Dr. Reichler’s Bio 301L Name:___KEY_____________________

In-class Exam #1 9 Feb 2001

Answer each question as succinctly as possible in the space provided. You may use the back if you need more space. Each question is worth 3 pts, unless otherwise noted, for a total of 70 points, which along with your 30 point take-home gives a possible 100 points for this exam. Read each question carefully, and don’t hesitate to ask if a question seems unclear.

1. Using ONE of the rules of Strong Inference, describe how Cleve Backster (the lie detector analyst who studied plant ESP in his spare time) did or did not follow this rule. Describe the rule and how he did or did not follow it in his experiments. (4pts)

Rule 1, make multiple hypotheses: Not followed, he only had a single hypothesis

Rule 2, design multiple experiments to disprove hypotheses: Not followed, experiments only designed to prove his hypothesis.

Rule 3, carry out experiment to get clean result: Followed, changed the experiments to try and get better/cleaner results.

2. a) As discussed in class, DNA has both covalent and hydrogen bonds, while RNA has only covalent bonds. Why is this so?

DNA has covalent bonds along a strand and H bonds between strands.

RNA is single stranded and so only has covalent bonds.

b) How does radioactivity damage a living cell? Include in your answer what the radioactive molecule does to cause the damage, and how is this translated into cellular damage? (4pts)

Radioactive atoms emit electrons. These electrons can pass through other atoms causing them to be damaged. Also these emitted electrons can cause activated oxygen to form, which will then interact and damage cellular molecules.

c) Enzymes allow chemical reactions to take place in a cell. How do they do this?

By lowering the energy of activation.

d) Enzymes are proteins. Why do high temperatures inactivate most enzymes?

The enzymes/proteins are denatured in high temp, and lose their 3-D structure and thereby their activity.

3. a) What are the 3 types of biomolecules that can be found as part of the nucleus?

Nucleotides, Protein, Lipids

Dr. Reichler’s Bio 301L Name:_______KEY__________________

In-class Exam #1 9 Feb 2001

b) Briefly describe the function of two cell parts from this list: Endoplasmic Reticulum, Golgi Apparatus, Vacuole, Cytoskeleton. (6pts)

ER: processing of proteins.

GA: makes lipids.

Vac: storage of extra stuff (toxins, sugar, water, salts)

Cyto: cell structure and internal and external movement

c) What happens if the cell membrane solidifies? How do cells avoid this problem? (4pts)

The cell will leak and die. Add kinks/double bonds to lipid tails to give more disorder.

4. a) Plant cells have both chloroplasts and mitochondria, while animal cells only have mitochondria. Why is this?

Plants do both photosynthesis and respiration, while animals get their sugar from external sources and then only do respiration.

b) Yeast that utilize the anaerobic respiration pathway are used to ferment grapes to make wine. But this fermentation can only make wine with a maximum of 14% alcohol content. Biologically speaking, why can’t the yeast make wine with a higher alcohol content?

Alcohol is a poison, and too much kills the yeast.

5. a) Rubisco, one of the main enzymes involved in photosynthesis, sometimes makes a mistake. What is this mistake, and under what conditions does Rubisco make this mistake?

Rubisco should use CO2 to make sugar, but soometimes, when CO2 levels are low, it will use O2 instead and NOT make sugar.

b) How do C4 plants avoid this mistake?

They use PEP Carboxylase, which is a specific enzyme for CO2, and they separate the fixing of CO2 in the mesophyll, and the use of CO2 in the Bundle Sheath cells.

 

Dr. Reichler’s Bio 301L Name:_____________KEY____________

In-class Exam #1 9 Feb 2001

c) Where is a common place to find CAM plants?

Desert environment.

6. a) What are two ways in which viruses fit the definition of life? (4pts)

Viruses are: organized, react to their environment, evolve over time

b) What is one way in which viruses do not fit this definition?

Viruses do NOT: reproduce except in cells, acquire energy, have metabolism

7. The coding region of a gene has an important part before and after it. What are these parts, and what do they do? (4pts)

Before, promotor: tells when the gene should be made. After, termination: tells where the coding region ends.

8. a) If a cell has 5 pairs of chromosomes, and it undergoes mitosis. How many cells will there be, and how many chromosomes will each cell have?

2 cells, each with 5 pairs or 10 total chromosomes.

b) Why do organisms that use sexual reproduction need to be diploid?

Because they need to go through meiosis to make haploid cells that can recombine to make a new diploid cell (offspring).

9. a) Vampires are allegedly immortal. How could you identify an adult vampire by screening the proteins present in his or her body? (4pts)

b) Why do vampires need this difference that you identified in 9a? (4pts)