help me with some college biology?

Posted on 2015-09-14 06:45:00 in Biology by ADRINA

1. Which one of the following is an example of potential energy?
A. light
B. heat
C. wind
D. an electrochemical gradient
E. a moving muscle

2. Consider three different enzymes (identified as 1-3, below), each of which has a unique complement of three amino acids that are crucial for the binding of the substrate at the active site. Select from choices A–D the characteristic you would predict a substrate would possess that would bind to an active site where these amino acids are present. (Consult Figure 4.2 from Chapter 4 to help you make your predictions.)
1. Enzyme 1: leucine, tryptophan, and alanine.
2. Enzyme 2: threonine, serine, and glutamic acid.
3. Enzyme 3: arginine, lysine, and histidine.
A. hydrophilic, with a positive charge
B. relatively hydrophobic
C. hydrophilic, but without a charge
D. hydrophilic, with a negative charge

3. The sodium/potassium pump is an example of:
A. channel-mediated diffusion.
B. an antiporter.
C. None of these choices is correct.
D. a symporter.
E. passive transport.

4. Complete the matching exercise below by choosing whether mitochondria are present in the following organisms.
1. Plants
2. Animals
3. Bacteria
A. Yes
B. No

5. Complete the matching exercise below by choosing the correct number of membranes for mitochondria and chloroplasts.
1. Mitochondria
2. Chloroplasts
A. Two membranes.
B. Three membranes.

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