BI 112 Midterm #2

NAME:

This is anopen book, open notesexam. I would rather you did not work together, but I will allow it as long as all answers are in your own words. If you use the same or similar wording as another student or source, you will get a zero on the exam. Carefully read the question and think about your answer before answering it (there are no trick questions but the questions will be challenging). All answers must be typed and turned in by 6/6, email it for one point. Good luck!

  1. Discussin detail the history and fate of a protein that is secreted in mass by exocytosis from a cell. Start with the DNA that codes for the protein in the nucleus, discuss what happens and where it happens at every step of the way until the protein is made, modified, and is finally transported outside the cell.
  2. We are made up of carbohydrates, lipids, proteins, and nucleic acids. Our cells must have these four molecules of life in order to survive. Yet, our genes only code for proteins (most genes) and a few nucleic acids (such as rRNA and tRNA genes). How is it that cells have and/or can make DNA, carbohydrates, and lipids?
  3. Compare and contrast the mitochondria and chloroplasts. Be detailed in your answer, discussing structure and function.
  4. Our body temperature is 98.6 degrees F (37 deg. C). When it is 86 deg. F (30 deg. C) outside, we feel warm or hot even though the temperature is considerably below our body temperature. Explain why we feel hot in detail.
  5. Max Evans is a human-alien hybrid. He has a human appearance and skeleton, but his cells have more of an alien structure. Using what you know of biology, explain why each of his cellular features below is more efficient, less efficient, or the about the same efficiency as human cells. (Be reasonable in your explanationsof why, after all, Max is part human and he lives and functions as a normal human at least most of the time.)
  1. All of Max’s cells generate 38 molecules of ATP/glucose. (Using what you know about aerobic respiration, explain in detail why this is more, less, or the about the same efficiency as human cells.)
  2. His cells are more distinct and much more uniform in size than human cells. (Using what you know about cell size, explain why this is more, less, or the about the same efficiency as human cells.)
  3. His nuclear membraneis not a double membrane; it has only one bilayer like his and our cell membrane.
  4. His nuclear membrane does not disintegrate in mitosis;it instead enlarges in anaphase and splits in two in telophase.
  5. Humans have a regulatory gene that regulates the expression of the alcohol dehydrogenase gene in the liver depending on the presence or absence of ethanol. Max lacks this regulatory gene.
  6. Max has gap junction proteins in both his cell membranes and his organelle membranes.
  7. Max’s mitochondria have three membranes, the outer membrane found in humans, an inner membrane folded in on itself which is also found in humans, and a unique inner most membrane surrounding the mitochondrial DNA.
  8. When Max makes mRNA, only the exons are transcribed.
  9. Max’s cells differ in meiosis, instead of undergoing two rounds of meiosis; Max’s germ cells first undergo one round of mitosis and then one round of meiosis.
  10. Every one of Max’s chromosomes isa hybrid, they appear to be broken alien and human chromosomes that have been put together nearly half and half. It appears that Max’s chromosomes will successfully pair in meiosis with both alien and human chromosomes. This implies that Max and his descendants will be fertile with both humans and aliens.
  1. When discussing enzymes, people use models, such as the lock and key model, the hand and glove model, and the handshake model. Considering how enzymes actually function, which model is the best model? Discuss your reasons why.

  1. An engineer claims that she has created a child robot that is capable of growing and developing in a manner similar to humans, and is capable of generating about 90 ATP molecules from a molecule of glucose. This is about a 100% energy conversion rate. She orders the robot to eat and then perform some heavy work to verify her claim. He/it complies, stopping only once to remove his shirt because he was over heating and otherwise was unable to carry out his orders. Because of your training in Bi102, you are on the panel that investigates. Are you sceptical of her claim of generating 90 ATP molecules/glucose? Why or why not, be detailed in your answer.
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  1. The engineer claims that her child robot harvests energy from food using aerobic respiration. Only instead of burning glucose into CO2 and H2O, the robot first burns glucose to CO2 and H2O, then the robot burns the CO2 and H2O into carbon, oxygen gas, and hydrogen gas. She claims in burning CO2 and H2O, the robot collects extra electrons and hydrogen in the form of NADH and shunts the extra NADH to the electron transport chain of the inner mitochondrial membrane. In this way, the robot’s tissues generate more ATP than is normal for aerobic respiration. Is her claim feasible? Explain your answer using what you know about aerobic respiration.
  2. Assume that the engineer’s claims are valid to answer this last question of the exam (regardless of whether they are or not) and use all the information in the previous questions to answer this one. Is the robot alive? Explain your answer in detail using biology.

12.

  1. The ball of light follows you out as you leave, giving a plaintive meow every once in a while. Is the ball of light alive?
  2. Your skin is coated by oils or lipids to help protect it and help keep it pliable. Lipids are also in your skin cells. Explain why your hands will wrinkle quicker in soapy dishwater compared to when placed in distilled water.

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