AP Survival Guide

A little guide to help those who fear the month of May

[apsurvivalguide]

My AP friends:

Good luck to you all! Just remember that after the test, you can relax and look at fresh ap memes. As for me, this is my final ap test ever, and I am happy to see that this tumblr was able to bring ap sufferers together. It's been a honor y'all, hopefully my ap credit will count at ucsd

Tips for the SATs: Things Prep Books Won’t Tell You

I took the SATs twice. First time I got 2080. Second time I got 2390. It’s a bullshit test that isn’t correlated with future success or grades, and it has several weak spots. So here’s a guide of unconventional hacks, tips, and tricks that you won’t learn in most test prep books. This is specifically for people taking the SAT before March 2016. OKAY HERE WE GO:

Past Tests and Prep

Past Tests 

http://ineedapencil.ck12.org/

http://www.majortests.com/sat/

Google Drive of Prep 1

Google Drive of Prep 2

Barron’s book is great and harder than Princeton, so I recommend getting it

Grubers is highly recommended as well

There’s tons of masterposts on here if you google, so not going into detail

Miscellaneous (important!) tips: Essay

5 paragraphs- intro, 3 points, conclusion. Yada yada, you’ve heard this before.

Pick a side. Don’t try to be all smart and argue both. You think you can, and you’re probably right, but your argument will be a lot more nuanced and well-supported (which is a chunk of the mark) if you choose one side

You don’t need to worry about actually forming an argument supported by evidence. Spend 2 minutes planning and come up with exactly 3 points. In each paragraph, make your point and then bam, you’re good to go. You know why? Because you make up examples. Whatever you want- Make up dates! Make up people! Make up absolute shit that the grader knows isn’t true! I mean, try not to write 500 words on how Shakespeare’s most famous play, ‘Roly-poly Ollie and Julianne Moore’, changed your life, but. Make up books, plays, personal anecdotes, whatever. It does not matter. You can do that. They’re marking you on whether or not you have examples, not whether or not they happen to be true.

Listen up, because this is the most important: write a lot. Write two pages, or more, and if you can’t, write bullshit but write two pages as long as it’s semi-coherent.

There is a direct and strong correlation between length of essay and mark assigned. What does this mean? You write shit, you get a higher mark. Collegeboard says it ain’t so, but the facts disprove it. 

Memorize a couple of big words like “deluge”, “guile”, and “plethora”, and make sure you know how to use them. Then just shove ‘em in when you’re sure you’ve used them right. Preferably in the first page, and the conclusion.

Here’s a handy guide to basically bullshitting your way through the essay

Miscellaneous (important!) tips: Vocabulary/Grammar

Do not try to cram vocabulary two weeks in advance. The words aren’t obscure enough to justify that.

Read. Read books, read newspapers, read articles, read journals. If you read voraciously the year before you take the SAT, I guarantee you’ll ace the vocab section without studying.

But. If you don’t have a year and you gotta hit the vocab lists, here’s how to do it:

Get a list of a certain number of words to memorize, depending on how long you have: like this, for 100 words, or this one, for 500 words. Use the good/medium/bad system. Every day, do the words in the bad pile. If you can do them after 4 days, move them to the medium pile. Those are words you do every 3 or 4 days. The good pile is words you go over every week. If you fail at a word in the good or medium pile, move it down to bad.

Learn the meanings of some prefixes and suffixes, and several or more common roots of words (again, depending on time). This means if you come across words you don’t know, you can make a good guess.

Seriously though, just read

Memorize the grammar rules. There’s about 10 that they always re-use and they’re not complicated

Miscellaneous (important!) tips: Math

During the SATs you’re allowed to bring in a calculator with programs. DO NOT WASTE THIS OPPORTUNITY. But don’t waste precious time using a program when you could use your head and be faster

Here’s the programs you can put in yourself

Here are ones you can download (about the same)

A program isn’t there to do hard math; it’s there to save time. You need time. 

You also don’t need to memorize formulas for anything because you can get a program that’ll do anything with formulas for you

I highly 150% recommend getting your hands on a graphing calculator if you don’t have one. Get one off your friend or rent one or something, but get one

Miscellaneous (important!) tips: Critical Reading

In my opinion, the most bullshit part of the whole test. And the essay is a thing that exists, so.

Don’t read the text first. That’s ridiculous. Skim the text, just the first bit of every paragraph. Then close your eyes and in less than 10 seconds, think of a summary. What’s the author’s main point? A line or two, like ‘Technology is helping restaurants. The food is cheaper which is benefitting consumers.’ It sounds stupid but do it.

Read the question and go to that part of the text (it goes in order). Knock off any that are obviously wrong. Now you’re looking for the ‘most correct’ one which, what the fuck, should not be a thing! But anyways, most times, from the remaining options one will be in-line with your little summary from before, and one won’t.

There will never be two right answers. If two answers seem right to you, it’s because you’re thinking ‘oh, but this sentence suggests that-’ stop. Don’t overthink these questions. Often, people will be trying to think of the implications, themes, etc. and you don’t need to. This section is superficial as fuck.

If y’all have any specific questions you want to send me to get advice on how to tackle them, feel free.

General Advice for the Day Before/On the Day

Get a good night’s sleep! You got this. But if you can’t sleep, don’t worry! You still got this.

Get there early if you can, so you’re not adding anxiety to yourself

Don’t spend longer than a minute on a question. If you haven’t got it in that time, come back to it at the end. You’ll be more relaxed after having finished the ones you do know.

Once You’re Done

Yay! I’m proud of you

Don’t look up the answers. And if you do, don’t stress about any that you got wrong

Go have lunch or dinner with your friends or family and rant about how you just spent 6 hours in a stuffy room and stuff your face with cheesy pizza and chips bc you deserve it

Important Final Points

No matter what CollegeBoard says, the SATs are not an IQ test. It is very possible to boost your scores by 300 points

Your score does not define you. All it does is tell you how you did on that one day, but that’s not all you are. That’s not even 0.0001% of who you are

If a college doesn’t accept you because your score isn’t as high as they’d like, even after going over the rest of your application, then you don’t want to be there anyways

You will get in somewhere, and you’ll have a great time

Any juniors/seniors/college freshmen, feel free to hmu for general or specific advice on college, SATs, or studying

[apsurvivalguide]

July 5th is tomorrow/today

Reminder that it is not the end of the world if you do not pass an AP test. They are hard and you have fought through many. Do not give up because of a number. Breathe, you did it, it’s over, and now you can relax and enjoy your summer. I might be posting my scores, and if you passed anything and are proud shoot me a message! 

Best wishes!

[apsurvivalguide]

Shoutout

Follow @hellyesapeuro for cool euro notes. Have a nice summer! See you guys in July!

[apsurvivalguide]

Good luck APUSH students!!

[apsurvivalguide]

Good luck ap calc students!! Remember: +c!!

[apsurvivalguide]

Ap calc AB kids: ask me questions

If you have any last minute questions on calc stuff for tomorrow's test, shoot me an ask or reblog! Reminder: I'm only taking AB questions and not BC! Good luck!

[apsurvivalguide]

Everyone taking the AP Lit exam today, good luck!

[apsurvivalguide]

Help for those in ap euro

Hey so my friend made this really cool/informative website WITH ALL HER AP EURO NOTES/ TIPS ON IT. It is literally the bomb and everyone in ap euro should check it out. Even if you have already passed ap euro you should still look at this awesome resource. 

INCASE YOU DIDN’T KNOW CLICK ON THE LINK.

NOW. JUST DO IT. AP. EURO. RESOURCES. 

GO.

[apsurvivalguide]

Alrighty guys

So, as you may have noticed, May is right around the corner and quickly creeping up to us. 

And that means AP Tests. Oh boy.

I’ve got a few messages requesting some classes, so I am going to do a broad generalization for a few courses. 

AP SCIENCES

Whether it be chemistry or bio, remember not to get overwhelmed with the insane amount of info in your textbook. DO NOT REREAD CHAPTERS. Skim, read chapter summaries, look at chapter notes online (coursenotes is a great website for this). Rereading the book will over stress you and discourage you from your objective:

Get the big picture, focus on important details, and move on. We only have a week, so do NOT get caught up on these things. Watch Bozeman videos or Khan Academy. If you find you are spending 6 hours on a topic, thats your sign that you are taking too long. 

Also: get used to the multiple choice format (for bio kids) and learn how to skim/take notes on the test. Its ok to make your paper look crappy with tons of pencil marks. 

AP HISTORY

Again, do not forget the big picture-- they like turning points, how events affected civilians and other countries around them, and comparisons. Get a few dates memorized so you can slap them on your test. It looks good on an FRQ. For DBQ’s my best advice is to try to get through the reading fast and jot down notes. These things will slow you down and suck up all your time, so use it wisely. 

AGAIN: Get the big picture, focus on important details, and move on.

AP MATH

Get used to the format. You may know the subject material really well, but that doesn’t mean much when their choice of words is abstract and confusing. Take FRQs. Practice multiple choice. Learn what graphs mean when relating them to other functions (I’m looking at you, derivatives!!). Master the ‘hint’ words like rates, average, accumulation etc that will help guide you on the test. 

AP LIT

LOOK AT THE QUESTIONS FIRST. They will reveal what the passages are about. Read fast, take notes, read it again. Answer some questions. If they take too long? Move on and the next question may help you answer your previous question. For essays, ADDRESS ALL PARTS OF THE PROMPT. That is extremely important. And for at least one passage, they will recommend that you use the given literary terms so USE IT AND EXPAND ON IT. Review some literary terms for some books you read during the year and then relax. You can’t really study for this test, just trust in your abilities and get used to the time limit. 

To all AP students: I wish you luck on your studying! Breathe, drink lots of water, and change environments. Sometimes studying in one place will suck out your soul. Reward yourself. Take small breaks. You can do this and will do this!

Now go study!

[apsurvivalguide]

AP Bio Math Studies Part 1

Hardy Weinberg Equilibrium Problems!

To start, what does p^2, q^2, and 2pq mean?

p^2= percentage of offspring who will be homozygous dominant 

q^2= percentage of offspring who will be homozygous recessive

2pq= percentage of offspring who will be heterozygous dominant 

This is given info you will have on your AP Bio Equations and Formulas sheet. No need to memorize. Just know the difference between p and p^2 etc. 

I am using a problem from a released test question that basically states:

In a Hardy Weinberg Population, there is:

11,088 individuals with the dominant trait 

1,759 individuals with the recessive trait 

And are asking: What proportion of the offspring will be heterozygous? 

Since we are trying to find the heterozygous offspring, we will be trying to find 2pq. 

So how to start...?

Use the branching method.

Split your paper into three sections (homo dominant, heter dominant, and homo recessive). 

We don’t care about the dominant individuals right now. 

Start with the recessive alleles.

I found q^2 by creating a ratio of recessive individuals (1,759) to all of the individuals (12,847) and got .1369.

To find q, I took the square root of .1369 to get .3700.

Cool, we got q^2 and q. 

Use the formula p+q=1.

Now we got what p is. 

To find 2pq, we can just stop here, but I found p^2 anyways. 

Find p^2.

We basically just did exactly the same thing with q, but backwards. Now we have all our info (and more) to find 2pq. 

Find 2pq using the info you found. 

2pq= .47! Now you know that 47% of the offspring in Hardy Weinberg Equilibrium will be Heterozygous Dominant for the selected trait!

The good thing about the branching method is that you can find all sorts of info in an organized manor. Remember, ALWAYS start with recessive, find q, etc. If you start from the dominant side, it will not work.

If you have questions, or want to see something specific, just shoot me a message. Good luck!

[apsurvivalguide]

Help for those in ap euro

Hey so my friend made this really cool/informative website WITH ALL HER AP EURO NOTES/ TIPS ON IT. It is literally the bomb and everyone in ap euro should check it out. Even if you have already passed ap euro you should still look at this awesome resource. 

INCASE YOU DIDN’T KNOW CLICK ON THE LINK.

NOW. JUST DO IT. AP. EURO. RESOURCES. 

GO.

[nikimontage]

How to Get Good Grades and Still Have a Life

Work Smarter, Not Harder

During my last two years of my undergraduate, I came across this notion of working smarter, not harder (a.k.a. working more efficiently to maximize your grades). This is one of a few main concepts that raised my GPA by 1.0 whole point. Here are some tips that if you truly follow, you’ll see incredible results. 

Stay on top of the work 

Review lecture slides or textbook material before going to class 

Go to class (or if online, schedule a regular time to review the material)

Complete all practice problems because chances are it’ll be on the final

Own your note taking method; either on your laptop, on lecture slides, or a notebook (and don’t think of dramatically switching it up half way through the semester)

Summarize your notes at the top or bottom with a few quick bullets on what the lecture focused on to help you organize later on

Ask questions when you are uncertain or need clarification 

How Can I Work Smarter?

Go through the course syllabus for learning objectives and course description to see what areas are to be focused on

Create a daily, weekly, and monthly study plan and don’t be scared to adjust

Get enough sleep; this one is my number one tip, there’s nothing worse than hearing about people pull all-nighters before an exam (I’ve also know people who have accidentally slept through and missed it entirely)

Eat, eat, eat (and eat well); fuel your body and your brain with superfoods and plant goodness b/c everything is connected and it will pay off than eating artificial vending machine junk (trust me)

Use the 50/10 rule (50 minutes focus, 10 minute break), or whatever version you find most effective

Find your study place and rotate (i.e. use library for one course and a coffee shop for another)

Make school your 9-5pm job - the top people in my program go to the library at 9am to start their “job” and it’s so so important 

Study Plan

Focus on the course(s) you try to avoid them out (and try to focus on them at the beginning of the week when you feel more motivated)

Always start study sessions with what you reviewed last time

Plan sessions in 2-3 hour blocks throughout the day and spend time studying a different course in each session (or at least one different course in-between the same course to reduce boredom)

Create practice tests and quiz yourself on material by shifting memorization to true understanding

Use summary notes to help destress before exams 

Create study groups (if that’s your cup of tea) to quiz each other and explain concepts 

Happy studying! 

[apsurvivalguide]

Update

Since we are nearing AP testing again, I am going to be more active on this blog. I plan on posting mostly AP Bio and AP Calc info, but if anyone wants stuff on AP Lit just shoot me a message. AP Euro is also ok by request. Good luck studying!

[sapphystudies]

[AP Bio] TEST FIVE: Photosynthesis

*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

Pigments = substances that absorb visible light -> diff. pigments absorb diff. wavelengths

-wavelengths that are absorbed, disappear!!!

-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.

Pigments

*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

Photosynthetic Structures

-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

Photosystems

-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.)!

—-

Summary

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.

Calvin Cycle

-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

-carbohydrate produced-G3P (glyceraldehyde 3-phosphate)

-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)

PHASES

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)

[apstudying]

Final review from our only AP Bio Lord and Savior, Mr. Bozeman! It’s a bit long, so skim along until you find the sections you want to review. He also has a whole bunch of videos, sorted into topics for last-minute studying! GOOD LUCK PALS

[sapphystudies]

[AP Bio] TEST THREE: Metabolism

REGULAR HIGHLIGHTED VERSION CAN BE FOUND HERE

Metabolism

Metabolism = the totality of an organism’s chemical reactions -> “roadmap” of thousands of Rx’s w/i a cell

metabolic pathway = begins w/ specific molecule -> altered in series of steps -> results in product *each step is CATALYZED by an enzyme -> SPEEDS UP Rx’s

-mechanisms to regulate enzymes & balance the supply and demand (if deficits/surpluses/etc should occur)

*metabolism manages the material & energy resources of the cell

Catabolic Pathways vs. Anabolic Pathways

catabolic = release energy by breaking down complex molecules -> simpler ones ex: cellular respiration, ciliary beating, membrane transport

anabolic = consume energy to build complex molecules from simpler ones *AKA “biosynthetic” pathways ex: protein synthesis

Coupled reactions: free energy released during catabolic Rx may be used to drive anabolic Rx! -ATP powers cellular work by doing this coupling of Rx’s

chemical energy = potential energy available for release in a chem Rx

*STRUCTURES and BIOCHEMICAL PATHWAYS of cells allow release of chem energy from food molecules -> powers life processes

Systems

“system”: used to indicate the matter being studied

“surroundings”: everything outside the system

CLOSED system = isolated from its surroundings ex: liquid in thermos bottle

OPEN system = energy & matter can be transferred between system & surroundings ex: organisms!

Thermodynamics

thermodynamics = study of energy transformations that occur in a collection of matter

FIRST law of thermodynamics: *the energy of the universe is CONSTANT -it cannot be created or destroyed, ONLY transferred/transformed (AKA = CONSERVATION OF ENERGY)

ex: 1) chem bond energy in food transformed to chem bond energy of ATP (cellular respiration) 2) sunlight transformed to chem bond energy by plants (photosynthesis)

SECOND law of thermodynamics: -every energy transfer/transformation increases the entropy (disorder) of the universe (some energy is available for work and some is not) OR -for a process to occur SPONTANEOUSLY (can occur on its own w/o input of energy), it must INC. the entropy of the universe

entropy = loss of useable energy during energy transformation

-amount of chem energy lost is accounted for by amount of heat generated during metabolism (energy is given off as heat -> this is why we are 98.6 degrees F!)

-entropy of a system may actually decrease as long as the TOTAL entropy of the universe (system + surroundings) increases

Free Energy

free energy = portion of system’s energy that is available to perform work -measure of system’s instability (tendency to change to more stable state) -unless something prevents it, system will move towards greater stability

*the free energy change of a Rx tells us if it occurred spontaneously or not

free energy = G

free energy change = DELTA G *find by G final state - G initial state)

DELTA G = DELTA H - T x DELTA S

DELTA G = free energy change DELTA H = change in system’s enthalpy (total energy) T = abs. temp (K) DELTA S = change in system’s entropy

*neg. DELTA G = spontaneous (if DELTA H decreases, T DELTA S decreases, or both)

*pos. or ZERO DELTA G = nonspontaneous

-spontaneous changes can be harnessed to perform work

-system AT equilibrium CANNOT spontaneously change, CANNOT do work -> ONLY when moving towards eq.

bioenergetics = study of how organisms manage their energy resources for metabolism

more free energy -> less stable -> greater work capacity -> SPONTANEOUS CHANGE -> free energy decreases -> release of free energy available for work -> less free energy -> more stable -> less work capacity

Exergonic vs. Endergonic Reactions

exergonic = “energy outward” = spontaneous, net release of free energy -NEGATIVE DELTA G -greater work done -might take a long time with enzyme

endergonic = “energy inward” = absorbs free energy from surroundings -stores free energy in molecules -POSITIVE DELTA G -nonspontaneous (NEEDS HELP!)

*processes reverse

*METABOLISM AS A WHOLE IS NEVER AT EQUILIBRIUM! IF CELL REACHES METABOLIC EQUILIBIRUM -> DEAD!!

Metabolism & Equilibrium

A Rx in a closed system will, due to being closed, eventually reach equilibrium and will be UNABLE to do work! (at chem equilibrium, there is no net change in free energy)

However, cells are in OPEN systems, and therefore are not in equilibrium. Each cell has a CONSTANT FLOW of material into and out of the cell. The input of energy is constantly required to maintain their high level of organization.

Ex: A proton pump within the plasma membrane uses ATP/energy to send H+ ions out of the cell, keeping a constant [HIGH] of H+ on the outside within the ECM. The H+ then moves down its concentration gradient and to do so it must bind with a Sucrose-H+ transporter. Due to H+’s charge, doing this changes the confirmation (shape) of the protein to fit that of a sucrose molecule, and allows sucrose to be transported.

relationship b/t free energy & equilibrium -> eq. INC.    , FE DEC.    , (inverse)

ATP

made up of triphosphate, ribose, and adenine

-unstable due to having 3 phosphate groups with all neg. charges

ATP <- most unstable, but also most potential energy ADP AMP

enzymatic hydrolysis: adds H2O to ATP, breaks off inorganic phosphate, becomes ADP + energy (exergonic, DELTA G, heat released)

ex. of how ATP performs work: motor protein movement, solute transportation, creation of glutamine from glutamic acid and ammonia

*phosphorylation = adding of an inorganic phosphate (also is force behind the moving of a motor protein)

Regeneration of ATP: 1) ATP is a renewable resource and can be regenerated by the addition of a phosphate group to ADP. 2) The energy to phosphorylate ADP comes from catabolic Rx’s in the cell. 3) The chemical potential energy is temporarily stored in ATP and drives most cellular work.  ( 4) Free energy is released. )

Enzymes

Enzymes are proteins that break down their specific substrates. They are created through protein confirmation, either at the free ribosomes or the rough ER.

When a substrate joins an enzyme at the active site to form an enzyme-substrate complex, the conformation changes slightly and forms an “induced fit” to better fit the substrate. The substrate is held here by weak bonds such as hydrogen or ionic bonds. The substrate is converted into a product, and released. The active site is now again available for substrate molecules.

Enzyme activity levels can be affected by temperature and pH. There are different “optimal” temperatures and pH’s for each enzyme out there. When the temperature or pH is too low or too high compared to the optimal, the enzyme can denature in its confirmation and become inactive, unable to work properly. For example: For temperature, as the temperature gets too high past the optimal, the increased molecular collisions batter the enzyme; as temperature is too low, there will not be nearly enough collisions for the substrates to wind up hitting and joining with the enzymes. For pH, as acidity increases, the [H+] increases. The H+ ions bond with enzymes’ amino acid side chains, affecting the charge and in turn the overall shape of the enzyme, rendering it unable to work. However, if these conditions are reversed, enzymes can be re-natured. Enzyme activity can also be affected by salt solutions.

For a reactant to become a product, there is a certain activation energy amount that is needed or it to reach the transition state. Enzymes, as they catalyze reactions and speed them up, lower the amount of activation energy required (Ea barrier). DELTA G is not affected by this, instead, there is just a speeding up of spontaneous Rx’s that otherwise might take a long time to occur.

Enzyme activation may require the binding of a cofactor. There are two types of cofactors: inorganic and organic. Inorganic includes zinc, copper, iron, etc. Organic includes coenzymes and vitamins.

There needs to be a regulation of enzyme activity in order to help control metabolism. 1) The cell switches on or off the genes that encode specific enzymes, so enzymes either are or are not produced. There is the “compartmentalization” of enzymes in defined organelles. 2) Enzymes that are already produced are regulated by enzyme inhibitors. For example, there are competitive and noncompetitive inhibitors. Competitive inhibitors bind to the active site of an enzyme before a substrate can, competing with it. The enzyme becomes blocked and cannot break down substrates. Noncompetitive, or allosteric inhibitors bind to the remote site on another part of the enzyme, sneakily, which changes the shape of the enzyme and therefore affects the shape of the active site, so substrates cannot fit, and the enzyme cannot work. Inhibitors work on quaternary structures as well, and can also be activators for them. However, within quaternary structures, cooperativity may occur, where the binding of one substrate to the active site of one of the enzymes can lock all of the “subunits” in an active form. Another form of inhibition is feedback inhibition. Basically the end product of a reaction can go off to be used by the body, but if not, it might end up binding to the allosteric site of the enzyme that initially catalyzed the reaction, and stops the enzyme from working on that metabolic pathway early on, causing a decline in the production of the product that inhibited.