Transcription: from DNA to messenger RNA
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Ari reads a model pre-mRNA. The introns are cut out and the exons are joined. How many bases are in the mature mRNA?
- 45 bases
- 33 bases
- 60 bases
- 27 bases
Bo reads a second model pre-mRNA. Three bases make one codon. How many codons are in the mature mRNA?
- 17 codons
- 19 codons
- 57 codons
- 36 codons
Read this first
Model rate card (model data)
fact value bases added each second by E. coli RNA polymerase 40 codons in the model mRNA 400 bases in one codon 3 Esme reads a rate card. About how many seconds does the polymerase need to build the whole model mRNA?
- 1,240 seconds
- 30 seconds
- 48,000 seconds
- 10 seconds
Model gene (not to scale). Jun reads a model template. RNA polymerase builds a pre-mRNA from it, and then the intron is cut out. Which mature mRNA is left?
- UACUGUAAGCUG
- AUGACAGUAAAGUUCGAC
- AUGACAUUCGAC
- ATGACATTCGAC
Luz reads a model template. Which RNA does the polymerase build first, before any splicing?
- AUGCACCGAUUC
- UACGUGCAGUUCGCUAAG
- ATGCACGTCAAGCGATTC
- AUGCACGUCAAGCGAUUC
Use this
Notebook on transcription (model data), 4 rows. Columns: line, what it says. 1, RNA polymerase reads the template strand of one gene. 2, The mRNA is built by pairing bases with the template. 3, Compared with the coding strand, the mRNA has U where the DNA has T. 4, The mRNA has the same letters as the template strand.
Milo checks a classmate’s notebook on transcription. Exactly one line is wrong. Which line, and why?
- Line 1, because both strands of a gene are read
- Line 2, because mRNA is built from the coding strand
- Line 3, because RNA keeps T like DNA
- Line 4, because the mRNA pairs with the template
Notebook on a plant cell’s mRNA (model data)
line what it says 1 Transcription of a gene takes place in the nucleus 2 A cap is added at the 5′ end and a poly-A tail at the 3′ end 3 Introns are cut out and the exons are joined 4 The finished mRNA keeps its introns when it leaves the nucleus Noah checks a classmate’s notebook on a plant cell’s mRNA. Exactly one line is wrong. Which line, and why?
- Line 3, because the exons are the parts cut out
- Line 2, because the cap and tail are added to the DNA
- Line 1, because transcription takes place in the cytoplasm
- Line 4, because introns are cut out in the nucleus
Use this
Notebook on strands and direction (model data), 4 rows. Columns: line, what it says. 1, The DNA opens in front of the moving polymerase and closes again behind it. 2, RNA polymerase builds the mRNA from its 5′ end toward its 3′ end. 3, The mRNA matches the coding strand, with U where the DNA has T. 4, One gene is read from both of its strands, so two mRNAs form.
Pia checks a classmate’s notebook on strands and direction. Exactly one line is wrong. Which line, and why?
- Line 2, because the mRNA is built from its 3′ end
- Line 3, because the mRNA has the same letters as the template
- Line 1, because the DNA stays open behind the polymerase
- Line 4, because one strand is the template for a gene
Two cells card (model data)
cell has a nucleus bacterial cell no plant cell yes Ren compares a bacterial cell and a plant cell. Which claim and reason are correct?
- In the bacterial cell, a ribosome must wait for the finished mRNA, because the DNA is kept in a nucleus
- In the plant cell, a ribosome can start reading the mRNA during its building, because transcription takes place in the cytoplasm
- In the plant cell, a ribosome reads the pre-mRNA with its introns, because splicing is not needed
- In the bacterial cell, a ribosome can start reading the mRNA during its building, because there is no nucleus
Model template (not to scale). Zee predicts the coding strand and the mRNA for this template. Which claim and reason are correct?
- Coding strand GTACCT and mRNA GUACCU, because both copy the template
- Coding strand CATGGA and mRNA CATGGA, because RNA keeps T like DNA
- Coding strand CATGGA and mRNA CAUGGA, because U replaces T
- Coding strand CATGGA and mRNA GUACCU, because the mRNA pairs with it
