3.2 - Photosynthesis Flashcards
What is absorption spectra?
A graph showing the wavelengths of light absorbed by a pigment
What is action spectra?
A graph of the rate of photosynthesis against each wavelength of light absorbed by a pigment
What is the Calvin cycle?
Light-independent reaction - The second stage of photosynthesis in which the products of the light-dependent stage and carbon dioxide are used to build organic molecules. It does not require light energy and takes place in the stroma.
Define chlorophyll
A photosynthetic pigment located in the thylakoids of the chloroplasts that absorbs light energy. There are two main types, chlorophyll a and chlorophyll b.
Explain what chloroplasts are
An organelle found in plants and algae that is the site of photosynthesis
What does chromatography mean?
The process of separating different substances from a mixture
What is cyclic photophosphorylation?
The formation of ATP involving photosystem I only
Define what Glycerate-3-phosphate (GP) is
A three-carbon molecule that is reduced by reduced NADP in the light-independent stage of photosynthesis to form 2 molecules of TP. This requires ATP
Explain what the light-dependent reaction is
the fist stage of photosynthesis that uses light energy to produce ATP, reduced NADP and oxygen. It takes place in the thylakoids of the chloroplast
What is the light-harvesting system? (Antennae Complex)
A collection of protein and chlorophyll molecules found in the thylakoid membranes of chloroplasts that absorbs light energy of varying wavelengths and transfers it to the reaction centre. It is also known as an antennae complex
What is the light-independent stage?
The second stage of photosynthesis, also known as the Calvin cycle, in which the products of the light-dependent stage and carbon dioxide are used to build organic molecules. It does not require light energy and takes place in the stroma
What is a limiting factor?
A variable that limits the rate of a particular reaction
Define magnesium
An inorganic nutrient required in plant metabolism for the production of chlorophyll
What is NADP?
A coenzyme that becomes reduced when it takes up hydrogen atoms during the light-dependent stage of photosynthesis, forming reduced NADP
What is nitrogen?
An inorganic nutrient required in plant metabolism for the production of amino acids, nucleotides and chlorophyll.
What is non-cyclic photophosphorylation?
The formation of ATP and reduced NADP involving both photosystems I and II
Define oxidation
The loss of electrons, gain of oxygen or loss of hydrogen in a substance
What is photolysis?
the splitting of a molecule of water in the presence of light that occurs during the light-dependent stage of photosynthesis. This produces protons, electrons and oxygen:
H2O -> 2H+ + 2e- + 1/2 O2
Define photosynthesis
A complex metabolic pathway that synthesises organic molecules in the presence of light. It consists of 2 main stages: light-dependent and light-independent reactions.
6CO2 + 6H2O > C6H12O6 + 6O2
What are photosynthetic pigments?
Molecules present in the chloroplasts that absorb certain wavelengths of light e.. chlorophyll a, chlorophyll b, xanthophylls and carotenoids
What is a photosystem?
A protein complex consisting of a light-harvesting system and reaction centre, hat is involved in the absorption of light and transfer of electrons in photosynthesis. There are 2 types, photosystems I and II.
What is a reaction centre?
The region of a photosystem where energy is funnelled and photosynthetic reactions take place. It contains 2 chlorophyll a molecules.
Define reduction
The gain of electrons, loss of oxygen or gain of hydrogen in a substance
What is retention value (R1)?
Calculated using the equation;
Rf = distance travelled by component
What is retention value (R1)?
Calculated using the equation;
Rf = distance travelled by component
distance travelled by solvent
What is ribulose bisphosphate (RuBP)?
A five-carbon compound that reacts with carbon dioxide in the light-independent stage of photosynthesis, forming 2 molecules of GP
What is ribulose bisphosphate carboxylase (Rubisco)?
an enzyme that catalyses the reaction of RuBP and the carbon dioxide in the light-independent stage of photosynthesis
What is a transducer?
Something that converts one type of energy into another e.g. chloroplasts transform light energy into the chemical energy of ATP.
What is triose phosphate (TP) ?
A three-carbon compound formed in the glycolysis and the light-independent stage of photosynthesis. It may serve as a starting material for the formation of organic molecules or be used to regenerate RuBP.
