Many amino acids in our diet are absorbed via the transcellu

Many amino acids in our diet are absorbed via the transcellular transport pathway by the intestinal eprthellal cells. This process requires ATP hydrolysis by ... the apical do the Na -a no acid symporters the plasma membrane. Na -a acid antiporters in the apical domain of the plasma membrane. The amino the Na pumps in the basolateral plasma membrane. the amino acid the basal domain of the plasma membrane F-type ATases In the a domain of the plasma membrane. An ion channel ... always mediates passrvo transport. is typically several orders of magnitude faster than atransporter. is usually gated. Al of the above For each membrane protein in the following schematic drawings, indicate whether the cytoplasmic sideof the membrane is more likely to be on the left or on the rignt. The plasma membrane is indicated as grey bar. Image 1 cytosol on the left image 2: cytol is on cytosol is on the left image 1: tytosol is on the right image 2: kytosol is on the left image 3 cytosol on the lat cytosol on the left image 2: cytosol is on the right image 3: kytosol is on the left the left cytosol is on the right image 1: cytosol us on the left image 2: cytol Image 3: cytosol is on the right

Solution

1)

The movement of amino acids into intestinal lumen occurs by import of amino acids at the apical surface of microvilli in the plasma membrane. The amino acids are transported as Na⁺ / amino acid symport and this is accomplished by hydrolysis of Na⁺ / K ⁺ ATPase that provides ATP for transport process. Option 1 is correct.

2)

These are very selective and specific for ions like Na⁺, K⁺ and Cl^- etc…For example, the K⁺ channels are 10,000 fold more permeable and selective for K⁺ than Na⁺. The specificity is due to strong interaction between the protein and K⁺ ions. The K⁺ ion channel transports up to 10⁸ K⁺ ions per second. Further the ion channels are gated and select ions by opening the gates. The ions pass across the cell membranes by specific energy driven pumps and are discharged through Na⁺ and K⁺ channels. The gates are normally shut, and are opened according to need of the cell to perform a specific task. The opening and closing of ion channels is called ‘Gating’ which occurs in response to the specific stimulus sent by the cell. Option 5 is correct.

3)

All the above given images show plasma membrane as grey colored. The cytoplasmic side is always left to the plasma membrane and ions, proteins or fatty acids anchor the plasma membrane on the right side. Therefore, in all three images cytoplasmic side is on the left of plasma membrane. Option 1 is correct.