Arnel, Kimberlyanne, Wendy

Motivation

Find how the different spectrums

of light affect the rate of

photosynthesis in plants. If a plant is placed under a green colored light, less

photosynthesis occurs compared to other colors on

light spectrum.

What is photosynthesis?

Photosynthesis is the process of

converting solar energy into

chemical energy.

Chloroplast a & b

e- transport chain

Materials 3 Beakers

3 Petri Dishes

Green, Blue, and Red Food Coloring

5 Cuvettes

Water

Chloroplast Solution

DPIP

6.5 pH Phosphate Buffer

Spectrophotometer

Light Source

Methodology3 cuvettes containing solution were placed

in separate beakers

Covered with petri dish lids filled with

red, blue, and green food coloring

1 cuvette was placed and covered under a

large bin.

1 cuvette was placed under the normal

lighting

… Every five minutes for twenty minutes, the cuvettes

were taken from the beakers and placed into the

spectrophotometer to measure the transmittance of

light.

Setup

Percent Transmittance vs. Time

Minutes Control

(%)

Blue (%) Red (%) Green (%) Dark (%)

0 21.8 35 55.8 50.6 17.2

5 20 65 50.2 53.2 16

10 20.2 71.6 70.4 53.6 16.4

15 19.8 70.6 62.4 53.2 16

20 19.6 70.8 69.8 53.8 16.2

Graph

0

10

20

30

40

50

60

70

80

5 5 10 15 20

Ligh

t Tr

ansm

itta

nce

(%

)

Time (minutes)

Rate of Photosynthesis

Blue

Red

Green

Dark

Blue & red lightChloroplasts contain pigments named

chlorophyll a and chlorophyll b which

absorb photons from the sunlight.

The pigments absorb blue and red

light best.

Green light

Green light is reflected

By reflecting the green, little to

no sunlight is absorbed.

Dark

Decreased due to no light being

absorbed.

Light is needed to create ATP and

power photosynthesis.

Photosynthesis