Prokaryotic Cell Structure: Life Without a Nucleus

1. What is the most defining feature of a prokaryotic cell?

It lacks a nucleus

It has a large brain

It is made of many cells

It has no DNA

It only lives in water

If a cell is classified as a prokaryote, then it does not have a protective membrane around its genetic material. If it lacks this membrane, then it is defined as having no nucleus.

Explanation

If a cell is classified as a prokaryote, then it does not have a protective membrane around its genetic material. If it lacks this membrane, then it is defined as having no nucleus.

2. Which of these organisms is a perfect example of a prokaryote?

Bacteria

Human

Oak Tree

Mushroom

Goldfish

If prokaryotes are almost always single-celled and very simple, then bacteria fit this description. If humans and trees have complex cells with nuclei, then they are eukaryotes, not prokaryotes.

Explanation

If prokaryotes are almost always single-celled and very simple, then bacteria fit this description. If humans and trees have complex cells with nuclei, then they are eukaryotes, not prokaryotes.

3. Looking at the prokaryotic cell structure, we find that these cells are generally much smaller than eukaryotic cells.

True

False

If prokaryotes lack complex internal organs (organelles), then they do not need as much space. If they are simpler and more efficient at a small scale, then they will be smaller than complex cells.

Explanation

If prokaryotes lack complex internal organs (organelles), then they do not need as much space. If they are simpler and more efficient at a small scale, then they will be smaller than complex cells.

4. Even though they are simple, why does the prokaryotic cell structure still include ribosomes?

To build proteins needed for life

To help the cell swim

To store extra water

To change the cell's color

To protect the DNA

If every living thing needs proteins to function and grow, then every cell must have a way to make them. If ribosomes are the "factories" for proteins, then they are essential even in simple cells.

Explanation

If every living thing needs proteins to function and grow, then every cell must have a way to make them. If ribosomes are the "factories" for proteins, then they are essential even in simple cells.

5. The prokaryotic cell structure contains organelles like chloroplasts and lysosomes.

True

False

If an organelle has its own membrane (like a chloroplast), then it is "membrane-bound." If prokaryotes are defined by a lack of membrane-bound parts, then they cannot have these organelles.

Explanation

If an organelle has its own membrane (like a chloroplast), then it is "membrane-bound." If prokaryotes are defined by a lack of membrane-bound parts, then they cannot have these organelles.

6. When discussing prokaryotic cell structure, what does the term "unicellular" mean?

The organism is made of only one cell

It has one nucleus

It can only eat one thing

It has only one ribosome

It lives for only one day

If the prefix "uni-" means one, then a unicellular organism consists of a single cell. If bacteria are prokaryotes and exist as independent units, then they are unicellular.

Explanation

If the prefix "uni-" means one, then a unicellular organism consists of a single cell. If bacteria are prokaryotes and exist as independent units, then they are unicellular.

7. Scientists believe that the prokaryotic cell structure represents the oldest form of life on Earth.

True

False

If fossil evidence shows simple cells existed billions of years before complex ones, then the simpler cells came first. If prokaryotes are the simplest cells, then they are the oldest form of life.

Explanation

If fossil evidence shows simple cells existed billions of years before complex ones, then the simpler cells came first. If prokaryotes are the simplest cells, then they are the oldest form of life.

8. The jelly-like fluid that fills the inside of a prokaryotic cell is the ______.

If the cell contains ribosomes and DNA, then those parts need a fluid to float in. If that internal fluid fills the space between the membrane and the nucleoid, then it is the cytoplasm.

Explanation

If the cell contains ribosomes and DNA, then those parts need a fluid to float in. If that internal fluid fills the space between the membrane and the nucleoid, then it is the cytoplasm.

Submit

9. Which summary best describes the prokaryotic cell structure?

A simple, small "bag" of life with floating DNA and no nucleus

A giant factory with many different rooms and a central office

A solid rock with no moving parts

A complex machine with a large computer brain

A group of many cells working together as one

If prokaryotes lack internal membranes and a nucleus, then they are like a single open room. If they are tiny and carry DNA freely, then they are best described as a simple "bag" of life.

Explanation

If prokaryotes lack internal membranes and a nucleus, then they are like a single open room. If they are tiny and carry DNA freely, then they are best described as a simple "bag" of life.

10. A typical prokaryotic cell structure includes a membrane-bound nucleus to store DNA.

True

False

If the term "prokaryote" literally means "before nucleus," then these cells evolved before the nucleus existed. If they evolved before it, then they cannot have a nucleus in their structure.

Explanation

If the term "prokaryote" literally means "before nucleus," then these cells evolved before the nucleus existed. If they evolved before it, then they cannot have a nucleus in their structure.

11. In a prokaryotic cell structure, the DNA is usually shaped like a single circular loop.

True

False

If eukaryotes have long, linear strands of DNA, then prokaryotes have a different arrangement. If their DNA is simpler and joined at the ends, then it forms a circular chromosome.

Explanation

If eukaryotes have long, linear strands of DNA, then prokaryotes have a different arrangement. If their DNA is simpler and joined at the ends, then it forms a circular chromosome.

12. What is the function of the plasma membrane in the prokaryotic cell structure?

To control what enters and leaves the cell

To make the cell stiff and hard

To store the cell's food

To create sunlight

If a bacterium needs to swim through a liquid to find food, then it needs a propeller. If it has a tail that spins or whips to push it forward, then that tail is a flagellum.

Explanation

If a bacterium needs to swim through a liquid to find food, then it needs a propeller. If it has a tail that spins or whips to push it forward, then that tail is a flagellum.

Submit

Simple but Powerful: Prokaryotic Cell Structure

1. What is the most defining feature of a prokaryotic cell?

2. Which of these organisms is a perfect example of a prokaryote?

3. Looking at the prokaryotic cell structure, we find that these cells are generally much smaller than eukaryotic cells.

4. Even though they are simple, why does the prokaryotic cell structure still include ribosomes?

5. The prokaryotic cell structure contains organelles like chloroplasts and lysosomes.

6. When discussing prokaryotic cell structure, what does the term "unicellular" mean?

7. Scientists believe that the prokaryotic cell structure represents the oldest form of life on Earth.

8. The jelly-like fluid that fills the inside of a prokaryotic cell is the ______.

9. Which summary best describes the prokaryotic cell structure?

10. A typical prokaryotic cell structure includes a membrane-bound nucleus to store DNA.

11. In a prokaryotic cell structure, the DNA is usually shaped like a single circular loop.

12. What is the function of the plasma membrane in the prokaryotic cell structure?

13. Most prokaryotes have a stiff ______ ______ outside the cell membrane to provide protection and shape.

14. In a prokaryote, the DNA is found in a messy, central region called the ______.

15. How does a prokaryotic cell differ from a eukaryotic cell?

16. The small, hair-like structures on the outside of a prokaryote used for attachment are called ______.

17. Which of the following components are always part of a basic prokaryotic cell structure?

18. Which of the following "Domains of Life" contain organisms with a prokaryotic cell structure?

19. Which of the following can be found on the very outside of some bacteria to help them stick to surfaces?

20. Some prokaryotes have a long, whip-like tail used for movement called a ______.

13. Most prokaryotes have a stiff outside the cell membrane to provide protection and shape.