Quiz: Animal Research Regulation and Techniques — 24 domande

1. What is the main purpose of a Personal Licence in the UK animal research framework?

A. Approving the overall research programme and scientific justification for the project

B. Exempting non-protected species from the legal requirements for animal procedures

C. Authorizing an individual to carry out a specific regulated procedure after verified training

D. Certifying that the facility meets standards for housing, care, and veterinary support

Answer: (C)

Spiegazione

A Personal Licence permits a named person to perform a specific procedure and confirms they have the required training and competency. The Project Licence covers the research plan, while the Establishment Licence covers the facility.

2. Why does the 3Rs principle require researchers to choose replacement, reduction, or refinement whenever possible in animal research?

A. To increase the number of animals so results become more reliable

B. To prioritize convenience over experimental control

C. To replace every animal study with a human clinical trial

D. To limit animal use while maintaining scientific quality and welfare

Answer: (D)

Spiegazione

The 3Rs are designed to improve animal welfare while still supporting sound science: replacement avoids animals, reduction uses fewer animals, and refinement reduces pain and distress. The other options contradict the purpose of the principle.

3. What does the rodent open field test primarily measure?

A. Forelimb strength during forced pulling

B. Balance and coordination on a rotating rod

C. Anxiety-related avoidance in open versus closed arms

D. Baseline locomotion and exploratory activity

Answer: (D)

Spiegazione

The open field test is used to assess locomotion and exploratory behavior, typically by counting line crossings or grid entries. Anxiety can be a secondary measure, but it is not the main purpose of the test.

4. In the sucrose preference test, what does a reduced preference for sucrose over water most directly indicate?

A. Improved motor coordination and balance

B. Enhanced short-term recognition memory

C. Anhedonia and loss of reward-seeking behavior

D. Increased anxiety-related thigmotaxis

Answer: (C)

Spiegazione

A drop in sucrose preference is used as a readout of anhedonia, which is a key depressive-like symptom. The other options refer to different behavioral domains tested by other assays.

5. Which feature is used as the primary coordinate origin in stereotaxic surgery, while the other landmark is mainly used to level the skull?

A. The tooth bar, with ear bars used to confirm levelness

B. Bregma, with lambda used to confirm skull levelness

C. Lambda, with bregma used to confirm skull levelness

D. The sagittal midline, with the burr hole used to confirm levelness

Answer: (B)

Spiegazione

Bregma serves as the (0,0,0) stereotaxic reference origin. Lambda is used to ensure the skull is level in the frame before coordinates are applied.

6. Which experimental approach is best for testing whether a C. elegans mutant has a defect in habituation to repeated harmless stimulation?

A. Repeated placement on a rotating rod and measurement of latency to fall

B. Repeated mechanical tap stimulation with measurement of the decline in reversal responses

C. Repeated blue-light exposure and measurement of locomotor paralysis

D. Repeated exposure to a novel object and measurement of exploration time

Answer: (B)

Spiegazione

Habituation in C. elegans is commonly assayed by delivering repeated tap stimuli to the culture dish and observing whether reversal responses decrease over time. A mutant with impaired habituation will fail to show the normal progressive reduction in responding.

7. How does reverse transcription PCR differ from standard PCR in the type of starting material it can amplify?

A. It requires a fluorescent probe to detect mRNA in real time

B. It first converts RNA into cDNA before amplification

C. It uses protein as the starting template for amplification

D. It amplifies DNA directly without any enzyme conversion step

Answer: (B)

Spiegazione

RT-PCR includes a reverse transcription step that converts mRNA into complementary DNA before PCR amplification. Standard PCR amplifies DNA directly and cannot amplify RNA on its own.

8. Which approach is used to determine the exact starting copy number of a DNA sample in qPCR rather than comparing it to a control group?

A. Relative quantification using the ΔΔCt method

B. Endpoint analysis using an agarose gel

C. Absolute quantification using a standard curve

D. Normalization with a housekeeping gene only

Answer: (C)

Spiegazione

Absolute quantification uses a standard curve generated from known concentrations to read out the sample’s initial copy number or concentration. Relative quantification instead compares the sample to a control and usually relies on a housekeeping gene.

9. What is the main function of a DNA ladder in agarose gel electrophoresis?

A. To increase the electrical current so fragments separate faster

B. To neutralize the negative charge of DNA before it migrates

C. To stain DNA so the bands become visible under brightfield light

D. To provide known fragment sizes for estimating unknown DNA lengths

Answer: (D)

Spiegazione

A DNA ladder contains pre-measured fragments of known size that run alongside the sample, creating a reference for estimating the length of unknown bands. It does not stain DNA or alter its charge.

10. Why is Coomassie Blue often chosen for 2D-SDS-PAGE even though it is less sensitive than silver staining?

A. It is easier to use and gives a clear visual stain for separated protein spots

B. It identifies protein spots by measuring their mass-to-charge ratio

C. It directly labels proteins with fluorescent tags during electrophoresis

D. It permanently fixes proteins to the gel without any staining step

Answer: (A)

Spiegazione

Coomassie Blue is described as a moderate-sensitivity stain that is easy to use for visualizing separated protein spots. Silver staining is more sensitive, but the question asks why Coomassie is often chosen, which is its simplicity and practicality.

11. What does label-free quantification in mass spectrometry proteomics mean?

A. Calculating abundance from DNA standard curves in a qPCR assay

B. Comparing protein abundance across separate MS runs without chemical tags

C. Measuring protein abundance only after radioactive labeling of peptides

D. Identifying proteins by staining intact gels before digestion

Answer: (B)

Spiegazione

Label-free quantification analyzes samples in independent mass spectrometry runs and estimates abundance from spectral counts or peptide peak areas. Unlike label-based methods, it does not use isotopic chemical tags.

12. A researcher needs to perform a regulated procedure on a live mouse in the UK, but the work will occur in an approved institute with an existing programme and a trained operator. Which licence specifically authorises the individual to carry out the procedure?

A. Establishment Licence (PEL)

B. Procedure Approval Certificate

C. Personal Licence (PIL)

D. Project Licence (PPL)

Answer: (C)

Spiegazione

The Personal Licence authorises the specific person performing the procedure and confirms they have the required training and competency. The PEL covers the facility, while the PPL covers the research programme.

13. Which replacement strategy in the 3Rs principle uses computer simulations, mathematical modeling, or inert chemical systems instead of animals?

A. Absolute replacement

B. Reduction

C. Refinement

D. Relative replacement

Answer: (A)

Spiegazione

Absolute replacement avoids animal use by substituting non-animal systems such as computer simulations, mathematical models, or inert chemical systems. Relative replacement instead uses living non-protected systems like cell cultures or invertebrates.

14. Which comparison best distinguishes the rotarod test from the grip strength test in rodents?

A. Rotarod measures olfactory learning, whereas grip strength measures motor learning only

B. Rotarod measures forelimb asymmetry, whereas grip strength measures exploratory locomotion

C. Rotarod measures anxiety-related exploration, whereas grip strength measures recognition memory

D. Rotarod measures coordination and balance, whereas grip strength measures neuromuscular force

Answer: (D)

Spiegazione

The rotarod test assesses motor coordination, motor learning, and balance by timing how long the animal stays on the rotating rod. The grip strength test instead measures the force generated by the animal’s muscles against a transducer.

15. Which behavioral assay is used to detect rodent anhedonia by offering a choice between water and a sweet solution?

A. Elevated plus maze

B. Rotarod test

C. Cylinder test

D. Sucrose preference test

Answer: (D)

Spiegazione

The sucrose preference test measures how strongly a rodent prefers sucrose over water, and a reduced preference suggests anhedonia. The other tests assess anxiety or motor function rather than reward-related behavior.

16. What is the main function of bregma during stereotaxic surgery?

A. It indicates the target depth for the micro-syringe

B. It is used to level the skull horizontally in the frame

C. It serves as the zero-reference origin for coordinate measurements

D. It marks the posterior limit of the cranial drill site

Answer: (C)

Spiegazione

Bregma is the primary (0,0,0) reference point for stereotaxic coordinates. Lambda is the landmark used to help ensure the skull is level, not to define the coordinate origin.

17. What is the most direct consequence of a worm lacking a normal habituation response to repeated harmless tap stimulation?

A. It keeps reversing strongly instead of gradually reducing the response

B. It develops a preference for the tap stimulus

C. It shows improved learning after repeated taps

D. It stops moving permanently after the first tap

Answer: (A)

Spiegazione

Habituation is a progressive decrease in response to a repeated harmless stimulus. If the response is defective, the worm fails to show the normal reduction in reversals after repeated taps.

18. What is the denaturation step in PCR?

A. The separation of double-stranded DNA into single strands

B. The conversion of mRNA into cDNA before amplification

C. The synthesis of new complementary DNA strands

D. The binding of primers to target DNA sequences

Answer: (A)

Spiegazione

Denaturation is the high-temperature step that breaks the double helix into single strands so primers can bind. Primer binding is annealing, not denaturation.

19. In reverse transcription PCR, which event happens first before standard PCR amplification of the target sequence begins?

A. The DNA template is fragmented by sonication

B. Reverse transcriptase converts mRNA into complementary DNA

C. Taq polymerase directly copies the RNA template

D. The amplified product is visualized on an agarose gel

Answer: (B)

Spiegazione

RT-PCR begins by using reverse transcriptase to convert unstable mRNA into cDNA. Standard PCR amplification then proceeds from that DNA template.

20. Which qPCR feature is most directly required for absolute quantification rather than relative quantification?

A. A housekeeping gene used for normalization

B. A Ct value measured at the threshold line

C. A standard curve generated from known concentrations

D. A fluorescent dye that binds double-stranded DNA

Answer: (C)

Spiegazione

Absolute quantification requires a standard curve made from known, pre-quantified standards to determine the exact starting copy number or concentration. Relative quantification instead compares the sample to a reference or control, often using a housekeeping gene and the ΔΔCt method.

21. A researcher wants to separate PCR products on an agarose gel to estimate whether one fragment is about 300 bp and another is about 900 bp. What is the main reason the smaller fragment will migrate farther through the gel?

A. It faces less resistance moving through the gel pores

B. It is pulled toward the negative electrode

C. It contains more phosphate groups per base pair

D. It binds more strongly to the fluorescent stain

Answer: (A)

Spiegazione

Smaller DNA fragments pass more easily through the agarose matrix, so they move faster and farther toward the positive electrode. The stain only enables visualization and does not determine migration.

22. How does label-free quantification in mass spectrometry proteomics differ from label-based quantification?

A. It relies on a housekeeping protein to normalize protein abundance across groups

B. It mixes samples after isotopic tagging so they can be analyzed in a single MS run

C. It analyzes each sample in separate MS runs and estimates abundance from spectral counts or peptide peak areas

D. It measures protein amount directly from band intensity on a stained gel

Answer: (C)

Spiegazione

Label-free quantification keeps experimental groups separate and estimates abundance from spectral counting or the area under chromatographic peaks. In contrast, label-based methods tag samples and combine them for one run.

23. Which step of a standard PCR cycle separates the DNA template into single strands so primers can bind in the next step?

A. Annealing at 50°C to 65°C

B. Extension at 72°C

C. Denaturation at 94°C to 98°C

D. Reverse transcription into cDNA

Answer: (C)

Spiegazione

Denaturation is the high-temperature step that breaks double-stranded DNA into single strands. Annealing and extension occur afterward, while reverse transcription is part of RT-PCR rather than standard PCR.

24. What is the main purpose of visualization stains in gel-based proteomics after protein separation?

A. To convert proteins into peptides for mass spectrometry

B. To determine the exact amino acid sequence of each protein spot

C. To make separated protein spots visible for comparison and analysis

D. To amplify proteins so they can be detected by PCR

Answer: (C)

Spiegazione

Visualization stains such as Coomassie Blue, silver stain, or fluorescent dyes are used to reveal the separated protein spots after 2D-SDS-PAGE. They do not amplify proteins or determine sequence.