1. 1. A mutation occurs at the midpoint of a gene, altering all amino acids encoded after the point of mutation. Which mutation could have produced this change? A. Deletion of two nucleotides b. Deletion of three nucleotides c. Insertion of six nucleotides d. Insertion of twelve nucleotides

2. a. Deletion of two nucleotides

3. 2. Look at the picture below
2. Look at the picture below. Which of the following correctly identifies the processes occurring at A and B? a. replication and transcription b. transcription and translation c. translation and transcription d. transcription and replication

4. b. transcription and translation

5. 3. If a species contains 23% adenine in its DNA, what is the percentage of guanine it would contain? A. 46% b. 25% c. 23% d. 27%

6. d. 27%

7. 4. Which is most directly responsible for the sequence of amino acids in a protein? A. The sequence of codons in mRNA. B. The number of codons in mRNA. C. The proteins associated with rRNA. D. The sequence of the anti-codons.

8. A. The sequence of codons in mRNA.

9. Questions 5–6 refer to the mRNA sequence CUC–AAG–UGC–UUC and the table below, which lists mRNA codons.

10. 5. Which of the following would represent the sequence of DNA from which the mRNA sequence (CUC–AAG–UGC–UUC) was made?
a. CUC–AAG–UGC–UUC
b. GAG–UUC–ACG–AAG
c. GAG–TTC–ACG–AAG
d. AGA–CCT–GTA–GGA

11. c. GAG–TTC–ACG–AAG

12. 6. Which of the following represents the portion of the protein molecule coded for by the mRNA sequence CUC–AAG–UGC–UUC ?
a. serine–tyrosine–arginine–glycine
b. valine–aspartic acid–proline–histidine
c. leucine–lysine–cysteine–phenylalanine
d. glutamic acid–phenylalanine–threonine–lysine

13. c. leucine–lysine–cysteine–phenylalanine

15. 7. What is the control variable in this experiment?
a. No hormone
b. Hormone A
c. Hormone B
d. Hormone A and B

16. a. No hormone

17. 8. What can you conclude about the effect Hormone B has on the rate of gene transcription compared to the control treatment?
a. It increases gene transcription rate.
b. It decreases gene transcription rate.
c. It does not change gene transcription rate compared to the control.
d. It has a smaller effect on transcription rate than Hormone A does.

18. c. It does not change gene transcription rate compared to the control.

19. 9. Explain how RNA differs from DNA.

20. DNA has the sugar deoxyribose, RNA has ribose
DNA is double-stranded, RNA is single-stranded
DNA is in a double helix, RNA is not
DNA is found inside the nucleus, RNA is found inside and outside the nucleus
DNA has thymine, RNA has uracil

21. 10. Compare the roles of mRNA and tRNA in the making of a protein.

22. mRNA takes the instructions for making a protein from the nucleus to the ribosome, while tRNA brings amino acids to the ribosome