複選題

25. Which of the following is/are NOT a feature of miRNAs?
(A) The enzyme that catalyzes the initial processing of miRNAs in the nucleus is Dicer.
(B) Primary miRNA transcripts have internal complementary sequences capable of forming hairpin structures.
(C) Precursor miRNAs have internal complementary sequences capable of forming hairpin structures.
(D) miRNAs are exported to nuclease in their single-stranded form.
(E)Precursor miRNAs are approximately 60-70 nucleotides long.

複選題21. Which of the following is/are a component of a ribonucleotide? (A) Deoxyribose (B) Phosphate group (C) Uracil (D) Adenine (E) Thymine

複選題22. Which of the following modifications found on amino acids is/are also used to modify nucleic acids? (A) Phosphorylation (B) Glycosylation (C) Methylation (D) Fatty acid modification (E)Hydroxylation

複選題23. Which of the following statements is/are known to be part of signal transduction cascade? (A) phosphorylation of fibronectin (B) dissociation of the components of a heterotrimeric G-protein (C) enzymatic breakdown of phosphatidyl inositol bisphosphate (PIP2) (D) elevation of intracellular [Ca2+] (E)activation of cGMP phosphodiesterase

複選題24. Which of the following is/are characteristic of a eukaryotic enhancer element? (A) It may be found as far as 1 to 2 kilobase from the promoter. (B) Its activity is dependent on its distance from the start site of transcription. (C) It may be positioned at the 5' end or the 3' end of the gene. (D) Its activity is dependent of its orientation. (E)It increases the level of transcription of genes under its control.

複選題26. Which of the following amino acids is/are a target for phosphorylation by a protein kinase? (A) Ala (B) Tyr (C) Arg (D) Thr (E)Asp

複選題27. Which of the following statements about eukaryotic translation is/are FALSE? (A) All polypeptides synthesized by cytosolic ribosomes begin with a Met residue, not an fMet. (B) A special initiator tRNA is utilized for initiation by cytosolic ribomes. (C) Polypeptides synthesized by mitochondrial ribosomes begin with fMet. (D) The 40S ribosomal subunit binds the mRNA before any initiation factors. (E)The eIF2a factor binds to the eukaryotic internal ribosome entry site (IRES).

複選題28. Which of the following is/are NOT an example of a regulatory DNA site? (A) Enhancer (B) Insulator (C) Repressor (D) Operator (E)Activator

複選題29. Below is a map of the pBR322 plasmid, numbers on the map refer to the base where the site is located. Which of the following statements is/are FALSE?(A) If a recombinant plasmid were obtained inserting DNA into the BamHI site, the recombinant plasmid would be resistant to the antibiotic tetracycline. (B) If a recombinant plasmid were obtained by inserting DNA into the EcoRV site, the plasmid will be resistant to ampicillin. (C) If the region between Ndel and PstI were deleted, the resulting plasmid would work well for cloning. (D) If a recombinant plasmid was obtained inserting DNA into the BamHI site, screening for the recombinant plasmid can be plate on nutrient agar plates that contain ampicillin, followed by replica plating on tetracycline. (E) If the plasmid were completely digested with the three restriction enzymes BamHI, Ndel and PstI, the resulting fragments would be 1920, 1312, 754, and 375 base pairs long.

複選題30. Which of the following statements is/are TRUE? (A) Restriction endonucleases can cut DNA and RNA. (B) It is common to use ddNTPs (dideoxyribonucleoside triphosphates) in DNA sequencing. (C) Enzymes that seal nicks in DNA are called ligases. (D) In recombinant DNA technology, a YAC is an enzyme isolated from a large South American four-legged mammal. (E)The "c" in cDNA stands for Circular.

31. Which of the following is/are FALSE about the E. coli Lac operon? (A) It is polycistronic. (B) It is an example of negative control. (C) The presence of lactose acts as an inducer. (D) The repressor binds to the operator. (E)The mRNA for the repressor binds to the operator.