Modern Genetics | Edexcel A-Level Biology B (9BI0)
Modern Genetics
- 100 questions
- 8 subtopics
- Topics 5 to 7, examined on Paper 1 and Paper 3
- Paper 1 and Paper 3
What gene sequencing makes possible, how gene expression is controlled by transcription factors and by epigenetic change, what stem cells can do, and how DNA is cut, inserted and expressed in another organism..
It covers using gene sequencing, transcription factors and RNA splicing, epigenetics and gene expression, stem cells, producing recombinant DNA, vectors and transformation, knockout mice and GM soya beans and the debate over genetically modified crops.
Sample questions from Modern Genetics
Answer each one closed book first, then open the answer.
-
Using gene sequencing
Why is the temperature raised to 72°C during the extension phase of PCR?
Show the answer
This is the optimum temperature for DNA polymerase (typically Taq polymerase) to synthesise new DNA strands. -
Transcription factors and RNA splicing
How do transcription factors influence the activity of RNA polymerase?
Show the answer
They influence the recruitment of RNA polymerase to the promoter region, either enhancing or inhibiting its binding. -
Epigenetics and gene expression
In DNA methylation, which DNA base has methyl groups added to it?
Show the answer
Cytosine bases. -
Stem cells
What is the differentiation potential of pluripotent stem cells?
Show the answer
They can differentiate into any cell type of the body but not extraembryonic tissues. -
Producing recombinant DNA
Why are sticky ends useful in genetic engineering?
Show the answer
Sticky ends are complementary single-stranded overhangs that can form hydrogen bonds with other complementary sticky ends, allowing DNA fragments to join together. -
Vectors and transformation
Why are gene guns particularly useful for transforming plant cells?
Show the answer
Plant cells have cell walls that are difficult to penetrate by other methods, but gene guns can fire DNA-coated particles directly through them. -
Knockout mice and GM soya beans
How do knockout mice help scientists investigate gene function?
Show the answer
By observing the phenotypic effects when a specific gene is absent, researchers can determine what function that gene normally performs. -
The debate over genetically modified crops
State one advantage of genetic modification of crops relating to weed control.
Show the answer
Herbicide tolerance, allowing crops to survive herbicide application while weeds are killed.
The 8 subtopics
One subtopic is one session. Work down the list.
| Subtopic | What it covers | Questions |
|---|---|---|
| Using gene sequencing | Recall questions on genomes, the denaturation, annealing and extension steps of PCR, how gene sequencing predicts protein structure and identifies mutations, and DNA profiling for forensics and paternity, with when to use each technique. | 15 |
| Transcription factors and RNA splicing | Recall questions on transcription factors as activators and repressors that bind near genes and control RNA polymerase, and RNA splicing of pre-mRNA: exons, introns and how alternative splicing lets one gene code for several proteins. | 12 |
| Epigenetics and gene expression | Recall questions on epigenetic modification, non-coding RNA, histone acetylation and methylation, DNA methylation at CpG sites, and how accumulating epigenetic silencing restricts cells from totipotent to pluripotent to differentiated. | 13 |
| Stem cells | Recall questions on totipotent, pluripotent and multipotent stem cells and where they are found, the medical promise and ethical concerns of embryonic stem cells, and producing induced pluripotent stem cells from fibroblasts with transcription factors. | 22 |
| Producing recombinant DNA | Recall questions on recombinant DNA, restriction endonucleases and sticky ends, why donor and vector DNA are cut with the same enzyme, annealing of the fragments, and sealing the joins with DNA ligase. | 9 |
| Vectors and transformation | Recall questions on vectors, viral vectors and gene guns for plant cells, antibiotic resistance marker genes, and using replica plating to identify cells that carry recombinant DNA. | 9 |
| Knockout mice and GM soya beans | Recall questions on how knockout mice are produced and used to study gene function and disease, and why soya beans were modified to alter their balance of fatty acids and prevent oxidation. | 8 |
| The debate over genetically modified crops | Recall questions on the benefits claimed, the ecological and economic concerns, and the arguments on each side. | 12 |
How the guide is worked
Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.
-
Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
-
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
-
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.
Read the full method, the return schedule and the research behind it.
Nearby topics
Edexcel A-Level Biology B Active Recall Guide
Every topic, not just this one. 2,073 questions with their answers.