Prokaryotic and Eukaryotic Cells

Prokaryotic and Eukaryotic Cells

Middle School

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Learning Objectives

• Define prokaryotic and eukaryotic cells by looking at their different parts.

• Describe the major differences in the structure of prokaryotic and eukaryotic cells.

• Name the important organelles and parts that are found in both types of cells.

• Compare the simple structure of prokaryotic cells to the more complex eukaryotic cells.

Key Vocabulary

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Prokaryotic Cell

A prokaryotic cell is a single-celled organism without a membrane-bound nucleus or specialized parts.

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Eukaryotic Cell

A eukaryotic cell has a true nucleus and other membrane-bound organelles to perform specific jobs.

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Nucleus

The nucleus is the control center of a eukaryotic cell, containing all the genetic material.

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Organelle

An organelle is a tiny structure inside a cell's cytoplasm that carries out a specific function.

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Cytoplasm

Cytoplasm is the jelly-like substance filling the cell and surrounding all of the organelles within.

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What Are Cells?

• Cells are the basic building blocks of all living things.

• New cells are always made from cells that already exist.

• The two main types of cells are prokaryotic and eukaryotic.

• Eukaryotic cells have a nucleus to protect their DNA.

Multiple Choice

According to the presentation, what is the primary structure used to classify cells as either prokaryotic or eukaryotic?

• The ribosomes

• The nucleus

• The cell membrane

• The cytoplasm

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What Are Prokaryotic Cells?

• Prokaryotic cells are simple cells that do not have a true nucleus.

• Their genetic material is located in a part of the cytoplasm called the nucleoid.

• They are tiny, unicellular organisms like bacteria and lack membrane-bound organelles.

• They have a plasma membrane, cytoplasm, DNA, ribosomes, and often a cell wall.

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Multiple Choice

Which of the following is a key characteristic of a prokaryotic cell?

• It contains many membrane-bound organelles.

• It is large and complex.

• Its DNA is in the cytoplasm in a region called the nucleoid.

• Its DNA is enclosed within a nucleus.

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What Are Eukaryotic Cells?

• These cells contain a true nucleus that is enclosed by a membrane.

• ​They are found in organisms like plants, animals, fungi, and protists.

• Their DNA is organized into chromosomes, which are located inside the nucleus.

• They have organelles like mitochondria for energy and vacuoles for storing substances.

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Multiple Choice

What is the primary advantage of eukaryotic cells having organelles?

• It helps them reproduce more quickly.

• They can perform multiple functions at same time.

• It removes the need for a cell membrane.

• It makes them simpler than prokaryotic cells.

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Comparing Cell Types

Prokaryotic Cells

• These cells do not have a nucleus to hold their genetic material.

• They also lack other small parts called membrane-bound organelles.

• They have DNA, ribosomes, cytoplasm, and a cell membrane.

Eukaryotic Cells

• These cells have a true nucleus that contains the cell's DNA.

• They contain many specialized parts called membrane-bound organelles.

• They also have DNA, ribosomes, cytoplasm, and a cell membrane.

Multiple Choice

Which of the following structures is found in BOTH prokaryotic and eukaryotic cells?

• Mitochondria

• Vacuoles

• Ribosomes

• A membrane-enclosed nucleus

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Common Misconceptions About Cells

Misconception	Correction
All cells must have a nucleus.	Only eukaryotic cells have a nucleus. Prokaryotic cells have DNA in their cytoplasm.
Prokaryotes are not important because they are simple.	Prokaryotes were the first life forms and are the most abundant organisms on Earth.
Unicellular means it must be a prokaryote.	Some eukaryotes, such as protists and yeast, are also unicellular.

Multiple Choice

How do the organelles in a eukaryotic cell, such as mitochondria, contribute to its overall function compared to a prokaryotic cell?

• They store the DNA outside of the nucleus.

• They have no impact on the cell's function.

• They perform specialized jobs, allowing for greater complexity and specificity.

• They decrease the cell's efficiency by taking up space.

Multiple Choice

Why is the presence of a membrane-bound nucleus the defining difference between eukaryotic and prokaryotic cells?

• Because only cells with a nucleus can move.

• Because the nucleus makes the cell wall rigid.

• Because it reflects a fundamental difference in how genetic material is stored and protected.

• Because the nucleus is responsible for producing energy.

Multiple Choice

A scientist discovers a new unicellular organism. It has ribosomes and a cell membrane, but its DNA is not contained within a nucleus. How would you classify this organism and why?

• Eukaryote, because it is unicellular.

• Prokaryote, because it has a cell membrane.

• Eukaryote, because it has ribosomes.

• Prokaryote, because it lacks a membrane-bound nucleus.

Multiple Choice

If a mutation caused a eukaryotic cell to lose its mitochondria, what would be the most likely consequence?

• The cell would become a prokaryote.

• The cell would lose its primary source of energy.

• The cell would no longer have a cytoplasm.

• The cell's DNA would no longer be organized into chromosomes.

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Summary

• All living things are made of cells, which are either prokaryotic or eukaryotic.

• The main difference is that eukaryotic cells have a nucleus, while prokaryotic cells do not.

• Eukaryotic cells are complex, with a nucleus and other organelles for specialized functions.

• Both cell types share a cell membrane, cytoplasm, ribosomes, and DNA.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

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• 4