Translation: read a codon table to build a protein
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
DNA template strand (model, not to scale), 3′ to 5′, cut into triplets
TAC CGA AAC ATT. The mRNA pairs with it base by base: A with U, T with A, C with G, G with C. Table excerpt of the standard genetic code: AUG, methionine; GCU, alanine; UUG, leucine; UAA, stop; UAC, tyrosine; CGA, arginine; AAC, asparagine; AUU, isoleucine.
Noah turns the DNA template strand into mRNA, then reads the mRNA with the table. Which chain results?
- methionine, alanine, leucine, stop
- alanine, leucine
- tyrosine, arginine, asparagine, isoleucine
- methionine, alanine, leucine
DNA template strand (model, not to scale), 3′ to 5′, 17 bases
CGTACCTTTGGGAAATC. The mRNA pairs with it base by base: A with U, T with A, C with G, G with C. Table excerpt of the standard genetic code: AUG, methionine; GAA, glutamic acid; ACC, threonine; CUU, leucine; UAG, stop; AAA, lysine; UUU, phenylalanine.
Pia makes mRNA from this DNA template strand. The ribosome begins at the first AUG. Which amino acid is last in the chain?
- leucine, from the codon CUU before the stop
- phenylalanine, from cutting groups from the first base
- stop, from the codon UAG at the end
- lysine, from the template triplet AAA
DNA coding strand (model, not to scale), 5′ to 3′, 14 bases
ATGTGGGACTAGCC. The mRNA has the same letters as this strand, with U in place of T. Table excerpt of the standard genetic code: AUG, methionine; UGG, tryptophan; GAC, aspartic acid; UAG, stop; UAC, tyrosine; ACC, threonine; CUG, leucine; AUC, isoleucine.
Ren has only the DNA coding strand. The ribosome begins at the first AUG of the mRNA. Which chain results?
- tryptophan, aspartic acid
- tyrosine, threonine, leucine, isoleucine
- methionine, tryptophan, aspartic acid, stop
- methionine, tryptophan, aspartic acid
Rate card (textbook rate, model length)
item value unit time to add one amino acid 0.05 seconds coding part from AUG to the end of the stop codon 120 bases Tala reads a rate card for a model mRNA in a bacterium. At that rate, how long does the ribosome take to build the chain?
- 3 seconds, counting each pair of the 120 bases
- 2 seconds, counting 40 codons as amino acids
- 1.95 seconds, for 39 amino acids
- 6 seconds, counting each of the 120 bases
Comparison card (model data)
mRNA bases before AUG bases from AUG to the end of the stop codon bases after the stop codon P 9 48 12 Q 3 51 3 R 0 45 30 Ari compares three model mRNAs on a card. The ribosome begins at AUG and ends at the stop codon. Which mRNA builds the longest chain?
- Q, with 17 amino acids, counting the stop codon
- R, with the longest whole mRNA of 75 bases
- Q, with 16 amino acids once the stop is not counted
- P, with the longest start region of 9 bases
Use this
Notebook (model data), 4 rows. Columns: line, what it says. 1, The standard code has 64 codons. 2, Three of the codons are stop codons. 3, Each amino acid has only one codon, so 20 codons are used. 4, Nearly all living things use this same code.
Esme reviews a classmate's notebook on the genetic code. Exactly one line is wrong. Which line, and why?
- Line 4, because each species has its own code
- Line 1, because the code has 16 codons from pairs of bases
- Line 3, because one amino acid can have several codons
- Line 2, because each stop codon adds one amino acid
Notebook (model data)
line what it says 1 The start codon AUG codes for methionine 2 The second codon GGC codes for glycine 3 The tRNA that pairs with the third codon CAU has the anticodon CAU 4 The chain has three amino acids Jun reviews a classmate's notebook on the message AUG GGC CAU UAG. Exactly one line is wrong. Which line, and why?
- Line 2, because glycine has just one codon
- Line 1, because the ribosome begins at the first base
- Line 3, because the anticodon pairs with CAU, so it is GUA
- Line 4, because the stop codon adds a fourth amino acid
Use this
Message card (model data), 2 rows. Columns: message, codons. M, AUG GCU CUU UAA. N, AUG GCC CUC UAA. Table excerpt of the standard genetic code: AUG, methionine; GCU, alanine; GCC, alanine; CUU, leucine; CUC, leucine; UAA, stop.
Kira asks whether two different model mRNAs can build the same chain. Which claim and reason go together?
- No, because each amino acid has one codon and N uses new codons
- Yes, because one amino acid can have several codons
- Yes, because both messages begin with AUG and end with UAA
- No, because N has more bases than M and so builds a longer chain
Model mRNA (not to scale), 5′ to 3′, cut into codons
AUG GGC UUU UAA. A plant cell and a bacterium cell each read it. Table excerpt of the standard genetic code: AUG, methionine; GGC, glycine; UUU, phenylalanine; UAA, stop.
Luz imagines a model mRNA moved from a plant cell into a bacterium cell. Which claim and reason go together?
- Different amino acids, because each species has its own table
- The same amino acids, because the code is identical across species with no exception
- The same amino acids, because the code is nearly universal
- Different amino acids, because a bacterium reads codons as two bases
AUG CCU UAA GGA. Table excerpt of the standard genetic code: AUG, methionine; CCU, proline; UAA, stop; GGA, glycine. Milo asks why the ribosome stops at UAA. Which claim and reason go together?
- The ribosome reads past UAA to GGA, because stop codons are ignored
- The chain ends at UAA, because no tRNA pairs with a stop codon
- A last amino acid is added at UAA, because each codon has a tRNA
- The chain ends at UAA, because a tRNA with the anticodon UAA fits and ends it