Dismiss Notice
Hey Texans—join us for a DFW meetup! Click here to learn more.

about Cellular respiration

Discussion in 'DAT Discussions' started by joonkimdds, Nov 21, 2005.

  1. joonkimdds

    joonkimdds Senior Member
    7+ Year Member

    Joined:
    Jun 30, 2005
    Messages:
    2,780
    Likes Received:
    2
    Status:
    Pre-Dental
    Hi, I am taking biology course and I just took an exam about cellular metabolism, respiration and mitosis.

    metabolism and mitosis were easy to understand but i had trouble with respiration during the test.

    When i studied for mitosis(for example) i memorized every single part of the organelles and how it works for each phase and so on.
    I took bio when i was in high school and this was the 2nd time that i learned it so it wasn't hard to understand.

    but cellular respiration is a new chapter that learned and had a test. it's much more complicated to memorize compared to mitosis and i bombed this section.

    other students told me to forget about it since the test is over, but i am a bio major student and i know that i should study for DAT exam.

    Do u guys think it's good enough to just look at kaplan blue book or more in detail?
    I still have hard time understanding how glucose, ATP, NADH, FADH and blah blah blah stuff.
    any advice of how to study the cellular respiration? especially to prepare for DAT exam? because i also heard that DAT exam may not ask too much in depth.
     
  2. Note: SDN Members do not see this ad.

  3. SMC2UCLA2_

    SMC2UCLA2_ Senior Member
    5+ Year Member

    Joined:
    May 7, 2004
    Messages:
    173
    Likes Received:
    0

    I would say forget about it for now and you will study it when its time for the DAT. If you are like me then studying it now wont do any good if ur taking the DAT a year from now.

    As far as respiration- I dont find it that difficult. Its really just a matter of memorization. If you post some more specific questions then maybe I or someone else can elaborate.
     
  4. food4thots

    food4thots Senior Member
    5+ Year Member

    Joined:
    Sep 5, 2005
    Messages:
    644
    Likes Received:
    0
    Status:
    Dental Student
    the DAT ?'s are pretty general. but, i would try to understand cellular respiration anyhow. many classes touch on it, so hopefully u will get a better understanding next time around.
     
  5. joonkimdds

    joonkimdds Senior Member
    7+ Year Member

    Joined:
    Jun 30, 2005
    Messages:
    2,780
    Likes Received:
    2
    Status:
    Pre-Dental
    For those of u who understand it without any problem may think I sound stupid but I seriously don't understand any of the cellular respiration stuffs.

    if i want to memorize the cellular respiration, we start with glucose, then suddenly 2 ATP from nowhere pops up and becomes 2 ATP, then 4ADP and 2NAD just pop up from nowhere and becomes 4 ATP and 2NADH. Then it makes me wonder where they come from and why they become what they become. Ok, let's say I just want to memorize it. But where does first 2 ATP come from? why does it have to be 2 not 3 or other numbers and why does it have to be ADP? I thought cellular respiration makes ATP but why does it use ATP since the beginning? and what's the point of using ATP if u were gonna end up with making it? and so on. so basically, this one step makes me come up with so many questions that i cannot answer. Glycolysis has 10 steps and Kreb's cycle has 8 steps and each steps are very complicated and make me wonder how it happens.

    On the other hand, if i want to study mitosis, Centioles, chromosome, they just move their position, so it's understandable.
    Even when nuclear membraine and nucleoli disappear and spinder fibers were created, each phase explains this step by step, so there is no problem understanding each steps.

    Does anyone have any tips for understanding or memorizing the cellular respiration? plz help me~?
     
  6. tinman831

    tinman831 ¯\_(ツ)_/¯
    Administrator Dentist Lifetime Donor Classifieds Approved 10+ Year Member

    Joined:
    Dec 11, 2004
    Messages:
    11,346
    Likes Received:
    72
    Status:
    Dentist

    whoa, you don't have to know the exact steps that occur in the krebs cycle. do you have the kaplan blue book? they do a pretty good job of describing this process. you just have to take it slow, and start from the begining with 1 molecule of glucose, know that in glycolysis it breaks down into 2 molecules of pyruvate which costs 2 ATP. This process produces 4 ATP and 2 NADH


    You don't need to know specifics like the molecules glucose is changed into or the enzymes that catalyze the reaction. The Kaplan blue book does a decent job of describing how it all happens. All the specifics you will eventually learn in biochemistry.
     
  7. joonkimdds

    joonkimdds Senior Member
    7+ Year Member

    Joined:
    Jun 30, 2005
    Messages:
    2,780
    Likes Received:
    2
    Status:
    Pre-Dental
    Ok, so...glucose is break down into 2 pyrovate and this happens because 2ATP becomes 2ADP....but why? :rolleyes:
    I learned that ATP has adenine, ribose and a chain of 3 phosphate.
    when ATP becomes ADP + inorganic phosphate + Energy, that energy goes to another ADP and make it into ATP, and this is all I learned about ATP in the previous chapter. I think that's why I am confused here. why does ATP -->ADP makes glucose break down into 2 pyrovate. I mean...I can just simply memorize as..

    "glucose is break down into 2 pyrovate because 2 ATP becomes 2 ADP(which i don't understand why), then 4ADP becomes 4ATP(i still wonder why) and 2 NAD becomes 2 NADH(I don't know why), so that we end up with 2 pyruavte, 2 ATP and 2 NADH"

    I may gonna look smart if i memorize it that way and get 100 on the test, but none of these really make me understand anything. Am I thinking too much or do you guys think I just have to memorize without questioning any of these becaue kaplan blue book also doesn't really answer my questions and just explain those steps?
     
  8. SMC2UCLA2_

    SMC2UCLA2_ Senior Member
    5+ Year Member

    Joined:
    May 7, 2004
    Messages:
    173
    Likes Received:
    0

    All these questions are indicative of your naivety to biology. This is by no means an insult. If you are majoring in bio you will learn so much more of this stuf over the years and I understand your frusteration now since you taking taking one of the first classes. If you want the answer to most of your questions...major in physiology.

    Where stuff came from is pretty useless to me but for example, the ATP that is used for glycolysis comes from the cytoplasm. It is lingering around in there. When it realeases its highly energized phosphate, it releases energy which can be used to couple an endergonic reaction. I majored in neuroscience and as a senior ive seen this stuff 1000 times.

    At your stage in the game, id focus on understanding that this is what happens and not why it happens like this -that sounds wrong but trust me, if u want to understand why it happens and get nit picky about every single step then you need to go the PHD route and spends years on this.
     
  9. joonkimdds

    joonkimdds Senior Member
    7+ Year Member

    Joined:
    Jun 30, 2005
    Messages:
    2,780
    Likes Received:
    2
    Status:
    Pre-Dental
    Thanks for an advice, i guess i just have to memorize them without asking why whether i like it or not.

    Can i ask one more question?
    I need help on Kreb's cycle, like...what r the products after the entire cycle.
    I know that we start with 2 acetyl COA, but I don't know the product.
    One of the kaplan blue book question asks "what's the product after 10 turns of th e calvin cycle" and the answer is 20 PGAL. I heard of PGAL during the glycolysis but i never read about PGAL during kreb's cycle. Even glycolysis doesn't make PGAL, cuz it's just one of the step to become pyruvic acid. So could u explain to me about this?
     
  10. Gasedo

    Gasedo Senior Member
    5+ Year Member

    Joined:
    Nov 15, 2005
    Messages:
    192
    Likes Received:
    1
    Status:
    Pre-Dental
    You are mixing up Calvin Cycle, which takes place in photosynthesis ( i.e. plants), with Krebs cycle, which takes place in cellular respiration.
    Glycolysis takes place:
    -in the presence of oxygen: Kreb cycle + electron transport in mitochondria
    -in the absence of oxygen: Fermentation in cytoplasm
    Krebs cycle:
    - the conversion of pyruvic acid to acetylCoA links glycolysis and the Kreb cycle, and acetyl CoA is the product that enters the Kreb cycle
    - 1 glucose molecule yields 2 molecules of acetylCoA. THEREFORE 1 GLUCOSE MOLECULE IS ASSOCIATED WITH 2 TURNS OF THE KREB CYCLE.
    - Each turn of the Kreb cycle generates:
    * 1 ATP
    * 3 NADH
    * 1 FADH2
    * 2 CO2
    Now you multiply by 2 b/c as I said 1 glucose = 2 Kreb cycle, and the final output is :

    * 2 ATP
    * 6 NADH
    * 2 FADH2
    * 4 CO2
    This is the only thing that you need to know for the Kreb cycle.
    Hope helps.
    Good luck!
    :luck:
     

Share This Page