AOS2 Flashcards
what is a exergonic reaction?
A reaction that releases energy
what is a endergonic reaction?
A reaction that requires energy
what is a catabolic reaction?
A chemical reaction that breaks big molecules into smaller molecules
what is a anabolic reaction?
A chemical reaction that builds a bigger molecule from small molecules
What enzyme is used in C4 and Cam plants to bind CO2?
PEP Carboxylase
What type of cell is PEP Carboxylase found in?
Mesophyll cell
What type of cell is Rubisco found in?
Bundle Sheath cell
Balanced equation for photosynthesis
6CO2+12H20 light/chlorophyll- C6H12O6+6H2O+6O2
Where does glycolysis occur?
Cytosol
Name of cell where Calvin cycle occurs in a C4 plant
Bundle Sheath cell
How do CAM plants save water?
They close their stomata during the day where the temperatures are too got and open at night where it is cooler to collect CO2
What is it called when C3 plants mistake CO2 for O2
Photorespiration
Role of accessory pigments
Can collect energy from wavelengths Chlorophyll A can’t and delivers it to Chlorophyll A for photosynthesis
Name accessory pigments
Carotene and Chlorophyll B
How many ATP are created in alcoholic fermentation
2 ATP per glucose molecule
Place in which light dependant reactions occur
Thylakoid membrane
Form in which the Thylakoid membrane is found
Stacked on top of each other in discs (Grana) to increase surface area chlorophyll exposed to light so more glucose produced per second
Where does light independent reactions (Calvin Cycle) occur?
Stroma
Effect of exceeding optimal temperature on a plant and the effect on photosynthesis
The enzymes within the plants active sites denature and their tertiary structure is destroyed. Substrates can’t bind and photosynthesis is unable to be performed or not at a fast enough rate
What is feedback inhibition
The product being made from an enzyme is used as a non-competitive inhibitor of the original enzyme to stop the production of that particular product
Coenzymes involved in photosynthesis
NADPH+ and ATP
Do plants gain or loose weight overnight?
All plants loose weight over night as their is no sun to photosynthesise as night so they can’t create energy yet they need to respirate which required glucose
What is also the outputs of the light dependant reactions
The inputs of the light independent reactions plus CO2
Factors which effect enzyme activity include…
Ph, temperature, presence of inhibitors, concentration of substrates and enzymes, presence of cofactors
What is the purpose of folds of the Cristae of the Mitochondria
The folds increase the surface area to allow more chemical reactions to occur
In which things does photosynthesis occur in?
Plants and algae
What coenzyme does Rubisco rely on?
NADPH
what happens to enzymes when exposed to heat?
Enzyme and substrate molecules gain kinetic energy allowing for more frequent collisions between substrates and active sites, hence more enzyme-substrate complexes are formed. Therefore, increasing reaction rates.
what happens to enzymes exposed to excess heat?
enzymes denature meaning their 3-D conformational shapes change, hence the tertiary structure of their active sites are destroyed. Meaning enzyme-substrate complexes cannot form and reaction rates fall.
what happens to enzymes after excessive heat loss?
enzyme and substrate molecules lose kinetic energy, so collision between active sites and substrates occur less often. Therefore, enzyme-substrate complexes are less likely to form and reaction rates fall. The effect is fully reversible with the addition of heat.
What are cofactors?
non-protein molecules or ions that are necessary for the function of particular enzymes. Inorganic cofactors are not changed during the reaction and are firmly bound to the enzyme while organic cofactors (coenzymes) are altered.
what are coenzymes?
small organic(non-protein) molecules that are necessary for certain enzymes to catalyse a reaction. They loosely bind with the enzyme to form the active enzyme only when the enzyme is acting on the substrate.
what is a competitive inhibitor?
it mimics the substrate and competes for the active site.
what is a non-competitive inhibitor?
binds to enzyme at location away from active site, but alters the shape of the enzyme so that the active site is no longer functional.
what is allostery?
a form of non-competitive inhibition.
what are reversible inhibitors?
attach to enzymes with non-covalent interactions such as hydrogen bonds, hydrophobic interactions and ionic bonds.
what are irreversible inhibitors?
usually covalently modify an enzyme and inhibition can therefore not be reversed.
what is photosynthesis?
the synthesis of organic molecules (eg.glucose) from water and carbon dioxide using light energy absorbed by chlorophyll.
what organisms photosynthesise?
plants, algae and cyanobacteria
what is the thylakoid?
membranes that form stacks (grana) which contain chlorophyll a and accessory pigments (site of the light dependent reactions)
what is the stroma?
the inner membrane encloses fluid called stroma which is the site of the light independent reactions
Light dependent reaction inputs and outputs?
inputs: light energy, 12H2O, NADP+, ADP + Pi.
outputs: 6O2, NADPH, ATP
Light independent reaction inputs and outputs?
inputs: NADPH, ATP, 6CO2
outputs: NADP+, ADP + Pi, glucose, 6H2O
what is rubisco?
an enzyme which captures carbon dioxide during the light independent stage of photosynthesis. It is the most common protein on earth!!!
what are chloroplasts?
the site of photosynthesis in many plants cells and protists.
