Question
Leptin helps to regulate body mass in humans and mice. The image shows an obese mouse (O)
and a normal mouse (N).
What hypothesis could account for the differences between the mice?
A. The hypothalamus of mouse O stopped producing leptin.
B. Adipose cells of mouse O are continuously producing leptin.
C. Mouse N has a defective leptin receptor.
D. Leptin binds to receptors in the hypothalamus of mouse N.
Answer/Explanation
Question
The image shows a replication fork.
Which row identifies X, Y and Z in the diagram?
Answer/Explanation
Question
During modification in eukaryotes, mRNA is spliced. What is splicing of mRNA?
A. Separation of mRNA from DNA during transcription
B. The removal of non-coding RNA sections in prokaryotic cells
C. Linking together exons
D. Replacement of primers with RNA bases
Answer/Explanation
Ans:
Question
The graph shows the effect of increasing substrate concentration on the rate of an enzyme-catalysed reaction.
Which type of inhibition corresponds to the labelled curves?
Answer/Explanation
Question
The diagram shows the structure of E. coli ribonuclease HI, a bacterial protein consisting of
one polypeptide chain.
Which level(s) of protein structure is/are shown?
A. Alpha helix only
B. Quaternary only
C. Primary and secondary
D. Secondary and tertiary