31. Which statement of ribosome is INCORRECT?
(A) Ribosomes are composed of rRNA and ribosomal proteins
(B) tRNA can enter the ribosome and bind to the messenger RNA via an anti-codon stem loop
(C) The start codon in all mRNA molecules has the sequence UAG
(D) The A-site binds to an aminoacyl-tRNA
(E) The ribosome assembles on the start codon, located within the Kozak sequence in eukaryotes.

27. Jennifer ordered the primers for the PCR reaction and received dried oligos in the tubes. She got 30 nanomoles (nmol) oligos of the forward primer, and 25 nanomoles (nmol) oligos of the reverse primer. She would like to the prepare stock solution in 100 nM. How much water should be added into the tubes to make the stock solutions for these primers? (A)300 µl for the forward primer, 250 µl for the reverse primer (B) 30 µl for the forward primer, 25 µl for the reverse primer (C) 3 ml for the forward primer, 2.5 ml for the reverse primer (D)3 µl for the forward primer, 2.5 µl for the reverse primer (E) 30 ml for the forward primer, 25 ml for the reverse primer

28. Which statement of post-translational modification is INCORRECT? (A) Phosphorylation is very common mechanism for regulating the activity of enzymes. (B) Ubiquitylation is usually associated with protein degradation. (C) SUMOylation plays a role in the major DNA repair pathways. (D) O-linked glycosylation is the attachment of a sugar molecule to the oxygen atom of serine or threonine residues in a protein. (E) Acetylation is usually on a glycine residue.

29. Which statement of enhancer is INCORRECT? (A) A region of DNA that can be bound by activators to increase the transcription. (B) It only can be found in eukaryotes. (C) Enhancers can be transcribed into RNAs called enhancer RNAs. (D) The active enhancers are usually in euchromatin. (E) H3K27ac is usually found in an active enhancer.

30. What statement of autophagy is INCORRECT? (A) Apoptosis is associated with the appearance of autophagosomes. (B) Autophagy is the nature, conserved degradation mechanism that removes dysfunctional components. (C) It goes through a lysosome-dependent mechanism. (D) Nutrient starvation usually represses autophagy. (E) Autophagy can contribute to cancer by promoting survival of tumor cells.

32. What statement of transposon is INCORRECT? (A) Transposable elements make up a large fraction of the genome in eukaryotic cells (B) Retrotransposons (Class I) are transcribed from DNA to RNA, and the RNA is then reversed transcribed to DNA (C) DNA transposons (Class II) function via reverse transcription (D) DNA transposons encode the protein transposase (E) A DNA sequence that can change its position within a genome

33. What statement of non-coding RNA is INCORRECT? (A) miRNA, piRNA and ribosomal RNAs are non-coding RNAs (B) The size of long non-coding RNA is above 200 bp (C) Non-coding RNAs are not found in prokaryotes (D) Genes encoding non-coding RNAs are not as conserved as coding genes (E) Non-coding RNAs can regulate gene expression

34. What statement of mitosis is INCORRECT? (A) Prophase-chromatin fibers condense into chromosomes (B) Prometaphase-microtubes begin to search and attach to kinetochores (C) Metaphase--chromosomes are aligned along the metaphase plate (D) Anaphase-the cohesins that bind sister chromatids together are cleaved (E) The mitosis phase is a relatively long period of the cell cycle

35. Which of the following is a neurotransmitter? (A) Glutamate (B) GABA (C) Acetylcholine (D) Dopamine (E) All of above

36. What are minimal features of yeast artificial chromosomes (YAC)? 1. Centromere  2. Promoter 3. Coding genes  4. Telomere  5. Replication origin (A) 1, 2,3 (B) 1,4,5 (C) 2,3 (D) 1,4 (E) 1,2,3,4

37. Which statement of DNA replication is INCORRECT? (A) Okazaki fragments are short DNA fragments that bind to lagging strand (B) Primase add RNA primers onto lagging strand (C) DNA ligase I connects Okazaki fragments (D) Proliferating cell nuclear antigen (PCNA) is a DNA clamp that acts as a processivity factor for DNA polymerase in eukaryotic cells (E) Flap endonuclease 1 (FENI) is responsible for removing RNA primer of an Okazaki fragment