EXERCISE NO. 3

Question 1

Title

Answer 1

Photosynthesis

Question 2

the main function of leaves

Answer 2

photosynthesis

Question 3

the manufacture of sugar through participation of carbon dioxide and water in the chloroplast with the use of light energy and the release of oxygen

Answer 3

photosynthesis

Question 4

formula

Answer 4

carbon dioxide + water — ( light, chlorophyll) –> glucose + oxygen

Question 5

both ____ and _____ features of the leaf enable photosynthesis to proceed

Answer 5

external and internal

Question 6

through photosynthesis the green plants: construct _______ from water, mineral, and gases ; captures the energy of the sun’s light waves and converts it into a biologically usable form of ___________ energy; and replenishes the atmosphere of the earth with _______.

Answer 6

organic compound

chemical energy

oxygen

Question 7

for photosynthesis to transform light energy from the sun into chemical energy (______ energy) in plants, ___________ absorb light to power the chemical reactions.

Answer 7

bond energy

pigment molecules

Question 8

are macromolecules produced by the plant and these pigments absorb specified wavelengths of visible light to provide the energy required for photosynthesis

Answer 8

plant pigments

Question 9

________ is necessary for photosynthesis, but ________ collect and transfer energy to chlorophyll.

Answer 9

chlorophyll

accessory pigments

Question 10

Although pigments absorb light, the wavelengths of light that are not absorbed by the plant pigments are

Answer 10

reflected back to the eye

Question 11

are the colors we see in observing the plant

Answer 11

reflected wavelengths

Question 12

four pigments that may separate out into their respective colors are

Answer 12

chlorophyll a - blue green color
chlorophyll b - pale green color
xanthophylls - pale yellow color
carotene - orange yellow color

Question 13

least soluble pigment

Answer 13

chlorophyll b

Question 14

most soluble pigment

Answer 14

carotene

Question 15

the easiest way to analyze th pigments is to separate them using ________

Answer 15

paper chromatography

Question 16

works on the principle that different pigments, when dissolved in a solvent will move through a piece of paper at different rates

Answer 16

paper chromatography

Question 17

examples of solvent used in paper chromatography

Answer 17

petroleum ether and acetone

Question 18

is determined by how soluble the pigment is in the solvent and the degree of adhesion of the pigment to the surface of paper

Answer 18

rate

Question 19

the pigments are carried at different rates because they are ____

Answer 19

not equally soluble

Question 20

a pigment that is ______ soluble will travel the greatest distance and a pigment that is _____ soluble will move shorter distance

Answer 20

most soluble = greater distance
less = shorter distance

Question 21

is unique for that pigment in set conditions and is used to identify the pigment

Answer 21

the distance the pigment travels

Question 22

the ratio or retention factor

Answer 22

Rf = distance traveled by the pigment/ distance traveled by the solvent 😡

Question 23

objectives

Answer 23

1. demonstrate the role of pigments in photosynthesis
2. isolate and identify photosynthetic pigments in Mayana, San Francisco, or star apple leaves
3. calculate Rf values of photosynthetic pigments

Question 24

star apple

Answer 24

CHRYSOPHYLLUM CAINITO

Question 25

mayana

Answer 25

COLEUS BLUEMEI

Question 26

San Francisco

Answer 26

CODIAEUM VARIEGATUM

Question 27

What do you call the solvent used for paper chromatography?

Answer 27

Chromatogram Solvent

Question 28

Chromatogram solvent is made up of?

Answer 28

95% petroleum ether and 5% percent acetone

Question 29

the set-up should be observed for ___ minutes

Answer 29

15

Question 30

is a point where the mobile phase travelled before the stationary phase was removed

Answer 30

Solvent front

Question 31

mobile phase

Answer 31

the solvent

Question 32

stationary phase

Answer 32

paper

Question 33

The differential adsorption to the paper and the differential solubility of these pigments in the solvent has effectively done what to the pigments in the plant leaves

Answer 33

separate

Question 34

Chromatogram solvent is composed of two solvents, petroleum ether and acetone. Why are two solvents used in the process?

Answer 34

Petroleum ether is a nonpolar solvent that helps dissolve nonpolar pigments like carotenoids found in lichens, while acetone is a polar solvent that dissolves more polar pigments like chlorophylls. By using a combination of these solvents, a broader range of pigments can be extracted and separated, allowing for a more comprehensive analysis of the lichen’s pigment composition. The two solvents complement each other in their ability to dissolve different types of pigments, facilitating a more complete pigment separation.

Question 35

what if the significance of the Rf values?

Answer 35

The Rf (Retention Factor) values in chromatography are significant because they provide quantitative information about the separation of compounds in a mixture. A higher Rf value indicates that a compound has moved a greater distance relative to the solvent front, suggesting it’s more soluble in the mobile phase and less attracted to the stationary phase. This information helps in identifying and characterizing the components of a mixture, making Rf values a valuable tool in analytical chemistry.

Question 36

why are plants generally green

Answer 36

Plants are generally green because of the presence of a pigment called chlorophyll. Chlorophyll molecules absorb light most efficiently in the blue and red parts of the electromagnetic spectrum but reflect green light, giving plants their characteristic green color. This reflects the fact that green light is less absorbed by chlorophyll and is instead transmitted or reflected, making it the predominant color that we perceive in plants.