Protein structure and function: a) Name two common post-translational modifications of proteins in the cell that will affect their structure/function. b) What are prions? Briefly describe their structure and function.

8.) Answer the following questions regarding the following DNA sequence. 3'TACGGGGATAGCCGGCGAATTAAATAGCTGTC - 5" A.) What is the MRNA sequence that would result from transcription of this sequence? Assume that the DNA would be read from left to right. What is the amino acid sequence that would result from translation of B.) the MRNA resulting from the sequence? See Codon Table on next page. 20 C.) What is the anti-codon found on the tRNA that would deliver the amino acid for the first codon in the MRNA sequence? D.) If the fourth nucleotide in the DNA sequence were deleted due to a mutation during DNA replication, what would the resulting amino acid sequence be? What type of mutation is this? E.) What impact would the mutation in the DNA sequence in PART D have on the function of the protein produced from original sequence? Why?

WVA1 is a protein that is secreted by epithelial tissues of mice. Which of the following is not predicted to be found in the DNA sequence of the gene that codes for WVA1? a) A DNA sequence corresponding to an exon. Ob) 5'-AATAAA-3! c) 5'-UUGACA-3'. d) A DNA sequence corresponding to a signal peptide of the amino acids chain. e) A DNA sequence corresponding to the 5'-UTR of the mRNA.

Cystic fibrosis (CF) is an inherited disorder caused by different types of mutations, many of which prevent ions from moving across cell membranes. Normally there are channel proteins that allow passage of the ions, but in patients with one kind of CF these proteins seem odd. Closer examination shows that these proteins display the correct amino acid sequence. However, they fail to do their job. A) Given that the primary structure of the protein is correct, what can you infer about the DNA sequence for the gene coding this protein on this patient, is there a mutation? Explain. B) Why is the primary structure insufficient to guarantee the proper function of the protein?

8

In a particular region of the genome of a certain bacterium, one DNA strand is transcribed to give rise to an mRNA for protein A and the other DNA strand is transcribed to give rise to an mRNA for protein B.   a) Would there be any problem in expressing the two genes?   2. b) If a mutation occurred to affect the structure of protein A, what would you observe in the structure of protein B?

The activity provides you with a version of the NGF pathway, an example of a RTK. All of the proteins involved can be in ON/OFF states. Using this cell signaling pathway you will be asked a variety of questions to determine how the molecules are regulated, but also how a cell would respond if this cell signaling party steps were interrupted or activated. Neural Growth Factir (NGF) Ras- Ras- GDP GTP Trk-A Ras-GEF braf braf МЕК МЕК ERK ERK ERK ERK STAT STAT Spiouty DNA Nucleus Cytosol

Shown below is a double-stranded bacterial (E. coli) DNA sequence coding for a hypothetical protein. The nucleotides are numbered 1 to 100.  a)Although the transcription start site begins at the underlined C/G, which of the following is the nucleotide sequences needed upstream for transcription to actually occur? b)What are the first 15 nucleotides of the mRNA? c)What are the first 5 amino acids translated from the resulting mRNA? d)A different mutation results in the substitution of the T/A base pair at position 30 (shown in bold and underlined) with a G/C base pair. How would this mutation affect the sequence of the protein that is produced?

#17 #18 please I will give you ?

True or False. 1. a.) RNA polymerase decodes mRNA so the ribosome can make proteins. b.) Only coding RNA can interact with the ribosome. c.) The ribosome is composed of both protein and ncRNA. d.)The ncRNA components of the ribosome behave as a ribozyme. Pick one of the FALSE statements from the 4 previous questions and explain why it is incorrect.