photosynthesis notes ni teeya Flashcards
❛ organisms that make their food ❜
-producers
-Types: plants, algae, and some bacteria
autotrophs
use the energy in sunlight to make food in a process called
photosynthesis
-are living things that cannot make their food
-consumers
heterotrophs
-A compound that absorbs light
-Different pigments absorb different wavelengths of white light
pigment
○ is a pigment that absorbs red and blue light (photons) so green is reflected or transmitted.
○ located in thylakoid membranes
chlorophyll
Two types of Chlorophyll
-chlorophyll a
-chlorophyll b
○ involved in light reactions
chlorophyll a
○ assists in capturing light energy
○ accessory pigments
chlorophyll b
● captures more light energy
● red, orange, & yellow
carotenoids
Plants are green because
the green wavelength is reflected and not absorbed
is the process by which autotrophic organisms use light energy to make sugar and oxygen gas from carbon dioxide and water
photosynthesis
○ product of photosynthesis
○ used for the synthesis of glucose
Triose phosphate (Glyceraldehyde 3-phosphate)
formula of photosynthesis
6CO2 + 6H2O + light —— C6H12O6 + 6O2
carbon dioxide + water + light ——- carbohydrate (sugar) + oxygen
Importance of Photosynthesis
● Makes organic molecules out of inorganic materials.
● It begins all food chains and webs.
● It also makes oxygen gas.
● Responsible for the growth of pants.
● Nourishes almost the entire living world directly or indirectly
Plants use the energy from sunlight to make:
-ATP
-Sugars
releases energy when it releases one phosphate
ATP (Adenosine Triphosphate)
Phosphorylation:
Dephosphorylation:
ADP ——- ATP
ATP ——-ADP
○ Glucose, sucrose, cellulose, starch & more
sugars
What does plants need to grow?
● The “factory” for making energy and sugars
○ chloroplast
● Fuels
○ sunlight, carbon dioxide, water
● The Helpers
○ enzymes
Site of Photosynthesis
Chloroplast in the Mesophyll of leaves
Light-Dependent reactions
● Thylakoid membrane
Calvin Cycle reactions
● Stroma
Two Stages of Photosynthesis:
Light-Dependent reactions (Energy building)
Calvin Cycle reactions (Sugar building)
● Convert light energy to the chemical energy of ATP and NADPH
● Split H2 O and release O 2 to the atmosphere
Light-Dependent reactions
products of Light-Dependent reactions
ATP, NADPH, O 2(byproduct)
● Use ATP and NADPH to convert C0 2 to the sugar G3P
● Return ADP, inorganic phosphate, and NADP + to hte light reactions
Calvin Cycle reactions
products of Calvin Cycle reactions
NADP+, ADP, Triose Phosphate
Photosynthesis is a redox process in which:
H2 O is oxidized and CO 2 is reduced
types of photosystems (2)
● Photosystem II - best absorbs red-light (680 nm)
● Photosystem I - best absorbs far-red light (700 nm)
reaction center of photosystems
PS II= P680
PS I= P700
primary electron acceptor of photosystems
PS II= pheophytine
PS I= Ao
Mobile Electron Carriers
● Pq - Plastoquinone
● Pc - Plastocyanine
● Fd - Ferredocxin
● Pumps hydrogen ions from strome to lumen
Cytochrome Complex
● is highly exergonic and produces ATP
ATP Synthase
● uses the electrons to reduce NADP + to NADPH
NADP + reductase
● is a series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions
Electron Transport Chain
The ATP and NADPH formed in the light-dependent reaction are used to fuel the
calvin cycle
Steps involved in Calvin Cycle
- Carbon Fixation
- G3P Production
- Regeneration of RuBP
● enzyme which fixes carbon from air
● most abundant and important enzyme in the world
RuBisCo - Ribulose Bisphosphate Carboxylase
phosphoglycerate
PGA
G3P / TP
Glyceraldehyde 3-Phosphate / Triose Phosphate
starting molecule of Glucose
Glucose Phosphate
● The (3) CO 2 is attached to (3) RuBP with the help RuBisCo which catalyzes the reaction.
● The resulting (3) 6C compound is unstable and breaks down into (6) PGA (3C)
Carbon fixation
(6) GPA is converted into (6) G3P/TP using (6) NADPH and (6) ATP
○ Reduction by NADPH transfers hydrogen atoms to the compound and producing NADP.
○ While the hydrolysis of ATP provides energy and ADP
G3P production
● (1) G3P/TP leaves the cycle and will be used to form glucose
○ It takes(2) G3P to make (1) glucose phosphate.
● (5) G3P/TP will be recycled to regenerate the RuBP acceptor.
○ Regeneration involves a complex series of reactions and requires ATP
Regeneration of RuBP
The Calvin cycle has to run __________ to produce one molecule of glucose molecules
2 times
