Which of the following best explains how substances are transported across the cell membrane?

Nucleic acids absorb light strongly in the ultraviolet region of the spectrum because they have ________ double-bond systems.  

Ceramides contain a fatty acid linked by an____________ via the C-3 hydroxyl group of sphingosine.

As DNA denatures, its UV absorbance at 260nm increases due to the “hyperchromic effect.” All of the following statements about DNA denaturation are true, EXCEPT:

Which of the following does NOT describe the secondary structure of DNA as proposed by Watson and Crick?

Mitochondrial complex I is a large protein complex located in the inner mitochondrial membrane. During cellular respiration, this complex uses energy to transport hydrogen ions (H+) against their concentration gradient. The steps of (H+) transport carried out by mitochondrial complex I are depicted in the following diagram:     Given the concentration gradient established by mitochondrial complex I, which of the following movements can occur?

Membrane passive transport and transport by channels and pores requires ________.  

Purines and pyrimidines exist in two tautomeric forms (lactam and lactim); nucleosides exist in two conformations (syn and anti). The most common forms found in cells are ________.  

Saturated fatty acids are different to unsaturated fatty acids because they ________.  

Low potassium is hypocalcemia. (B7)