I have questions about cell biology.;1. Which of the following statements about nuclear transport is true? (I chose a);a. mRNAs and proteins transit the nucleus through different types of nuclear pores.;b. "Nuclear import receptors bind to proteins in the cytosol and bring the proteins to the nuclear pores, where the proteins are released from the nucleus.;c. "Nuclear pores have water-filled pass through in a nonselective fashion.;d. Nuclear pores are made up of many copies of a single protein.;2. Which of the following statements is true? (I chose d);a. "DNA molecules, like proteins, consist of a single, long polymeric chain that is assembles from small monomeric subunits.;b. The polarity of a DNA strand results from the polarity of the nucleotide subunits.;c. There are five different nucleotides that become incorporated into a DNA strand.;d. Hydrogen bonds between each nucleotide hold individual DNA strands together.;3. What is the role of the nuclear localization sequence in a nuclear protein? (I chose c);a. It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore.;b. It aids in protein unfolding so that the protein can thread through nuclear pores.;c. It is a hydrophobic sequence that enables the protein to enter the nuclear membranes.;d. It prevents the protein from diffusing out of the nucleus through nuclear pores.;4. How do changes in histone modifications lead to changes in chromatin structure? (I chose b);a. They directly lead to changes in the positions of the core histones.;b. They change the affinity between the histone octamer and the DNA.;c. They help recruit other proteins to the chromatin.;d. They cause the histone N-terminal trails to become hyperextended.
Paper#15295 | Written in 18-Jul-2015Price : $32