Reference no: EM133477533

Question 1. Problem set one includes opportunities to demonstrate your proficiency with the following learning standards:

Question 2. Explain how genetic information stored in living systems is used to produce proteins and phenotypes

a). Construct a model that illustrates how information stored in DNA results in phenotype within an individual.

b). Use evidence to make a claim that genetic variation in a population is the result of mutation within individuals.

SARS-CoV-2 and COVID are a great example of biology in the news that biologists often get asked to explain. Based on what we've learned so far in Biol 151, there's a lot you already know and understand about COVID and the COVID vaccines. Use the HTMI Virus Explorer to help build your understanding of viruses - many of these ideas should be similar and familiar to what we've discussed in class.

A distinguishing feature of SARS-CoV-2 are the protruding spikes that form a "crown" on the virus. Biologists have identified the nucleotide sequence responsible for producing those spikes.

The following represents an excerpt of the nucleotide sequence that codes for the spike protein in SARS-CoV-2[1]:

5'-UAAGAUGGAGAGCGAUCUUGUCCCUGGUUUCUAGAACGAGAAAAC-3'

Viruses like SARS-CoV-2 can cause severe illness in many organisms - like humans! In response, humans possess an innate immune system - immunity you are born with. The complement system is one component of our innate immune system. On chromosome 19, humans have a gene for the Human Complement Component 3 or C3, which contributes to an organism's ability to detect and destroy a novel pathogen, like a virus.

The following represents an excerpt of the nucleotide sequence from the C3 gene[2]:

5'-GCACCATGGGACCCACCTCAGGTCATATACCAGCCTGTGACTGCTCCTGCGCGCAGCTC-3'

[1] Sequence modified from Wu et al., Nature 2020. 579: 265-269

[2] Sequence modified from De Bruijn and Fey, PNAS 1985. 82: 708-712

Standard 2a, modeling

Question 1. Create a box-and-arrow model that shows how information stored in the C3 gene results in a protein. Your model must be contextualized to this case and should include the following structures, although you may add or repeat structures as needed:

gene, DNA, mRNA, amino acid

Question2. On your box-and-arrow model for the previous question, circle the portion of the model that would be different for a coronavirus. Briefly describe these differences in the space below.

Standard 2a, predicting the polypeptide

Question 3. Using your understanding of biology, predict the polypeptide sequence for this excerpt of the C3 gene:

Coding strand:

5'-GCACCATGGGACCCACCTCAGGTCATATACCAGCCTGTGACTGCTCCTGCGCGCAGCTC-3'

Promoter: 5'-GCAC-3'

Terminator: 5'-CGCGCAGC-3'

Intron: 5'-ATATA-3'

Complete each step in the process, as indicated below. Show directionality where appropriate. In your template strand, underline and label the promoter and terminator. In your mRNA, underline and label the start and stop codons.

Question 4. Using your understanding of biology, predict the polypeptide sequence for this excerpt of the nucleotide sequence responsible for the spike protein.

Standard 2b

Question 5. Draw a box-and-arrow model that represents how information stored in RNA in SARS-CoV-2 results in the production of the spike protein.

In recent months, biologists and epidemiologists are increasingly concerned about variants of SARS-CoV-2. Once variant, which emerged in the UK, has a mutation in the receptor binding domain of the spike protein which results in the amino acid asparagine being replaced with tyrosine.

Question 6. Based on this information, what type of mutation has likely happened? Briefly explain your reasoning - use the biology to support your answer!

Question 7. Use your model from question 9 as a starting point. Add to that model to describe how variation in spike proteins among SARS-CoV-2 viruses is the result of mutation.