Chapters 11 and 12- Cell Signaling and The Cell Cycle

Disclaimer-- I've been doing my own thing with these chapters, so this post is mostly just resources. Hope it helps and/or is interesting.


First, on cell signaling- I tried reading the chapter in my textbook on this stuff- and it was honestly gibberish until I watched this video. It's pretty casual- but he hammers on a lot of info- so it's a good study tool.... (it's some college professor guy so he knows what he's talking about).

This is basically an extension of the above video- it repeats itself a little, but it's GREAT if you need a way to get this stuff memorized and/or understand it better.

This one is interesting. Don't get too caught up in all the weird protein names- just pay attention to the ligand, and the signaling. Oh, and to the cool cancer application. (And she's British- so it's epic anyway :)

And here's the Crash course video for Mitosis- it's wonderful. Crash course is amazing. 

And Meiosis..... 

http://www.youtube.com/watch?list=SP3EED4C1D684D3ADF&feature=player_detailpage&v=qCLmR9-YY7o

(Sorry, I would have posted the actually video but Blogger is being icky...) 

And that's all I've got for you. Seriously though, if this isn't enough, you just need to go read your textbook. Or google it. When all else fails- google it. :)

Photosynthesis

Hola.  I hope you're recent biology endeavors have been going smoothly. I've been learning LOADS, and in a very nerdy way- I'm extremely excited about this chapter. 

You see, we've all heard at least a million times from our science teachers about how great Photosynthesis is, and up until now, I really didn't get why it was so great. But let me tell you something- if you really GET the intricacy of this process- and its magnitude- then yes, it really is that amazing. 

I'm sure you all know the basics- Plants take CO2, Water, and Sunlight and make Sugar and O2. But what you probably DONT know- is HOW. That's what this chapter is about. It's not just the process- it's the itty bitty inner workings of this concept. 

This diagram is "the next step" so to speak. It's a little more complex than the basics, but it's still the watered down version of the video. So, see if you can make sense of it, and then maybe come back after the "crash course". 

Let me just warn you- the terms can be a bit daunting. But- it's completely worth puzzling it all out. 

First off- I hope you have a textbook with a chapter on this- videos are great- but READING about this stuff is crucial. 

Here's the video that helped me really understand it: 

And here's all the Khan videos (but if you watched the one above, and you get it- you don't need to actually spend time watching these). 

Overview of Photosynthesis: 

Light Reactions: 

Calvin Cycle: 

Some pretty good reading/diagrams: 

http://www.bio.umass.edu/biology/conn.river/photosyn.html

And, that's all I've got today. 

Cellular Respiration

Hey everyone. Hows the Bio learning coming? Well I hope.  I've been taking in bite sized chunks and really mulling over this concept the past few days- and I finally think I understand it enough to explain it. Which, if you think about it, is the best way to learn. After soaking up a concept, explaining it to other people in different terms allows you to check yourself to see if you really understand it. 

Think of it this way- if you're having trouble with a concept- listen to a bunch of different explanations (whether from teachers or videos or diagrams or books) and then try explaining it to a friend. You sort of end up reaching a higher level of understanding. 

Come to think of it... this is exactly why teachers are so darn educated in their field. It takes a seriously deep understanding to be able to teach other people a concept. 

So, all that jazz aside, we have Cellular Respiration. Prepare yourself- this concept is all about zooming in and zooming out. And all I mean by that is that we have a really complicated multi-step process, so to understand it, we go from each chunk, back to the "whole", back to a chunk, out to the whole, etc. That way we get how each piece fits- but we don't forget the "point" of it all. 

First things first then, what the heck is Cellular Respiration? Well, in essence, it's when we take food and turn it into energy. More specifically- it's when we bust apart a sugar for it's energy so we can slap a bunch of ATP's together and Voilà- you have a "useable" energy currency. 

I say currency because that's essentially what energy is. It's money- but it's got to be in the right form to be "cashed" in. You can't just go to Walmart with a bunch of Canadian money and expect to buy anything. (They'll just look at you funny). 

So how does our body turn that delicious blueberry muffin you ate for breakfast into cashable ATP (and hence into muscle contractions and/or movement) ??? 

Lets start with the organic molecule that makes up the muffin. Starch, and simple sugars. Maltase comes in and helps bust apart the long starch chains into disaccarides, and other enzymes in your stomach break those up into individual glucose molecules. 

So, we have a glucose molecule. Now what? 

There are FOUR stages to harvesting this energy: Glycolosis, The Krebs Cycle (or Citric Acid Cycle), the Electron Transport Chain, and ATP synthesis. I'm going to provide a BREIF explanation of each, and then give you the video that I learned from. My advice is to watch the video, and then try and put the info in your OWN words. Make sense? Okay, here we go....

For each molecule of Glucose we should (best case scenario) get 38 ATPS. 

Glycolosis: 

In a nutshell- this is just where the Sugar gets broken up and turned into two molecules of Pyruvic Acid. There's an investment phase, where you "spend" two ATP's, and a "payoff" phase, where you get four ATP's back- for a net of two ATP's. 

Krebs Cycle: 

This is where each of those pyruvates turns into Acetyl CoA, then into Citric Acid, and back again. In the process a bunch of NADH's and FADH2's are made (you'll learn what those are if you watch the videos). 

ETC: 

The Coenzymes NADH and FADH2 are used to pump H+ across the membrane of the mitochondria- resulting in an electro chemical gradient (a charge across a membrane). An electron "falls" down this chain of enzymes- releasing energy (more NADH and FADH2). 

ATP SYNTHESIS: 

Finally, with the energy we've accumulated, a protein complex is turned like a peice of machinery, and ATP's are squished together. 



Now, I know my explanations are pretty sad compared to the videos- but thats the point. We go back and forth between detail and generalizations to show that a concept really makes sense. So, off you go. Below are the Khan videos, and an excellent "sum it all up" video from Crash Course (really funny science guy). 

Here you go.... 




INTRO TO CELLULAR RESPIRATION

GLYCOLOSIS: 

KREBS CYCLE: 

ETC: 

OXIDATIVE PHOSPHORALATION AND CHEMIOSMOSIS: 

Crash Course ATP Synthesis Video: 

NOTE: 
This video was actually in a previous post- BUT, now that you've picked up quite a few new vocab terms and morsels of info- you might want to take a second look. I did, and it was tremendously helpful. Besides, he's a funny guy... 

Chapter 8- Metabolism

This chapter is all about the changes that occur in a cell that enable it to "live". Metabolism really just refers to all the reactions (mostly chemical) in a cell that allow it to stay at homeostasis. The word metabolism comes from the greek word metabolē, or change. It's not just turning food into energy- its TONS of different complex chemical reactions working in sync with each other (to do things like maintain the cell structure, respond to it's environment, and synthesize energy for other functions). 

There are a lot of varying concepts presented in this chapter, pooled into a sort of metabolism blob. If that makes any sense....

So, here we go. 

First off, we have a bit of a chemistry lesson. If you've taken AP Chemistry, then you know all about Enthalpy, and Entropy. If those terms are gibberish to you, then you might want to check out these resources... (in fact, even if you are familiar with these terms, you should really watch the video. This guy is pretty great). 

So, now that we're clear on Entropy (and Enthalpy as well), we can move on to how this translates into biology. 

Side note:  Something I've discovered over this past year is that Chemistry and Biology are actually like a double helix- they revolve around each other. In an ideal world, they would be taught together, all mashed into one, but alas, we have our Chemistry classes, and we have Biology. 

The world of metabolism is highly controlled by ENZYMES. You might be wondering what the caps lock is for... well, it's that important. Remember back to some of my previous posts- an enzyme is a globular protein that has a specific shape and a specific chemical job. They are catalysts- which means they make reactions happen lightning fast. 

Now, this video is about Biological Molecules- so it's sort of review. But- it talks about proteins a bit, so I'm sticking it in this post. If you start watching, and feel like you already get it, well, then move on. 

Along with Enzymes comes a whole bunch of VOCAB. 

Here are some really important terms to know: 

Catabolic Pathways
Anabolic Pathways
Exergonic and Endergonic
Energy Coupling 
Phosphorylate
Substrate 
Substrate/Enzyme Complex
Allosteric Regulation
Feedback Inhibition
Cofactors
Cooperativity
Activation Energy
Competitive and Non-competative Inhibitors


Enzymes: 

And now for ATP- this is HUGE in understanding cell metabolism. ATP is pretty much the reason we function as human beings. (ok, so there's a bit more to it than that, but you know what I mean). 

Here's another great "Crash Course" Bio video on ATP. It goes a bit deep- so hang in there. 

And that's about all I have for you for today. Just remember- no amount of youtube videos can substitute a good textbook :) So make sure to be reading like crazy. 

Here's a comic, just for fun... 

Chapters 6 and 7: The Cell (and the Phospholipid Bilayer Membrane)

Hola Everyone. I've got some some cool stuff to share today.

The reason I put these two chapters together mainly has to do with vocab. AP Bio is HUGELY vocab oriented. My mom always jokes that it should be worth a foreign language credit. :)  It's a lingo that needs to be mastered for the concepts to fully be absorbed. And the lingo used to describe organelles (chapter 6) is used a lot when describing the phospholipid membrane (chapter 7), therefore I've put the resources for both chapters in this post.

Again, let me just remind everyone, this blog isn't so much reflection, or me teaching necessarily, it's just resources I found useful/ that I think you'll find useful. And I also might clarify some things, especially if I struggled to understand it. Oh, and there's always going to be a comic at the end. But anywho...

Back to cells. I'll start with some good video links, and maybe some flashcards. Like I said, before you get into the nitty gritty stuff- you need to know the terms!

Cool Cell Animation:

It's not necessarily educational, but if you're like me, and you've already taken Bio, then you'll recognize a bunch of different organelles- and it's really quite exciting.

http://www.youtube.com/watch?v=ZDH8sWiUsAM


Another fantastic animation- sort of intense music, but it's good. As you watch, really pick out organelles and try and recall their function. The video isn't much good unless you add to it with your own knowledge.

http://www.youtube.com/watch?v=yKW4F0Nu-UY




Here are a few very basic flashcards for Organelle practice...

http://quizlet.com/1207358/functions-of-cell-organelles-flash-cards/


Something I didn't understand at first was Co-transport. The way the book describes it is like water pumped uphill, that performs "work" as it flows back down. Which I get, but translating that to hydrogen ions and glucose can be a bit confusing. As soon as I find a good resource for this concept, I'll put it up here.

And, last but not least, here's a bit of a biology related laugh...

Chapter 5: Macromolocules

Hello again. Sorry this post has taken me so long to complete- this was kind of a big chapter to chew on and really absorb. Some of it was review, but since I haven't seen this stuff in about a year, it took a while to remember.

This chapter had four main components- Proteins, Carbohydrates, Nucleic Acids, and Lipids.

These four types of molecules basically make us who we are. Literally. So naturally, they're pretty important to understand.

I'm not going to go into a lot of depth, just mainly overview, but if you have a textbook with a chapter on these molecules- READ IT. Not only is it pretty fascinating to ponder how such simple building blocks in their multitude of variations combine to make us, but reading helps get the vocab down, and you can be sure that this vocab is going to resurface a LOT in AP bio. So, here we go...

First off, heres a few concept maps to warm up your brains. The one I came up with on my own fits my mind, but isn't exactly the clearest. And everyone is different. My suggestion is to take these as suggestions, and struggle with making your own. It's the process that really helps.

Proteins:

Carbs:

Lipids:

This is a PDF doc with  TONS of great info. It's got several concept map, lots of pictures, and some really simple explanations for the different types of lipids and their functions. Check it out...

http://www2.bakersfieldcollege.edu/deharvey/Powerpoints/Chem%2011%20Tmberlake%20Powerpoints/Chem%2011.Chapter%2015.12-10-11.dch.pdf


Nucleic Acids:

Another REALLY important concept introduced (or rather, reintroduced, because you should be familiar with it) was transcription (and translation). Basically, that's when DNA becomes mRNA, and then a ribosome transcribes it into a protein (usually an enzyme).

Here's an amazing video that explains these concepts with a visual animation:

The only other "Big" concept presented was the phospholipid bilayer. Here's a diagram to jog your memory...

Sort of a fuzzy picture. Sorry.

And that's all I've got for you. Next unit is cells (I'M SO EXCITED!). Stay tuned for a post on organelles.

And last but not least, a comic....

This one especially felt relevant... nucleic acids. :)

Chapters 3 and 4: Water and Carbon

Hello Everyone! I've finished two more chapters in my textbook (one on Water and another on Organic Chemistry). This post will include highlights from the text and outside resources I found useful.


Alrighty, so Water first.

 I think we can all agree- water is pretty sweet. I mean, its the #1 reason we're able to live on planet Earth. So, what makes it so special? Why can it dissolve almost anything (without being corrosive)? Why does it comprise 70% of our body mass? Campbell (my textbook) explains that the following properties of water allow it to be the "super" substance:

• High Heat of Vaporization-- it takes a LOT of energy to get 1 gram to evaporate. 

• High Specific Heat-- this one's pretty similar to the above quality- it just means it can absorb a lot of heat before actually going up a degree in temp.

• Hydrogen Bonding-- the hydrogen atoms are positive, and make bonds between the slightly negative oxygen. This pretty much makes all the other properties possible. 

• Evaporative Cooling-- as the "excited" molecules evaporate, the kinetic energy loss "cools" down the substance left behind (ie our skin). 

• Adhesion and Cohesion-- the first is water sticking to other things, and the second is water sticking essentially to itself. 

Practical application of cohesion and adhesion-- plants draw water up through their roots using this chemical property. 

• Floatation of Ice-- as water freezes it expands- preventing bodies of water from freezing solid (the ice floats to the top leaving liquid underneath). 

• Universal Solvent-- Water dissolves ionic and polar substances. It's also pretty good at forming colloids with large hydrophilic molecules. 

• Surface Tension-- because of the hydrogen bonding, water's surface acts like a piece of plastic wrap. This is pretty useful for a wide assortment of bugs, as seen in the picture. 

Another really important topic touched in the chapter was the pH scale. 

I hope you're all familiar with water's dissociation into H+ and -OH. In pure water this 'reaction' happens back and forth equally (we call that equilibrium). When you start adding acids and bases, the respective levels of H+ and -OH teeter-toter, causing a shift in the pH scale. Also note that it goes by logarithms- so powers of 10, not 1.


Alrighty, next comes the Organic Chemistry stuff. I'll make this short, sweet, and to the point...


Carbon Basics:

http://www.dummies.com/how-to/content/the-basics-of-organic-chemistry.html

Functional Groups 'Cheat Sheet':

http://www.dummies.com/how-to/content/organic-chemistry-1-for-dummies-cheat-sheet.html

Most of this chapter was about the role Carbon plays in forming the 'molecules of life'. In other words, it was an overview of the practical molecular 'uses' of carbon (just as the previous chapter highlighted useful properties of water and the respective application). 

Something I found VERY interesting-- Carbon is what it is because of it's four valence electrons. It's ability to make four bonds allows hydrocarbons, ketones, alkenes, alcohols, etc. to be formed. We are carbon based life forms. That being said- researchers are now looking into Silicon based life. This compound also has four valence electrons and may have similar bonding abilities as carbon. Hmm... Silicon based aliens? Food for thought. 

And Finally, if you've stuck with me this far, I've got a comic for you. It has nothing to do with the properties of water or carbon, but it is funny, and it sort of has to do with biology. So enjoy. And stay tuned for a post on Large Biological Molecules. :)