What is a eukaryote? A look at animal and plant cells

1. Plant and animal cells are eukaryotic, meaning that they have nuclei

Eukaryotic cells are found in plants, animals, fungi, and protists. They generally have a nucleus—an organelle surrounded by a membrane called the nuclear envelope—where DNA is stored. There are a few exceptions to this generalization, such as human red blood cells, which don’t have a nucleus when mature. Eukaryotic cells are typically larger than prokaryotic cells, ranging from around 10 to 100 μm in diameter. While many eukaryotes consist of multiple cells, there are also single-celled eukaryotes.

2. Animal cells are supported by a cytoskeleton, use mitochondria to generate energy, and use lysosomes to help remove waste

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Animal cell

Animal cells contain a wide variety of organelles to help them carry out their functions.

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Like bacteria, animal cells have a plasma membrane, cytoplasm, and DNA. However, you’ll notice that the inside and outside of animal cells looks quite different from that of bacteria. For one, animal cells don’t have a cell wall. Instead, they have a cytoskeleton, a network of filaments composed of proteins. The cytoskeleton provides support and internal transport for the cell.

In addition, most animal cells have a nucleus, a special organelle that stores DNA. The DNA inside the nucleus is usually organized into strings called chromosomes.

3d rendering of a cell nucleus, including chromosomes

The cytoplasm of animal cells is filled with a variety of organelles that help the cells survive and reproduce. Here are some key cytoplasm-dwelling organelles and their functions:

Organelle

Function

Centrosome

The centrioles and pericentriolar material inside play a role in cell division and building microtubules

Golgi apparatus

Modifies, sorts and packs proteins into transfer vesicles, so they can go elsewhere in the cell or be secreted

Lysosomes & peroxisomes

Help remove waste, break down toxic compounds, and recycle cell structures

Mitochondria

Generate energy

Ribosomes

Synthesize proteins

Rough endoplasmic reticulum

Continuous with outer layer of nuclear envelope and has ribosomes embedded on the outer membrane; helps transport materials within the cell; segregates newly-made proteins for transport by vesicles

Smooth endoplasmic reticulum

Separate from the nuclear membrane, but continuous with the rough endoplasmic reticulum, and does not contain ribosomes; site of lipid synthesis, carbohydrate metabolism and detoxification; helps transport materials within the cell

Vesicles

Small membranous sacs that transport materials within the cell; can fuse with the cell membrane to release contents

3. Plant cells are supported by a cell wall, use chloroplasts to carry out photosynthesis, and contain a large central vacuole that stores water

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Plant cell

Plant cells have a cell wall and use organelles called chloroplasts to carry out photosynthesis.

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Like animal cells and other eukaryotic cells, plant cells have a nucleus that stores their DNA. However, plant cells differ from animal cells in several important ways. First, unlike animal cells, plant cells have a cell wall, which is very different from prokaryotic cell walls. Plant cell walls have channels called plasmodesmata (sg. plasmodesma) that allow cells to communicate by passing sugars, ions, and even proteins and RNA from one cell to another.

Animal and plant cells both have mitochondria. Mitochondria use glucose and oxygen to carry out cellular respiration and create ATP, a molecule that powers processes throughout the cell. In addition to mitochondria, plant cells also have special structures called chloroplasts that are essential to the process of photosynthesis. In this process, plants use light, water, and carbon dioxide to produce glucose, which can later be broken down by cellular respiration.

Did you know that mitochondria and chloroplasts have their own DNA, separate and distinct from the DNA in the nucleus?

Another structure that is present in plant cells, but not in animal cells, is the central vacuole. In plant cells, central vacuoles are used to maintain turgor pressure by keeping the large vacuole filled with water to support the cell.

3d rendering of the structures of a plant cell

4. A quick comparison of plant and animal cells

Here are the structures that are unique to animal cells, contrasted with the ones that are unique to plant cells:

In Animal Cells Only

In Plant Cells Only

Centrosomes
Centrioles
Cell wall
Central vacuole
Chloroplasts
Plasmodesma

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External Sources

An article about plasmodesmata from the Journal of Cell Science.

A definition of a vacuole from the National Human Genome Research Institute.