StudySmarter - The all-in-one study app.
4.8 • +11k Ratings
More than 3 Million Downloads
Free
A eukaryotic cell is a compartmentalised cell that contains organelles such as a nucleus and mitochondria.
There are four main types of eukaryotic cells: plant, animal, fungi and protist cells. In this article, we will mainly cover animal and plant cells. Unlike prokaryotes which do not have a nucleus, all eukaryotes have a nucleus.
As mentioned, the main differences between eukaryotic cells and prokaryotic cells are that eukaryotes have a nucleus. Instead of a nucleus, prokaryotes have loose chromosomes that contain DNA information. Bacteria and other cells can also contain plasmids - small, circular DNA. Interestingly, these are separate from the main chromosome and will replicate independently. Almost like a mind of its own! Plasmids often provide a genetic advantage - this is where antibiotic resistance can occur. In addition, cells can exchange these plasmids via bacterial conjugation. Prokaryotes are "smart" with their adaptations.
Bacterial conjugation: DNA plasmids are transferred between two bacteria via a pilus (hair-like appendage).
Below you will find a table showing the differences between eukaryotic and prokaryotic cells, also known as the ultrastructure or the composition of eukaryotic cells.
Table 1. Summary of differences between prokaryotic and eukaryotic cells.
Prokaryotic cells | Eukaryotic cells | |
Size | 1-2 μm | Up to 100 μm |
Compartmentalisation | No | Membranes that separate different organelles of the cell |
DNA | Circular, in the cytoplasm, no histones | Linear, in the nucleus, packed with histones |
Cell membrane | Lipid bilayer | Lipid bilayer |
Cell wall | Yes | Yes |
Nucleus | No | Yes |
Endoplasmic reticulum | No | Yes |
Golgi apparatus | No | Yes |
Lysosomes & Peroxisomes | No | Yes |
Mitochondria | No | Yes |
Vacuole | No | Some |
Ribosomes | Yes | Yes |
Plastids | No | Yes |
Plasmids | Yes | No |
Flagella | Some | Some |
Cytoskeleton | Yes | Yes |
As you already know, eukaryotic cells are "defined" by the presence of a nucleus. A nuclear membrane surrounds the nucleus. The nucleus contains the cell's genetic information - which is contained within the chromosomes; however, mitochondria and chloroplasts have their own DNA.
The size of eukaryotic cells varies quite a bit. Eukaryotic cells are usually bigger than prokaryotic cells ranging from 10–100 µm, making them up to 1000 times bigger than prokaryotic cells. When referencing cell size, we are referring to the diameter. Animal cells are usually up to 30µm, while plant cells can reach 100µm.
Let's take a closer look at the nucleus, cell nuclei store cell's DNA and control cell's activities. The nucleus is enclosed by a double nuclear membrane continuous with the endoplasmic reticulum. Inside the nucleus, a nucleolus plays a key role in the transcription and processing of rRNA (ribosomal RNA).
See our article on cell structure to learn more about different organelles in cells.
The nucleus is the most noticeable feature in a microscope because it is the biggest, approximately 10-20 micrometres.
The nuclear envelope is the double membrane surrounding the nucleus. The outer part of the membrane is directly attached to the endoplasmic reticulum.
The nuclear pores act as a passageway for larger molecules, such as the messenger RNA (mRNA). There are 3000 nuclear pores in a nucleus, each with an approximate diameter of 40 to 100 nm.
The chromosomes are composed of DNA bound to proteins called histones
A nucleoplasm is similar to a cell's cytoplasm. It is a jelly-like liquid surrounding the nucleolus
Within the nucleus, the nucleolus is where ribosomal RNA is produced. The nucleolus is also where ribosomes are assembled. Cells can have more than one nucleus.
Figure 1. Cell's nucleus. Source: StudySmarter Originals.
Below you will find a diagram of two eukaryotic cells - one is a plant, and the other is an animal cell. Note the difference in structures of these two cells.
Example differences between plant and animal cells:
Table 2. Summary of the main differences between animal and plant cells.
Plant Cell | Animal cell | |
Size | 10 - 100 micrometres | 10 - 30micrometres |
Shape | regular | irregular |
Nucleus | yes | yes |
Mitochondria | yes | yes |
Ribosomes | yes | yes |
Golgi Apparatus | yes | yes |
Cytoskeleton | yes | yes |
Cell membrane | yes | yes |
Endoplasmic reticulum | yes | yes |
Center vacuole | yes | no |
Chloroplasts | yes | no |
Cell wall | yes | no |
Vacuole | yes | yes, but smaller and different function |
Cilia | no | yes |
Figure 2. An animal cell. Source: StudySmarter Originals.
Figure 3, A plant cell. Source: StudySmarter Originals.
The animal cell is depicted as round. However, we know that the membrane around animal cells is fluid and mostly made out of phospholipids, meaning that the shape of the animal cell is irregular. A plant cell has a more restricted shape similar to a cube/rectangle due to the presence of a cell wall.
Figure 4. Phospholipid bilayer of the membrane. Source: Public Domain, via Wikimedia Commons.
Let's take a look at what A level biology can teach us about plant organelles.
Chloroplasts represent another notable distinction between a plant and animal cell. Similar to mitochondria, they have their own DNA and ribosomes. Both mitochondria and chloroplasts are found in plant cells.
Chloroplasts are sites where photosynthesis occurs. The chloroplast has the following structural features:
Chloroplast envelope: Like the nuclear envelope, chloroplasts have a double membrane.
Grana: stacks of disc-like structures found inside the chloroplasts. These discs are called thylakoids. This is where chlorophyll is found, which is the pigment that gives plants their green colour. It is also the photosynthetic pigment of plant cells.
Stroma: is the place where the second part of photosynthesis takes place. In this fluid-filled space, there are a lot of enzymes. These are needed to synthesise sugars.
While some animal cells can have multiple small vacuoles, the single vacuole in plant cells is much larger and can take up as much as 90% of a plant cell.
The vacuole in animal cells can store and digest substances.
In plants, the vacuole has multiple functions:
Xerophytes are plants adapted to dry habitats. Xerophytes possess a series of adaptations that help them survive in these conditions. This involves thick waxy cuticles to prevent water loss, increased water storage, rolling of the leaves and others.
Turgor: the pressure caused by the fluid in the cell and is regulated by the vacuole.
Imagine a crunchy piece of salad; this is high turgor pressure; when the pressure is low, the salad gets soft and limp. This phenomenon happens when there is not enough fluid in the cell, up to 90% found in the vacuole. Putting a soggy piece of salad in water can make it crunchy again by elevating the turgor.
Plant cells have cell walls. The cell wall of plants consists of cellulose. The cell wall is vital for tensile strength and protection against osmotic stress, i.e., it does not allow the cell to burst.
Prokaryotes, fungi and some protists also have cell walls; however, they have different structural components.
Additionally, the cell wall is responsible for water movement throughout the plant through plasmodesmata (membrane-lined pores that connect adjacent cells). Water can move through symplast and apoplast pathways. Symplast pathways occur through the cell wall, while apoplast through the cytoplasm.
As previously mentioned, plant cells and animal cells are both eukaryotic cells. While they seem like very different organisms at first glance, they have some similarities. The most profound is the presence of specialised cells that have similar characteristics. For example, the skin cells of an animal and epidermal cells of a plant are, in both cases, the outermost layer that protects the underlying structures.
All stem cells can develop into any specialised cell. An early embryo contains these types of cells, which differentiate into different cells in the body. When the embryo is fully developed, stem cells can still be found in the human body in small numbers.
You have probably heard about stem cells from bone marrow. Stem cells in the bone marrow can differentiate into red blood cells, white blood cells and platelets. Adult stem cells have also been previously found in the brain, blood vessels, skeletal muscle, heart and even teeth.
Stem cells in a plant can be found in meristems of the plant, which are located in roots and shoots.
Here is a list of plant and animal cell types for you to compare. We will first look at types of plant cells and then cat types of animal cells in direct comparison.
Skin cells: Outer layer for protection.
Blood cells: Oxygen transport and essential for the immune system.
Muscle cells: For strength and movement.
Fat cells: For energy storage and source.
Nerve cells: Present in the whole body to send and receive signals from and to the brain.
Reproductive cells: Sperm and ovum (egg cells) are needed to produce offspring.
Cells can often differentiate further. For example, above mentioned blood cells can differentiate into white blood cells of various types and red blood cells.
Parenchyma cells: For synthesis and storage of materials.
Collenchyma cells: Shock absorbing also have a support function in young plants.
Sclerenchyma cells: Structural support.
Xylem cells: Cells for structural support and transportation of water within the plant. When the water in the mesophyll cells evaporates (plant leaves), it is replaced by water transported by the xylem cells.
Phloem cells: Transportation of nutrients.
Reproductive cells: For the production of offspring (plants often have both male and female produce cells that together produce seeds).
Epidermal cell: Tightly packed cells that make up the outer layer of a plant, similar to our skin making up our body's outer, protective layer. Root hair cells are a type of epidermal cell in the root region. They exchange material with the outside world and absorb water and minerals.
Eukaryotes are mostly multicellular organisms (with some exceptions, including phytoplankton, zooplankton, yeast and others).
The first step in understanding how multicellular structures work is to understand single cells and their organelles. As each organelle performs a specific function, a cell's type can be determined by the number and the size of the organelles found inside. An example would be cells with many mitochondria, which metabolise a lot of ATP for energy - like muscle cells.
Multicellular organisms require cells to perform specific tasks. Cells are tailored to achieve this by having a specific structure and set of organelles. Despite the fact that all cells have the same DNA sequence at the start, only specific genes are expressed in specific cells. For example, muscle cells have a different gene expression than skin cells.
Some cells lose their ability to multiply after differentiating. Others, however, keep that ability and are able to regenerate tissue if there was a lesion, for example. As in the more general statement "all cells come from another cell" that applies to unicellular organisms, all cells within a multicellular organism come from another cell.
Cells can be grouped into tissues where they perform a similar function, such as muscular tissue. Organs are constructed from groups of tissues. For example, the heart is composed of various tissues, such as muscle and epithelial tissue. Organ systems are made up of organs that work together, such as the cardiovascular system, which is made up of the heart and blood vessels.
Prokaryotes do not have a nucleus, eukaryotic cells have a nucleus and membrane bound organelles
Animal cells 10-30 micrometers, Plant cells 10-100 micrometers
Yes all eukaryotic cells have a nucleus, even if they are unicellular organisms, they are still considered eukaryotes if they have a nucleus
A cell with membrane bound organelles and membrane bound organelles. They are more complex than prokaryotic cells. They are most commonly found in multicellular organism, such as plants or animals.
Eukaryotic cells can form multicellular organisms in which the cells adapt to do specific functions.
Animals, plants, fungi, protists
Be perfectly prepared on time with an individual plan.
Test your knowledge with gamified quizzes.
Create and find flashcards in record time.
Create beautiful notes faster than ever before.
Have all your study materials in one place.
Upload unlimited documents and save them online.
Identify your study strength and weaknesses.
Set individual study goals and earn points reaching them.
Stop procrastinating with our study reminders.
Earn points, unlock badges and level up while studying.
Create flashcards in notes completely automatically.
Create the most beautiful study materials using our templates.
Sign up to highlight and take notes. It’s 100% free.