1. How do the titration curves differ between nonionizable and ionizable R groups? Why

2.Is the pKa of a Histidine side chain always the same as that of the free amino acid? Why or Why not?3. What is eliminated when two amino acids are combined to form a dipeptide?

Biochemistry

9. The major site of amino acid metabolism is the liver. One of the initial reactions in amino acid metabolism is the transamination. a. What are the two major transaminases in the liver? Write balanced equations for the reactions catalyzed by these two enzymes. b. What is the main physiological function of glutamate dehydrogenase with respect to amino acid metabolism? Write a chemical equation for the reaction catalyzed by this enzyme.c. What is the role of glutamine synthetase in amino acid metabolism? Write the reaction catalyzed by this enzyme. Include all the substrates, products and cofactors.

\Match the following descriptions with the corresponding amino acids:

This amino acid is responsible for the strength of rhino horns and wood lignin due to the strong hydrophobic interactions between them.

Subtle decreases in the serum pH lead to the protonation of this amino acid, which promotes O2 release from hemoglobin.

This amino acid is the nucleophile chymotrypsin uses to attack peptide bonds.

This amino acid disrupts α-helices because it makes the nearby protein backbone too flexible (and prevents proper hydrogen bonding).

This amino acid is believed by some to make you sleepy because it can be converted by our body into serotonin and melatonin.

This amino acid gives the titration curve shown below and it is not arginine.

The phosphorylation of this amino acid often signals for cells to grow and divide (its permanent phosphorylation could contribute to cancer).

This amino acid is added to food as a flavor enhancer because it excites neurons.

The hydroxylated version of this amino acid is essential to collagen synthesis. This amino acid forms disulfide bonds.

1, DNA polymerase a. adds new nucleotides to a strand. b. proofreads DNA strands to see that they are correct. c. makes rare mistakes resulting in mutation. d. is an enzyme. e. is all of thes

2.The three “stop” codons cause what to happen? a. They cause the ribosome to stop building a protein. b. They instruct ribosomes to build proteins. c. They initiate DNA replication. d. They code for three amino acids.

3 True-False. Messenger RNA is the same length as the entire chromosome. True False In transcription in eukaryotic cells, RNA polymerase: a. cannot function until the two sides of the entire chromosome have completely separated. b. 5′ caps are removed from the messenger RNA. c. needs RNA primase to lay down 5-10 RNA nucleotides as a primer. d. cuts the hydrogen bonds holding together DNA base pairs A-T and G-C.

4.Which is FALSE concerning a codon? a. a single codon never codes for more than one amino acid. b. two or more codons may code for the same amino acid. c. codons are unique to each species. d. a single codon consists of three nucleotides.

5,The anti-codon of individual transfer RNA molecules is a. the part of transfer RNA that bonds to a specific amino acid. b. complementary to the corresponding codon in ribosomal RNA. c. complementary to the corresponding codon in messenger RNA. d. the “stop” codon

which ends translation of an mRNA strand.

Complete the chart below.

DNA mRNA

                                  5 ’                                3’

                                            T   --

                                            T   --   

                                            A   --

                                            C    ---   

                                          G   ---

                                            G    ---

                                            C    ---

                                            A   --   

                                          T   --   

                                  3’                                 5’

Re-state the mRNA strand, write it in the 5’ to 3’ direction. Answer the following questions.

mRNA strand:   5’ __________________________ 3’

8. What is the first codon on the mRNA strand?

9. What is the anticodon for the tRNA at the P site?

10. What amino acid is this tRNA bringing?

11. What is the second codon on the mRNA strand?

12. What is the anticodon for the tRNA at the A site?

13. What amino acid is this tRNA bringing?

14. What forms between the two amino acids? Use the exact name of the union.

15. What is the third codon on the mRNA strand?

16. What is the anti-codon for the tRNA that will bind to the A site? Explain your answer.

17. What is the amino acid sequence of your peptide? Include STOP in your sequence.

18. How many kinds of codons exist in the Universal Code?

19. How many codons actually code for an amino acid?

20. What do the others code for?

21. How many different kinds of amino acids are coded for in the Universal Code?

Explain how the concept of translational fidelity is hijacked in the following cases: by bacteria in the evolution of stop suppression, and by scientists in the incorporation of unnatural amino acids.

protection factors provide information on the stability of individual amino acids in proteins. why is the determination of protection factors not possible using HDX-MS?

1. If muscle-derived amino acids are used for gluconeogenesis, why does the rate of glucose output by the liver slow during prolonged starvation?