Chapter 1.7 Photosynthesis Flashcards
Photosynthesis is the
chemical process by which green plants make carbohydrate.
Photosynthesis is a series of
enzyme-controlled reactions in two stages
The first stage of photosynthesis is
photolysis (light-dependent stage)
In photolysis light energy from the sun is
trapped by the chlorophyll in the chloroplasts and is converted into chemical energy in molecules of ATP
In photolysis water molecules are
split to produce hydrogen and oxygen.
Excess oxygen from photolysis is
diffused out from chloroplasts and out of the cell
The second stage of photosynthesis is the
carbon-fixation stage.
In the carbon fixation stage, hydrogen from photolysis is
combined with carbon dioxide to produce sugar
In the carbon fixation stage, energy from
ATP id used in the production of sugar
The chemical energy in sugar can be released during
respiration
Sugar not used in respiration can be converted to plant products such as
starch or cellulose
Starch acts as a store of energy in plants while cellulose is a main chemical component of
plant cell walls
A limiting factor is a variable that
when in short supply can limit the rate of a chemical reaction such as photosynthesis.
The rate of photosynthesis is limited by various factors such as
temperature, light intensity and the concentration of carbon dioxide available.
