Chapters 8-10 Flashcards
Catabolic pathways
Break large molecules into smaller ones, releasing energy in the process
Metabolism
All chemical processes that occur within an organism. Energy is constantly being traded
Anabolic pathways
Build larger molecules from less complex ones, requiring energy input
Energy
Capacity to do work
First Law of Thermodynamics
Energy can not be made nor destroyed only change shape
Second law of thermodynamics
All natural processes proceed in the direction if increasing entropy
Entropy
Randomness or disorder (if you don’t clean your room it will only get messier)
Characteristics of Heat
Most entropic form of energy and is produced in every step of energy transfer between organisms (often “lost to environment”)
Exergonic reaction
Reactions that release energy
Endergonic reaction
Reactions capture energy in cell
Coupled reactions
Exergonic reactions provide energy for endergonic reactions
Enzyme
A class of protein catalysts that lower the activation energy needed to get a chemical reaction going in cells
Structure of enzyme
3-dimensional and have an active site to which substrates bind to allow the reaction to occur. Each enzyme carries out a very specific function
Enzymes are not altered permanently and can be recycled
Each enzyme has an optimal temperature and pH to function
Cell wall
Limits water movement, maintains cell shape, protection. Cellulose is bonded with lignin for strength.
Central vacuole
Large vacuole in center of cell containing approximately 95% water, where digestion and metabolism occurs. Stores waste and pigments (in some red and blue flowers). Usually 1 or 2 central vacuoles per cell and may comprise 90% of cell volume.
Plastids
Organelle that gathers or stores food or contains pigments
Ex. Chloroplast and chromoplast
Chloroplast
Contains chlorophyll
Where does the light-dependent reaction take place?
In the thylakoid membrane
What wavelength does Photosystem I best work at?
700 nm
What wavelength does Photosystem II best work at?
680 nm
What happens for for light-dependent reaction to produce more ATP?
Cyclic electron flow sends electron from primary acceptor of Photosystem I back to cytochrome complex.
How does the primary acceptor replenish its electron?
Water is broken into hydrogen and oxygen. The electron is stripped into ions and electrons and the ions are out into the thylakoid space. The oxygen is released as waste
How is NADPH created?
NADP+ floating in stroma from the Calvin cycle is combined with the electron from Photosystem I to make NADPH. NADP+ is the final electron acceptor on the electron chain.
First phase of Calvin Cycle
Carbon fixation. 3 molecules of CO2 are attached to 3 molecules of Ribulose Biphosphate (RuBp) a 5-carbon molecule. Each of the six-molecules break in half and form 3-PGA, which has 3 carbon atoms.
Phase 2 of Calvin Cycle
6 molecules of ATP produced in the light-dependent reaction put a phosphate on the 6 3-PGA molecules. NADPH adds two electrons to each. This makes G3P and one of the 6 molecules leaves the cycle. Phase 2 is called reduction.
Phase 3 of Calvin cycle
5 remaining G3P go on to be regenerated. The 5 G3P (15 carbon atoms total) are rearranged with 3 ATP molecules and some other steps to make 3 5-carbon RuBp molecules.
Why is c3 photosynthesis ineffective?
Enzyme rubisco is only 75% effective because it sometimes picks up oxygen instead of carbon dioxide. On hot days stomata will close and this will cause Rubisco to make more mistakes as the oxygen level increases and carbon dioxide decreases.
