Plant and animal cells have a surprising amount in common. Although plants and animals are usually seen as two very separate forms of life, this is not strictly true. When studied at the cellular level, the student will discover that the basic building blocks of both plant and animal life are unexpectedly similar.
Animal Cell Basics
Like all organisms, animals are built from cells. There are many different types of animal cells, each with a job and a purpose. However, there are some general characteristics that all cells share. Both the cells of animals and plants (and fungi) are what is known as eukaryotic. Eukaryotic cells are relatively large, contain a nucleus and other structures called organelles. Many eukaryotic life forms consist of a single cell. This group includes bacteria as well as more complex organisms called protozoa. Animal cells and plant cells have features in common: They both have a nucleus, cytoplasm, a cell membrane, mitochondria and ribosomes. Plant cells also have a cell wall, and often have chloroplasts and a permanent vacuole.
Protozoa
The protozoans are a large group of single-celled animals which live almost everywhere. Some live at the expense of a host, causing disease and even death, but some are symbiotic, being of benefit to their hosts and receiving benefit from their hosts in return.
Two Main Types of Protozoa
- Amoeboid Protozoa: An amoeboid protozoan is a mass of protoplasm, which is the basic living substance of all organisms. Amoebas feed mainly on bacteria and reproduce by splitting their protoplasm into two, which is known as fission.
- Ciliated Protozoa: This group of single-celled organisms have cilia (hair like structures) covering their bodies. Cilia enables an organism to move. A common ciliated protozoa is the Paramecium. Paramecium feed on bacteria and smaller protozoa. Paramecium reproduce both by fission and by conjugation. Conjugation is a type of sexual reproduction because in the process the paramecia exchange nuclear material before dividing.
Plant Basics
Plants are living organisms. Most plants make their own food using a process called photosynthesis. Plants are made of eukaryotic cells but, unlike animal cells, plant cells have rigid cell walls in addition to cell membranes. You can download the following comparison images for home use by clicking on them to open the larger versions, then saving to your computer.
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Cell Structure
| Cell Part | Description | Function | Plant or Animal? |
|---|---|---|---|
| Nucleus | Spherical. Often in the center of the cell | Control center or "brain" of the cell | Both |
| Mitochondria | An organelle with an outer and inner membrane. The inner membrane is layered | The site of energy creation within the cell | Animal |
| Cell Membrane | Semi-permeable membrane surrounding the cell | It selects what enters and exits the cell | Both |
| Cytoplasm | Jelly-like substance within the cell | It holds up the other parts within the cell | Both |
| Vacuole | The cell's storage pods |
Permanent Vacuoles are found in plants and are filled with cell sap to keep the cell turgid Excreting Vacuoles are found in some protozoa and help control water intake and output Food Vacuoles are found in some protozoa and help to break food down Contracting vacuoles are found in some protozoa and work in a similar way to excreting vacuoles |
Both, but large permanent vacuoles are ONLY in plants |
| Cell Wall | Surrounds a plant cell | It supports the cell and holds its shape | Plant |
| Chloroplast | An organelle with an inner and outer membrane which contains chlorophyll | The site of photosynthesis within the cell | Plant |
| Endoplasmic Reticulum | A vast system of interconnected sacks and tubes | Transports materials through the cell | Both |
| Ribosomes | Tiny organelles found in the cytoplasm or attached to the Endoplasmic Reticulum | The site of protein synthesis | Animal |
| Golgi Bodies | A flattish layer of organelles | Transports protein and carbohydrates for export from the cell | Both |
| Lysosome | Spherical organelle used for digestion | Holds enzymes and digests things for the cell | Animal |
| Centrosome | A small body, or organelle, located near the nucleus | It replicates just before the cell divides and plays a role in ensuring that the two sets of chromosomes stay on opposite sides and thus end up in both new cells | Both |
| Nuclear Membrane | A membrane which surrounds the nucleus | Keeps the DNA (Deoxyribonucleic acid) safe inside the nucleus | Both |
| Nucleolus | An organelle within the nucleus | It is where RNA (ribonucleic acid) is made | Both |
| Amyloplast | A non-pigmented organelle found in some plants | Stores starch | Plant |
Lesson Objectives
In this lesson, students will:
- Learn the names for the different structures found in plant and animal cells
- Compare plant and animal cells
- Craw and label plant and animal cells
Microorganism Discovery
Anton van Leeuwenhoek (Lay-ven-hook), a Dutch student of natural history who lived from 1632 to 1723, was the first to describe microorganisms accurately. He made careful observations and descriptions of his findings, which he reported to the Royal Society of London.
Evaluation
Have your student/s complete the cell part definitions matching, the Venn diagram, and label the cells on this fun worksheet to see what they have learned about animal and plant cell comparison. Follow these instructions to help download the pdf printables.
Optional Experiment
Materials Needed
- Microscope
- Prepared slides of amoeba, paramecium or or other single celled organisms.
OR:
- Microscope
- Four well slides or four ordinary slides
- Vaseline (To draw circle with toothpick the area of approximately a dime to contain the drop of pond water on the ordinary slides. This is not necessary with a well slide).
- Toothpicks (If using ordinary slides. This is not necessary with a well slide).
- Four cover slides
- Dropper
- Four small samples of pond water in separate containers
- One teaspoon of chopped hay (lespedeza, alfalfa, or timothy)
- 1/4 teaspoon of polished rice
- 1/16 teaspoon of egg yolk
- One teaspoon of rich garden soil
Prepared Slide Methodology
- Place the prepared slide under the microscope and examine on medium power.
Pond Water Methodology
- Add only one type of nutrient (hay, rice, yolk or soil) to each container of pond water.
- Place the containers in subdued light (not direct sunlight).
- Check the culture growth after 3 to 5 days.
- When growth has occurred, prepare slides by adding a drop of the culture solution to a well slide or a slide prepared with a circle of Vaseline.
- Place a cover slide over the drop
- Take your microscope and look at the slide under medium power.
- In addition to protozoa, other organisms such as freshwater worms, algae etc may be present.
Extending your Knowledge
If this lesson on animal and plant cell biology has merely whetted your appetite for the subject, check out these free online biology resources to go deeper.
Similarities and Differences
Although plant and animal cells are extremely similar in many ways, the differences between them are highly significant. In animal cells, the mitochondria provide the cells with energy they have synthesized from food. In plants, it is the chloroplasts who do this job, using sunlight and chlorophyll to create energy. Plant cells also have a rigid cell wall whilst animal cells do not. These differences are crucial. It is these differences which allow the cells to perform their own unique jobs and thus ensure the continuation of life.
