photosynthesis Flashcards
name 5 processes in plants that need energy
photosynthesis / active transport / DNA replication / cell division / protein synthesis
name 6 processes in animals that need energy
muscle contraction / body temp / active transport / DNA replication / cell division / protein synthesis
define metabolic pathway
a series of small reactions controlled by enzymes (like photosynthesis)
define phosphorylation
adding a phosphate to a molecule
define photolysis
splitting of a molecule using light energy
define phtophosphorylation
adding phosphate to a molecule using light
define hydrolysis
splitting of a molecule using water
define decarboxylation
removal of carbon dioxide from a molecule
define dehydrogenation
removal of hydrogen from a molecule
Define autotroph
Organism that makes its own nutrients using inorganic carbon source
Define heterotroph
Organism that requires organic nutrients to supply with a source of carbon
What does NADP stand for ?
Nicotinamide adenine dinucleotide phosphate
What is good about photosystem 1?
Doesn’t require water and generates energy
what is a coenzyme ?
a molecule that aids the function of an enzyme
what is the coenzyme in photosynthesis ?
NADP
where does photosynthesis take place ?
chloroplasts
what is the double membrane of the chloroplast called ?
chloroplast envelope
what is a thylakoid ?
fluid filled sac in the chloroplast
what is a granum ? (grana)
a stack of thylakoid
what links the grana together in the chloroplast ?
thylakoid membranes called lamellae
give examples of photosynthetic pigments
chlorophyll a / chlorophyll b / carotene
what are photosynthetic pigments ?
coloured substances that absorb light
what does a photo system contain ?
primary and accessory pigment (attached to a protein)
what are primary pigments ?
reaction centers, where electrons are excited
what are accessory pigments ?
make up light-harvesting systems, which transfer light energy to reaction centers (energy for electron excitement)
what wavelength light does photo system 1 absorb?
700 nm
what wavelength light does photo system 2 absorb?
680 nm
what is the stroma ?
gel like substance in chloroplast (similar to cytoplasm)
what does the stroma contain ?
enzymes, sugars, organic acids
describe DNA of chloroplast
- chloroplasts have their own DNA
- found in stroma
- circular
what happens to carbohydrates produced by photosynthesis ?
stored as starch grains in stroma
where do the light-dependent reactions take place ?
thylakoid membranes
where does the light-independent reaction take place ?
stroma
what are the products of light dependent stage ?
ATP, NADPH and oxygen as a waste product
what happens during the electron passing through the electron transport chain ?
- passes between proteins
- Redox reactions
- energy released from the electron
- photo phosphorylation
For photo system 2, where does the electron come from ?
photolysis (splitting of water)
H2O — 2e- + 2H+ + O
For photo system 1, where does the electron come from ?
photo system 2
where is the electron most excited ?
electron acceptor
where does the hydrogen for the reduction of NADP come from ?
photolysis
what is another name for the light independent stage ?
calvin cycle
what starts the calvin cycle ?
carbon dioxide entering through the stroma
summaries the fixation stage of Calvin cycle
carbon dioxide is fixed (incorporated into a organic molecule)
summaries the reduction stage of Calvin cycle
GP is reduced to TP by adding H+ from NADPH
summaries the regeneration stage of Calvin cycle
RuBP is regenerated from recycled TP using energy from ATP
how many turns in calvin cycle to make 1 glucose ?
6
state the full name for GP
Glycerate 3-phosphate
state the full name for TP
Triose phosphate
state the full name for RuBP
Ribulose bisphosphate
state the steps in fixation stage
- CO2 converted to intermediate compound using rubisco
- decomposes to 2x GP
state the steps in reduction stage
2x GP — 2x TP using energy from ATP and H+ from NADPH
state the steps in regeneration stage
5/6th of TP used to regenerate RuBP using energy
what is the other 1/6th of TP used for ?
make glucose / amino acids / other carbs / lipids
what colour do the pigments absorb in chlorophyll ?
red and blue
name the enzymes in photosynthesis
RuBisCo and ATP synthase
how does temp affect photosynthesis :
- enzymes
- stomata close ( less CO2 )
- may damage thylakoid membranes
- may damage chloroplast envelope (enzymes released)
- may damage chlorophyll ( reduce amount of pigment that can absorb light )
how does increasing CO2 conc to above 0.4% affect photosynthesis ?
stomata will start to close, reducing rate
what is the saturation point ?
point where a factor is no longer a limiting factor
what are the 3 things that light energy is used for in light dependent stage
- photo phosphorylation (making ATP)
- reducing NADP
- photolysis
what does granum contain ?
enzymes, sugars, organic acids
where does light dependent reaction take place ?
thylakoid membrane
where does calvin cycle take place ?
stroma