3. Which one of the following amino acid side chains can be used in acid-base catalysis?
(A) Glycine.
(B) Histidine.
(C) Leucine.
(D) Valine.
(E) Alanine.

199. What does Anna expect from Blue Wave Travel in response to her email? (A) Anna demands a full refund for the Summer Island travel package due to a lack of advertised services and compensation for the inconveniences she faced. (B) Anna expects a discount on future travel packages as a token of appreciation for her feedback and experience. (C) Anna wants an apology and a gift card for her troubles during the Summer Island travel package. (D) Anna wants a free trip to another destination of her choice as compensation for the inconveniences she faced during the Summer Island travel package.

200. Which of the following statements is incorrect regarding the email from Blue Wave Travel to Anna about her Summer Island travel package? (A) The email apologizes for the unsatisfactory travel experience. (B) The email offers a half refund of Anna's travel expenses. (C) The email asks Anna to book another trip with Blue Wave Travel. (D) The email provides a breakdown of Anna's travel expenses and the discounted price

1. In Base Excision Repair, the enzyme to act is a_________. (A) gyrase (B) AP endonuclease helicase (C) dam methylase (D) helicase (E) DNA glycosylase

2. Glycogen phosphorylase can be regulated by_________. (A) glycosylation (B) phosphorylation (C) methylation (D) ADP ribosylation (E) acetylation

4. Which of the following amino acid residues of a protein is involved in ubiquitinylation? (A) Asparagine. (B) Aspartic acid. (C) Lysine. (D) Arginine. (E) Histidine.

5. For the double-strand break repair of DNA, several proteins are directly involved, such as_______ . (A) cyclins (B) globulin (C) histone protein (D) DNA-dependent protein kinase (E) DNA primase

6. Please estimate the molecular weight (g/mole) of a plasmid DNA of E. coli that contains 3000 base pairs.(A)2.20 x 105(B)7.00 x 105 (C) 1.26 x 106 (D) 1.89 x 106 (E) 2.52 x 106

7. For different IgG molecules, antibody diversity is generated by_____. (A) alternative splicing of the RNA transcripts (B) highly regulated expression of one thousand differently antibody genes (C) post translational modification of antibody genes (D) somatic recombination and somatic mutations of antibody genes (E) intron shuffling of antibody genes

8. Tay-Sachs disease is caused by deficiency of_____. (A) ceramidase (B) sphingomyelinase (C) beta-galactosidase (D) hexaminidase A (E) alpha-fucosidase

9. Which amino acid is the substrate for NO synthetase to form nitric oxide (NO)? (A) Glutamine. (B) Arginine. (C) Asparagine. (D) Histidine. (E) Proline.