental design: investigating limiting factors in photosynthesis
Light and light absorption
Light and light absorption
The greater the energy, the larger the frequency and the shorter (smaller) the wavelength.
The greater the energy, the larger the frequency and the shorter (smaller) the wavelength.
The wavelength and frequency of light energy are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength. That number, also known as the frequency, will be larger for a short-wavelength wave than for a long-wavelength wave. A different parameter is the wave's amplitude: the greater the amplitude the higher the energy of the wave.
ROYGBIV
ROYGBIV
A typical human eye responds to wavelengths between 370 (violet) and 750 (red) nanometers. The visible spectrum is made of the colors red, orange, yellow, green, blue, indigo, and violet: ROYGBIV.
Spectrophotometer
Spectrophotometer
Absorption and Action Spectrum
Absorption and Action Spectrum
Absorption and action spectra
Absorption and action spectra
The horizontal x-axis shows the legend wavelength (from 400 to 700 nanometers).
- On an action spectrum the y-axis shows the percentage of the maximum rate of photosynthesis (from 0 to 1 00%).
- On an absorption spectrum the y-axis shows the percent absorption (0 to 1 00%).
Watch some of these videos to improve your understanding of light absorption and photosynthesis. There is a great virtual lab linked below... give it a go!
Review the steps of light absorption and photosynthesis with this animation. Take notes from the written information provided and make diagrams to enhance your understanding of this fascinating process.
Energy storage in carbohydrates
Energy storage in carbohydrates
Energy storage
Energy storage
Photosynthesis can be described as a series of reactions in which carbon dioxide and water are fixed into glucose, and oxygen is produced as a by-product. The energy to create the glucose (in the light independent reactions) comes directly from the ATP and reduced NADP created in the first stage of photosynthesis (light-dependent reactions). Glucose is only one of the many possible organic molecules that can be formed from photosynthesis. Plants store glucose as starch. Starch is a polymer of glucoses.
Limiting factors in photosynthesis
Limiting factors in photosynthesis
The great oxidation event (GOE) - photosynthesis and Earth’s atmosphere
The great oxidation event (GOE) - photosynthesis and Earth’s atmosphere
Around 2.45 million years ago a major environmental change happened to the planet earth: biologically produced gas oxygen contaminated the earth's atmosphere. The event is also known as the oxygen catastrophe, or the oxygen holocaust, because it had a huge impact on the planet.
The earth experienced then the first glaciation, presumably due to a reduction in the greenhouse effect of the earth's atmosphere. This could have been due to the rise in oxygenation causing a decrease in the concentration of methane in the atmosphere and photosynthesis causing a decrease in carbon dioxide concentration (education.cambridge.org, 2015).
Great Oxidation Event
Great Oxidation Event
The Super Single Cell Organism
The Super Single Cell Organism
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