Jawaban soal2 MDE no.103-118

Minggu, 23 Desember 2007

Jawaban Soal-soal MDE FBS 3,4,5

104. D (Troponin C)
Pembahasan : Thin filaments terdiri dari protein actin , tropomyosin, dan troponin. Actin di sini merupakan F-actin yang merupakan hasil polomerisasi sari G-actin. Tropomyosin menempel pada actin sepanjang F-actin yang berpilin. Troponin merupakan sebuah kompleks yang terdiri dari 3 polipeptida: troponin T, I, dan C. Troponin T untuk berikatan dengan tropomyosin, troponin I untuk menghambat peran fungsi calcium dalam kontraksi, dan troponin C sebagai calcium-binding
Sumber : Med Cell hal.72

105. D (size)
Pembahasan : Chromatography merupakan salah satu metode dalam mengisolasi protein. Chromatography ini dapat dilakukan dengan 2 cara, yaitu: gel-filtration chromatography atau dengan ion-exchange chromatography. Pada gel-filtration, komponen-konponennya dipisahkan berdasarkan ukurannya (size), dengan molekul yang lebih besar akan melalui column lebih cepat. Sedangkan pada ion-exchange protein akan berikatan dengan matrix di dalam column yang bermuatan.
Sumber : Med Cell hal.18-19

106. C (mitochondria)
Pembahasan : Mitochondria have their own autonomous double-stranded circular DNA. The human mitochondrial genome has been completely sequenced and contains 15.569 nucleotides, which is less than 10-5 times of the human nuclear genome. There are five to ten mitochondrial genomes per human mitochondria and multiple mitochondrial per cell. Therefore, this DNA represent less than 1% of the total cellular DNA.
Sumber : Med Cell hal.150

107. D (Anti DNA)
Pembahasan : SLE (Systemic Lupus Erythmatosus) is the prototype of immune complex disease, which patients produce auto antibodies against their own DNA. The most common auto antibodies present at the time of diagnosis and correlated with disease activity are DNA-anti-DNA complexes
Sumber : Med Cell hal.24

108. A (enzyme)
Pembahasan : The movement of Na+ down to its electrochemical gradient can be coupled to the movement of another molecule against its gradient. This is referred to as secondary active transport because the Na+ electrochemical gradient is maintained by Na/K-ATPase. The Na/K-ATPase that pumps Na+ out the cell is located at the basolateral surface, constrained by interactions with ankyrin and nonerythroid spectrin.
Sumber : Med Cell hal.42

110. D (carbohydrate)
Pembahasan : The sugar residues of plasma membrane glycolipids almost always face the outside of the cell; that is, they have an asymmetric distribution, being found only in outer leaflet of the bilayer. The sugar residues are almost always found on the noncytoplasmic side of the membrane. This means that the carbohydrate will be outside of the cell and for the organelle membranes, the carbohydrate will be found within the lumen.
Sumber : Med Cell hal.30,33

113. C (Gap Junction)
Pembahasan : Cell junctions are classified into three functionally distinct groups: Occluding junction, also called tight junctions, form a physical barrier that prevents the leakage of even small molecules between cells. Anchoring junction, which include the hemidesmosomes, desmosomes, focal contacts, and adhesion belts, coupling neighboring cells either to each other or to the extra cellular matrix through interactions that are mediated by cytoskleleton. Communicating junctions, such the gap junctions, attach cells together in a manner that allows the transfer of chemical or electrical signals between neighboring cells
Sumber : Med Cell hal.196

114. B (Pinocytes)
Pembahasan : In endocytosis, the plasma membrane invaginates and fuses, internalizing small vesicles of 0.1-0.2 mm diameter. There are two forms of invaginating endocytosis: Fluid-phase endocytosis (pinocytosis) and receptor-mediated endocytosis. In receptor-mediated endocytosis, the molecule being internalized first binds to its receptor on the plasma membrane and is then captured within the budding vesicles. In pinocytosis, there is no such receptors-stimulated concentrating step.
Sumber : Med Cell hal.143-144

115. C (spanning plasma membrane)
Spanning = membentang
Sumber : Med Cell hal.29

118. E (hemidesmosome)
Pembahasan : Unlike desmosomes, the binding domains of hemidesmosomal transmembrane linker glycoproteins do not attach to other cells. Instead, the linkers bind to components of the specialized extracellular matrix of the basal lamina. By doing so, the basal surface of the epithelial cells is attached to the basement membrane.
Sumber : Med Cell hal.201

NB: maaf,ya, ga semuanya bias dikerjain…

0 komentar: