C & C page 254 #3-5 3. A signal sequence is a length of amino acids that binds to a receptor on the ER membrane to direct where a newly synthesized protein will go.

4. Codons of mRNA match to anticondons of tRNA

5. An amino acid attached to a specific tRNA constitutes a charged tRNA, which rings the specified amino acid to the ribosome. page 381 #2 2. The prokaryotic operon allows gene expression to be regulated by controlling access to RNA polymerase. If the operator sequence is blocked by a repressor molecule, the genes in the operon cannot be expressed. When the appropriate environmental signal is present, the repressor is removed and the genes are expressed. The situation in eukaryotes is more complex. Many transcription factors are used to stimulate gene expression. The activity of the transcription factors is influenced by a myriad of signals such as hormones and protein kinases. page 257 #1, 3, 4 1. Although both can replicate and evolve, viruses require a host cell to do this. Bacteria have DNA as their genetic information, while viruses may contain either DNA or RNA. Viruses o no carry out metabolism or respond to stimuli as bacteria do.

3. a retrovirus contains RNA as its genetic information an uses reverse transcriptase to make a DNA copy of its genetic information

4. Viruses do not have their own metabolism which makes antibiotic treatment ineffective.

RI page 258 #3, 9 3. No. There is specificity of gene expression with respect to time and place

9. The primary structure determines both secondary and tertiary structure page 389 # 10 10. Transposons are genetic elements that can move and insert themselves (or copies of themselves) into new chromosomal locations. Although this movement can disrupt the expression of the gene into which Transposons inserts, it also produces variation necessary for evolution.

UC Page 259 #2, 6, 7 2. UAA UGC GCC AGU CAU

6. It would result in a protein in which one or more amino acids were missing from the primary structure. The function of this “new” protein would also be altered.

7. A very different protein would be produced because the entire reading frame would be shifted.

Page 389 # 1 1. Since the mitochondria are inherited only from the mother, the genes in the mitochondrial genome are said to be maternally inherited.