Photosnthesis Flashcards
define photosynthesis
process whereby co2 and H2o combine to form high-energy carbohydrates such as glucose through the use of radiant energy from the sun and enzymes, Oxygen is a by-product and ATP is also produced to produce glucose
Process photosynthesis and materials/ products
6CO2+ 6H2O -(light energy/ enzymes)- C6H12O6 + 6O2
glucose produced can be stored as starch, a form of sucrose is transported and cellulose for packing tissue.
Oxygen is released into the atmosphere through the stoma
Explain Light phase
radiant energy from the sun is absorbed by chlorophyll in the thylakoid of granum. radiant energy converted into chemical energy which is sued for photolysis, where water is broken down into oxygen which is released into the atmosphere, and high energy H atoms in NADPH. ATP is then formed in cytosol and mitochondria and is the high-energy carrier used in the dark phase. ATP breaks into ADP when energy is needed as phosphate molecule breaks off to release energy and reverse when there is excess energy
explain photolysis
chemical energy breaks H2o into oxygen which is released to the atmosphere and high-energy H atoms.
Explain dark phase
the CO2 taken in from stomata combines with the high energy H atom from NADPH which then turns into NaDP through the use of enzymes in stroma produced by ribosomes in chloroplasts and ATP formed in the light phase. this forms glucose, stored as starch. also known as the Calvin cycle.
Importance of photosynthesis
balances O2 in the atmosphere and water for organisms that undergo cellular respiration
Balances CO2 levels in the atmosphere that is released from cellular respiration
produces glucose and this is the energy that is carried down all trophic levels.
How does ATP work
ATP, when energy is needed, breaks down into ADP and the phosphate released, releases energy that the cell needs for metabolic work,
when there is excess energy, the phosphate molecules bond with ADP to form ATP which stores the energy for when it is needed by the cell.
Structural adaptation for leaf for photosynthesis (7)
- flat blade/ lamina which allows for max sunlight area
- thin blade cross-section which allows for easy gaseous exchange
- impermeable cuticle prevents moisture loss and is transparent to allow sunlight through
- epidermis is transparent which allows sunlight through to palisade cells
- lower epidermis has stomata for gaseous exchange
- palisade cells are arranged longitudinally together for max surface area for sunlight and have many chloroplasts that rotate to absorb max sunlight and have thin cell walls for easy gas diffusion and osmosis
- spongy mesophyll have chloroplasts for sunlight absorption, spaces for gas exchange, and thin cell walls for easy diffusion and osmosis
Uses for glucose in plants
stored as starch for energy
as sucrose for transport
as cellulose for packing
what is NaDP?
a coenzyme that accepts high-energy hydrogen atoms from photolysis to form NADPH
Explain 3 factors that affect rate of photosynthesis
co2 concentration, more co2, more photosynthesis until optimal rate, after that too much CO2 will bond with H2O to form carbonic acid which will damage enzymes
light intensity. the increase will increase photosynthesis until optimal. more light will have no effect
temperature- low temp- enzymes will be inactive so less photosynthesis, increase until optimal rate after which sudden decline as enzymes denatured
Explain greenhouse
structure creating an optimal environment for plant growth by controlling factors that affect photosynthesis optimal levels and stopping pests/ predators from affecting plant growth. (light, glass with shade- temp, fan/heater- co2 (use pumps etc)) this allows for greater plant crop yield and healthy plants
Explain 5 photosynthesis practicals
starch- boil plant to stop functions and also in alcohol to dissolve chlorophyll. then put iodine (black/blue means starch reddish brown means no starch)
light- tinfoil- put in the sun- starch test
parts exposed= starch= photosynthesis
chlorophyll
co2 needed? bell jar with soda lime and caustic soda which absorb CO2
therefore no C02 and starch test shows no photosynthesis
O2 released? methylene and aquatic plant- turns blue means o2 present- ÓR test tube in water and splinter
explain stomata
structure formed by guard cells on the lower epidermis. with a vacuole that expands when there is sunlight as low water potential from photosynthesis, therefore, opening for gas exchange
vacuole shrinks when no photosynthesis as the water gradient is reversed and no gas exchange as the guard cells close.
