Hello! Being a Biology student, I figured that it will be nice to share to you all my experience with the course/program. Throughout my year of dealing with the ups and downs of bio, here’s what I have to tell you:
Read the course syllabus (if you have one) and find time to research or scan your books about the topics to be discussed in class.
It can be really tiring to read your book since most topics contain long chapters, but be sure to familiarize yourself with the indicated pictures or graphs.
Do not memorize the entire chapter! Just a background knowledge about the topic to be discussed and you’re good to go!
List down things that you don’t understand. Keep this list so that you can ask your teacher or professor during class.
One effective trick for me is that I will take down notes (like I normally would when in class) from a chapter of my book, bring those notes to class, take down notes again (this time, from what the professor is saying), combine those two notes, and revise (Yep, time-consuming but this one is very effective for me!).
*typically carbs are used but lipids (fats) can also be used due to the large amount of H’s in the hydrocarbon tails, & actually generate a lot of energy
fun tidbit: *the metabolic waste, C0 , is breathed out by the body and then taken in by plants, which use it to produce glucose -> thus the circle spins on & on
How Glucose is Broken Down
*energy cannot be efficiently harvested for work all at once, so rather it is broken down in a series of steps, called “stepwise energy harvesting”
1) Electrons taken from glucose (also, 1 proton) are given to Nicotinamide Adenine Dinucelotide (NAD+), a coenzyme -> NAD+ is an oxidizing agent, and so therefore is able to accept electrons
2) NAD+ is an “empty taxi cab”. The enzyme dehydrogenase oxidizes food (such as glucose) to get the 2 e’s & 2 p’s (H+’s) so they can be given to NAD+.
3) NAD+ is reduced by accepting electrons, and becomes NADH. NADH is a “full taxi cab”, containing 2 e’s & 1 p (H+). The other H+ is released into the cytosol. -> Each NADH represents potential energy that can be indirectly used to power the synthesis of ATP
4) NADH passes the e’s onto the electron transport chain (ETC). The ETC then passes the e’s on in a series of controlled steps to the oxygen molecules that pull them down the chain (b/c of its high EN). This process yields energy that can be used to re-generate ATP.
3- Series of steps where phosphates are taken off ATPs & then phosphorylated to molecules (TWICE) that are slightly changed each step
4- Eventually split into 2 3-carbon sugars (“G3Ps”)
Energy Yielding Phase
1- As the 2 G3Ps are oxidized, NAD+ is reduced to NADH -> this contributes to the ETC by carrying electrons (& protons)!
2- After, there is an “intermediate molecule” (ex: 1,3-biphosphoglycerate -> don’t need to know exact molecule) that has a phosphate. This phosphate is taken off and given to 2 ADPs to become 2 ATPs. This happens twice within the series of steps in this phase. Also, at one point, 2 H2Os are taken out.
3- Eventually transformed into 2 pyruvates
4- A total of 4 ATPs are made in this “payoff” phase. However, since 2 were invested originally, there is only a net of 2 ATPs.
C3H3O3 C6H1206 -pyruvates- C3H3O3
(*this diagram got really messed up on here too)
Energy Investment Phase
2 ADP + 2 p <—————— 2 ATP used
Phase 4 ADP +
4 p ———————-> 4 ATP formed
2 NAD+ + 4 e
+ 4 H+ —————————> 2 NADH + 2 H+
————–> 2 Pyruvate + 2 H2O
Net Glucose ————> 2 Pyruvate + 2 H2O
4 ATP formed - 2 ATP used ——-> 2 ATP
2 NAD+ + 4 e + H + ———-> 2 NADH + 2 H+
-not as efficient in producing ATP as oxidative phosphorylation
-used in both glycolysis & krebs/citric acid cycle
Citric Acid Cycle
-AKA “Krebs” Cycle
-COMPLETES energy-yielding oxidation of the organic molecules (ex: glucose)
-BEFORE the cycle can begin, the 2 Pyruvates must be converted to Acetyl CoA -> this links the cycle to glycolysis!
1) The 2 Pyruvates are oxidized and enter the Mitochondrion via a Transport Protein
2) CO2 is released (lungs -> exhale)
3) NAD+ is reduced to NADH & the e’s & p’s (H+’s) are stripped
4) A Coenzyme helps with the conversion to Acetyl CoA
-CAC uses BOTH molecules of pyruvate *cycle goes around TWICE!
*CITRIC ACID CYCLE SUMMARY*
2 CO2 X 2 = 4 (released)
3 NADH X 2 = 6 (reduced)
1 FADH X 2 = 2 (reduced)
1 ATP X 2 = 2 (produced)
*appreciate the many redox Rx’s going on to keep the cycle going, changing Acetyl CoA all the way to Oxaloacetate!
Ex: R = NAD+ -> NADH O = any previous molecule!
ETC - Chemiosmosis - Oxidative Phosphorylation
-located at the inner mitochondrial membrane (like the plasma membrane, but different proteins!)
*proteins are special ones made from the mtDNA (mitochondrial DNA)
*2 membranes! (DOUBLE)
PROTON MOTIVE FORCE
-a lot of energy & collisions b/c of flow of e’s
-*H’s come from glucose/pyruvate!
1) H+’s pumped out 2) O’s take H+’s to create H2O 3) Take protons in -> [low] guaranteed
-energy to power movement of H+ out! (POTENTIAL ENERGY -> from redox Rx’s!)
-if O2 NOT present, H+’s cannot be moved/slid out -> b/c O2 is the final e acceptor w/ a high EN & the e’s release potential energy when moving down the gradient to O which powers the proton motive force
-keeps getting more EN as e’s pulled down/along chain
-H+’s move into ATP Synthase (important and moves protons BACK into matrix) protein -> active transport -> change of shape -> ATPs
fun tidbit: -cyanide affects the enzyme that works w/ cytochrome oxidase, as it is an irreversible inhibitor that is tetravalent and desperate for a fourth bond, and therefore highly reactive (can shut down body systems and kill you within a matter of hours, and this is all due to bonding!)
ELECTRON TRANSPORT CHAIN
-oxidative phosphorylation & chemiosmosis couples the ETC to ATP synthesis
-located in cristae of mitochondrion
1) The components are proteins that exist in multiprotein complexes and are unique to the mitochondrion. These protein complexes alternate between reduced and oxidized states as they accept and donate electrons
2) Electrons drop in free energy as they go down the chain & are finally passed to O2 -> form H2O
3) NO ATP generated!!!!!
*THE FUNCTION OF THE ETC is to break the large free-energy drops from food to O2 into smaller steps that release energy in manageable amounts.
*the more redox Rx’s, the more energy is available.
*the energy-coupling mechanism
1) Redox Rx’s in the ETC -> provide energy for the transport proteins to pump H+ from the mitochondrial matrix to the intermembrane space.
NEXT STEP IMMEDIATELY FOLLOWS
2) Proton Motive Force develops as [H+] INC., w/i intermembrane space. Then, moves back across membrane & passes through channels in ATP Synthase.
3) ATP Synthase transports H+ BACK into matrix.
4) ATP Synthase uses exergonic flow of H+ to drive the phosphorylation of ADP -> ATP (endergonic).
*chemiosmosis = use of energy in H+ chemical gradient to drive ADP phosphorylation
*enables some cells to produce ATP w/o the use of oxygen!
How can food be oxidized w/o oxygen?
-NAD+ is actually the oxidizing agent of glucose. A net of 2 ATPs are produced by substrate-level phosphorylation. Then, if there IS oxygen, more (a lot of) ATP can be produced when NADH passes the removed e’s from glucose to the ETC & oxidative phosphorylation occurs.
*glycolysis STILL produces 2 ATP whether O is present of not, though!
(either aerobic or anaerobic)
-fermentation is the anaerobic catabolism of nutrients
-fermentation = the extension of glycolysis that can generate ATP solely by substrate-level phosphorylation -> *as long as there is a sufficient supply of NAD+ to accept e’s during the oxidation step of glycolysis
-NAD+ needs to be recycled from NADH
Aerobic Anaerobic Recycled by the transfer Recycled by the transfer of electrons from NADH to Pyruvate (end product of glycolysis!) of electrons to the ETC
TYPES OF FERMENTATION
fermentation = glycolysis + Rx’s that regenerate NAD+ (transfer of electrons from NADH -> Pyruvate)
Alcohol Fermentation = Pyruvate converted to Ethanol
1) RELEASES CO2 from Pyruvate -> converted to 2-carbon compound “acetaldehyde”
2) Acetaldehyde is reduced by NADH to Ethanol
-regenerate supply of NAD+ needed
*many bacteria carry out alcohol fermentation under anaerobic conditions, also fungi (ex: yeast)
yeast -> used for 1,000’s of years by humans for brewing, wine-making, baking (bread, gases released create bubbles that allow it to rise), etc.
Lactic Acid Fermentation = Pyruvate reduced DIRECTLY by NADH - > forms Lactate (ionized form of lactic acid) as end product -> NO release of CO2
*certain fungi & bacteria used to make cheese & yogurt
*other microbial fermentation used to make acetone & methanol (methyl alcohol)
1) When O is scarce, human muscle cells can still make ATP by using lactic acid fermentation.
2) Strenuous exercise -> sugar catabolism for ATP production outpaces muscle’s supply of O from blood
3) Cells switch from aerobic respiration to fermentation -> creates lactate -> buildup of lactate can cause muscle fatigue and pain!
4) Lactate is gradually carried away by the blood to the liver -> converted back to pyruvate by liver cells
*facultative anaerobes = make enough ATP to survive using either fermentation or respiration (ex: our muscle cells!) -> consume sugar at faster rate when fermenting to make the same amount
I think making Instructional comics is going to be my thing, I really enjoyed doing this. In case you didn’t I’ve done a lot of traveling, quite often to Hot Spots around the world, and I’ve picked up a few practical and not so practical skills and knowledge that I’d like to share with you guys in the form of these Comics.
The character taking you through this process is named Jackie from another comic that I’m working on called ‘The Blitz’. Let me know how I’m doing.
(but if you feel this relates to some other type of kin experience thats cool too!!)
its ok if youre not exactly the way you were before
its ok if you like different things now
its ok if you seem like you should be someone else when you know youre not
its ok if you dont have the powers or the face or the interests and habits you used to
they dont make you any less you!!
this is a new life and a new world and a new timeline and even though things are different and scary and some of our old friends are miles and miles away or we might not know where they are its going to be ok!!! youre still you and youre also the you youve become in this life and you can be whatever you you want to be or feel that you are and its great!!
we have to be strong for our friends both old and new! the world is big and vast and full of possibilities so we should try our best to stay positive for ourselves and for everyone else even when its hard just to wake up and convince yourself to live sometimes in the morning
youre doing great!!!
AP BIO Study Guide- Water, Carbon, & Macromolecules
H2O = two hydrogen ions bonded* to an oxygen ion
*bond = “polar covalent”: the molecule has opposite charges
on opposite ends; this is due to the electronegativity difference between the H’s
and O, causing the H’s to have partial negative charges and the O to have a
partial positive one; strong bond that keeps the water molecule together
H2O molecules bond to each other by “hydrogen bonding”:
these are weaker bonds that are able to be broken and reformed frequently; this
allows water its many emergent properties and to be the key to life
Four emergent properties:
Cohesion/Adhesion- This is the ability of water
molecules to stick to one another due to hydrogen bonding as well as to other
surfaces, respectively. This is what allows transpiration up the plant xylem
and out the leaves to occur (this is also due to the difference in water concentrations
between inside the plant and in the atmosphere, as water wants to go from a
high concentration to a low concentration). Also, surface tension is considered
a subtopic of this property.
Moderation of Temperature- Due to water’s high
specific heat, it is able to absorb heat from the environment (breaking bonds)
or release heat to it (forming bonds), without more than a slight change in its
own temperature. This allows water to regulate to temperature of the
environment around it and to make sure it is habitable enough for life. Water
also has a high heat of vaporization. This results in “evaporative cooling”: as
a surface is heated (heat is absorbed), the hydrogen bonds between water
molecules break, and water changes from its liquid form to a gas, and is
evaporated. This allows water to stabilize the temperatures of organisms and
bodies of water.
Expansion upon Freezing- When water freezes and
changes to its solid form, the H2O molecules form a crystal lattice, where the
hydrogen bonds keep each water molecule a certain distance away from each
other. Due to this further apart spacing, ice is less dense than liquid water.
Therefore, ice floats on top of liquid water. This allows ice to insulate what
is below it, and helps regulate life.
Versatility as a Solvent- Due to the partial pos.
and partial neg. charges within an H2O molecule, when a solute is introduced
into water, as long as that solute has charged ions, the H’s and O’s will be
attracted to the oppositely charged ions, creating a hydration shell around the
ions and pulling them away from the solute’s molecules, dissolving it (WATER IS
PRETTY CLOSE TO A UNIVERSAL SOLVENT.)
An “acid” is any substance that increases the hydrogen ion
concentration of a solution.
A “base” is any substance that reduces the hydrogen ion
concentration of a solution.
pH = “percent (%) hydrogen”
[H+] and [OH-] have an inverse relationship. This means as
one goes up in concentration, the other goes down. Their relationship always
has a constant of 10 ^ -14.)
(In a neutral solution, pH is 7, which means [H+] = 10 ^ 7,
and [OH-] = 10 ^ 7.)
*Know how to do a Mol equation/set-up*
Carbon can create up to four bonds with many different
elements due to its “tetravalence” (has 4 valence electrons, and needs 4 more)
Ability to create long chains, often with hydrogen,
resulting in organic molecules
Despite some organic molecules being isomers (same molecular
formula), the variation in their carbon skeletons (brancing, double bonds,
etc.) is what makes them completely different molecules.
Monomers are the “building blocks” of macromolecules, which,
when linked together, create polymers.
Monomers are bonded together using “dehydration synthesis”
(the removal of water molecules), and broken apart by “hydrolysis” (the
addition of water molecules).
Carbohydrates are sugars that provide fiber and a quick
source of energy for your body. The monomer of carbohydrates is called a
monosaccharide. Glucose is most common monosaccharide.
The type of links within carbohydrates are called “glycosidic
linkages”. Two monosaccharides linked together creates a disaccharide. For
example, two glucose molecules bonded together would create maltose.
Many monosaccharides linked together creates a
polysaccharide. In aqueous solutions they form rings.
Carbohydrates are used for many different purposes, such as
energy storage in plants (starch) and animals (glycogen), as well as for
structure within plants (cellulose, forms cell wall) and animals (chitin, forms
Carbohydrates contain a carbonyl group
Carbs contain “alpha” or “beta” links. We are unable to
digest beta links.
Lipids are not considered polymers because they are made up
of a few monomers they are not made up of many. Usually lipids consist of a
glycerol and three fatty acids (triglyceride). There are three types of lipids:
fats, phospholipids, and steroids, but they all have one thing in common: they
are hydrophobic. This is due to them being nonpolar and having no charge (fatty
acids are basically really long chains of hydrogen and carbon with no charge).
The types of links within lipids are called “ester linkages”.
Saturated fats have a straight molecule and are solid at
room temperature. These are bad for you, such as butter.
Unsaturated fats are “kinked” due to a carbon double bond
and are liquid at room temperature. These are good for you, such as different types
Phospholipids contain a hydrophilic head (this is due to it
actually having a charge due to its phosphate group’s neg. charge) and a hydrophobic
tail. They make up the cell membrane of animal cells.
Steroids are made up of 4 carbon rings. One common type of
steroid is cholesterol.
Amino acids are the building blocks, made from the ribosomes
of cells. They can either be nonpolar, polar, electrically charged, or etc.
There are 20 different amino acids in existence, but they can make up countless
Amino acids consist of an alpha carbon, a hydrogen, an R
group/side chain, a carboxyl group (COOH), and an amino group (N3H+). The “R”
group is the variable that makes the specific amino acid unique. All amino
acids are distinguishable by their “N-C-C” backbone.
The types of bonds present between amino acids are called peptide
bonds, and the polymers of amino acids are called “polypeptides” (proteins).
Amino acids sequences are controlled by DNA/genetics. Even
one amino acid being out of place can cause serious issues.
There are 4 levels of conformation to creating a protein.
CONFORMATION = STRUCTURE.
Primary structure consists of the unique amino acid
sequence. Secondary structure is the “backbone” of a protein, where the curves
and folding of polypeptide chains are created through the attraction of
hydrogen bonding. Tertiary structure by the interactions (Ex: types of bonds)
between the “R” groups. Quaternary structure is the creation of a macromolecule
through two or more polypeptides.
Some examples of quaternary structures are collagen (found
in hair) and hemoglobin (found in the blood, in RBC’s).
Monomers are called nucleotides.
They make up your genes.
There are two types, deoxyribonucleic acid (DNA) and ribonucleic
They consist of a phosphate group, a pentose sugar, and a
I actually had homework today (first time in like a week). I took some notes on philosophers and also worked on world history and honors bio study guides. I found my oral interp piece today so I’m pretty happy about that :)
How to Auto-Format your bios with Google Sheets Concatenate
Concatenate will stick things together. It can stick cells together, or plain text. You could, for example, enter a name in cell B5 and stick some formatting bits on the front and end:
=concatenate(”[size=6][b][i]”,B5,”[/i][/b][/size]”) Will give you:
Note: the parts all need to have a comma between them (no spaces!) and anything that isn’t a reference to a spreadsheet cell needs to be between quotation marks (”).
Of course, you can get way more complicated. It’s great for formatting biographies: instead of squinting at the wall of BBCode you just enter the variables into the spreadsheet and out rolls the bio code.
It makes some things a lot easier. For example, you could very easily give every dragon’s bio a different colour. Instead of having to find and change a bunch of [color] tags you only enter the colour’s hex code in one cell, and all the [color] codes refer to that cell (”[color=#”,B20,”]Text[/color]”)
hi love! I have a problem: I'm opening an rpg soon with ocs want to create about 10 pre made ocs like write their bios choose their fcs etc, but I've never done that before so I'm not sure how to make a believable character that's also fitting for their fc, name, etc. any tips on at least how to start? I've already begun searching for fcs and I have a few names but that's about it. thank you!
*Autotrophs will be focused on, particularly Photoautotrophs. They use sunlight/light energy, and fix CO2 to organic molecules to produce organic compounds.
Fun tidbit: -80% of atmospheric O2 comes from UNDERWATER plants!!!
*Although leaves are the major location of photosynthesis, Chloroplasts will be focused on, as they are essential to the process of Photosynthesis & we are looking at the process on a cellular level -> Chloroplasts’ Thylakoids transform light E to the chemical E of ATP & NADPH
Photosynthesis is, simply, the conversion of light energy into the chemical energy of food.
6 CO2 + 12 H2O + Light Energy -> C6H12O6 + 6 O2 + 6 H2O
Understanding Light Energy
-light energy is known as “electromagnetic” energy -> travels in rhythmic waves (disturbances of electrical and magnetic fields)
Wavelength = distance b/t CRESTS of E.M. waves -> range from < 1 nm - >1 km
Range of Radiation = ELECTROMAGNETIC SPECTRUM
-small portion most important to life -> narrow band from 380 nm - 750 nm -> “VISIBLE LIGHT”
Photons = light behaving as though it consists of these “discrete particles” -> not tangible but have a fixed quantity of energy
-relationship b/t wavelength & amount of energy is INVERSE Ex: photon of violet light has almost 2x as much energy as photon of red light
-atmosphere acts as “selective window”, letting visible light in, but not a lot of other radiation
-VISIBLE LIGHT drives photosynthesis!!!!!
-when light meets matter, it is either: 1) REFLECTED, 2) TRANSMITTED, or 3) ABSORBED
-when a pigment is illuminated w/ white light, we see the color that is most reflected or transmitted by it! Ex: leaf is green b/c chlorophyll absorbs violet-blue & red light, but TRANSMITS & REFLECTS green light Ex: if absorbs all wavelengths -> appears black
Spectrophotometer = instrument that measures ability of pigment to absorb various wavelengths of light -> machine directs beams of light at diff. wavelengths through solution of pigment & measures fraction of light transmitted @ each W.L.
Absorption Spectrum = graph plotting three diff. types of chloroplast pigments’ light absorption vs. wavelength -> helps us determine effectiveness of diff. wavelengths for driving photosynthesis
*light can perform work in chloroplasts ONLY if it is absorbed!
Action Spectrum = plots the rate of photosynthesis vs. wavelength and profiles the relative effectiveness of diff. W.L.’s of radiation in driving photosynthesis -> prepared by illuminating chloroplasts w/ light of diff. colors & plotting W.L. against some measure of photosynthetic rate (such as CO2 consumption & O2 release) -> resembles the action spectrum for chlorophyll a (but not EXACTLY -> this is partly due to the absorption of light by “accessory” pigments such as chlorophyll b & carotenoids) -> first demonstrated in Englemann’s experiment
Englemann’s Experiment = In 1883, Theodor W. Englemann illuminated a filamentous alga w/ light that had been passed thru a prism, exposing diff. segments of the alga to diff. W.L.’s. He used aerobic bacteria, which concentrate near an O2 source, to determine which segments of the alga were releasing the most O2 & thus photosynthesizing the most. Bacteria congregates in greatest numbers around the parts of the alga illuminated w/ violet-blue or red light. *There is a close match of the bacterial distribution to the Action Spectrum graph. -> CONCLUSION: violet-blue & red light are the most effective in driving photosynthesis! green light is the least effective color, as it is reflected/transmitted, not absorbed.
*absorption spectra & action spectra do not exactly match for chlorophyll a -> this is b/c “accessory” pigments w/ diff. absorption spectra are ALSO photosynthetically important in chloroplasts & broaden the spectrum of colors that can be used for photosynthesis (Ex: chlorophyll b & carotenoids)
*chlorophyll b & chlorophyll a are almost identical, but have a slight structural difference -> as a result, they have different colors (chlorophyll a is blue-green, chlorophyll b is yellow-green)
-both molecules consist of:
Porphyrin Ring = light-absorbing “head” of molecule; w/ magnesium atom @ center & Hydrocarbon Tail = interacts w/ hydrophobic regions of proteins inside thylakoid membranes of chloroplasts
*the ONLY difference between chlorophyll a & chlorophyll b is the functional group bonded to the porphyrin ring
Carotenoids = hydrocarbons that are various shades of yellow & oranges (b/c they absorb violet-blue & green light) -> broaden spectrum of colors that can drive photosynthesis
Photoprotection = important function of some carotenoids -> compounds absorb & dissipate excessive light energy that would otherwise damage chlorophyll or interact w/ O2, forming dangerous (to the cell), reactive oxidative molecules
Fun tidbit: -carotenoids similar to photoprotective ones in chloroplasts have photoprotective role in human eye! Highlighted in health food products as “phytochemicals” -> have antioxidant powers! Plants synthesize all the antioxidants they need, where humans & other animals must obtain from their diets
-when light is absorbed, W.L.’s disappear from spectrum, but energy CANNOT disappear! -> when molecule absorbs photon of light, 1 of the molecule’s e’s is elevated to an orbital of higher potential energy/“excited state” (when e in normal orbital -> pigment molecule said to be in ground state)
-only photons absorbed are those whose energy is exactly equal to energy diff. b/t ground & excited states (energy diff. varies from one kind of molecule/atom to another) -> particular compound absorbs only photons corresponding to specific W.L.’s, which is why each pigment has a unique absorption spectrum!
-once raised to excited state, electron cannot remain there long -> high energy state, therefore unstable
-when isolated pigment molecules absorb light, e’s drop back down to ground state in billionth of a sec. -> RELEASE excess energy as heat! Ex: why top of car is so hot on sunny day!
Fun tidbit: -white cars are coolest b/c paint reflects all W.L. of visible light!
-in isolation some pigments emit light, also -> “afterglow” = FLUORESCENCE Ex: if solution of chlorophyll is isolated from chloroplasts & illuminated, will fluoresce in red-orange & give off heat
-leaves get their green color from chlorophyll, the green pigment w/i chloroplasts, as it reflects green light
Stomata = The space where CO2 enters and O2 exits
Chloroplasts = found mainly in cells of the Mesophyll
Mesophyll = The interior tissue of the leaf
Guard Cells = Special cells (containing structural proteins) that will close (flaccid-> hypo inside cells & hyper outside cells) to conserve water if needed. When open (turgid-> hyper inside cells & hyper outside cells), they leave the space known as the Stomata. -> potassium plays a role in the opening & closing of the stomata. when proton pumps transport H+ ions, changing the membrane charge, the K+ “gates” open and K+ diffusion occurs. H2O will follow K+!!!
Stroma = a dense fluid w/i chloroplasts, similar to the cytosol of an animal cell
-chlorophyll molecules excited & in intact chloroplast produce diff. results -> *in native environment of thylakoid membrane, chlorophyll molecules organized w/ other small organic molecules & proteins into PHOTOSYSTEMS
Photosystem = reaction center surrounded by # of light-harvesting complexes
Light-Harvesting Complexes = pigment molecules bound to particular proteins -# & variety of pigment molecules enable a photosystem to harvest light over a larger surface & a larger portion of the spectrum than 1 single pigment alone
-together, light-harvesting complexes act as “antenna” for reaction center
-when pigment molecule absorbs photon, energy transferred from pigment molecule to pigment molecule w/i L-H C until funneled into Rx center
Reaction Center = protein complex -> includes molecules & molecule called “primary electron acceptor” -> includes “special” chlorophyll a molecules; these are special b/c their molecular environment (location to other associated molecules) allows them to use energy from light to boost one of their e’s to a higher E level to be captured by the primary electron acceptor
-(solar-powered) transfer of e from special chlorophyll a -> primary electron acceptor
-chlorophyll e is excited & PEA catches it -> REDOX RX (isolated chlorophyll would fluoresce b/c no e acceptor) -> drop right back down to ground state
*in chloroplast, immediate plunge back to ground state is prevented
-each photosystem (Rx center surrounded by L-H C’s) -> functions as a “unit” w/i chloroplast -> converts light E to chemical E (used for the synthesis of sugar)
-thylakoid membrane has 2 types of photosystems
Photosystem II (PS II) = Rx center chlorophyll a = “p680” (pigment best @ absorb light w/ W.L. of 680 nm/red)
Photosystem I (PS I) = Rx center chlorophyll a = “p700” (pigment best @ absorbing light w/ W.L. of 700 nm/“far” red)
*IMPORTANT: NAMED IN ORDER OF THEIR DISCOVERIES. PS II ACTUALLY OCCURS FIRST!!!!
-they both actually have identical chlorophyll a molecules, BUT they are associated w/ diff. proteins in the thylakoid membrane -> this affects the e distribution in chlorophyll molecules & accounts for their slight difference in light-absorbing properties
*WORK TOGETHER to use light E to create ATP & NADPH!!!!
*IMPORTANT CONCEPT SUMMARY: light drives the synthesis of NADPH & ATP by energizing 2 photosystems (embedded in the thylakoid membranes)
-> the key to E transformation is the FLOW OF E’S thru the PS’s (& other molecular components built into the thylakoid membrane)
*during light Rx’s, there are 2 possible routes for e flow: “cyclic” & “noncyclic” (the dominant route)
Noncyclic Electron Flow
1) Photon of light strikes a pigment molecule in L-H C & is bounced to other pigment molecules until it reaches 1 of 2 p680 chlorophyll a molecules in the PS II Rx center. 2) The electron is boosted up and captured by the Primary Electron Acceptor! 3) An enzyme splits H2O up into: 2 e’s, 2 H+’s, & 1 O. The e’s are supplied one by one to the p680 molecules -> replace the e lost to the PEA. (*As p680 is missing an e, it is the strongest biological oxidizing agent & the e hole must be filled.) The O atom combines w/ another O atom & forms O2. 4) Each photoexcited e passes from the PEA of PS II to PS I via an Electron Transport Chain. The ETC b/t PS II & PS I is made up of “electron carrier plastoquinone” (Pq), a cytochrome complex, & a protein called “plastocyanin” (Pc). 5) The exergonic “fall” of e’s to a lower E level provides the E to synthesize ATP. 6) Meanwhile, light E is transferred via L-H C to PS I’s Rx center. An e of 1 of 2 p700 chlorophyll a molecules is excited. The photoexcited e is captured by PS I’s PEA, creating an “e hole” in p700. This hole is “filled” by the e that reaches the bottom of the ETC from PS II. 7) Photoexcited e’s are passed from PS I’s PEA down a 2nd ETC thru a protein called “ferredoxin” (Fd). 8) The enzyme NADP+ Reductase transfers e’s from Fd to NADP+. 2 e’s are required for NADP+ to be reduced to NADPH.
Cyclic Electron Flow
-under certain conditions, photoexcited e’s take an “alternative path”, called Cyclic Electron Flow -> USES PS I but NOT PS II!!!!!
-SHORT circuit: e’s cycle back from ferredoxin (Fd) to cytochrome complex, then continue on to the p700 chlorophyll in PS I’s Rx Center -> NO production of NADPH & no release of O -> BUT DOES generate ATP
*IMPORTANT CONCEPT: The function of CEF is to produce more ATP to make up for the difference b/c the Calvin Cycle consumes more ATP than NADPH
*The concentration of NADPH in chloroplast helps regulate which pathway e’s take thru light Rx’s!!!!
-photosynthesis generates ATP by the same basic mechanism as cellular respiration: chemiosmosis!
-the thylakoid membrane of the chloroplast pumps protons from the stroma into the thylakoid space (which functions as an H+/proton reservoir)
-the thylakoid membrane makes ATP as H+’s/protons diffuse down the concentration gradient from [HIGH] in the thylakoid space back to [LOW] in the stroma thru ATP Synthase (like in cell resp!) complexes (the knobs of ATP Synthase are on the Stroma side)
-thus -> ATP forms in the Stroma, which is used to help drive sugar synthesis during the Calvin Cycle
*when chloroplasts are illuminated: pH in the thylakoid space drop to about 5 ([H+] INC.), & pH in the Stroma inc. to about 8 ([H+] DEC.)!
Noncyclic Electron Flow pushes e’s from H2O (low state of PE) to NADPH (stored @ high state of PE). The light-driven electron current also produces ATP. The thylakoid membrane converts light E to chemical E (which is stored in NADPH & ATP). Also, O2 is a by-product.
-similar to the citric acid cycle in cellular respiration, a starting molecule is regenerated after molecules enter & leave -> HOWEVER: calvin cycle is ANABOLIC (builds + consumes)
-carbon enters as CO2 & leaves as sugar
-spends ATP as energy source & consumes NADPH as “reducing power” for adding high energy e’s to make sugar
-net synthesis of 1 molecule of sugar -> CC must take place 3 TIMES!!!!!! (fixes 3 molecules of CO2, 1 time for each one that goes)
1) “Carbon Fixation” = incorporates each CO2 molecule (1 at a time) by attaching to 5-C sugar RuBP (ribulose biphosphate) a. -> enzyme that catalyzes 1st step = RuBP Carboxylase (“RUBISCO”) b. -> most abundant protein on earth c. PRODUCT = 6-C intermediate -> SO UNSTABLE it immediately splits in half -> becomes 2 molecules of 3-phosphoglycerate (for EACH CO2!!)
2) “Reduction” = each molecule of 3-phosphoglycerate receives an additional phosphate from ATP -> becomes 1, 3-biphosphoglycerate a. -> pair of e’s donated from NADPH b. -> reduces 1 , 3-biphosphoglycerate to G3P c. -> e’s from NADPH reduce carboxyl group 3-phosphoflycerate to aldehyde group of G3P (stores more ATP) d. ->*for every 3 CO2, there are 6 C3P e. ->*only 1 molecule of G3P can be counted as net gain! -> 1 molecule exits the calvin cycle to be used by plant cell -> other 5 recycled to regenerate the 3 molecules of RuBP!
3) “Regeneration of the CO2 Acceptor (RuBP)” = in a complex series of Rx’s, the carbon skeletons of 5 G3P’s are rearranged by the last steps of the calvin cycle into 3 RuBP -> to work, the calvin cycle needs to spend 3 molecules of ATP -> RuBP is now prepared to receive CO2 again!!!! -> for the net synthesis of 1 G3P, the calvin cycle consumes a total of 9 molecules of ATP & 6 molecules of NADPH!!!!!
Conservation of Water
-plants have anatomical & metabolic adaptations to help them conserve water (water is super duper important to plants, as it is like “feeding them electrons”!!!!)
-photorespiration (photo = light, respiration = the consumption of O2 & production of CO2) is a wasteful metabolic process & may kill plans if it continues for too long.
-“closed stomata” conditions for photorespiration
C3 Plants = 1st organic product of carbon fixation is 3-C “3-phosphoglycerate” -> *most plants: initial fixation of C occurs via Rubisco, a calvin cycle enzyme that adds CO2 to RuBP
Ex: rice, wheat, & soy beans
-> stomata partially closed on hot, dry days & produce less sugar b/c less CO2 can get in -> also, Rubisco can bind O2 in place of CO2!! -> product splits, 2-C compound leaves chloroplast -> peroxisomes & mitochondria rearrange & split compound -> RELEASES CO2
-> called “photorespiration” (occurs in light, & consumes O2 while producing CO2!!)
-> does not generate ATP, CONSUMES IT
-> does not produce sugar
-> decreases photosynthetic output (siphons organic material from the calvin cycle)
-> modern Rubisco retains some chance affinity for O2 -> certain amount of photorespiration is inevitable now
C4 Plants = an alternate mode of carbon fixation that forms 4-C as 1st product Ex: sugar cane & corn
-> unique leaf anatomy: 1) Bundle-Sheath Cells; tightly-packed sheaths around veins of leaf, Calvin Cycle takes place here in these plants & 2) Mesophyll Cells; more loosely arranged
-> cycle preceded by incorporation of CO2 into organic compounds in the Mesophyll
-> 1st step: the enzyme PEP Carboxylase adds CO2 to phosphoenolpyruvate (PEP)
-> forms 4-C oxaloacetate
-> *PEP Carboxylase can fix carbon when Rubisco can’t b/c of a high affinity for CO2
-> Mesophyll then “exports”/pumps 4-C product to bundle-sheath cells thru Plasmodesmata (*SPATIAL ADAPTATION)
-> w/i cells -> 4-C’s RELEASE CO2
CAM Plants = “crassulacean acid metabolism” = open stomata @ night & close during day (TEMPORAL/time relationship) Ex: succulents, pineapples, etc.
-> allows desert plants to conserve H2O
-> *Mesophyll cells store organic acids made @ night in vacuoles until morning (stomata close)
Auto Formatting Bios with Google Sheets Concatenate: PART 2! Automatic Flight Layouts
I’ve written a new template which will change the whole look of your bio when you select the flight. The code can be altered to do different things, of course. You could, for example, add a gender symbol or alter the entire layout based on relationship status.
How it works: In cell B18 you can select the flight. I made this a drop down menu for ease of use (right click>data validation>select “list of items”). Cell C18 and D18 then check to see what’s selected, and change their content based on that. E.G., if cell B18 is “Lightning”, display “[color=#30B1B8]”. The code for this looks as follows:
Change A, B, etc into what you want it to display
The Concatenate cell, B27, then refers to those cells, drawing the code for the font colour from them as well as the banner url.
My spreadsheet with templates can be found HERE If you make a template you want to share I’d love to add it there - you will be credited, of course.
As requested by anonymous, under the cut you’ll find a guide on how to write poetic skeletons like in my rp, @wardlawhq. If you have any further questions about the style, please don’t hesitate to contact me!