3.1 food supply, plant growth and productivity Flashcards
food security
is the ability of human populations to produce food of sufficient quality and quantity in order to support the population
three needs for food security
quantity
quality
access
food sustainability
the ability of food systems to keep production and distribution going continuously without environmental degradation
how is increased crop yield achieved
fertilisers, pesticides, intensive farming methods
by manipulating certain factors the rate of what should be increased
photosynthesis
abiotic factors affecting rate of photosynthesis
light intensity
CO2 concentration
temperature
PH
accessibility
sufficient economic and infrastructure resources to get available food resources
sufficient economic and infrastructure resources to get available food resources
accessibility
availability
existence of food in sufficient quantities and of appropriate quality over time
existence of food in sufficient quantities and of appropriate quality over time
availability
N5 photosynthesis equation
light
co2 +water——————> glucose and oxygen
chlorophyll
what % of energy is loss over trophic levels
90%
livestock production produces ………………… food per unit area than plant production
less
why is all land not farmed for crops
some habitats are unsuitable for cultivation of crop plants but can efficiently produce livestock
what is the energy released by respiration used for
movement and other life processes and is eventually lost as heat to the surroundings
where does photosynthesis occur
chloroplasts
what do photosynthetic pigments in the chloroplasts do
absorb light energy and turn it into chemical energy
what do accessory pigments such as carotenoids do
absorb wave length of light not absorbed by chlorophyll A
broaden the absorption spectrum
provide more energy for photo synthesis
what does an absorption spectrum show
the extent to which different colours of light are absorbed by a pigment
what does an action spectrum show
the effectiveness if different wavelengths of light at bringing about the process of phtotosynthesis
what is the photolysis of water
the water is split into oxygen and hydrogen
where does photolysis take place
grana of the chloroplast
where does the carbon cycle (carbon fixation take place)
stroma of the chloroplast
how is light energy absorbed
by photosynthetic pigments to generate ATP and for photolysis
how does the light energy absorb affect the electron
excites,
transfer of these electrons through the electron transport chain releases energy to release ATP
what is the coenzyme that transports hydrogen ions to the calvin cycle
NADP
how is 3PG formed
enzyme rubisco attaches CO2 to ribulose bisphosphate (rubp)
what happens to 3GP to form G3P
photophosphorylated by ATP and combines with hydrogen ions from NADPH from the light reaction
what happens to the G3P
can be recycled back into RuBP
used in the synthesis of glucose
how are the sugars produced used
used for cellular respiration to provide the plant with energy for growth
the remaining sugar molecules can be synthesised into a molecule of complex carbohydrates
