The DNA molecule is made up of two strands — each of which is a sequence of sugar and phosphate molecules linked by covalent bonds. The two chains are held together by much weaker hydrogen bonds between bases on opposite chains. The fact that the two chains are held together […]

Q1. An efficient DNA probe can sometimes be developed by knowing the amino acid sequence of the protein encoded by the gene. A student argued that this is too time-consuming as the complete amino acid sequence must be determined in order to create the probe. Does the student have a […]

1. Which of the following cell types does HIV preferentially infect? A) helper T cellsB) natural killer cellsC) phagocytic cellsD) B cells 2. Put the following parts of a nerve cell in the sequence that a signal would pass through them: synaptic terminal, dendrite, axon, cell body A) axon ? […]

The UV absorption in proteins at 280 nm is largely due to tryptophan residues. The molar extinction coefficient of tryptophan is 5380 M-1cm-1. Exactly 0.25 g of a protein is dissolved in 200 milliliters of a neutral buffer. The molecular mass of the protein is 36,000 g mol-1. The absorbance […]