7. Small interfering RNAs repress transcription by ______.
(A) binding to and cleaving the gene.
(B) binding to and methylating the DNA of the gene.
(C) hybridizing with and blocking transcription of a gene.
(D) hybridizing with a nascent mRNA and binding a RITS complex, which condenses the chromatin of a gene.
(E) All of the above

3. In allosteric regulation, binding of a small regulatory molecule to an enzyme ______ the enzyme activity. (A) inhibits (B) stimulates (C) either stimulates or inhibits (D) neither stimulates nor inhibits (E) both stimulates and inhibits

4. The first enzymatic step in making a cDNA uses which of the following? (A) EcoRI nuclease (B) Taq polymerase (C) DNA polymerase (D) RNA polymerase (E) reverse transcriptase

5. The Arabidopsis genome, like many plant genomes, contains more genes than many animals and this is due largely to ______. (A) gene duplication (B) larger exons (C) larger introns (D) fewer stop codons (E) None of the above

6. The proofreading property of DNA polymerase is due to its ______ activity. (A) 3' to 5' exonuclease (B) 5' to 3' exonuclease (C) excision repair (D) mismatch repair (E) endonuclease

8. Eukaryotic ribosomes recognize and initially bind to what structure on the mRNA? (A) A Shine-Dalgarno sequence (B) The 7-methylguanosine cap (C) A TATA sequence (D) An AUG initiation codon (E) A CAT sequence

9. The nuclear localization signal is recognized by and binds to which protein in the process of nuclear protein import? (A) Ran (B) Exportin (C) Importin (D) Nucleoporin (E) The outer fibril protein

10. Which of the following is not a contiguous membrane domain? (A) Rough ER (B) Nuclear envelope (C) Smooth ER (D) Transitional ER (E) Secretory granules

11. Most higher eukaryotic plasma membrane proteins are synthesized on ______. (A) free ribosomes and inserted after translation into the plasma membrane (B) ribosomes associated with the plasma membrane and inserted into the membrane cotranslationally (C) smooth ER and carried to the plasma membrane by vesicles that pinch off from the Golgi apparatus (D) rough ER ribosomes and carried to the plasma membrane by vesicles that pinch off from the rough ER (E) rough ER ribosomes and carried to the plasma membrane by vesicles that pinch off from the Golgi apparatus.

12. Most mitochondrial proteins are synthesized on ______. (A) mitochondrial ribosomes from nuclear mRNAs (B) mitochondrial ribosomes from mitochondrial mRNAS (C) cytoplasmic ribosomes from mitochondrial mRNAs (D) cytoplasmic ribosomes; they are imported after they are completely synthesized (E) cytoplasmic ribosomes; they are imported cotranslationally as they are being synthesized

13. Electron transport and oxidative phosphorylation are performed by protein complexes in the mitochondrial ______. (A) inner membrane (B) outer membrane (C) intermembrane space (D) matrix (E) Both a and c