The Control of Gene Expression | AQA A-Level Biology (7402)

The Control of Gene Expression

221 questions
18 subtopics
Paper 2, and available on Paper 3
Paper 2 and Paper 3

The Control of Gene Expression is examined on Papers 2 and 3 of AQA Biology, which draw on topics 5 to 8.

212 recall questions across 18 subtopics.

Sample questions from The Control of Gene Expression

Answer each one closed book first, then open the answer.

Types of gene mutation and mutagenic agents

Define a substitution mutation.

Show the answer
A type of gene mutation where one base is replaced by a different base
Totipotent, pluripotent and induced pluripotent stem cells

Define unipotent cells and state where they are found.

Show the answer
Unipotent cells are found in mature mammals and can divide to form only one cell type.
DNA methylation, histone acetylation and cancer

What are histones?

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Proteins that DNA wraps around to form chromatin.
Benign and malignant tumours, suppressor genes and oncogenes

What structural difference exists between benign and malignant tumours regarding encapsulation?

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Benign tumours are usually surrounded by a capsule of fibrous tissue whereas malignant tumours are not encapsulated.
Genome projects, the proteome and sequencing methods

What range of organisms have had their complete genomes determined through sequencing projects?

Show the answer
A wide range of organisms, including humans.
The polymerase chain reaction

What is the role of primers in PCR?

Show the answer
Primers are short sequences complementary to regions flanking the target DNA; they bind and allow DNA polymerase to start synthesis.
Transformation, marker genes and uses of recombinant DNA

How do marker genes help identify successfully transformed cells?

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They allow identification of cells that have taken up recombinant DNA, e.g. by conferring antibiotic resistance or producing a visible product.
DNA probes, hybridisation and screening for alleles

What must happen to target DNA before hybridisation with a probe can occur?

Show the answer
The target DNA must be made single-stranded, typically by heating or chemical treatment to break the hydrogen bonds between the two strands.

The 18 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Types of gene mutation and mutagenic agents	Recall questions on addition, deletion, substitution, inversion, duplication and translocation of bases, spontaneous mutation and mutagenic agents, and how a mutation can change the polypeptide.	11
Silent, frameshift, missense and nonsense mutations	Recall questions on why degeneracy makes some substitutions silent, frameshifts from additions and deletions, missense and nonsense mutations, and why a change at an active site matters most.	12
Totipotent, pluripotent and induced pluripotent stem cells	Recall questions on totipotent, pluripotent, multipotent and unipotent cells, how cells translate only part of their DNA as they specialise, induced pluripotent stem cells, and the uses and ethics of stem cell therapy.	19
Transcription factors, oestrogen, epigenetics and twin studies	Recall questions on how transcriptional factors and oestrogen switch on target genes, epigenetics, and how twin studies and cloned plants separate the effects of genes and environment.	18
DNA methylation, histone acetylation and cancer	Recall questions on how increased DNA methylation and decreased histone acetylation stop transcription, whether epigenetic changes are inherited, and how abnormal methylation relates to cancer and its treatment.	13
RNA interference and epigenetic drug targets	Recall questions on why epigenetic changes suit drug therapy, how small double-stranded RNA breaks down or blocks target mRNA in RNA interference, and how epigenetic changes differ from mutations.	11
Benign and malignant tumours, suppressor genes and oncogenes	Recall questions on how benign and malignant tumours differ in growth, encapsulation, metastasis and recurrence, and the roles of tumour suppressor genes, proto-oncogenes and oncogenes.	12
Abnormal methylation, oestrogen and evidence on causes of cancer	Recall questions on hypermethylation of tumour suppressor genes and hypomethylation of oncogenes, oestrogen and breast cancer, and evaluating genetic and environmental evidence from migrant and population studies.	16
Genome projects, the proteome and sequencing methods	Recall questions on sequencing the genomes of simple and complex organisms, why the proteome is easier to predict in simpler organisms, uses in vaccine development, and how sequencing methods have changed.	11
Transgenic organisms and making DNA fragments	Recall questions on recombinant DNA technology and why a universal code lets transferred genes be expressed, and making fragments with reverse transcriptase, restriction endonucleases or a gene machine.	11
The polymerase chain reaction	Recall questions on in vitro amplification by PCR, the roles of the template, primers, free nucleotides and heat-stable DNA polymerase, and the denaturation, annealing and extension steps of each cycle.	10
Promoters, restriction endonucleases, sticky ends and ligase	Recall questions on in vivo amplification, adding promoter and terminator regions, how restriction endonucleases make sticky or blunt ends, and joining fragments to a vector with DNA ligase.	10
Transformation, marker genes and uses of recombinant DNA	Recall questions on transforming host cells, how marker genes identify transformed cells, gene therapy, and the applications and ethical, financial and social issues of recombinant DNA technology.	9
The humanitarian debate, cDNA and in vivo cloning	Recall questions on the humanitarian benefits of recombinant DNA and why some groups oppose it, why cDNA lacks introns, and cloning fragments in vivo with restriction endonucleases, sticky ends and ligase.	11
DNA probes, hybridisation and screening for alleles	Recall questions on labelled DNA probes and DNA hybridisation, screening for heritable conditions and carriers, and pharmacogenomics and screening for drug responses.	11
Genetic counselling, personalised medicine and screening ethics	Recall questions on genetic counselling and personalised medicine, the advantages and psychological and ethical costs of genetic screening, and false positives, false negatives and reliability.	11
VNTRs, PCR and gel electrophoresis	Recall questions on variable number tandem repeats, amplifying them with PCR, and how gel electrophoresis separates DNA fragments by size to produce a genetic fingerprint.	15
Using and interpreting genetic fingerprints	Recall questions on reading shared bands to judge relatedness and genetic variability, and the uses of genetic fingerprinting in forensic science, medical diagnosis and animal and plant breeding.	10

The Control of Gene Expression is 221 of the 1,977 questions in the guide.Get the guide, £8

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.