Biology 115, Fifth Quiz: 18 April 2000

A. Multiple choice questions: 0.5 points each.

• 1. Crossing-over occurs during
  • (a) both divisions of meiosis and during mitosis.
  • (b) the second division of meiosis.
  • (c) mitosis.
  • (d) the first division of meiosis.
  • (e) both divisions of meiosis.
• 2. Suppose a sex-linked recessive trait, carried on the X chromosome, carries no strong survival preference. If this trait is present with frequency f in males, at what frequency will it appear in females?

(a) f; (b) greater than f; (c) less than f but nonzero; (d) zero.

• 3. The process by which an RNA strand is created from DNA is called

(a) translocation; (b) transpiration; (c) transcription; (d) translation; (e) intercession.

• 4. In eucaryotes, messenger RNA is processed after it is synthesized. How?
  • (a) extra nucleotides are added as it passes out of the nucleus
  • (b) nucleotides are deleted as it passes out of the nucleus
  • (c) extra nucleotides are added at the ribosome.
  • (d) nucleotides are deleted at the ribosome.
• 5. Which of the following is not one of the common types of ribonucleic acid?

(a) messenger; (b) transfer; (c) ribosomal; (d) memory.

• 6. A cell that lacks an active p53 gene will be likely to act as a
  • (a) clonal precursor to a tumor due to suppression of apoptosis.
  • (b) tumor suppressor due to enhancement of apoptosis.
  • (c) clonal precursor to a tumor through suppression of killer T-cell activity.
  • (d) tumor suppressor through enhancement of killer T-cell activity.

B. Definitions: 0.5 points each.

Provide a one-sentence definition for each word or phrase.

• 7. polar body.
  
  
  
  
  
• 8. codon.
  
  
  
  
  

C. Reverse Definitions: 0.5 points each.

Match the terms to these definitions.

• 9. ___________ Half the diploid number; the number of chromosomes in the gametes.
  
  
• 10. __________ Normal gene involved in cell growth and differentiation that becomes an oncogene through mutation.

D. Fill in the blanks: 0.5 point each.

• 11. Meiosis in males is part of ___________; meiosis in females is part of ___________.
  
  
• 12. Cancer cells lack ____________; that is, they are unspecialized. They often have
  
  abnormal ______________ and induce ______________, i.e. the production of new blood vessels.

E. Short answers: 1 point each.

Provide a one-sentence answer for each question.

• 13. (Chapter 18, "Applying your knowledge to the concepts," #4):
  Normally, the two cells that result from the first mitotic division of the zygote stay together. If, instead, the two cells separate and each develops on its own, what is the result?
  
  
  
• 14. (a) Write out the base sequence of the DNA strand that is complementary to the following template strand: 5'-A-C-C-G-A-T-A-T-G-T-A-T-C-C-T-A-G-G-3'
  
  
  (b) What tRNA anticodons would be produced from the template strand?
  
  
  

F. Full-paragraph answer: 2 points.

Answer either of the following two questions. If you answer both, you will receive credit for neither.

• 15. Dr. Howard's mother has type O- (i.e. type O, Rh negative) blood; his older sister has type A+ blood. Dr. Howard himself has type B+ blood.
  • (a) What blood type is Dr. Howard's father? Why?
    
  • (b) What difference between Dr. Howard and his mother's blood type is likely to have caused problems immediately after birth? Why?
    
• 16. A study was conducted in the 1960's of the incidence of lung cancer among four groups: uranium miners who smoke, uranium miners who do not smoke, non-miners living in the same region who smoke, and non-miners in the region who do not smoke. The study showed that nonsmoking miners are almost exactly as likely to contract lung cancer as nonsmoking non-miners. Smoking non-miners show a higher incidence of lung cancer than either group of non-smokers. Smoking miners show the highest incidence of lung cancer of any of the groups. Explain this finding. Include in your answer some mention of the multi-stage (two- or three-stage) model of carcinogenesis.