A-LevelBiologyImmunity9700/21 · May/June 2022 · Q212 Marks

B-lymphocytes are activated to form plasma cells during immune responses. Fig. 2.1 is a drawing of a plasma cell made from a transmission electron micrograph.

(a)(i)State the name of the process that is occurring at T.[1]
(a)(ii)Complete Table 2.1 to show the names and functions of the cell structures labelled P, Q, R and S in the plasma cell shown in Fig. 2.1. Table 2.1 cell structure in Fig. 2.1 name of cell structure function of cell structure in plasma cell P Q R S[4]
(b)Plasma cells can be used in the commercial production of some monoclonal antibodies. The method of production is known as the hybridoma method. Outline the steps in the production of monoclonal antibodies by the hybridoma method.[3]
(c)Antibodies can be collected from human blood donors and used to treat people that may have been infected with a pathogen. This prevents them becoming ill with the disease. Explain why this treatment does not prevent people becoming ill if they are infected again with the same pathogen.[4]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

Mark scheme

Marking points from the official mark scheme (May/June 2022). The mark or mark type is shown in brackets.

[1] exocytosis;
[4] one mark per row
[4] P nucleolus production / assembly, of (sub-units of) ribosomes ; A manufacture, ribosomal RNA/rRNA / transfer RNA/tRNA
[4] Q mitochondrion R if answer refers to, ATP/energy, for aerobic respiration aerobic respiration; A oxidative phosphorylation A provide, ATP / energy A produce / AW, ATP
[4] R rough endoplasmic reticulum R rough ER/RER / ribosome protein / antibody, synthesis / transport; A synthesis of, polypeptide(s) / heavy and light chains A (post-translational) modification of, polypeptide / protein / antibody allow example A forms (transport) vesicles
[4] S Golgi body A Golgi, complex/apparatus I lipids (post-translational) modification of, polypeptide / protein / antibody allow example or packaging, qualified ; e.g. packaging of antibodies / protein, into vesicles A formation of, vesicles / (primary) lysosomes
[3] any three from:
[3] 1 (named) small mammal, injected / AW, with antigen; A immune response described
[3] 2 plasma cells / B-lymphocytes / B-cells / splenocytes, extracted from spleen ;
[3] 3 immune response occurs (over several weeks);
[3] 4 plasma cells / activated B-lymphocytes / activated B-cells, fused with, myeloma / tumour / cancer / AW, cells (to form hybridomas);
[3] 5 AVP; e.g. hybridoma cells separated (into wells) to produce clones screening / selection / AW, for hybridomas producing desired, (monoclonal) antibodies / Mabs ref. to large scale production
[4] any four from:
[4] 1 (artificial) passive immunity ; R natural
[4] 2 no immune response; I primary / secondary
[4] 3 idea that antibodies are, broken down / degraded / destroyed (in the body / blood); R 'antibodies die'
[4] 4 no long-term / only short-term / only temporary, immunity; A no formation of immunological memory
[4] 5 memory cells not produced ; A memory cells only produced, in active immunity / during an immune response / after presentation of antigen
[4] 6 AVP; e.g. ref. to no, clonal selection / clonal expansion / antibodies produced