Respiratory syncytial virus (RSV) can infect the human gas exchange system and cause disease in human populations. Explain why the disease caused by RSV is an example of an infectious disease.

Answer

0 words

4(b)Pathogens Communicable DiseaseEasy2 marks

Figure 4.1 shows the structure of RSV.

Figure 4.1, a diagram of the structure of respiratory syncytial virus (RSV): a roughly circular particle whose outer boundary is a shaded grey ring (the envelope), studded all the way round its outside with paired, club-shaped protein spikes; inside the envelope a long, tightly coiled strand of RNA runs through the particle, packed along its length with small round and hexagonal protein subunits; the label Q, with a bracket, marks a short segment of the grey envelope ring that sits beneath one of the protein spikes, not the spike itself

State the name of the outer layer labelled Q in Figure 4.1, and the name of the structure in Figure 4.1 composed of protein subunits.

Outer layer labelled Q

Structure composed of protein subunits

4(c)(i)Gas ExchangeMedium1 mark

RSV can infect tissues of the bronchus. Figure 4.2 is a photomicrograph of tissues in a bronchus.

Figure 4.2, a photomicrograph (magnification $\times 500$) of bronchus tissue: the lumen is lined on the right by a folded layer of tall ciliated columnar epithelial cells with cilia fringing their free surface, one of which is labelled Y; running vertically just beneath this epithelium is a band of elongated, spindle-shaped smooth muscle cells, labelled X; a rounded island of cartilage and loose connective tissue are visible to the left

State the name of the tissue labelled X in Figure 4.2.

4(c)(ii)Gas ExchangeMedium1 mark

State the function of the cell labelled Y in Figure 4.2.

4(d)(i)Antibodies VaccinationMedium2 marks

There are two methods that can be used to prevent people from becoming ill if they come into contact with RSV. These methods are injection with a monoclonal antibody, and vaccination. State the forms of immunity that people would be expected to develop as a result of each of these two methods. Use two words to describe each form of immunity.

Injection with a monoclonal antibody

Vaccination

4(d)(ii)Antibodies VaccinationHard4 marks

Outline how a monoclonal antibody to protect people against RSV is produced by the hybridoma method.

Answer

0 words

4(d)(iii)Antibodies VaccinationEasy1 mark

State one advantage of using a vaccine, instead of a monoclonal antibody, to protect against RSV infection.

Answer

0 words

4(e)(i)Immune System DefencesEasy2 marks

Phagocytes can remove cells in the body that have been infected with viruses such as RSV. (i) Outline the events that lead to the formation of a phagocytic vacuole after detection of the infected body cells by a phagocyte.

Answer

0 words

4(e)(ii)Cell Structure OrganellesEasy1 mark

State the name of the organelle in a phagocyte that contains enzymes to destroy the infected cells.