Q.Match the following
Column I — Column II

The correct matches are:

• (a) Cristae — (ii) Infoldings in mitochondria
• (b) Cisternae — (iii) Disc-shaped sacs in Golgi apparatus
• (c) Thylakoids — (i) Flat membranous sacs in stroma

Each term belongs to a different organelle: cristae are the folds of the inner mitochondrial membrane, cisternae are the stacked flattened sacs of the Golgi apparatus, and thylakoids are the flattened membranous sacs lying within the stroma of the chloroplast.

This matching exercise checks whether you can attach each membrane structure to its parent organelle. Taking them one at a time:

• Cristae are a feature of the mitochondrion. Each mitochondrion has a double membrane, and its inner membrane is thrown into numerous infoldings that project towards the matrix. These folds are the cristae, and their value lies in greatly increasing the surface area available inside the organelle. This matches (ii), infoldings in mitochondria.
• Cisternae belong to the Golgi apparatus. The Golgi is built from many flat, disc-shaped sacs called cisternae, stacked one above another and lying parallel to each other. This matches (iii), disc-shaped sacs in the Golgi apparatus.
• Thylakoids are found inside the chloroplast. The space enclosed by the chloroplast's inner membrane is the stroma, and within the stroma lie flattened membranous sacs called thylakoids, stacked like piles of coins to form grana. This matches (i), flat membranous sacs in the stroma.

Method: Anchor Each Term to Its Home Organelle First

Matching questions across multiple organelles are solved most reliably by treating each Column-I term as a search for "which organelle does this word belong to" before you even look at the Column-II descriptions — the parent organelle is usually the piece of knowledge you're most confident about, and the structural detail follows from it.

Here: "cristae" should immediately trigger "mitochondrion" (it's the standard vocabulary for its inner-membrane folds); "cisternae" should trigger "Golgi apparatus" (its stacked flattened sacs); and "thylakoids" should trigger "chloroplast" (its light-capturing internal membranes within the stroma). Doing this first pass purely on vocabulary recall, before reading Column II closely, avoids getting misled if two descriptions in Column II sound superficially similar (e.g., both cristae and thylakoids are "membrane infoldings/sacs" in a loose sense).

Only once each term is pinned to its organelle should you go back and match the specific wording in Column II — at that point it's just confirming that "infoldings in mitochondria" matches your mitochondrion anchor, "disc-shaped sacs in Golgi apparatus" matches your Golgi anchor, and "flat membranous sacs in stroma" matches your chloroplast anchor. This two-pass approach (anchor organelle first, then confirm wording) is more robust under time pressure than trying to match all three simultaneously from the phrasing alone.