PHOTOSYNTHESIS Flashcards
process used for plants to produce their own food for energy
photosynthesis
heterotrophic nutrition
organisms that do not produce their own food for energy and have to eat other organisms to provide them with energy
heterotrophs
ingest organic molecules
autotrophic
synthesizes own organic molecules
photosynthesis
the process where carbon dioxide and water are combined, in the presence of chlorophyll and light energy, to and from carbohydrates/glucose(chemical potential energy)
requirements of photosynthesis
- carbon dioxide(from atmosphere)
- water(absorbed by roots and delivered via xylem)
- chlorophyll(present in chloroplasts)
- energy(sunlight)
products of photosynthesis
- glucose(converted to insoluble starch and stored)
2. oxygen(released into atmosphere via stomata pores)
biological importance of photosynthesis
- forms energy rich carbohydrates
- use carbon dioxide for photosynthesis to keep it at a constant level in the atmosphere
- produces oxygen to keep levels constant
where photosynthesis takes place
chloroplast
function of double membrane
permeable for CO2, O2, H2O and glucose
function of starch
- is osmotic inactive meaning that it inhibits the occurrence of osmosis and stores starch
function of intergranum lamella
connects thylakoids or granny to one another
function of ribosomes
where protein synthesis occurs
function of stroma
colourless fluid where dark phase of photosynthesis occurs
function of thylakoids
photosynthetic membranes which contains chlorophyll and is where light phase occurs
function of granum
increases the surface area for the light phase to occur
2 phases in which photosynthesis occurs
- light phase(light dependent phase)
2. dark phase(light independent phase)
summary of light phase
- required radiant energy is absorbed by chlorophyll in grana
- water is absorbed into grana of chloroplast
- radiant enrgy causes the water molecule to split(photolysis)
- energy rich hydrogen ions is released which are taken by a carrier molecule (NADP+) into the light independent phase
- oxygen is released through stomata to atmosphere
- produces ATP(energy carrier) during phosphorylation which will be used in dark phase
summary of dark phase
- carbon dioxide is absorbed from the atmosphere and moves to the stroma
- carbon dioxide and energy rich hydrogen ions are combined by using ATP(dephosphorylation) to fron glucose
- excess glucose is stored as starch in starch granules
produces 38 ATP molecules
1 glucose molecule
3 factors affecting photosynthesis
- light intensity
- carbon dioxide concentration
- temperature
how does light intensity affect photosynthesis?
rate of photosynthesis increases as the light intensity increases until it reaches an intensity where the rate will stay constant
how carbon dioxide concentration affects photosynthesis
increases in the carbon dioxide concentration increases the rate of photosynthesis HOWEVER at high levels of carbon dioxide the rate of photosynthesis stays at a relatively constant level
how temperature affects photosynthesis
as temperature increases towards 25°C, the rate of photosynthesis will also increase and the further the increase in temperature enzymes will begin to denature causing a decrease in the rate of photosynthesis