Chloroplast — Structure & Function

Role of Chloroplasts

Chloroplasts are organelles which are only found in plant cells. Their job is to absorb sunlight and use it (along with water and carbon dioxide) to produce a simple sugar called glucose.

The process in which chloroplasts convert sunlight into sugar is called photosynthesis.

Chloroplasts are also the reason why plants are green. They contain a pigment (almost like a dye) called chlorophyll. Chlorophyll has a green color.

To help myself remember this, I always think that "chloroplasts are phylled (filled) with chlorophyll".

We also need to talk about the parts of a chloroplast. Let's look at a picture first.

This picture shows a chloroplast (it looks like a green potato) with part of the top carved off so we can see the inside.

Here's what's inside:

There are actually two membranes surrounding the chloroplast. In the middle of these membranes is the intermembrane space, where certain reactions take place during photosynthesis.

Inside, chloroplasts have stacks of pancake-like sacs. A single pancake is called a thylakoid. Many thylakoids stacked together is called a granum (plural: grana). The thylakoids are green because this is where chlorophyll is stored.

There is a watery liquid surrounding all of the stacks. This liquid is called stroma.

All of these spaces and the products made in them are important for different process of photosynthesis. They are all connected in some way. For example, the light reactions produce ATP and NADPH, which are then used for carbon fixation during the Calvin cycle.

Key Vocabulary:

1. Chloroplast
2. Chlorophyll
3. Photosynthesis
4. Granum
5. Stroma

What Are Chloroplasts?

Chloroplasts are organelles inside of plant cells that help the plant generate its own food (glucose). Chlorophyll, located inside them, makes this glucose, and the process of making glucose is called photosynthesis. Photosynthesis comes from photo, meaning "light", and synthesis, meaning "to make". So, photosynthesis means making something from light (in this case glucose). To perform the reactions of photosynthesis, plants need:

• Sunlight
• Water
• Carbon Dioxide

Plants perform photosynthesis by combining these three things to get glucose and oxygen, as shown in the following chemical equation: $$6CO_{2} + 6H_{2}O + energy \rightarrow C_{6}H_{12}O_{6} + 6O_{2}$$ Remember, this all happens inside of the chloroplast. Chloroplasts are a type of plastid. Plastids are organelles in plants and algae that create and store food or pigments and are important for photosynthesis.

Chloroplast

Chloroplasts are used in plant cells to perform photosynthesis, which is the process used to make the energy-rich molecule glucose. They are thought to have originated from bacteria that were consumed by eukaryotic cells. Here are a few important traits about chloroplasts:

• They contain stacked discs called thylakoids. Photosynthesis is performed across the thylakoid membrane.

• They are similar to mitochondria in that they contain their own DNA (chloroplast DNA). They also rely on the increased surface area in their interior membrane to increase ATP productivity.

• They use the green pigment chlorophyll to capture light energy from the sun and, combined with carbon dioxide, produce glucose and oxygen.

• They are a type of plastid. Plastids are organelles found within plants and algae that play a large role in photosynthesis. They are used to create and store food or pigments.

Chloroplasts and Chlorophyll

Chloroplasts are neat little things. They are plant-exclusive organelles that convert solar energy (light) into chemical energy for the cells to use. This process is known as photosynthesis. You've probably heard of it before. Chloroplasts contain the green pigment chlorophyll. They are a type of plastid. Plastids are organelles in plants and algae that create and store food or pigment, and they are really important in the process of photosynthesis.

They are the solar panels of the plant cell.

You can actually see this organelle in plant cells when viewing them under a microscope. It's really, really cool.

$$\color{#8925AE}{\text{Vocabulary Review:}}$$

$\color{#8925AE}{\text{Cell Wall}}$ : Gives plant cells extra stability and structure

$\color{#8925AE}{\text{Chloroplast}}$ : Captures energy from light for photosynthesis

(Video) The Chloroplast

by Bozeman Science

What do chloroplasts do for plants? In this video, you will learn about the structure, actions, and function of these organelles in plant cells.