Quantum Aspects of Photosynthesis

Question 1

When do quantum effects become revelant in biology?

Answer 1

When things are small or fast

Question 2

On what time scale do fundamental biochemical events occur?

Answer 2

Picosecond and fentoseconds

Question 3

How does ultrafast pump-probe spectroscopy work?

Answer 3

• One laserpulse is used to initiate the reaction
• A second laser is used to measure the response

Question 4

What are the characteristics of an excitation pump pulse?

Answer 4

Usually strong and monochromatic

Question 5

Why is the excitation pulse usually strong and monochromatic?

Answer 5

To excite all molecules in the whole sample in a specific way simultaneously

Question 6

What are the characteristics of the measuring pulse?

Answer 6

Typically weak and spectrally broad

Question 7

Why is the measuring pulse typically weak?

Answer 7

To prevent further excitation

Question 8

How is measurement of the evolution of the sample response over time achieved in pump probe spectroscopy?

Answer 8

By varying the delay between arrival of the pump and probe pulses at the sample

Question 9

What is a wavefunction?

Answer 9

Probability amplitudes

Question 10

How is the probability of finding a particle in a particular location calculated?

Answer 10

It is proportional to the square of the amplitude of the wave function

Question 11

What is Heisenberg’s uncertainty principle?

Answer 11

• You can never be certain of both the position and momentum of a microscopic particle
• The more you know of the position, the less you know of the momentum and vice versa

Question 12

What is an exciton?

Answer 12

A bound state of an electron and an electron hole that are atttracted to one another by an electrostatic coulombic interaction