Transcription: from DNA to messenger RNA

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Model gene (not to scale). Ari reads a model of one gene being copied into mRNA. DNA strand W is the strand the mRNA pairs with. What is strand W called?

   • The new strand, the strand RNA polymerase builds
   • The template strand, the strand RNA polymerase reads
   • The coding strand, the strand with the same letters as the mRNA
   • The promoter, the strand where transcription starts
2. 2.

   Bo reads a model of transcription. Enzyme X moves along the DNA and builds the mRNA. What is enzyme X?

   • RNA polymerase, the enzyme that builds mRNA on both DNA strands at once
   • RNA polymerase, the enzyme that builds mRNA on one DNA strand
   • A ribosome, the structure that joins amino acids
   • DNA polymerase, the enzyme that builds a new DNA strand

3. Read this first

   Use this

   Model strands (not to scale).

4. 3.

   Jun fills in the blank in the mRNA built from this template. Which base goes in the blank?

   • G, guanine
   • U, uracil
   • A, adenine
   • T, thymine
5. 4.

   Kira fills in the blank in the mRNA built from this template. Which base goes in the blank?

   • U, uracil
   • G, guanine
   • A, adenine
   • T, thymine
6. 5.

   Luz fills in the blank in the mRNA built from this template. Which base goes in the blank?

   • U, uracil
   • A, adenine
   • C, cytosine
   • G, guanine
7. 6.

   Milo compares two mRNAs built from the same template. Which case is correct, and why?

   • Case P, because RNA has U where DNA has T
   • Case Q, because mRNA keeps T the way DNA does
   • Case P, because the mRNA copies the template letters
   • Case Q, because RNA is made from the same letters as DNA
8. 7.

   Model gene (not to scale). Noah compares two cases at one gene. Which case is right, and why?

   • Case P, because RNA polymerase needs no template
   • Case P, because the mRNA is built on the coding strand
   • Case P, because one strand is the template for a gene
   • Case Q, because both strands of a gene are templates
9. 8.

   Pia compares two cases in a cell with a nucleus. Which case is right, and why?

   • Case Q, because the ribosomes are in the cytoplasm
   • Case P, because the mRNA stays in the nucleus
   • Case P, because the DNA stays in the nucleus
   • Case Q, because the DNA moves out to the cytoplasm

10. Use this

    Model strands (not to scale). DNA template strand, 3′ end on the left and 5′ end on the right: T A C G G T A C G. mRNA, 5′ end on the left and 3′ end on the right: A U G C C A U G C.

11. 9.

    Ren counts the bases in the mRNA strand of this model. How many bases does the mRNA have?

    • 3 bases
    • 18 bases
    • 9 bases
    • 8 bases

12. Use this

    Model strands (not to scale). DNA template strand, 3′ end on the left and 5′ end on the right: T A C G G T. mRNA, 5′ end on the left and 3′ end on the right: A U G C C A. The U is base 2 of the mRNA.

13. 10.

    Tala reads a model. Which template base sits across from the U in the mRNA?

    • T, thymine
    • A, adenine
    • C, cytosine
    • U, uracil