A&P 1 Spring 08 - page 18

Hi y'all! Anybody taking A&P 1 this coming spring semester? I'm trying to get as many pre-req's out of the way as possible and could use a study buddy or 2! Thanks! :)... Read More

  1. by   PreRN Katie
    Ok, so does anyone know any good ways to remember and understand what makes up carbs, proteins, lipids, and nucleic acids?...also those are organic compounds, correct (since they contain carbon and all)?

    I'm just having a hard time differentiating between what they all look like chemically. It seems like they're so similar but there's like 1 thing that makes them different. Or are you guys even doing this stuff in your classes? From what I gather it's actually biochem but we're learning it anyways:selfbonk:. Thanks!
  2. by   justcharlotte
    ^ we're learning it too, but I have not figured out a good way to learn it yet and I'm having difficulties with it too. I'll let you know if I come up with anything.
  3. by   WantAccel.BSN
    Hey guys. I'm really struggling with the concept of Osmotic Pressure. We have it defined as "the amount of hydrostatic pressure required to stop osmosis." The teacher said that "osmosis slows down due to filtration of water back across the membrane due to increased hydrostatic pressure." So osmotic pressure stops osmosis. So...the increased water (on the side that originally started with lesser water) produces water pressure (i.e. hydrostatic pressure) which stops osmosis? Maybe something just isn't clicking yet.

    I'm also struggling with the hypotonic/hypertonic thing. Why would increased water outside the cell cause the cell to burst? Why doesn't the concept of osmotic pressure apply to this situation (so that hydrostatic pressure stops the cell from taking in more water then it needs)? Is it because the cell can never reach equilibrium with the outside because there is always going to be way more water on the outside of the cell, then in it?

    I don't know if any of that makes sense to anyone, but if it does, I'd love some help!
  4. by   NXS
    When looking at tonicity (concentration of non-penetrating solutes)
    Remember that solutes occupy space that would normally be occupied by water molecules. Think about it this way... you have 2 cups. I decided to fill one cup half way with rocks and the other cup is rock free. Which one contains more water? The cup without the rocks.

    Diffusion of water, the movement of water in and out of cells work based on how much solute is inside the cell compare to its surroundings. Remember: Water will always move to the less occupied area.

    If a cell contained same amount of solute ("rocks" - cell contains ~300mOsm) inside the cell compare to the surrounding fluid outside the cell, there are equal amount of water so there is no movement of water molecules - This is Isotonic solution. Isotonic solution by definition is solutions containing 300 mOsm of non-penetrating solute.

    Now what happens if solution contained less than 300 mOsm of non-penetrating solute? So the cell has more solutes which means it has less amount of water (right? because solutes take up space) so all that extra water in the solution will rush in and cause the cell to swell up. Such a solution is known as hypotonic solution.

    Hypertonic solution is the opposite and the solution contains more than 300 mOsm of non-penetrating solute. Since there's more water inside the cell compare to outside, the water will rush out of the cell causing the cell to shrink.

    Hope that helps.
  5. by   NXS
    Quote from PreRN Katie
    Ok, so does anyone know any good ways to remember and understand what makes up carbs, proteins, lipids, and nucleic acids?...also those are organic compounds, correct (since they contain carbon and all)?

    I'm just having a hard time differentiating between what they all look like chemically. It seems like they're so similar but there's like 1 thing that makes them different. Or are you guys even doing this stuff in your classes? From what I gather it's actually biochem but we're learning it anyways:selfbonk:. Thanks!
    I'll try to answer as best as I can.

    Proteins are made up of amino acids (20 amino acids) arranged in certain orders that make up their 3D shape which defines their function. Common characteristics shared amoung all amino acids are the alpha carbon that covalently attached to carboxylic acid group (-COOH) and amino group (-N2H). So you need to know the last group that's attached to the alpha carbon to determine what type of amino acid it is and how they interact with other amino acids to create protein.

    Nucleic Acids: Making up DNA (TCAG) and RNA (UCAG)
    They are very similar structure when looking at it but you just have to know the minor differences between each acids. Also remember that...
    Pyrimidines = UTC are similar in structure
    Purines = AG are similar to each other

    Lipids are hydrocarbon like molecules... bunch of carbons chained together and have COOH at the end and behaves hydrophobically.

    Carbohydrates are the sugars. Monosaccharride or simple sugar is aldehyde or keytone with 2 additional hydroxy groups (-OH).
    example: OHC-CH(OH)-CH2OH
  6. by   Lennonninja
    The way that I was able to get the hypo/hypertonic solution eventually was pretty different. I was struggling with thinking of it completely backwards, so my teacher came up with a different way completely. The surrounding liquid is the chlorine in the pool, and the cell is a beach ball inside of the pool. If the beach ball is filled with the pure water, it will lose all of its water trying to give the water up to the outside solution, and then the beach ball will deflate which means it's hypertonic.

    If the beach ball was filled with the chlorine, and the pool was filled with water, the water would try to get inside the beach ball, and so much would have to come in to try to equalise that the beach ball would burst, which would be hypotonic.

    This method is completely different, but it worked for me lol
  7. by   justcharlotte
    ugh- SNOW DAY
    that means 4 hours of lecture that we wont be having!! I guess we just learn everything in our course package by ourself? I don't really know the deal
    just mad because I was so ready for the quiz!! haha oh well, I guess I'll use today to study up on what I should be learning tonight!
  8. by   siby.siby
    does anyone know of any good sites for practice tests?
  9. by   AlishiaRN77
    Quote from siby.siby
    does anyone know of any good sites for practice tests?

    http://www.fortlewis.edu/academics/s...s/mainmenu.htm


    http://msjensen.cehd.umn.edu/webanat...lf/default.htm

    these two sites looked pretty good for online testing.
    good luck!
  10. by   B2728
    i had my first a&p i exam on monday. i never studied for something so thoroughly in my entire life! i thought i was going to fail, there was just too much information.

    then i was surprised at how easy the test actually was. i was memorizing the molecular formulas for carbs, lipids, proteins, acids and bases... but the questions about them on the actual exam were more generalized. granted, having memorized the molecular structures gave me a better overall understanding and helped me memorize other characteristics more easily, but the actual exam did not test us to this level of scrutinization.

    our exam consisted of approx 30 multiple choice, which basically tested us on definitions of terms. then a few short answer, which was more terminology. then about 15 short answer/essay. these were the most difficult - we had to take concepts like tonicity and homeostatis and apply them to real world scenarios. we also had to explain cell division in detail (which i studied the least because i thought it was so biology 101 that there was no way they'd put it on the exam and make us regurgitate it again!).

    is this pretty much everyone else's experience?
  11. by   siby.siby
    thanks! these will help out a lot!

    Quote from allieinaz
  12. by   Hoping4RNin2010
    By now you may have figured a way to understand the hypertonic/hypotonic thing, but just in case I wanted to give you a  bit of info. We learned this in Allied Health Chemistry last semester and my prof. explained it as the molecules will travel FROM the more pure area to the less pure area, so consider it a party and you want to be where all the action is, so you will travel from the empty room to the room with all the people.
    Another way to look at it is, with an area of the party with less people will be easier to get out of than a room packed with people and so if the cell is the one that is more dense the "water" will flow into it and eventually it wont hold any more and will explode. If the "water" is denser than the molecules in the cell will want to leave this dull party and join  the rest of their friends out there and so the cell will shrivel.
    I hope this helps!
    Last edit by Hoping4RNin2010 on Feb 3, '08 : Reason: all these weird things showed up in my post
  13. by   Hoping4RNin2010
    We haven't had an actual test yet, we have had one quiz in lecture and 2 in lab so far.
    The lecture quiz was a mixture of multiple choice, matching, modified true false (if false we had to make it true) and fill ins. I studied my butt off and although I knew I passed it, it was harder than I expected since I studied so much. She likes to make you APPLY the information you study and so instead of just spitting out the memorized information from the notes/text she will think about the problem...and apply it. I wound up with a 94 and so I was happy with that, it was just hard.
    The 2 lab quizzes I took I got a 96 on both. (24 correct out of 25).

    I just hope I can keep it up through tissues.

    :P

    Kim

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