5.5 Photosynthesis - plant cells Flashcards
define photosynthesis:
the process in which light energy is used to build complex organic molecules e.g. glucose
in photosynthesis light energy is made into what? and where is it stored?
chemical energy
stored in bonds of the complex organic molecules made
what are autotrophs?
organisms that can photosynthesise e.g. plants, algae
what are heterotrophs?
organisms which obtain complex molecules through eating
both autotrophs and heterotrophs breakdown complex organic molecules in which process? and what is the purpose of this?
respiration
to release energy for metabolic processes
where in a plant cell does photosynthesis take place?
chloroplast
chloroplasts have a network of membranes, for what purpose?
to give a large surface area to maximise light absorption
the membranes within chloroplasts form flattened sacs called what?
thylakoids
(chloroplasts) thylakoids are stacked to form what?
grana
(chloroplasts) grana are joined by lamellae what is lamellae?
membranous channels
(chloroplasts) light is absorbed by what and where are they found?
pigments e.g. chlorophyll
found embedded in thylakoid membranes
(chloroplasts) what is the fluid inside the chloroplasts and what is its purpose?
stroma
site of chemical reactions resulting in formation of complex organic molecules
why are leaves green?
due to pigment chlorophyll - it reflects green light
what is the primary pigment in plants?
chlorophyll a
what are some other pigments in plants?
chlorophyll b
xanthophylls
carotenoids
why are plants sometimes different colours?
different combinations of pigments which reflect different wavelengths of light
what are the two stages of photosynthesis?
light dependant stage
light independent stage
in the light dependant reaction light is converted to what type of energy?
chemical energy
in the light dependant reaction, electron flow is created by what?
the effect of light on the chlorophyll causing photolysis
what is photolysis?
splitting of water into protons, electrons and oxygen
what are the products of the light dependant reaction?
reduced NADP
ATP
oxygen
in the light independent reaction protons are used to reduce what?
CO2
to produce sugars and other organic molecules
