Photosynthesis
The process that starts the food chain is when autotrophs, things that make their own energy. Before being consumed by another organism, which then gets consumed by another, of course.
Water and light are converted into chemical energy in this process. There are 2 types. Non-cyclic is important to us; cyclic is good for bacteria.
Cyanobacteria and chloroplasts
Cyanobacteria are very similar to chloroplasts. They both have an inner and outer membrane, a nucleoid (the important one), thylakoids, lipid droplets, and ribosomes.
However, they do differ.
Cyanobacteria have:
peptidoglycan wall (I probably misspelled that)
nucleoid sheath
capsule
slime coat
carboxysome
Meanwhile, features unique to the chloroplast are:
intermediate space
granum
Remember how I said that the nucleoid is the important one? This is because it is the DNA spot of both the cyanobacteria and the chloroplast. In fact, there is a theory that the reason why cyanobacteria and chloroplasts are so similar is that chloroplasts used to be a type of cyanobacteria that got consumed by, and integrated into, plant cells
Metabolic Pathways are photosynthesis and cellular respiration. Photosynthesis is anabolic, and cell resperation is catabolic.
Pigments
You might already know that chlorophyll makes a plant green. Other pigments cause other colors in plants:
Chlorophyll is dark green
Xanthophyll is a yellow/light green
Carotene is orange
Anthocyanin is purple/red
Tannin is brown
This pigmentation is really due to the pigments absorbing and reflecting different sections of the visible light spectrum. For example, chlorophyll absorbs red and violet light best but reflects back dark green.
the process
This is the chemical formula for photosynthesis.
Where the light comes in is the thylakoid, a part of the cyanobacteria or chloroplast that gets excited when exposed to light.
Where the CO2 comes in is the stoma, a little hole made up of two guardian cells that can close or open it. It’s sort of like a nostril.
Plants and bacteria do it very differently
Non-cyclic photosynthesis is done by plants, algae, and cyanobacteria. they make O2, ATP, NADPH, and O2, which eventually leaves the cell as a waste product.
Photosystems
There are two photosystems, photosystem 1 and photosystem 2. They were discovered out of order so actually photosystem 2 is used first.
Photosystem 2 splits water to make ATP, like some kind of water divorce court.
18 ATP is used in this process for the glucose, which sounds like a lot, but is worth it because more ATP is made later.
Photosystem 1 makes NADPH. Known as reducing power; gets CO2 in the atmosphere
Calvin cycle
Many large words make enzymes
The enzyme that fixes CO2 is Rubisco, not to be confused with Nabisco.
Global climate change!
More CO2 in the atmosphere from human activity means that more heat is trapped on Earth. Bad stuff.
Plants are part of a solution, as they take in CO2 and give out oxygen. This is why places like forests are called “carbon sinks.”
More plants doing photosynthesis means less carbon in the atmosphere.
Thus, plants are part of the solution to climate change, and that’s why more and more ideas relating to re-greening, anti-desertification, green roofs, etc. are becoming more commonplace.