Transcription: from DNA to messenger RNA

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   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
   • DNA polymerase, the enzyme that builds a new DNA strand
   • A ribosome, the structure that joins amino acids
   • RNA polymerase, the enzyme that builds mRNA on one DNA strand
2. 2.

   “not to scale” Esme reads a model of a gene in a cell with a nucleus. The mRNA is built inside compartment Z. What is Z?

   • The nucleus, the compartment that holds the DNA
   • The cytoplasm, the compartment where the ribosomes are
   • A ribosome, the structure that builds proteins
   • A nuclear pore, the opening in the nuclear envelope

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?

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

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

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

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

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

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

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

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

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

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

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

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. 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.

11. 9.

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

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

12. Use this

    DNA and RNA card (model data), 3 rows. Columns: feature, DNA, RNA. sugar, deoxyribose, ribose. bases, A T C G, A U C G. strands, two, usually one.

13. 10.

    Zee reads a card that compares DNA and RNA. Which base is found in RNA but not in DNA?

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