Protein expression
Tue, Dec 8, 2026 · Week 16 · Genetics of Disease (Medical Interventions)
Today's goal: Explain how a host cell expresses the inserted gene to produce the target protein.
This is a model of the work you should turn in today. Use it to check your own: match the structure and the level of detail, do not copy it. Your data and wording should be your own.
What expression means: expression is the cell reading the inserted gene and using it to build the target protein.
Tracing the steps:
1. Transcription: the host cell's machinery copies the inserted gene into mRNA, but only if the gene has a promoter the host cell recognizes.
2. Translation: ribosomes read the mRNA and assemble the amino acid chain that folds into the target protein.
Two conditions that change yield:
- Temperature: too high or too low can slow the cell or cause the protein to misfold, lowering usable yield.
- Inducer concentration: adding the right amount of inducer can switch the gene on strongly, raising protein output.
Evidence expression worked: in the sample data, the cells glowed green under UV light. Because GFP fluorescence is a visible proxy for the protein being made, the glow tells me the inserted gene was expressed.
This model shows the level of evidence and organization needed to complete: Completes the expression task: annotated notes tracing transcription and translation of the inserted gene, two conditions that change yield, and one piece of expression evidence from sample data.
- Date and label the entry.
- Record the procedure, observation, or design decision clearly.
- End with what the evidence means and the next step.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
Also due today: Add your expression notes to your Unit 4 PLTW tracker and submit to Schoology.
Turn in: Protein expression annotated notes
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Claim ceiling: Today's evidence supports a classroom claim about protein expression. It cannot prove causation, diagnose a real patient, or justify action outside this room.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Explaining gene expression and recognizing evidence that it succeeded.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.