Question

Explain transport of protein across the mitochondria.

Answer 1

Hint: Protein synthesis is defined as the process in which amino acids get arranged in linear order into proteins. The synthesis of protein involves all types of RNAs including ribosomal RNA, messenger RNA and transfer RNA. Protein synthesis also involves use of certain enzymes.

Complete answer:
Ribosomes are sites of protein synthesis. The free ribosomes are involved in the synthesis of nonsecretory proteins while the Endoplasmic reticulum that binds ribosomes synthesizes secretory proteins. Free ribosomes are involved in synthesizing structural and enzymatic proteins for use inside the cell. The attached ribosomes synthesise proteins for transport.

Most mitochondrial proteins are nuclear-encoded and produced as preproteins on polysomes in the cytosol. They must be targeted and translocated into mitochondria. Lately manufactured preproteins interrelate with cytosolic features till their credit by receptors on the external of mitochondria. Import into or across the outer membrane is mediated by an active protein composite creating the translocase of the outside layer. Pre Proteins that are imported into the atmosphere or inner membrane of mitochondria require the act of one of two translocation developments of the inner membrane (TIMs). The import path of preproteins is prearranged by their basic directing and arrangement indications.

Energy input in the form of ATP and the electrical rise across the inner membrane is vital for protein translocation into mitochondria. Newly imported proteins may need molecular chaperones for their right traveling.

Note: The ribosomes are composed of two subunits. One ribosomal subunit is always large in size and has a shape like that of the dome, and the other ribosomal subunit is smaller in size and occurs above the larger subunit and forms a cap-like structure.