Q) Describe rough endoplasmic reticulum, mitochondria and ribosomes in terms of their structural features
Main points | |
Key idea: | Structural features of rough endoplasmic reticulum (rER) |
· Complex network of membranous tubules + sacs (cisternae) · Ribosomes attached to outer surf of membrane · which is continous w outer membr of nucleus | |
Key idea: | Structural features of mitochondria |
· Cylindrical or rod-shaped · Double membrane-bound: outer + inner membr sep by inter-membrane space · (i) outer membrane - smooth cont layer + (ii) inner membrane - folded inward, form cristae, project into semi-fluid matrix · Matrix contains circular DNA + 70S ribo. · Stalked particles containing ATP synthase (or ATPase) embedded w/n inner membr, for ATP syn | |
Key idea: | Structural features of ribosomes |
· Made up of proteins + ribosomal RNA (rRNA) · One small + one large subunit (contains peptidyl transferase) · Euk cell - 40S & 60S subunits ; Prok cell - 30S & 50S subunits · Exist suspended in cytosol or attached to outer surf of ER · Has specific sites : (i) Aminoacyl-tRNA binding site (A site) which bind to tRNA w aa (ii) Peptidyl-tRNA binding site (P site) which bind to tRNA w growing polypep | |
Comments: (i) Visualize the answer with the aid of labelled pictures of the organelles (refer to URL provided) (ii) Verbalize the answer + write down the main points w/o referring to the answer (use abbreviations) (iii) Read again within the next 24h & once more within 72h (do not spend more than 10min) (iv) Ribosomes also contains the E site where the uncharged tRNA exits | |
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