Melibiose is a disaccharide found in some plant-derived pathogens.
Melibiose is formed from one molecule of glucose and one molecule of galactose. Both glucose and galactose are hexose monosaccharides with the chemical formula C6H12O6\text{C}_6\text{H}_{12}\text{O}_6C6H12O6.
Give the chemical formula for the disaccharide, melibiose, and describe how it is formed from glucose and galactose.
In some agricultural workers, inhalation of pathogen spores triggers an immune response where antibodies are produced against surface glycoproteins containing melibiose. Draw a labelled diagram of an antibody and identify the specific site where melibiose would bind.
Suggest how a single antibody can show cross-reactivity, binding specifically to both the plant-derived melibiose and a structurally distinct bacterial membrane protein.
14 exam-style questions on AQA A Level Biology Cell recognition and the immune system, covering Cell recognition and the immune system. Each one has a worked solution and a mark scheme showing where the marks go.