Chapter 13, Problem 19STP

Summary Introduction

To determine:

The similarities of the structures of chloroplast and mitochondria with their functions.

Introduction:

Chloroplasts are membrane bound organelles which capture light energy. They are found in all plant cells. A chloroplast has two parts; sac like structures called thylakoids and a fluid filled space called stroma.

Mitochondria are membrane bound organelles that make energy available to all parts of a cell.

Answer to Problem 19STP

The structures of chloroplast and mitochondria are similar as both are double membrane organelles. Chloroplasts are organelles that capture light energy and convert it to chemical energy in the form of ATP and NADPH. Mitochondria are organelles that release energy from sugar molecules and store them in ATP through the process of oxidative phosphorylation. Both organelles have large surface area in the inner membrane through which electron transport occurs.

Explanation of Solution

Chloroplast- These are organelles that capture light energy and convert it into chemical energy through the process of photosynthesis. They have double membranes; an outer membrane and an inner membrane that has many disc shaped compartments called thylakoids. The thylakoids trap the solar energy with the help of a pigment called chlorophyll. Chloroplasts produce chemical energy in the form of ATP and NADPH. The thylakoid membranes have large surface area to hold large numbers of electron transporting molecules and protein complexes. Mitochondria- They too have double membranes; an outer membrane and a highly folded inner membrane that provides large surface area for breaking the bonds in sugar molecules. Electron transport occurs across the mitochondrial membranes. The energy produced from this breakage is stored in other molecules such as ATP. This energy is used by the cell for other cellular activities.