A single G-to-A change in FGFR3, followed from codon to a receptor that stays switched on, explains achondroplasia in this SC435 Unit 7 case application about a composite newborn. Searches like "sc 435 unit 7 assignment example", "sc435 unit 7 sample" and "sc435 unit 7 example" land here.
What a finished SC435 Unit 7 mutation case application looks like
Four pages answering five case questions under headings, with one figure. The figure shows the codon change, GGG to AGG, the amino acid change, glycine to arginine, and the receptor spanning the membrane with the substitution marked in its transmembrane segment. Answer one classifies the mutation as a missense substitution and a transition. Answer two notes that the rarer G-to-C change at the same position, GGG to CGG, also encodes arginine, so two different base changes give one protein. Answer three explains the gain of function: the receptor normally restrains cartilage cell division in growth plates, and the altered receptor restrains it constantly. Answer four explains why roughly four in five cases arise new in families with no history. Answer five gives the recurrence risk for the parents and for [Name] as a future adult.
How a SC435 Unit 7 example is structured
Answers follow the central dogma in order, DNA to mRNA to protein to cell to growth, so no consequence appears before its cause. The classification answer names the mutation twice, by type of base change and by effect on the codon, because the course treats those as separate questions. The second answer uses the codon table directly, showing both GGG changes on the page. The mechanism answer carries the case's twist: most mutations in this course break a protein, while this one removes its brake, and the answer explains why a gain of function behaves as dominant. De novo origin is linked to the paternal allele and to rising paternal age, stated as an association from published studies. Recurrence risk closes the case, with the parents' risk described as low and the child's future risk as one-half per pregnancy, and counseling left to a genetics professional.
Two names for one change
The substitution is a transition, one purine for another, and a missense change, one amino acid for another. The answer keeps the two classifications separate, as the course does.
Two bases, one arginine
GGG to AGG and GGG to CGG both encode arginine. Showing both on the codon table explains why nearly every case carries the same protein change.
A brake that never releases
FGFR3 slows cartilage cell division in growth plates. The altered receptor signals even without its usual trigger, so bones lengthen slowly from the start of growth.
New in the family
Roughly four in five affected children have average-height parents. Published studies link these new changes to the father's allele and to increasing paternal age.
Risk stated, counseling deferred
The parents face a low recurrence risk, and [Name] as an adult would pass the allele to each child with probability one-half. The case leaves decisions to a genetics professional.
Where marks go in SC435 Unit 7
Mutation cases in SC435 are typically graded on correct classification, the protein consequence, the link from protein to phenotype and the inheritance implications. The single largest loss comes from stopping at the base change, so an answer that names the mutation but never reaches the receptor forfeits most of the analysis credit. Classification slips follow, missense confused with nonsense or transition with transversion. The phenotype link earns credit only when the gain of function is explained; describing the protein as broken reverses the mechanism. Inheritance answers are marked on recurrence risk stated correctly for each person, with de novo origin distinguished from inherited cases. Codon errors the table would have caught, and figures whose sequence disagrees with the text, cost further points. Treatment advice beyond the course's scope draws a comment.
Get a SC435 Unit 7 example written to your instructions
Every SC435 Unit 7 case hinges on its own base change, so paste the full case text and questions, with the rubric, in the order given. A free first custom case application, ready in 24-48h, carries that change through codon and protein to phenotype and states the inheritance risk for each person named.
SC435 Unit 7 questions, answered
What is the difference between a transition and a transversion?
A transition swaps one purine for another, A and G, or one pyrimidine for another, C and T. A transversion swaps a purine for a pyrimidine or the reverse. Transitions are more common in most genomes. Case questions often ask for this classification separately from the effect on the codon, so answer both.
How can one mutation be dominant if the other copy is normal?
When the altered protein gains an activity, one copy is enough to produce the effect, whatever the unaltered copy does. That is typical of gain-of-function changes. Loss-of-function mutations are more often recessive, because one working copy usually makes enough protein. Explaining which kind a case involves shows the mechanism behind the inheritance pattern.
Should a case application give medical advice?
No. A genetics case is graded on mechanism and inheritance. Where a question asks about options, a sentence stating that decisions belong to the family and a genetics professional is enough. Recurrence risks can be stated as probabilities, since they follow from the inheritance pattern, but interpretation for a real family is a clinician's job.