Biologi Dasar: Campbell Bab 5 (CHECKPOINT)

Bab ini sangat penting untuk dibaca karena bisa dibilang tujuan membahas bab 2, 3, dan 4 adalah supaya kita bisa mengerti bab 5 yang super krusial ini. Sebelum beranjak ke bab tentang sel, kita harus memastikan dulu untuk paham luar dalam bab ini.

Teman-teman bisa latihan dari soal di internet dan OSK sebelumnya

Sekarang coba kerjakan soal ini yang terambil dari IBO 2014 Part B

A helix-wheel projection is a model of amino acid sequences of the alpha helix domain of a protein. The model can be used to show the distribution of amino acid residues along with its hydrophobicity throughout the helix. Reading the model is like looking at the helix vertically from the top so the helix will appear as a circle. The side group of each amino acid residue will face outwards as shown in Figure 2.1:

A full circle of a helix consists of 3.6 amino acid residues. The following sequences show one alpha helix domain consisting of 18 amino acids from three different proteins (A-C). Information about the hydrophobicity of all 20 common amino acids is shown in Figure 2.2.

Protein A : MLQSMVSLLQSLVSSIIQ

Protein B : TGAAAYAVVLFIMAYYMS

Protein C : KSSRKTPKKATARKSQRT

Hint: Bingung bolak balik kertas nyocokin asam amino mana?? Ingat: “FAMILY VW” untuk asam amino non polar

Indicate whether the following statements are true or false. An alpha helix:

1. similar to the one in protein A can be found in the transmembrane region of water-channel proteins i.e. aquaporins.

2. similar to the one in protein C can be found in the outer surface of cytosolic proteins.

3. similar to the one in protein C is amphipathic.

4. similar to the one in protein B might be found in the transmembrane domain of a receptor.