Photosynthesis: (Chloroplasts And Chlorophyll) Flashcards
Membrane transport mechanism: diffusion:
Follows concentration gradient; no energy from the cell is required.
Membrane transport mechanism:
Osmosis:
Follows concentration gradient; no energy from the cell is required.
Membrane transport mechanism:
Facilitated diffusion:
Follows concentration gradient, assisted by channel proteins or carrier proteins; no energy from the cell is required.
Concentration gradients:
High-low.
Membrane transport mechanism:
Active transport:
Moves against concentration gradient, assisted by channel or carrier proteins and with the input of energy (usually from ATP molecules).
Membrane transport mechanism:
Endocytosis (may be pinocytosis, phagocytosis, and receptor-assisted endocytosis):
Membrane engulfs a substance and draws it into the cell in membrane-bounded vesicle.
Membrane transport mechanism:
Exocytosis:
Membrane-bounded vesicle fuses with cell membrane, releasing the cells contents outside of the cell.
Photosynthesis:
-photosynthesis is the process by which plants and other photosynthetic organisms trap the suns energy and transform it into energy-rich chemical compounds.
Cellular respiration:
-cellular respiration is the process by which cells break down high-energy compounds and generate ATP.
Adenosine Triphosphate (ATP):
-the direct source of energy for nearly all types of energy-requiring activities of living organisms.
Overall reactions (photosynthesis):
•photosynthesis takes carbon dioxide, water and light energy and produces glucose and oxygen.
6 CO2 + 6 H2O + Light Energy —> C6H12O6 + 6 O2
•an example of an anabolic pathway.
-synthesizes larger molecules.
Overall reactions (cellular respiration):
•cellular respiration takes glucose and oxygen and produces carbon dioxide and water and releases energy.
C6H12O6 6 O2 —> 6 CO2 + 6 H2O + Energy
•an example of a catabolic pathway.
-breaks down large molecules into smaller ones.
•these are the end results of large series of reactions they are not simply the perfect reverse of each other.
•the steps along each pathway are quite different.
Oxidation and reduction (photosynthesis):
-Energy from sunlight is stored in the bonds of glucose.
-plants can convert the glucose into a structural molecule called cellulose.
-Plants may also convert glucose into energy storage molecules like starch.
Chloroplasts:
-outer membranes.
-inner membrane.
-inner solution called the stroma.
-flattened sacs called thylakoids.
-stacks of thylakoids are called grana (granum for one).
Chlorophyll:
-the molecules that trap solar energy.
-bound to the thylakoid membranes in chloroplasts.
-chlorophyll gives plants their green colour.
Metabolic pathway:
-overall reaction is actually a series of over 100 distinct enzyme mediated reactions!
-two major processes:
•light dependent reactions:
-solar energy is trapped and used to make high-energy compounds (NADPH).
•light independent reactions:
-the energy of ATP and the reducing power of NADPH are used to reduce carbon dioxide to make glucose,
-which can then be converted into starch for storage.
Light dependent reactions:
•solar energy is trapped in pigments found in the thylakoid membranes of chloroplast.
•the following pigments are found in leaves:
-chlorophyll a - main photosynthetic pigment.
-chlorophyll b.
•these absorb almost everything but green.
•green is reflected not absorbed (which is why leaves look green!)
Pigments and light absorption:
•chlorophylls a and b and carotenoids are photosynthetic pigments that absorb light.
•also found:
-β carotene (a carotenoid), a class of other pigments in plants.
-they absorb blue/green light and are yellow, orange, red in colour.
-β carotene is converted into Vitamin A, which we make into Retinal, the visual pigment in our eyes.
Fall leaves:
-the chlorophyll masks the other pigments in the spring/summer months.
-cooler temperatures in fall stop chlorophyll production revealing the other carotenoid pigments.
Oxidation:
Removing/loosing an electron.
Reduction:
Gaining an electron.
Catabolic pathway:
Breaking down complex molecules into simpler ones and usually release energy.
Anabolic pathway:
Those that need energy to synthesize larger molecules.
Xanthophyll(s):
-pigments that are one of the significant divisions of the carotenoid group.
-function: accessory light-harvesting pigments. They protect photosynthetic organisms from the potentially toxic effects of light.
Accessory pigments:
Light absorbing compounds.
