Biology 101 SP08 Exam II(03/26/08)

1.Fats can be broken down into..
  1. amino acids
  2. fatty acids
  3. sugars
  4. nucleic acids
2. Proteins can be broken down into..
  1. amino acids
  2. fatty acids
  3. sugars
  4. nucleic acids
/ 3. Starches can be broken down into..
  1. amino acids
  2. fatty acids
  3. sugars
  4. nucleic acids
4. DNA can be broken down into..
  1. amino acids
  2. fatty acids
  3. sugars
  4. nucleic acids

1 pt

  1. Circle the fatty acids that are most likely to be solid at room temperature (on answer sheet)

1 pt

  1. Why does oleic acid have a kink?

3 pts

  1. The compound to the right has two regions.

a)Circle and label the portion that is hydrophobic.

b)Circle and label the portion that is hydrophilic.

c)Explain why you chose the hydrophilic region.

The following text is an excerpt describing the action of a specific type of molecule in the cell (bold underlined protein, figure at right). Read the excerpt, look at the diagram and answer the questions below. The goal of this question is to test your ability to pick out information that you already know from technical text. There are a lot of words you don’t need to know to answer the problem.

When a ligand activates the G protein-coupled protein, it induces a conformation change in the protein (a change in shape) that allows the protein to function as a guanine nucleotide exchange factor (GEF) that exchanges GTP in place of GDP on the Gα subunit. In the traditional view of heterotrimeric protein activation, this exchange triggers the dissociation of the Gα subunit, bound to GTP, from the Gβγ dimer and the protein. However, models that suggest molecular rearrangement, reorganization, and pre-complexing of effect rmolecules are beginning to be accepted. Both, Gα-GTP and Gβγ, can then activate different signaling cascades (or seconaryd messenger pathways) and effector proteins, while the protein is able to activate the next G protein.

  1. Based on the figure, what structure in the cell is this protein located?

a)Actin filament

b)Cell membrane

c)Chromosome

d)Ribosome

1 pt

  1. What is the type of protein (based upon its role in signal transduction) described in the text?

2 pts

  1. Where does the signaling cascade send information and what happens when the signal arrives?

(two short answers please)

1 pt

  1. Why would a cell need mitochondria for the reactions above?
    9 pts
  2. Testing a signal transduction model: A scientist has proposed the following signal transduction model for the formation of root nodules in plants (N-fixing bacteria grow in some plant roots and provide NH3 in exchange for carbon). The infection thread is a change in the cell structure that allows N-fixing bacteria to enter the cell. Once again there is more information than you need in this model. As a student in the scientists lab you have been asked to design an experiment using gene deletionto test a portion of the model. (note you can delete genes that are not shown in the model and use other techniques such as GFR in your experiment)

a)Identify the portion of the model you are testing (you can only test a small portion of the complete model).

b)State your null and alternative hypotheses

c)State your dependent and independent variables

d)Show the results of your experiment if 1) the model is supported and if 2) the model is not supported. (picture of a slide or compounds production, be sure to show the results of the experiment, do not redraw the model)

There is at least one gene that increases susceptibility of individuals to Parkinson’s. The parkinson’s gene variant has two different nucleotides than the wild type (normal). Each mutation resulted in a change of one amino acid.

Circle the mutation type and effect below.

13. Mutation Type
  1. Point
  2. Insertion
  3. Delection
/ 14.Mutation Effect
  1. silent mutation
  2. missense mutation
  3. nonsense mutation
  4. frameshift mutation

4 pts

15. You are a scientists trying to figure out if the Parkinson’s gene is rescessive or dominant. What is the probability that the progeny of two heterozygous parents would have a child susceptible to Parkinson’s disease if.. Show the genotypes linked to the phenotypes for each condition

  1. The trait is dominantb.The trait is recessive.

5 pts

16. In a science fiction book written by Heinlen (Space Cadet), space ships have plants on board to provide food and oxygen for the astronauts. In one chapter of the book Heinlen describes a ship in which all of the crew dies but the plant growth chambers continue to function, however in the book the plants died because they ran out of CO2.This is a misconception. Why wouldn’t the plants run out of CO2?

Using your knowledge of cell biology and the carbon cycle answer the following questions.

a)Draw a picture of a plant cell showing the processes and organelles that process CO2 and O2. Include all inputs and outputs for each process and show how they are connected.

b)Draw a graph predicting the change in CO2, O2 and glucose production over time after the death of the astronauts. (The astronauts died and decomposed during the gray portion of the graph)

c)Use your model and your knowledge of the carbon cycle to explain your predictions.

1