photosynthesis

Question 1

Define Photosynthesis and list the general equation of it

Answer 1

The process in which simple inorganic molecules are converted into complex organic ones

It is a form of energy conversion, light energy to chemical energy

Can be thought of as the opposite of respiration, respiration releases energy.

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 2

What are the wavelengths of red and violet in the visible light spectrum, which is shortest which is longest.

Answer 2

Violet light has the shortest wavelenth at about 400nm

Red light has the longest wavelength at about 700nm

Green light is somewhere in the middle at about 550nm

Question 3

What is chlorophyll and where is it found?

Answer 3

Chlorophyll is the main photosynthetic pigment that absorbs light to provide energy for photosynthesis.

It is found in the chloroplast

Question 4

Where is the site of photosynthesis in plants?

Answer 4

Chloroplasts, an organelle found in plant cells.

Question 5

Explain why plant leaves often appear green

Answer 5

It is because of chlorophyll, chlorophyll appears green because it absorbs red and violet light very well, but not green.

It is not very good at absorbing green light and therefore it reflects it, making it appear green.

Question 6

How many forms of chlorophyll are there?

Answer 6

2 forms, chlorophyll A and Chlorophyll B

Question 7

What are the 2 groups of photosynthetic pigments and how do they differ?

Answer 7

Primary pigments, known as chlorophylls. Chlorophylls absorb light in the violet and red regions of the light spectrum.

Accessory pigments, known as Carotenoids, they absorb light mainly in the violet region of the spectrum.

The combination of pigments maximizes the amount of light energy that can be captured.

Question 8

What is the photolysis of water, and what is its importance in photosynthesis?

Answer 8

The photolysis of water is the breakdown of water molecules using light energy.

2H2O → 4e- + 4H+ + O2

This produces O2 gas as a waste product, but a plant can also use some of this oxygen for its own respiration (mainly during the day)

The electrons and protons produced in the reaction play a crucial role in further reactions of photosynthesis.

Question 9

Is photosynthesis anabolic or catabolic

Is photosynthesis endothermic or exothermic

Answer 9

Anabolic

Endothermic

Question 10

What is the formula for calculating Rf value?

Answer 10

Rf value = Distance travelled by component (pigment) / Distance travelled by the solvent

Question 11

What are the axis of an absorption spectrum labelled?

What are the axis of an action spectrum labelled?

Answer 11

Absorption:
X: Wavelength (Nm)
Y: Absorbance of pigment (%)

Action:
X: Wavelength (Nm)
Y: Rate of photosynthesis (% at max rate)

Question 12

What are the limiting factor graphs like for light intensity, temperature, and CO2 concentration?

Answer 12

CO2 concentration: Increases uniformly then plateaus, when plateau is reached it means some other factor is now limiting

Light intensity: Increases uniformly then plateaus, when plateau is reached it means some other factor is now limiting

Temperature:

1. Increases constantly as speed of particles increases and the number of collisions between reactants increases
2. Temperature reaches optimum temperature with highest possible rate of photosynthesis
3. If temperature continues to increase, rate of photosynthesis starts decreasig since enzymes beginto denature