Biotechnology: PCR, gel electrophoresis and genetic engineering

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   PCR step card (model data)

   step	temperature	what happens
   X	low	short primers join the single strands

2. 1.

   Bo reads a card for one step in a model PCR cycle. What is step X called?

   • Extend
   • Anneal
   • Denature
   • Cut
3. 2.

   Esme reads a card for one step in a model PCR cycle. What is step Y called?

   • Extend
   • Anneal
   • Cut
   • Denature
4. 3.

   Each cycle doubles the pieces. Kira reads a count table for a model PCR. Which number goes in the ? box?

   • 12 pieces
   • 9 pieces
   • 8 pieces
   • 18 pieces

5. Model PCR card (model data)

   item	value
   start	1 piece
   each cycle	doubles the pieces
   goal	8 pieces

6. 4.

   Luz reads a card for a model PCR. How many cycles does it take to reach the goal?

   • 4 cycles
   • 8 cycles
   • 3 cycles
   • 7 cycles
7. 5.

   Milo reads a model gel. During the run, DNA pieces start in the wells at the top. Which way do they move, and why?

   • Toward the positive (+) end, because the gel pulls small pieces
   • Toward the negative (−) end, because DNA is negatively charged
   • They stay in the wells, because DNA has no charge
   • Toward the positive (+) end, because DNA is negatively charged
8. 6.

   Model gel (not to scale; model data). Noah reads a model gel after the run. Which band in lane 1 moved farthest from the wells?

   • The 150 bp band
   • The 300 bp band
   • The 900 bp band
   • The 600 bp band
9. 7.

   Model gel setup (not to scale; model data). Then the power is switched on. Pia loads two DNA pieces in one well and runs the gel. Which result is correct?

   • The 100 bp piece moves toward the positive (+) end; the other stays in the well
   • Both move toward the positive (+) end; the 1000 bp piece ends farther along
   • Both move toward the negative (−) end; the 100 bp piece ends farther along
   • Both move toward the positive (+) end; the 100 bp piece ends farther along

10. Gene-tool card (model data)

    tool	job
    W	cuts DNA at one specific short sequence

11. 8.

    Ren reads a card about tools used to put a gene into a plasmid. Which tool is W?

    • Restriction enzyme
    • Taq polymerase
    • DNA ligase
    • Primer
12. 9.

    Tala reads a card about tools used to put a gene into a plasmid. Which tool is X?

    • Plasmid
    • Restriction enzyme
    • Taq polymerase
    • DNA ligase

13. Bt corn card (model data)

    crop	fact
    Bt corn	the plant makes a protein that protects it from some insect pests
    Bt corn	the added DNA came from the bacterium Bacillus thuringiensis

14. 10.

    Zee reads a card about Bt corn. What was added to the corn plant's DNA?

    • A copy of the corn plant's own genes
    • A restriction enzyme from the bacterium
    • A gene from Bacillus thuringiensis
    • A gene from another corn plant