Photosynthesis Flashcards
What is photosynthesis?
The process by which photosynthetic organisms harness light energy and convert it to chemical energy in order to produce macromolecules from simple organic precursors.
Oxygenic photosynthesis
02 producing photosynthesis
Organisms which are able to carry out photosynthesis
- Plants
2. Micro-organisms eg. algae and cyanobacteria
Light-dependent reaction facts
- require light in the visible spectrum
- convert light energy to chemical energy
- produce ATP and NADPH-H+
- produce O2 as by-product
Light-independent reaction facts
- Doesn’t require light
- must be preceded by light-dependent reaction
- use ATP and NADPH-H+ from light-dependent
- carbon fixation occurs
- sugars/carbs produced
Where does photosynthesis occur?
Within chloroplasts.
Describe the structure of a chloroplast.
Within a chloroplast there are grana (singular = granum) which are made up of thylakoid discs. The granum are connected to one another via thylakoid lamellae and it is at the membrane of the thylakoid discs which is where the light-dependent reaction takes place. Furthermore each chloroplast contains 2 membranes and the inner membrane is impermeable to most ions and molecules (much like mitochondria).
Name the different types of chlorophyll found in both plants and algae.
Plants: chlorophyll a, chlorophyll b
Algae: chlorophyll a, chlorophyll c, chlorophyll d and chlorophyll e
Where does the light-independent reaction occur?
Within the stroma of the chloroplast.
Why do chlorophyll molecules contain Mg2+ ions?
They are important in the process of capturing light.
From which areas of the visible spectrum does chlorophyll absorb light?
The extremes of the visible spectrum - the violet/blue end and the ulterior red end.
What is the chlorophyll molecule within the middle of the antennae molecule referred to as?
It is referred to as the reaction centre. Antennae themselves are embedded within photosystems.
Name the type of chlorophyll acting as the reaction centre and wavelength at which said reaction centre becomes excited within photosystem 1.
The reaction centre is chlorophyll a and the wavelength at which it becomes excited is P700.
Name the type of chlorophyll acting as the reaction centre and wavelength at which said reaction centre becomes excited within photosystem 2.
The reaction centre can either be chlorophyll a or b and the wavelength at which it becomes excited is P680.
Why are plants green?
Green light Is reflected whereas other coloured light is absorbed by plant.