Photosynthesis UNIT 3 AOS 1 Flashcards
what is a photon?
a packet of light
what is chlorophyll?
the light absorbing green pigment that begins the process of photosynthesis
what is the thylakoid membrane?
the photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and electron transport chains
what is ATP?
A molecule containing three high energy phosphate bonds that acts as the primary energy-transferring molecule in a living organism.
what is ADP?
A molecule containing two high-energy phosphate bonds that may be formed by breaking one of the phosphate bonds in ATP.
what is NADP+?
A compound that accepts one hydrogen atom and two electrons forming NADPH; it is an electron acceptor.
what is NADPH?
A compound that donates one hydrogen aton and two electrons to another molecule, to reform NADP+; it is an electron donor.
what is a photosystem?
A cluster of photosynthetic pigments embedded in a thylakoid membrane of a chloroplast that absorbs light energy.
what is the chemical equation?
6CO2 + 12H2O -> C6H12O6 + 6O2 + 6H2O
what is the word equation?
carbon dioxide + water -> glucose + oxygen + water
what happens in the light dependent stage?
- light hits photosystem 1 and 2
- electrons from chlorophyll get excited an move down the chain of carriers
- water is split to replace the lost electrons
- O2 gas is released as a waste product
- NADPH and ATP are made
what happens in the light independent stage?
- CO2 is fixed and enters the krebs cycle
- NADPH and ATP are converted to NADP+ and ADP to power the chemical reactions in the cycle
- Glucose is made at the end left over electrons are used to make more water
what is the compensation point?
when the amount of carbon dioxide made in cellular respiration is equal the amount of carbon dioxide used up in photosynthesis
inputs of light dependent?
light, water, NADP+, ADP + Pi
inputs of light independent?
ATP, carbon dioxide, NADPH
outputs of light dependent?
NADPH, oxygen (waste), ATP
outputs of light independent?
glucose, water NADP+, ADP + Pi
why is photosynthesis a light dependent reaction?
the energy from light propels the electrons from a photosystem into a high-energy state.
define photosynthesis?
the synthesis of organic molecule from water and carbon dioxide using energy absorbed by chlorophyll from sunlight
how does carbon dioxide affect the rate of photosynthesis?
an increase in the atmospheric carbon dioxide will result in an increase in the rate of photosynthesis, However, you will get to a point where the enzymes will become saturated and will not catalyse the reaction any faster
how does light intensity affect the rate of photosynthesis?
a greater intensity leads to a higher rate of photosynthesis because the chlorophyll absorb more light providing more energy for the light dependent reaction
how does wavelength affect the rate of photosynthesis?
chlorophyll will absorb the blue and red end of the visible light spectrum. It will not absorb but reflect the green wavelength. The rate of photosynthesis is much greater in the blue and red range of the spectrum compared to the green.
how does temperature affect the rate of photosynthesis?
at high temps it will be faster because of the kinetic energy making the reactants move faster, however if temp is too high stomata will close to reduce water loss via transpiration
at low temps photosynthesis slows down because the kinetic energy is lower and the reactants move more slowly
how do water levels affect the rate of photosynthesis?
if there isn’t enough water in the plant the stomata will close to keep the guard cells turgid, so u get less carbon dioxide entering and the rate will decrease
what do oxygen levels affect the rate of photosynthesis?
too much oxygen can inhibit the rate of photosynthesis because oxygen competes with the enzyme that fixes carbon dioxide in the carbon cycle
