Plant Cell pH Regulation and Organic Acid Storage

Name : Course : 1. If organic acids accumulate in plant cells in sufficient quantity to significantly affect the cell's pH, then they are likely to be stored in…. A. cytosol B. vacuole C. nucleus D. mitochondria E. chloroplasts 2. Which of the following information can be obtained from determining the primary structure of an enzymatically active protein? A. The amino acids in the active site can be positively identified. B. The molecular weight of the protein can be accurately determined. C. The temperature at which thermal inactivation will occur can be determined accurately. D. Estimated Km can be calculated. E. An estimate of Vmax can be calculated. Use the following information to answer question no. 3-7 3. There is some debate about whether increased expression of a gene will always occu in line with the codon usage bias (the type of codon that is more often used by an organism to code for a particular amino acid from various possible codon variations) that the gene has, or there are other factors from the nucleotide composition of the gene that also play a significant role in influencing its expression. . Researchers have long suspected the importance of the N-terminal region of a gene in influencing expression levels. In various different observations, this is often associated with the presence of conserved sequences, the use of rare codons, or a tendency to form secondary structures in the N-terminal region. An experiment was carried out by varying the 10 start codons of a Green Fluorescence Protein using the codon wobble mutation method (codons where the third base does not always follow the Watson-Crick rule) and observing changes in gene expression levels based on a number of parameters related to variations in base composition. The codon wobble mutation method was used to avoid possible changes in the primary structure of the GFP protein which could affect the level of gene expression 4. Determine the expected nucleotide base composition of the GFP gene wobble codon mutant library (N = all bases, Y = pyrimidine, R = purine) A. AUN AGN AAN GGN GAN GAN CUN UUN ACN GGN B. AUG AGR AAY GGN GAY GAY CUN UUR ACN GGN C. NUG NGC NAA NGU NAA NAA NUG NUU NCC NGU D. AUG AGN AAR GGN GAR GAR CUR UUY ACN GGY E. AUG AGY AAR GGN GAR GAR CUN UUY ACN GGN 5. A mutant library of 10 start codons of the GFP protein was generated using the PCR site directed mutagenesis method using degenerate primers in the area to be mutated. PCR was optimized at different annealing temperature conditions. Below is a diagram of the DNA electrophoresis results of the PCR product 6. Which of the following criteria is not used to determine the codon usage bias of an organism? A. Type of codon used by highly expressed genes B. conserved codons found in the promoter region of a gene C. tRNA copy number of a codon D. the percentage of use of a codon from an organism's genome E. the type of codon used by ribosomal protein genes 7. Based on the results of the research above, predict at what stage gene expression is influenced by variations in the N-terminal sequence A. Initiation of translation B. Translational elongation C. Termination of transcription D. mRNA splicing E. DNA replication 8. Which of the following cellular structures provides similar functions between plants and animals? Plants A. B. C. D. E. Tight junctions Desmosomes Plasmodesmata Plasmodesmata Plasmodesmata Animals Gap junctions Gap junctions Gap junctions Desmosomes Tight junctions 9. In nerves, vesicles can move along axons at rates that far exceed those predicted for simple diffusion. Which of the following models best explains vesicle movement in these cells? A. Depolymerization of actin microfilaments bound to the vesicle pulls the vesicle toward the site of depolymerization. B. Vesicles are propelled by fluid movement produced by changes in osmotic potential within the cell. C. Vesicles are moved by alternating contraction and relaxation movements of the actinmyosin complex. D. Vesicles, because of their net negative charge, are attracted by the positively charged parts of the cell. E. Vesicles are pulled by the protein kinesin, which slides along microtubules by an ATPdependent process. 10. Adding or subtracting bases to the nucleotide sequence of a structural gene will produce...... A. a change in the amino acid sequence of the protein coded for by the gene. B. insertion of a new intron in the gene coding sequence. C. decreased histone binding. D. decreased DNA repair. E. increased levels of mRNA production