Aufgabe 2 - Teilaufgaben 2 und 3: DNA, Proteinbio… · Abitur NRW Biologie GK · Haupttermin · bilingual Englisch 2023

Material A: The Effect of the Pesticide Azamethiphos

Salmon lice ( Lepeophtheirus salmonis) are small parasitic crustaceans. They infect the Atlantic salmon, live on its body surface and feed on mucous, skin particles and the fish’s blood. Affected fish have open wounds in the skin and anaemia 1. This can be lethal for the fish.

In salmon farming, the infestation of the fish can cause great economic losses. As one measure, the pesticide Azamethiphos is used in aquafarming, where it is added to the breeding tanks in small amounts (0.2 µg per litre). In order to investigate the effect of the pesticide on the nervous system of salmon lice, homozygous wild type salmon lice were treated with Azamethiphos for 24 hours. The activity of the enzyme acetylcholine esterase (AChE) was then measured in the treated wild type salmon lice (Figure 1).

1 Blutarmut

Material B: Azamethiphos Resistance and its Genetic Causes

After many years of regular use of Azamethiphos in aquafarming, a widespread resistance to this pesticide was observed in salmon lice. While investigating the causes for the resistance, the ace1a gene was discovered in the louse. The gene codes for acetylcholine esterase.

Material C: Effectiveness of Azamethiphos in Different Lines of Salmon Lice

In salmon farming waters of Norway, salmon lice lines 2 which differed in the genotypes of the ace1a gene were found. The effectiveness of Azamethiphos on salmon lice of the three lines was investigated: three salmon lice lines were treated with this pesticide for 24 hours and the effects observed (Figure 2). Then, the activity of the enzyme acetylcholine esterase was determined in line 1 under the influence of Azamethiphos (Figure 3).

2 hier: Stämme

Material D: Diagram and Codon Table of the Genetic Code

Aufgabe 2 - Teilaufgabe 2

2. Work out, for the nucleotide sequences given in Table 1 (Materials B and D), the mRNA sequences, the amino acid sequences and the type of mutation involved. Illustrate how the mutations could affect the function of acetylcholine esterase (Materials A and B).

[16 Punkte]

a)

b)

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Aufgabe 2 - Teilaufgabe 3

3. Work out the genotypes of lines 1, 2 and 3 and give reasons for your answer (Materials B and C). Compare the results in Figure 3 with those in Figure 1 and develop a hypothesis to explain the observed results (Materials A to C).

[17 Punkte]

h)

i)

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