Photosynthesis Flashcards
how do plants make their own food?
what do they produce?
through photosynthesis
-glucose
which other organisms can photosynthesise?
algae
what is biomass?
the dry mass of an organism
how will plant biomass be affected because of photosynthesis?
it will increase
what is the word and symbol equation for photosynthesis?
carbon dioxide + water -> oxygen + glucose
6CO2 + 6H20 -> 6O2 + C6H12O6
which two components (non physical) are also required for photosynthesis?
light and chlorophyll
which type of reaction (exothermic or endothermic) is photosynthesis?
-why?
-endothermic reaction
-it requires light energy (to react carbon dioxide and water to produce glucose and oxygen.)
what happens to light energy within a leaf?
it is absorbed by the green pigment chlorophyll (within the chloroplasts)
why are plant leaves important within a plant?
they are the main organ for photosynthesis
where does the required carbon dioxide come from?
-how does it enter a leaf?
-the air.
-through the stomata
how does water enter the plant?
how it is then transported to the leaves?
- through the roots, and is transported to the leaves in the xylem.
what are the produced oxygen and glucose used for within a plant?
respiration
what are the three main ways of measuring the rate of photosynthesis?
-rate of oxygen production (number of bubbles or volume of oxygen gas given off in a set time)
-rate of carbon dioxide uptake
-rate of glucose production
which factors can affect the rate of photosynthesis? (3)
light intensity
carbon dioxide concentration
temperature
describe the relationship between photosynthetic rate and light intensity (2)
what in particular is the photosynthesis rate proportional to?
-increasing the light intensity increases the rate of photosynthesis,
-until a limiting factor - becomes in short supply
directly proportional to the light intensity until another factor becomes limiting.
what happens at very high light intensities? why is this unlikely to happen in the wilderness?
photosynthesis is slowed, but these light intensities do not occur in nature.
describe the relationship between carbon dioxide concentration and the photosynthetic rate. (3)
-Carbon dioxide is one of the reactants in photosynthesis.
-If the concentration of carbon dioxide is increased, the rate of photosynthesis will therefore increase.
-At some point, another factor may become limiting (this is shown by the plateau -flattened section- of the graph)
what are the chemical reactions involved in photosynthesis controlled by?
what does this mean? (in terms of what they are affected by)
enzymes
-they are affected by temperature
describe the relationship between temperature and photosynthetic rate. (3)
-At low temperatures, the rate of photosynthesis is limited by the number of collisions between enzymes and substrate.
-As temperature increases the number of collisions increases, therefore the rate of photosynthesis increases.
-However, at high temperatures, enzymes are denatured and this will decrease the rate of photosynthesis.
describe the relationship between photosynthetic rate and other (multiple) factors. (4)
-the rate of photosynthesis increases until factors becoming limiting
-if (factor) is increased, the rate increases further, and then another factor becomes limiting
-the rate can be increased further if the temperature is increased
-the rate increases again until another factor becomes limiting
what is the equation for the inverse square law?
L.I = 1/distance^2
explain why light intensity is directly proportional to photosynthetic rate? (2)
because photosynthesis is an energy requiring , endothermic, reaction.
-more light energy will increase the rate at which oxygen is given off so more bubbles of oxygen will be produced per minute.
why is light intensity inversely proportional to distance?
as the distance away from a light source increases, light energy becomes spread over a wider area.
why must you be careful with the x axis of 1/d^2 graphs? (2)
the x-axis is values of 1/d^2. It is not of light intensity.
1/d^2 is proportional to light intensity.
what is the function of a leaf?
what are leaves the sources of? (what are they referred to as?)
to photosynthesise
all food on Earth- they are producers
