Pierce_Gene to Protein_Handout

pdf

School

Union County College *

*We aren’t endorsed by this school

Course

240

Subject

Biology

Date

Jan 9, 2024

Type

pdf

Pages

Uploaded by juwetoefemena

Name: From Gene to Protein Page 1 of 5 From Gene to Protein Activity Background You have identified a (fictional!) gene Q . This gene is thought to play a role in liking chocolate. You have the wild-type se- quence of this gene. In talking to a coworker, you learn that she detests chocolate, so you ask to sequence her gene Q . When you get the sequence back, you realize she has a mutation in this gene. 1. Based on what you know about the genetic code, would a mutation in a gene always lead to an altered protein? In this activity, you will transcribe and translate the wild-type gene Q , and then determine whether your coworker’s mutation alters protein Q (and therefore whether it’s possible that your coworker detests chocolate because of this mutation). Part 1: The pre-mRNA The sequence of the (fictional) gene Q is below. Here, the bottom strand is the template strand. +1 5’…TACTAATCGA AAATTGCAGA CTGTAATGGA GTCAGATGAT 3’…ATGATTAGCT TTTAACGTCT GACATTACCT CAGTCTACTA GCATTAAGGT AAGT……A…TCAGG AGAAATTGAA ATAAA…3’ CGTAATTCCA TTCA……T…AGTCC TCTTTAACTT TATTT…5’ 2. Write out the primary sequence of the RNA transcript starting at +1 and continuing until the end of the sequence provided in Box I on the last page of this handout. (Write out the ‘…’s as well.) *Hint: Have one group member read out the bases from the correct strand in the correct 5’ → 3’ direction, and have another write them down. Part 2: The mature mRNA The sequence you have written out above corresponds to the pre-mRNA including the 5’ and 3’ untranslated sequences (5’ and 3’ UTRs), exon 1, intron 1, and exon 2 (the last exon in the gene). Introns are noncoding regions of the gene that are spliced out of the primary transcript as part of RNA processing. Splicing requires a 5’ splice site and a 3’ splice site in addition to a branch point.

Name: From Gene to Protein Page 2 of 5 These sequences can be identified based on their perfect or high identity to the consensus sequences as shown below. In the sequence you have, much of the intron 1 sequence is not given and is replaced by “…”. 3. Find and underline the sequence corresponding to the intron in the pre-mRNA sequence you wrote out in Box I. *Hint: Look for the four nucleotide stretch AGGU, which is invariant in the 5’ consensus sequence, and then look at flanking nucleotides to determine if they match the rest of the 5’ consensus sequence. Subsequently, look for the four nucleotide stretch CAGG, which is invariant in the 3’ consensus sequence. 4. Write the sequence of the mature mRNA after intron 1 has been spliced out in Box II (on the last page of this handout). Make sure you make the correct junction between exon 1 and exon 2 by paying attention to the precise 5’ and 3’ splice sites. Check in with your instructor before proceeding to translate protein Q! Part 3: Translating mRNA to protein After RNA processing, the mature mRNA is exported from the nucleus to the cytoplasm. At this point the mature mRNA can be translated based on its reading frame and the genetic code. The position of the start codon defines the reading frame of the mature mRNA. 5. Identify and underline the start codon in the mRNA sequence that you wrote out in Box II. *Hint: In the gene Q mRNA the start codon is located closest to the 5’ end of the mature mRNA. Once the reading frame start is located, the rest of the codons can be identified by organizing the nucleotides into contiguous sets of three at a time. The end of the reading frame is defined by the presence of one of the three possible stop codons in the same frame. 6. For the mature mRNA sequence above (Box II), identify the reading frame and all of the codons, including the stop codon, in the mature mRNA. Underline the start codon, circle the three bases that code for each following codon, and draw a square around the stop codon.

Name: From Gene to Protein Page 3 of 5 During translation amino acids are incorporated into a protein according to the genetic code. Each codon specifies an amino acid. The genetic code is shown below: 7. Based on the genetic code and mature gene mRNA sequence, write out the primary sequence (the sequence of amino acids of protein Q) in Box III (last page of this handout). Check with your instructor that you have the correct amino acid sequence! Part 4: Does the mutant gene Q code for an altered protein? You have the mutant version of gene Q below. The base pair difference is highlighted and underlined. +1 5’…TACTAATCGA AAATTGCAGA CTGTAATG G G AGTCAGATGA 3’…ATGATTAGCT TTTAACGTCT GACATTAC C C TCAGTCTACT TGCATTAAGG TAAGT……A…TCAG GAGAAATTGA AATAAA…3’ ACGTAATTCC ATTCA……T…AGTC CTCTTTAACT TTATTT…5’ 8. What consequence would this have on the protein? Would it affect the sequence of the protein, the length, or both? *Hint: Consider where the start codon is in the original gene sequence and consider the frame after introduction of the mutation.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

Name: From Gene to Protein Page 4 of 5 Pre-mRNA sequence Box I Mature mRNA sequence Box II Amino acid sequence of protein Q Box III

Name: From Gene to Protein Page 5 of 5 End-of-Activity Questions 1. Which sequences are present in both the pre-mRNA and the mature mRNA? (Select all that apply.) a. exons b. introns c. 5’ UTR d. 3’ UTR 2. Which sequences are important to predict the protein sequence from the DNA sequence? (Select all that apply.) a. start codon b. stop codon c. intron splice sites d. the transcription start site 3. How many amino acids are translated from a gene with no introns and 15 codons? a. 16 b. 15 c. 14 d. 10

Related Documents

Bio 30 Unit C Lesson 3.doc

Bio 30 Unit C Lesson 4.doc

Bio 30 Unit 3 Lesson 6 Assignment (1).doc

Bio 30 Unit 3 Lesson 2 Assignment.doc

BIO202 Lab 18.docx

Chapter 6 - Worksheet Activity.docx

Chp 11_Chromosome Structure Activity_BIO240.docx

Unit 5 Case Connection.docx

final lab report.docx

Aei-wksht-stu.pdf

Restriction Digestion of E. coli JM101 Utilizing Uncut, EcoR1, BamHI, and E+B Components, Followed b

Quantitative Analysis Lab: Serial Dilution and Standard Curve Construction for Precise Determination

Recommended textbooks for you

Biology Today and Tomorrow without Physiology (Mi...

Biology

ISBN:9781305117396

Author:Cecie Starr, Christine Evers, Lisa Starr

Publisher:Cengage Learning

Human Heredity: Principles and Issues (MindTap Co...

Biology

ISBN:9781305251052

Author:Michael Cummings

Publisher:Cengage Learning

Biology: The Dynamic Science (MindTap Course List)

Biology

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Cengage Learning

Biochemistry

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Cengage Learning

Biology 2e

Biology

ISBN:9781947172517

Author:Matthew Douglas, Jung Choi, Mary Ann Clark

Publisher:OpenStax

Human Biology (MindTap Course List)

Biology

ISBN:9781305112100

Author:Cecie Starr, Beverly McMillan

Publisher:Cengage Learning

SEE MORE TEXTBOOKS

Recommended textbooks for you

Biology Today and Tomorrow without Physiology (Mi...
Biology
ISBN:9781305117396
Author:Cecie Starr, Christine Evers, Lisa Starr
Publisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
Biology: The Dynamic Science (MindTap Course List)
Biology
ISBN:9781305389892
Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan
Publisher:Cengage Learning
Biochemistry
Biochemistry
ISBN:9781305577206
Author:Reginald H. Garrett, Charles M. Grisham
Publisher:Cengage Learning
Biology 2e
Biology
ISBN:9781947172517
Author:Matthew Douglas, Jung Choi, Mary Ann Clark
Publisher:OpenStax
Human Biology (MindTap Course List)
Biology
ISBN:9781305112100
Author:Cecie Starr, Beverly McMillan
Publisher:Cengage Learning