英文试题

生物化学试题 英语部分

I. Write down the relevant Chinese names:

1. NADP    2. ssDNA & dsDNA.    3. GSSG   4. IMP & UMP  5. SSB       6. UDPG    7. Trp & TPP        8. ctDNA & mtDNA   9.snRNA & hnRNA 10. Cm & m₃^2，2，7G  11. PAGE  12. SDS

II. Explanations:

1. Protein conformation             2. Enzyme activity  3. DNA melting temperature          4. Okazaki fragments  5. Degenerate codon                 6. lac operon model

7. zinc finger-                      8. signal peptide

III. Multiple choices:

1. A solution at pH 6 contains             H⁺ than the same amount of solution at pH 8.
a. 2 times more   b. 4 times more   c. 100 times more   d. 4 times less   e. 100 times less

2. What is the net charge on glycine at a pH of 6.5?

a. -2      b. +1       c. 0       d. -1       e. +2

3. Which of the following amino acid residues may participate in hydrophobic bonding in a globular protein?

a. Glycine    b. Aspartate     c. Lysine      d. Serine      e. Phenylalanine

4. Which of the following amino acids may participate in the formation of covalent crosslinks that stabilize the tertiary structure of many globular proteins?

a. Cysteine      b. Methionine       c. Serine     d. Leucine          e. Histidine

5. A can of cola consists mostly of sugar dissolved in water, with some carbon dioxide gas that makes it fizzy and makes the pH less than 7. In chemical terms, you could say that cola is an aqueous solution, where water is the        , sugar is a       , and carbon dioxide makes the solution      .
a. solvent…… solute…… acidic        b. solute…… solvent…… basic       c. solvent…… solute…… basic      d. solute…… solvent…… acidic  

6. Which of the following clues would tell you whether a cell is prokaryotic or eukaryotic?
a. whether or not the cell is partitioned by internal membranes            b. the presence or absence of a rigid cell wall
c. the presence or absence of ribosome               d. whether or not the cell carries out cellular metabolism       e. whether or not the cell contains DNA

7. Which of the following processes changes of enzymatic activity in an irreversible manner?

a. allosteric activation     b. phosphorylation       c. zymogen activation      d. coenzyme activation            e. competitive inhibition

8. An allosteric inhibitor of an enzyme usually

a. binds to the active site.      b. participates in feedback regulation.      c. denatures the enzyme.     d. is converted to an allosteric product.

9. The quaternary structure of hemoglobin is

a. not important for the functioning of this protein.      b. rigid and is not affected by oxygen binding.

c. maintained by hydrophobic, ionic, and hydrogen bonds.       d. stabilized by glycosidic bonds.       e. similar to that of myoglobin.

10. The nucleotide sequence of a DNA codon is GTA. A messenger RNA molecule with a complementary codon is transcribed from the DNA. In the process of protein synthesis, a transfer RNA pairs with the mRNA codon. What is the nucleotide sequence of the tRNA anticodon?

a. CAT b. CUT c. GUA       d. CAU e. GTA  

11. Which of the following correctly ranks the structure in order of size, from largest to smallest?

a. gene-chromosome-nucleotide-codon     b. chromosome-gene-codon-nucleotide    c. nucleotide-chromosome-gene-codon
d. chromosome-nucleotide-gene-codon      e. gene-chromosome-codon-nucleotide

12. Which of the following statements connecting genetic code is FALSE?

a. all 64 codons have function.       b. in some cases, more than one amino acid will be encoded by the same codon.
c. in some cases, more than one codon will base-pair with the same anticodon .    d. in some cases, more than one codon will code for the same amino acid.

13. During replication, DNA structure becomes disrupted. Between which parts of the molecule do the bonds break?

a. between deoxyribose and phosphate      b. between uracil and adenine    c. between the hydrogen-bonded base pair    d. between phosphate and thymine

14. Which of the following enhances separation of DNA strands during replication?

a. helicase     b. single-stranded DNA binding protein         c. DNA ligase     d. primase

15. Polymerization of lagging strand

a. requires a different DNA polymerase that used for the leading strand.                b. proceeds via the generation of Okazaki segments.
c. occurs more slowly than polymerization of the leading strand.                         d. does not require primase.

16. Transcription is the process by which

a. DNA is copied so that double stranded molecule becomes two.       b. mRNAs, tRNAs and rRNAs are produced.
c. RNA is modified so that it can be translated.                                         d. protein is produced

15. In eukaryotes, pre-mRNA must be processed to allow proper translation. These alterations include all of the following EXCEPT:

a. antitermination.      b. polyadenylation.     c. RNA capping.   d. RNA splicing.

18. Which of the following processes produces the most ATP molecules per glucose molecule consumed?

a. lactic acid fermentation        b. the Krebs cycle              c. glycolysis                   d. alcoholic fermentation

19. In glycolysis,          is oxidized and              is reduced

a. NAD⁺……glucose       b. Glucose……oxygen              c. ATP……..ADP          d. Glucose……NAD⁺

20. At a pH more acid than its isoelectric point, an amino acid will carry

a. no ionic charge         b. a net positive charge       c. a net negative charge.    d. a positive charge equal to the negative charge.

21. Which of the following amino acid residues may participate in hydrophobic bonding in a globular protein?

a. Glycine               b. Aspartate                             c. Lysine                d. Phenylalanine

22. Which of the following processes changes of enzymatic activity in an irreversible manner?

a. allosteric activation      b. phosphorylation         c. zymogen activation      d. competitive inhibition

23. An allosteric inhibitor of an enzyme usually

a. binds to the active site.   b. participates in feedback regulation.   c. denatures the enzyme.   d. is converted to an allosteric product.

24. Sigma factor is involved in which of the following processes?

a. termination of protein synthesis.   b. stable binding to promoters by RNA polymerase     

c. termination of transcription by RNA polymerase

d. regulation of transcription at the lac operon in response to glucose levels

25. During replication, DNA structure becomes disrupted. Between which parts of the molecule do the bonds break?

a. between deoxyribose and phosphate     b. between uracil and adenine    c. between the hydrogen-bonded base pair    d. between phosphate and thymine

26. Which of the following enhances separation of DNA strands during replication?

a. helicase          b. single-stranded DNA binding protein         c. DNA ligase        d. primase

27.  The pentose phosphate pathway serves all of the following purposes in metabolism EXCEPT

a. a source of ribose-5-phosphate.     b. a source of NADPH     c. a source of pyruvate   d. an alternate way of oxidizing glucose

IV. Questions:

1. Is there an amino acid that is always used to start protein synthesis? If yes, which one and is it found on the C or N-terminus of the synthesized protein?

2. According to Michaelis-Menten model, how do K_m and V_max will change in the reversible competitive inhibition?