AP BIOLOGY

Detailed explanation-1: -They are double-membrane organelle with the presence of outer, inner and intermembrane space. There are two distinct regions present inside a chloroplast known as the grana and stroma. Grana are made up of stacks of disc-shaped structures known as thylakoids or lamellae.

Detailed explanation-2: -The outer membrane of the chloroplast envelope, like that of mitochondria, contains porins and is therefore freely permeable to small molecules. In contrast, the inner membrane is impermeable to ions and metabolites, which are therefore able to enter chloroplasts only via specific membrane transporters.

Detailed explanation-3: -Structure of Chloroplasts Chloroplasts are oval-shaped and have two membranes: an outer membrane and an inner membrane. Between the outer and inner membrane is the intermembrane space approximately 10-20 nm wide. The space within the inner membrane is the stroma, the dense fluid within the chloroplast.

Detailed explanation-4: -The double membrane found in mitochondria and chloroplasts appears to be a relic of the absorption of the prokaryotic bacteria by the eukaryotic host cells. The inner membrane, which now contains numerous folds, apparently came from the bacterial membrane, while the outer membrane came from the host cell itself.

Detailed explanation-5: -Like mitochondria, chloroplasts are surrounded by two membranes. The outer membrane is permeable to small organic molecules, whereas the inner membrane is less permeable and studded with transport proteins.