Research Skills Paper LV 2021 Flashcards
What unit is commonly used to express protein molecular weight in SDS-PAGE?
Kilodaltons (kDa)
How does SDS-PAGE separate proteins by size?
SDS denatures proteins and gives them a uniform negative charge, allowing separation by size through a polyacrylamide gel—smaller proteins travel farther.
Why might multiple bands appear in SDS-PAGE for a single sample?
Multiple proteins may be present: native bacterial proteins, degradation products, or post-translational modifications.
List three reasons a recombinant protein may not be expressed in E. coli.
- Faulty plasmid/promoter, 2. Protein toxicity to host, 3. mRNA translation issues (e.g. codon bias).
How much protein (in µg) is in 1 µL of a 5 g/L solution?
5 µg
What three improvements should be made to a scientific biological drawing?
Add a title, a scale bar, and clear straight labels.
What does an R-squared value represent in correlation?
The proportion of variance in the dependent variable explained by the independent variable.
How would you test whether crabs outcompete shrimp for food?
Use controlled enclosures: shrimp-only, crab-only, and mixed groups; compare survival, growth, or feeding.
What does a wider distribution in morphospace indicate?
Greater morphological diversity among species, likely due to different environmental pressures or adaptations.
Why might shell morphology differ between near-shore and off-shore gastropods?
Near-shore species adapt for wave resistance; off-shore species may evolve for mobility or burrowing.
How does species diversity increase woodland resilience?
Diverse species have varied responses to stress, which helps maintain ecosystem functions after disturbances.
Why is tree age important in woodland dynamics?
It reflects reproduction potential, past disturbances, and helps predict future stand structure.
How does shade tolerance affect tree regeneration?
Tolerant species can survive under canopy shade and may outcompete intolerant ones in closed-canopy forests.
How would a mouse outbreak eating young sycamores affect two different stands?
Stand with more sycamore seedlings (e.g. Stand 2) would suffer more, potentially altering future species composition.
What is the formula for a 95% confidence interval of a regression slope?
Estimate ± 1.96 × Standard Error
What does an R² of 0.56 indicate?
56% of variation in the dependent variable is explained by the independent variable.
List three assumptions of linear regression.
Linearity, normally distributed residuals, and constant variance (homoscedasticity).
Why is combining new data with published data potentially problematic?
Variation in methods, bias in published data, and inconsistencies can distort analysis.
What does linear regression ignore in the cuckoo-host egg size study?
It overlooks individual variation and host-specific cuckoo adaptations.
