Dr. Reichlerπs Bio 301M MWF 9-10am Print Name:______________KEY_________

Mini-exam Sept. 19, 2003

Answer each question as succinctly as possible in the space provided. If needed, continue on the back. If you use a drawing as part of your answer, be sure to also include a written explanation. Read each question carefully and donπt hesitate to ask if a question seems unclear. These questions have specific answers, although for some, more than one answer is possible. To receive full credit you must clearly and fully answer the question being asked. Each question is worth 10 pts, unless otherwise noted, for a total of 100 points possible for this exam.

1. Apply rules 1 and 2 of Strong Inference, to answer the following question: When did humans arrive in North America?

Make at least two hypotheses and one experiment to disprove your hypotheses. EX. Hypos: Humans arrived 5,000 years ago. Humans arrived 10,000 years ago. Humans arrived 15,000 years ago. Expt: Check differences in mitochondrial DNA between Native Americans. Mitochondrial DNA changes about once every 10,000 years. The number of differences in Mitochondrial DNA will determine the time since arrival.

2. Are mitochondria alive? Include how mitochondria fit or do not fit the definition of life.

No. Mitochondria are organized, have metabolism, may or may not respond to their environment, can evolve, but canNOT reproduce themselves.

3. Describe two similarities and three differences between proteins and DNA.

Similarities- Any two of: primarily carbon; covalently bound to other subunit; found in nucleus; found in mitochondria; mutations can alter both

Differences- Any three of: proteins are in the cytoplasm, DNA not; proteins do things, DNA inert; proteins made of amino acids, DNA of nucleotides; proteins have varied 3-d structure, DNA always double helix; proteins are turned over, DNA stable

4. If you were comparing DNA between people, would you expect to find more differences in the genes or non-gene DNA? Why?

Non-gene DNA would likely have more differences because changes in genes would likely cause problems OR there is more non-gene DNA so it is most likely to get changed.

5. What would be the effect on the protein if introns were not spliced from the mRNA?

The protein would not be made correctly, it will have extra amino acids.

6. What is the relationship between DNA packaging and gene expression?

Very tight packaging inhibits gene expression and visa/versa.

7. What happens at the promoter? What protein might be found at the promoter, and what does it do?

Transcription starts at the promoter. RNA polymerase binds there and begins to copy RNA from the DNA.

8. What are two reasons that cells might be expressing different genes?

Any two of: different types of cells need different proteins; the cells may be responding to different environmental conditions; different cells may need to replace or turnover different components.

9. How could differences in gene expression affect the function of a membrane? (6 pts)

Membranes contain proteins for transport across the membrane. By expressing different genes the protein make up of the membrane could be altered. OR The lipids in membranes are produced by proteins, so changing gene expression could change the lipid producing proteins thus changing the lipid make up of the membrane.

10. There was a possibility that the frozen, 5,000 year-old ≥iceman≤ found in the Alps was really a mummy from South America. Could you determine the origin of the ≥iceman≤ by testing his blood type? Why or why not? (4 pts)

No, there are only 4 blood types. So even though there are regional differences in blood types, it would not be definitive evidence for someoneπs geographic origin.

11. What question is Dr. Sykes trying to answer by looking at the DNA of modern Europeans, and why did he choose to study this question in Europe?

To differentiate between the Out of Africa or multiregional origin of Homo sapiens. OR To determine the fate of hunter-gatherers as agriculture was introduced. He studied Europe for its proximity to Africa and Asia, OR for its proximity to his lab in England.