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MODULE 4:
MAKING CELLS AND PROTEINS
PART 1 OF 7
The new clinician’s first questions weren’t about this attack at all. They were about her childhood fevers, her relatives, the countries her family came from — the first time in twenty years anyone treated her history as a single whole.
Slide 1 Transcript
PATIENT CHART
STINA
Serositis, Pleural effusion, Self-limiting fever episodes
THIS PART
Age 30
PRESENTING WITH
Culture negative, self-limited fevers with serositis
ACTION TAKEN
Genetic Testing
TESTING ORDERED
Periodic Fever Panel
CHART CLUES
COLLECTED AS YOU GO
A Full Family & Ancestry History
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Put your money down: If it strikes everywhere, could it all trace to one gene?
Bet before the story opens. For twenty years each visit treated Stina as a fresh emergency — a belly, a chest, a joint to be quieted and discharged. Two quick fact-checks on what a gene is; then the ask: could a disease that strikes so many unrelated places really trace back to one inherited gene — or must these be separate problems?
Pick the answer you believe now. We’ll come back to it later!
The First Doctor Who Asked About Her Family
The appointment that changed everything started in a way Stina was not used to. The new clinician barely asked about the attack that had brought her in. Instead the questions reached backward — into her childhood fevers, her relatives, the illnesses that ran quietly through her family, the countries her people had come from. For two decades each visit had treated her as a fresh emergency: a belly, a chest, or a joint to be quieted and discharged before the next patient. This was the first time someone looked at the whole arc of her life at once and asked, in effect, what if all of this has been one thing the entire time?
Built from Nucleotides
The Lego pieces of the genetic codeThe set of rules by which DNA sequences are translated into proteins. — a sugar, a phosphate, and one ‘letter’ baseA substance that accepts hydrogen ions (H⁺) or releases hydroxide ions (OH⁻)..
Slide 2 Transcript
Cash out the clip
Single Choice: What three parts make up a single nucleotideThe basic building block of DNA and RNA, consisting of a sugar, phosphate group, and nitrogenous bas?
Five Letters, Strict Pairs
Two shapes and one unbreakable rule — G with C, A with T (A–U in RNA).
Slide 3 Transcript
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Drag the Words: Drop each base next to its correct partner.
A Double Helix with an Address
That question has a molecular shape, and it begins with DNA. DNA is a double helixThe twisted-ladder structure of DNA molecules. built from nucleotidesThe building blocks of nucleic acids. — a sugar, a phosphate, and one of four bases — paired by strict rules (A with T, G with C) and packed tightly into chromosomes. A gene is simply a stretch of that sequence: an instruction with an address. If a single gene carried an error, that error could surface anywhere the gene is used — which is exactly the pattern of a disease that strikes belly, chest, joints, and blood with no apparent connection between them.
A Twisted Ladder
Two strands, railed and runged — sugar-phosphate sides, base-pair rungs, running antiparallel.
Slide 4 Transcript
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Fill in the Blanks: Name the parts of the twisted ladder.
Packing in 9 meters
Nine meters of DNA wound down to a chromosome — around histones, coil upon coil.
Slide 5 Transcript
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Mark the Words: Mark every structure involved in packing DNA.
The Suspect’s Address: MEFV, Chromosome 16
So the hunt begins at the suspect’s address: the MEFV gene on chromosome 16. Naming where to look is the first real step toward explaining why Stina’s trouble was never confined to one organ. It was written into one line of code and then copied into all of them. The new clinician’s old-fashioned questions about family and ancestry were not small talk; they were the first move of someone who suspected, correctly, that the answer was inherited — that it had been with her since before she was born, waiting in a gene with a known street address.
FINDING!
A Full Family & Ancestry History
The new clinician did what twenty years of specialists hadn’t: took a full family and ancestry history and treated Stina’s scattered attacks as one inherited condition. The molecular anchor is concrete — familial Mediterranean fever traces to the MEFV gene on chromosome 16, which codes for pyrin. Because a gene is copied into every cell, one error there can surface in belly, chest, joints, and blood at once. Chart entry: candidate diagnosis is a single-gene disorder with a known address — MEFV, chromosome 16 — the target for testing.
Confirm or refute your bet: If it strikes everywhere, could it all trace to one gene?
Now that you’ve read the double helix — nucleotides, base pairingThe specific hydrogen bonding between complementary bases (A-T, C-G in DNA)., chromosomes — return to the bet. A gene is one stretch of that sequence with an address, and a single error there is copied into every cell, so it can surface anywhere the gene is used. That is exactly the pattern of Stina’s belly-chest-joint-blood attacks.
Slide 8 Transcript
NEXT PART
Finding the gene is only the beginning — a gene matters only when it is copied into every new cell. Next comes replication, where we watch DNA duplicate itself with perfect fidelity, and the typo quietly ride along into every copy.
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Overview
QUICK QUESTIONS
QUICK QUESTIONS
List of terms
- genetic code
- base
- nucleotide
- double helix
- nucleotides
- base pairing