Detecting Light Flashcards
How does light energy travel?
In the form of photons.
Give 2 examples of how organisms may use this light energy.
To generate ATP
To detect changes in their environment (increase survival)
- There are two methods of ATP generation; compare these two methods.
- Which two groups of organisms use these methods?
- They both use a proton gradient to drive ATP synthase.
They have different methods of generating proton gradient. - Archaea and Plants
What is the transmembrane protein found in archaea and what prosthetic group does it contain?.
Bacteriorhodopsin
Retinal prosthetic group.
The energy absorbed by the retinal is used for what?
To pump protons through the bacteriorhodopsin to generate a proton gradient.
Once the proton gradient is achieved in archaea, how is ATP generated?
Hydrogen ions diffuse through the membranes through ATP synthase, generating ATP from ADP and phosphate.
How is the energy from photons absorbed in plants?
By photosynthetic pigments found in chloroplasts
What does the absorbed energy in plants do?
Drives a flow of electrons along an electron transport chain. This flow pumps protons across a thylakoid membrane.
What molecule is used to capture light in eukaryotes?
Retinal prosthetic group.
What is the name of the polypeptide which retinal binds to?
Opsin
Identify the two classes of photoreceptor cells found in vertebrates.
Rods and Cones
Describe rod and cone cells and what kind of light they detect.
Rod cells contain rhodopsin and detect low levels of light.
Cone cells contain photopsins and allow colour vision.
