1

Do Plant Cells Have Mitochondria?

Table of Contents

Why do plant cells have mitochondria?

All living things in the world are made up of units called cells. Our cells can work together to make big things happen. For example, in humans, cells can team up and become organs, like your heart or your brain. The same is true for plants. Different parts of plants are made from cells with different tasks. From the roots to the flowers, plant cells work together to keep plants healthy, just like human cells do in our own bodies.

Red onion plant cells under a microscope
Red onion plant cells under a microscope, Credit: Wikimedia/Edoardo Simon, CC BY-SA 4.0

How are plant cells different from animal cells?

There are many different types of living things in the world. There are single cell organisms, which survive with just one cell. But animals and plants have many cells with many different functions. Plant cells behave differently than animal cells, so they have some different machinery. For example, plant cells have an additional outer shell called a cell wall. The cell wall gives plants a reliable, rigid structure. Animal cells can be more flexible and have different supports. To go with their rigid cell walls, plant cells generally have a more defined structure overall. Animal cells can be irregular and shaped differently from one another.

One more important difference between plants and animals is that plant cells have chloroplasts. Chloroplasts have a unique job. They perform a process called photosynthesis, in which energy from light is changed into energy that plants can use. Animal and human cells do not perform photosynthesis, so they do not need chloroplasts.

Plagiomnium
Plagiomnium affine laminazellen, Credit: Wikimedia/Kristian Peters — Fabelfroh, CC BY-SA 3.0

How are plant cells similar to animal cells?

Plant cells and animal cells came from the same ancestor a long time ago. Think of an ancestor, like a great, great grandparent. A long time ago, only very simple types of cells existed. They had similar functions. But over time, some of these cells changed to become plant cells or animal cells. This is why plant and animal cells have some similarities. They are long-lost relatives.

One structure that plant and animal cells share is the nucleus, where DNA is located. Although plant and animal cells have different DNA, they both organize their DNA into one location in the cell. Plant and animal cells contain other similar structures, including mitochondria. Mitochondria have a special job that helps a cell to survive and thrive.

Mitochondria are organelles that produce energy for the cell. You may have heard mitochondria referred to as the “powerhouse” of the cell. Does that sound familiar? Chloroplasts also produce energy in plant cells. However, plant cells have both chloroplasts and mitochondria, while animal cells have only mitochondria.

Mitochondria
Mitochondria, Credit: Wikimedia/Louisa Howard

Why do plant cells have both mitochondria and chloroplasts?

If plant cells already produce energy using chloroplasts, why do they need more energy from mitochondria? As you learned before, chloroplasts have the unique job of performing photosynthesis, in which light is changed into energy for the cell to use. You might be wondering what the energy from chloroplasts is like. Chloroplasts produce sugars for plants to use.

Once the sugar is produced from the chloroplasts, it can be changed into a new type of energy for the cell to use. That process is called respiration, and it can only happen in mitochondria. The sugar produced by photosynthesis in the chloroplasts becomes fuel for the mitochondria to make even more usable energy for the plant cell, called ATP.

Animal cells also need sugar for their mitochondria to perform respiration. So why don’t animal cells have chloroplasts? One thing that makes animals very different from plants is that animals can eat. So, the sugar that animal cells need for respiration comes from food instead of photosynthesis.

Do all plants and plant cells have chloroplasts?

Chloroplasts seem necessary to plant life because plants cannot eat food. However, some plant cells do not have chloroplasts at all. We know that chloroplasts change light energy into sugar. However, some cells in a plant never see any light! For example, plant roots are underground in the dark, so root cells do not use chloroplasts. Root cells have different machinery to help their energy production process. Also, flower cells may not have chloroplasts, because they have a different job than the rest of the plant. Flowers are made for plant reproduction, so they are not responsible for making energy.

It makes sense that only some cells in plants have chloroplasts. But some plants do not have chloroplasts at all. How does this work? One plant without chloroplasts is rafflesia. Rafflesia do not have visible roots or leaves, and leaves are where chloroplasts normally reside. Therefore, this plant does not do photosynthesis. However, it still needs sugar, just like other plants. Rafflesia manages to get its sugar by stealing it from a host. So, it needs and uses sugar, but it does not produce sugar itself as other plants do.

Rafflesia
Rafflesia, Credit: Wikimedia/ma_suska, CC BY 2.0

All different types of cells, from animal to plant cells, need sugar and energy. Over time, their ancestor cells found different ways to produce that sugar and make energy for their own growth and health. Plants from the desert to the forest and animals from the sea to the sky have similar life processes, performed in very different ways.

Glossary

Cells – the basic unit of living things

Single cell organisms – living things that only contain one cell

Cell wall – a rigid border found in plant cells

Chloroplasts – energy-producing structures that perform photosynthesis in plant cells

Photosynthesis – a process that changes light to energy used by a plant cell

 

Ancestor – an earlier type of cell

Nucleus – the structure that holds DNA in a cell

Mitochondria – the “powerhouse of the cell” which produces energy by performing respiration

Respiration – a process that produces usable energy for a cell

ATP – the energy currency of the cell, produced by mitochondria

Reproduction – the process that makes offspring

Flesch Kincaid Score: 67.8

Flesh-Kincaid Grade Level: 6.8

Reading Level: 8th and 9th grade

https://pubmed.ncbi.nlm.nih.gov/18369896/#:~:text=Mitochondria%20carry%20out%20a%20variety,via%20the%20electron%20transport%20chain.

https://biologydictionary.net/chloroplast/

https://www.ncbi.nlm.nih.gov/books/NBK9905/

https://cortland.edu/waldbauer-trail/8-non-photosynthetic-plants.html

https://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=12093#:~:text=Rafflesia%20was%20known%20to%20lack,energy%2C%20from%20its%20host%20vine.

https://www.reuters.com/article/us-flower-stench-idUSN1147389120070111