Biotechnology: PCR, gel electrophoresis and genetic engineering

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Model PCR card (model data)

   item	value
   start	1 piece
   each cycle	doubles the pieces
   goal	more than 1000 pieces

2. 1.

   Bo starts a model PCR with 1 piece. Each cycle doubles the pieces. What is the fewest cycles that pass 1,000 pieces?

   • 9 cycles
   • 100 cycles
   • 10 cycles
   • 500 cycles
3. 2.

   Jun reads a model of Taq polymerase extending a primer. What is the whole new strand, written 5′ to 3′?

   • ATGCCUAA
   • ATGCCTAA
   • ATGCGATT
   • ATGCAATC
4. 3.

   Model strands (not to scale). In each cycle, every single strand gets a new partner strand built by Taq polymerase. Kira follows a model PCR that starts with one double strand. Each cycle gives every single strand a new partner. How many single strands are there after 4 cycles?

   • 32 strands
   • 24 strands
   • 64 strands
   • 16 strands
5. 4.

   Model strands (not to scale). Luz reads a model of one PCR step. A primer is paired with the template. Which statement about Taq polymerase is correct?

   • Taq builds a copy of the whole genome starting from the primer
   • Taq builds GCTAATGG by adding bases to the primer
   • Taq cuts the template after the primer and keeps the first part
   • Taq builds GCTATACC by copying the template letters
6. 5.

   Model gel (not to scale; model data). Wells at the top, next to the negative (-) end. Milo reads a model gel. Lane 1 has one band between the 750 bp and 500 bp ladder bands. Which size fits that band best?

   • 600 bp
   • 900 bp
   • 300 bp
   • 1200 bp
7. 6.

   “not to scale; model data” Noah reads a model gel with four lanes after the run. Which lane has the band that moved farthest from the wells?

   • Lane 1, because it holds the largest piece, 900 bp
   • Lane 2, because it has the most bands
   • Lane 3, because it holds the smallest piece, 120 bp
   • Lane 4, because its band lines up with a ladder band
8. 7.

   (not to scale; model data). Pia compares model DNA from three soil bacteria samples, each cut by the same enzyme. Which two samples show the same band pattern?

   • P, Q and R, because three samples have a band at 800 bp
   • Q and R, because both have two bands
   • P and R, because both have bands at 800 bp and 300 bp
   • P and Q, because both have a band at 800 bp
9. 8.

   Ren reads four steps for putting a gene into a plasmid. Which order is correct?

   • W, X, Y, Z
   • X, Y, Z, W
   • X, W, Y, Z
   • X, Y, W, Z

10. Model gene count (model data; a real corn plant has far more genes)

    item	genes
    model corn plant before engineering	20
    gene added from Bacillus thuringiensis	1
    model Bt corn plant after engineering	21

11. 9.

    Tala reads a model gene count for Bt corn. How many of the model Bt corn plant's genes came from the bacterium?

    • 0 of 21 genes
    • 20 of 21 genes
    • 21 of 21 genes
    • 1 of 21 genes

12. Rice grain card (model data)

    fact	detail
    golden rice	a combination of added genes lets the endosperm make provitamin A (beta-carotene)
    rice grain	the endosperm is the edible part of the grain

13. 10.

    Zee reads a card about golden rice, a rice engineered to make provitamin A. Which statement does the card support?

    • The roots of the rice plant make provitamin A and send it to the grain
    • Added genes let the endosperm, the edible part, make provitamin A
    • The genes of the rice plant were replaced, so the grain makes provitamin A
    • Provitamin A is sprayed onto the grain after the plant is harvested