Question

-Give a brief background on the role of pigments in photosythensis.

-state your hypothesis.

-finish with stating the rationale for your hypothesis (how did you arrive at these hypothesis?)

Biod 20 PHOTOSYNTHESIS Background Plants harness the energy of the sun through a process called photosynthesis. The leaf is the plant organ that performs most of the photosynthesis of a plant. The green color of leaves is due to the presence of chlorophyll, (the pigment found in chloroplasts) the chemical that absorbs photons from the sun. There are two types of chlorophyll molecules, chlorophyll A and chlorophyll B. Each absorbs slightly different wavelengths of light. The different wavelengths that chlorophyll molecules absorb is called an absorption spectrum. Both molecules typically absorb in the blue and red wavelengths; these wavelengths are the most effective for photosynthesis. On the other hand, leaves transmit and reflect green light. The carotenoids are a third type of pigment molecule that absorb slightly longer wavelengths of light than the chlorophyll molecules. In today's lab, you will first determine an absorption spectrum for spinach using a spectrophotometer. You will also visualize the specific pigments found in spinach using chromatography, Purpose: • To determine the types of photosynthetic pigments that spinach contains. Methodology: • Determine an absorption spectrum from spinach leaves and compare to the individual absorption spectra of the purified pigments. • Determine via chromatography what pigments the spinach leaf contains. Research questions: • Is the absorption spectrum of spinach leaves different than the absorption spectrum of purified chlorophyll? • If the absorption spectrum is different, what would account for these differences? Hypotheses: • Generate these on your own. Equipment: Spectrophotometer Glass jars (chromatography container) Chromatography paper Scissors Petri dishes Pipettes (1-3 mL) Glass tube (for spinach homogenate) Reagents: Chromatography solvent (9 parts pet-ether to 1 part acetone; 10 mL per group) Acetone (10 mL per group)

this is an introduction piece, so it doesn't need the results to write the papee. introduction sections set up the background, purpose, rationale, and hypothesis for a study.

Answer 1

The primary function of pigments in plants is photosynthesis, which uses the green pigment chlorophyll and several colorful pigments that absorb as much light energy as possible. Other functions of pigments in plants include attracting insects to flowers to encourage pollination.

Plant pigments include many molecules, such as porphyrins, carotenoids, anthocyanins and betalains. All biological pigments selectively absorb certain wavelengths of light while reflecting others.