IB Biology HL 1.3.9 Photosystems Question Bank
Practise IB Biology HL 1.3.9 by applying photosystems concepts to exam-style questions.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Practise IB Biology HL 1.3.9 by applying photosystems concepts to exam-style questions.
In water, shorter wavelengths of light such as blue and green penetrate deepest, and longer wavelengths of light penetrate less far. Red light does not reach depths of more than 50 m . Marine algae live at various water depths. Certain species of algae contain the pigments that enable them to adapt to life at different depths.
The graphs show the absorption and action spectra for two species of algae: Ulva taeniata, which is green, and Porphyra nereocystis, which is red.

Absorption / \%


Outline the structure and location of photosystems.
Location:
a. located in thylakoid (membranes);
b. photosystem/PS II is linked to Photosystem/PS I (by electron carriers)
OR
PS II is located before PS I OWTTE;
Structure:
c. reaction center/chlorophyll/primary pigment AND accessory pigments / light harvesting complex/antenna;
d. P680/P700/special chlorophyll (a) as the reaction centre;
b. Do not accept only the names of the photosystems without reference to linkage or order.
c. Accept 'various' or 'an array of' pigments for accessory pigments.
2
Marking guidance:
max