Name:_______________________

(3 pts)

ENST 2101: Environmental Biology

Exam 1—100 pts

1. The picture here is an actual photo of the inside of a cell, showing the edge of a cell’s nucleus. First, tell me the basic summary of the central dogma of molecular biology:

Then show me where the steps in the central dogma actually take place by drawing on the picture. (10 pts total)

2. You gotta eat… (15 pts total)

Life on earth is centered around carbon-based molecules. The first carbon-based life forms did not capture solar energy. Instead they most likely lived off of the energy stored in energy rich molecules that were abundant in the oceans of the ancient world, but are rare in the oceans of today.

For example, the ancient oceans were filled with a natural energy rich molecule called acetate (CH₃COOH). Even today, some very primitive bacteria live directly off of acetate produced by non-biological processes. They subsist by ingesting acetate and carrying out the following reaction:

Acetate à CO₂ + CH₄ + energy.

a. The above pathway is analogous to what energy releasing reaction carried out by plants and animals in the presence of oxygen? ____________________________ (2 points)

b. What takes the place of acetate in this more common reaction I am referring to? (2 points)

d. What is the overall formula for this more common aerobic reaction? (6 points)

e. Why carbon? Make a plausible argument for why life on earth is carbon based. (5 pts)

3. Why you eat… (15 pts)

Let’s say you want to build yourself a protein. If you are a living thing, you are probably going to use the energy found in glucose to drive the project. Explain in words how the breakdown of glucose is coupled to the building of a protein energetically through the series of reactions shown on this diagram. First label the diagram. Make sure you tell me what happens to energy at each step of the process.

4. Define and tell me the significance (for this class) of each of the following terms. Use two sentences. More than two and I will get annoyed. (4 pts each—32 pts total)

a. Activation energy

b Covalent bond

c. Isotope

d. Endergonic reaction

e. Lysozomes

f. Active transport

g. Entropy

h. Dehydration synthesis

5. What is the important difference between cellulose and starch? Why is it important? (5 pts)

6. Explain, with words and a diagram, how irrigation can lead to long term damage to a farm field. (10 pts)

7. What are some of the basic difference between eukaryotic and prokaryotic cells? Do most people consider themselves to be eukaryotes or prokaryotes? Which cell type is more abundant in the human body? (5 pts)

8. Explain why phospholipids are a good material for living things to use in constructing their cell membranes. (5 pts)

9. For 2 extra credit pts….

What are the crazy European Scientists who run the CERN Supercollider looking for?