Biotechnology: PCR, gel electrophoresis and genetic engineering
Grade 9 Science Worksheet - Challenge Me
Circle the best answer.
Read this first
Model PCR card (model data)
item value start 5 pieces each cycle doubles the pieces goal more than 1000 pieces Ari starts a model PCR with 5 pieces. Each cycle doubles the pieces. After how many cycles does the count first pass 1,000?
- 498 cycles
- 7 cycles
- 200 cycles
- 8 cycles
Bo finds 192 pieces in a model PCR tube after 6 cycles. Each cycle doubled the pieces. How many pieces were in the tube at the start?
- 180 pieces
- 32 pieces
- 3 pieces
- 96 pieces
not to scale; model data. Lane 3, one band: 300 bp. Lane 4, one band: 1200 bp. Jun runs PCR on a long piece of model plant DNA and loads the main product in one lane. Which lane is it, and why?
- Lane 3, because each cycle halves the length of the product
- Lane 4, because each cycle doubles the length of the product
- Lane 2, because PCR copies the region between the primers
- Lane 1, because PCR copies the whole 5000 bp piece
Use this
Model gel (not to scale; model data). Lane 1 is model corn plant DNA and lane 2 is model soil bacterium DNA, both cut by the same enzyme.
Luz compares the two lanes of this model gel. Which statement matches the gel?
- The 700 bp bands match, and the pieces moved toward the negative (−) end
- The 700 bp bands match, and the 200 bp band moved farthest of all
- No bands match, because the samples come from different kinds of organisms
- The 700 bp bands match, and the 1200 bp band moved farthest of all
Notebook on gene cloning (model data)
line what it says 1 A restriction enzyme cuts DNA at a specific sequence 2 Cutting the plasmid and the gene with the same enzyme leaves matching sticky ends 3 DNA ligase cuts the plasmid so the gene can fit 4 Bacteria copy the plasmid as they divide Milo checks a classmate's notebook on putting a gene into a plasmid. Exactly one line is wrong. Which line, and why?
- Line 2, because sticky ends form with different enzymes, not the same one
- Line 3, because DNA ligase joins DNA and does not cut it
- Line 4, because a plasmid cannot be copied inside bacteria
- Line 1, because a restriction enzyme joins DNA pieces
Use this
Notebook on genetic engineering (model data), 4 rows. Columns: line, what it says. 1, Bt corn carries a gene from Bacillus thuringiensis. 2, Golden rice carries added genes that let the endosperm make provitamin A. 3, Adding the gene replaces the corn plant's whole genome with the genome of the bacterium. 4, An organism that gets recombinant DNA is a genetically modified organism.
Noah checks a classmate's notebook on genetic engineering. Exactly one line is wrong. Which line, and why?
- Line 3, because the plant keeps its own genes and gains the added gene
- Line 4, because a GMO must have a completely new genome from another species
- Line 2, because added genes cannot work in the edible part of a grain
- Line 1, because the gene comes from a plant and not from a bacterium
Use this
Notebook on PCR and gels (model data), 4 rows. Columns: line, what it says. 1, PCR copies the region between the two primers. 2, Each cycle doubles the target pieces, so 3 cycles turn 1 piece into 8. 3, In a gel, smaller pieces travel farther from the wells. 4, DNA pieces move toward the negative end of the gel.
Pia checks a classmate's notebook on PCR and gels. Exactly one line is wrong. Which line, and why?
- Line 1, because PCR makes copies of the whole genome in the cell
- Line 3, because larger pieces travel farther from the wells in a gel
- Line 2, because each cycle adds two pieces, so 3 cycles give 7 pieces
- Line 4, because negatively charged DNA moves toward the positive end
PCR step card (model data)
step temperature what happens denature high the two strands of the DNA pull apart anneal low short primers join the single strands extend medium Taq polymerase builds new strands from the primers Ren reads a PCR step card. Taq polymerase comes from the bacterium Thermus aquaticus. Which claim and reason about Taq are correct?
- Taq cuts the DNA at the primers, because strands must be cut before copying
- Taq keeps working when heated, because it comes from a heat-stable bacterium
- Taq is added fresh each cycle, because heat breaks it down
- Taq copies the whole genome at once, because it needs no primers
Model PCR card (model data)
item value start 1 piece each cycle doubles the pieces cycles 10 Tala predicts the pieces in a model PCR tube after 10 cycles. Which claim and reason are correct?
- 1,024 pieces, because each cycle doubles the number
- 21 pieces, because each cycle adds two pieces
- 10 pieces, because each cycle adds one piece
- 100 pieces, because each cycle multiplies the number by 10
Two crops card (model data)
crop what was added what it makes Bt corn a gene from Bacillus thuringiensis a protein that protects it from some insect pests golden rice a combination of added genes provitamin A in the endosperm Zee compares Bt corn and golden rice. Which claim and reason are correct?
- Each crop carries added genes, because engineering puts recombinant DNA into the organism
- Each crop has a replaced genome, because engineering swaps out the plant's genes
- Bt corn carries added genes but golden rice does not, because rice cannot take up recombinant DNA
- Each crop carries added genes, because restriction enzymes join them to the plant's DNA