AS Human Biology Unit 8

Text questions

P144/Q1		Optimum temperature, O2, H2O, ions, nutrients (aminoacids, glucose, etc.).
P145/Q2		Cilia remove mucus + micro-organism. If cilia paralysed → mucus + micro-organisms not removed → they stay in the optimum conditions for their growth → infection.
P146/Q3		Higher permeability of blood capillaries → more tissue fluid leaking out of capillaries → more WBC in the intercellular spaces available for phagocytosis.
P151/Q4		Serum: antibodies → antibodies bind to the antigen (meningitis bacteria) → number of antigens reduced.
P156/Q5		Hypoallergenic substances are less likely to cause an allergy/inflammatory response.

Assignment

P158/Q1	a)	Material from the smallpox (SP) pustule contains puss (dead host body cells + SP virus). SP virus has antigens on its surface → entry into the host body cell → antigens displayed on the surface of the cell → clonal selection → [Th cells and T-("Master") lymphocyte cells selected and bonded (via SP antigen and a chemical marker) onto the surface of the infected host's cell → cytokineses → T- ("Master") lymphocyte → cloning → differentiation → more Th cells + T-m cells + T-killer cells. After the second exposure to SP virus → increased concentration of antibodies in the blood → better chance of recovery.
	b)	Some SP viruses in the puss could become active → infection.
P158/Q2		Cow pox (CP) caused by a viral strain with similar antigens to those of SP virus → memory cells already present in the lymph nodes of the patient → rapid immunological response when infection caused by SP virus.
P158/Q3	a)	In some cases previous infection caused by CP did not protect the patient from developing symptoms of SP after inoculation with material from SP pustule.
	b)	There must be a variety of different forms/strains of CP virus, some of them more or less similar to SP virus.
P159/Q4	a)	Control: another patient not inoculated with CP virus.
	b)	Increasing the number of attempts/experiments in order to obtain a large number of statistical data for analysis.
P159/Q5		This could be the title for an essay to be included in your Coursework Portfolio.

Examinations

P159/Q1

Humoral immunity	Cell-mediated immunity
(1) Bacteria present in blood (2) Pathogen killed by antibodies	(1) Virus inside host's body cells (2) Virus killed by killer T-cells

Stage I: various clones of lymphocytes available for clonal selection
Stage II: clonal selection takes place
Stage III: selected types of lymphocytes kill the pathogen;

P160/Q2

Antibodies can completely surround the pathogen (B), or may bind only to some special molecules/antigens present on the surface of pathogens (C).

(i) Lysis of bacterial cell capsule/wall

(ii) Agglutination

1st exposure

Antigen-presenting M/phage binds with Th Cells & B-Cells
Th Cells → cytokines → B-Cells
B-Cells → cloning → differentiation → memory B-cells + plasma cells
Plasma cells → antibodies

2nd exposure

Antigen-presenting M/phage binds with memory B-Cell
Memory B-Cell activated → clones of plasma cells
Plasma cells → antibodies

P160/Q3

Vaccine → ingestion by macrophage → antigen presentation → clonal selection: T-h Cells → cytokines
→ B- ("Master") Cell activated → cloning → differentiation: B-plasma Cells + B- memory Cells produced/stored. If the organism is exposed to the same pathogen again, the events described in
Q2(c), p.160 will follow (for details see column: "2nd exposure")