Cell Basics

Chapter 29: Page 284 

In this unit, you will be exploring the tiny world of cells! 

If you remember in chapter 25, you first learned that your 

cells make up everything that is in your body! 

Your cells act just like building blocks...you can put them 

together to make all kinds of things like your skin, muscles, 

organs, blood and all other kinds of things as well. 

But you can find cells in 

every living creature, 

not just in humans! 

That’s right... 

Every organism 

in every kingdom 

is made up 

of at least one 

cell! 

In this unit, you will be looking at how animal cells, plant 

cells and bacteria cells look, act and work. 

But first, I think it would help if we reviewed 

some topics...


There is so much biodiversity on the planet (don’t forget 

that “biodiversity” means “all of the different kinds of life 

that exist on the world”) scientists have placed all living 

things into groups. They do this to make it easier to study 

them! These groups can be put in order from largest to 

smallest: 

Kingdoms 

Populations 

Organisms 

Organs 

Tissues 

Cells 

Out of all of these groups, kingdoms are the largest of 

them all! In fact, kingdoms are made up of many 

populations. These populations are made up of individual 

organisms. Some organisms use organs to stay alive. These 

organs are made up of tissues. Tissues are made up of 

large groups of cells!


Cells can be placed into two different groups: 

Prokaryotic (“pro-carry-ot-ik”) 

and 

Eukaryotic (“u-carry-ot-ik”) 

There are many things about prokaryotic and eukaryotic 

cells that are the same: 

They both must use 

food to keep them alive. 

They both must be able 

to grow. 

They both react to 

changes in the 

environment 

They both can make 

another of its own kind 

(which is known as 

“reproduction”) 

They both can let air in and out of themselves (for 

example...breathing) 

Do these things look familiar to you They should! These are the basic 

needs for all living organisms you learned about in chapter one!


And... 

They both have a membrane around them. 

A membrane is a covering that surrounds the cell 

and protects it! It also lets nutrients, water and 

air into and out of the cell! 

They both have DNA. 

DNA is a group of 

chemicals that contain 

all of the instructions 

for making all the 

structures and 

materials an organism 

needs to survive! 

 

They both have cytoplasm. 

cytoplasm (“sight-o-plaz-m”) is a gooey fluid that 

fills up the inside of a cell, just like a water 

balloon! 

Not all things are the 

same between 

prokaryotic and 

eukaryotic cells...


Let’s look at what makes them different! 

If you are prokaryotic, you are made up of only one cell and 

belong to the... 

Archaebacteria Kingdom 

or 

Eubacteria Kingdom 

If you are eukaryotic, you are made up of more than one 

cell and you belong to... 

Fungi Kingdom 

Protist Kingdom 

Plant Kingdom 

or the 

Animal Kingdom 

But the main difference between prokaryotic and 

eukaryotic organisms is this... 

Eukaryotic cells have 

organelles and prokaryotic 

cells do not!


Organelles 

(“or-ga-nells”) are 

small structures 

inside of cells that 

have a specific job. 

One kind of organelle 

makes all of the 

energy for the cell to 

work! Another 

organelle stores all of 

the food! And so on... 

Prokaryotic cells, like bacteria, 

do not have organelles. 

Eukaryotic cells have more parts in them. They are 

responsible for keeping large organisms, like us, alive! They 

have to be better organized in order to work well! The 

organelles in the eukaryotic cells are very good at their 

jobs. 

You are going to learn about many of the 

organelles in the cells of animals and plants 

in the next chapters.


Place the answers to the following clues in the boxes 

below. Each box should contain one letter. 

Across 

1. cells or organisms that belong to the Kingdoms Archaebacteria or 

Eubacteria 

5. small structures inside of cells that have a specific job 

Down 

2. a gooey fluid that fills up the inside of a cell 

3. a group of chemicals that contain all of the instructions for making all 

the structures and materials the organism needs to survive 

4. a covering that surrounds the cell and protects it 

6. cells or organisms that belong to the Kingdoms Animal, Plant, Protist 

or Fungi


Match the words in the first column to the 

best available answer in the second column. 

_____ Prokaryotic 

1) a covering that surrounds the cell 

and protects it 

_____ Eukaryotic 

2) cells or organisms that belong to any 

Kingdoms except Archaebacteria 

and Eubacteria 

_____ Membrane 

3) cells or organisms that belong to the 

Kingdoms Archaebacteria or 

Eubacteria 

_____ DNA 

4) a group of chemicals that contain all 

of the instructions for making all 

the structures and materials the 

organism needs to survive 

_____ Cytoplasm 

5) small structures inside of cells that 

have a specific job 

_____ Organelles 

6) a gooey fluid that fills up the inside 

of a cell


Which one is right Circle the correct answer. 

1. The following list is in order from smallest to largest: 

a. cells, tissues, organs, organisms, populations 

b. populations, organisms, organs, tissues, cells 

c. cells, tissues, organisms, organs, populations 

2. The main difference between prokaryotic and 

eukaryotic cells is: 

a. only prokaryotic cells have a membrane 

b. only eukaryotic cells have organelles 

c. only eukaryotic cells have DNA 

3. All prokaryotic cells belong to the following kingdoms: 

a. archaebacteria and eubacteria 

b. fungi, protist, plant and animal 

c. archaebacteria, eubacteria and fungi 

4. The cytoplasm inside a prokaryotic cell contains: 

a. organelles 

b. dna 

c. nucleus 

5. If an organism is only made of one cell, it is known as... 

a. an organelle 

b. prokaryotic 

c. eukaryotic 

6. Organelles are larger than cells. 

a. true 

b. false


In the last chapter, you learned about the difference 

between prokaryotic cells (bacteria) and eukaryotic cells 

(all other living organisms). This week... let’s take a closer 

look at what makes a eukaryotic cell work! 

I’m certain you have seen all kinds of plants and animals in 

your life. 

Some of these organisms can be very small, like a blade of grass... 

...while others can be very large, 

like an elephant! 

Both the grass and the elephant are made up of cells that 

work together to keep them alive! 

As you learned from the last chapter, all organisms in the 

plant and animal kingdoms are eukaryotic. Because of this, 

each of their cells contains organelles. 

Remember that organelles are small structures inside of 

cells that have a specific job. 

In eukaryotic cells, there are 

at least a dozen different 

organelles each working to 

keep the cell alive! In this 

chapter, you are not going to 

have to learn all of them! But 

there are a few that you really 

need to know...


Here is a list of the organelles you are going to learn today: 

Nucleus (“new-klee-us”) 

Ribosomes (“ri-bow-sowm”) 

“ER” (the real name for this organelle is really long. So instead 

just say the two letters…E and R.) 

Mitochondria (“might-o-con-dree-ah”) 

I know some of the words are long, but keep practicing! 

You are going to see these words a lot in this unit! 

First, let’s take a look at the nucleus... 

The nucleus is the largest organelle in a plant or animal cell. 

Like most organelles, the nucleus floats inside the 

cytoplasm of the cell. 

(Remember that cytoplasm is a gooey fluid that fills up the inside 

of a cell, just like a water balloon!) 

The most important job that the nucleus has is to hold onto 

DNA. Think of the nucleus as the office of a building. In 

reality, DNA is a group of 

chemicals that contain all of the 

instructions for making all the 

structures and materials the 

organism needs to survive!


Think of DNA as “the boss”. The DNA tells the rest of 

the cell what to do and when to do it! DNA is always 

sending out “messages” to the cell. These “messages” are 

called “RNA”. Once the RNA is made, it is sent out of the 

nucleus to float around in the cytoplasm. 

These messages 

can only be read 

by our next 

organelle... 

ribosomes! 

The job for each 

ribosome is to 

read the RNA... 

since no other 

organelle can 

read these messages! Once this message is read, the 

ribosome sends out new messages that the other organelles 

can read. These new messages are called proteins! 

Think of a ribosome as “the decoder” since its job is to 

read the special code of the RNA. After reading the RNA, 

it then makes new messages that the other organelles can 

read.


You learned in chapter 28 that Proteins are the most 

important part of the food that you eat. These proteins 

are digested by your body, broken down into small pieces 

and recycled!!! These smaller pieces are reused by the 

organelles in your cells... like the ribosomes! 

Remember! 

The DNA (the boss) wants to send out messages but it 

cannot leave its office (the nucleus). So it makes RNA 

(the message) and sends it out into the cytoplasm for 

the ribosomes (the decoders) to read. The ribosomes 

read the message (RNA) and make new messages 

(proteins) that can be read by the other organelles. 

These new messages will tell the organelles what to do and 

when to do it. 

These proteins can float around in the cytoplasm for a long 

time before they reach an 

organelle. There is a way 

to get the proteins to the 

organelles faster! If you 

want this to happen, you 

have to use another 

organelle, called “ER”.


Think of the “ER” as “the highway” that helps to 

deliver the messages throughout the cell faster. 

So... just to be certain that you are understanding how this 

works: 









Sometimes, these messages (proteins) are delivered 

faster by traveling on the “ER” (the highway). 

What if your cell needs more 

energy to breathe, grow or to 

reproduce


A message is sent to the 

mitochondria if you need 

more energy! Mitochondria 

(“might-o-con-dree-ah”) are 

the “energy creators” 

of the cell. When your 

body needs energy, it turns 

to mitochondria to make it! 

This organelle uses the 

nutrients that organisms 

have in their bodies and 

changes it into energy. 

This energy can be used for 

the cell to breathe, to grow and to reproduce (as well as 

many other things!) 

In the next chapter, you are 

going to learn about three other 

organelles that both plants and 

animals have in common.


Animal cell 

ribosomes 

nucleus 

vacuole 

ER 

cell 

membrane 

lysosome 

golgi 

body 

mitochondria 

cytoplasm


Plant cell 

vacuole 

nucleus 

golgi 

body 

ER 

chloroplast 

cytoplasm 

mitochondria 

cell membrane 

lysosome 

ribosomes 

cell wall


The table below contains words and phrases that 

have been chopped in half. Find the pieces that fit 

together and write them in the answer area below. 

Nuc Mitoch ondria leus 

e r somes Ribo 

Answers: 

1. ________________________________________ 

2. ________________________________________ 

3. ________________________________________ 

4. ________________________________________




_____ Nucleus 

1) makes protein for the cell 

_____ Ribosomes 

2) quickly sends protein messages 

to organelles 

_____ ER 

3) an organelle that takes 

nutrients from plants and 

animals and changes it into 

energy for the cell 

_____ Mitochondria 

4) the largest organelle in a plant 

or animal cell; contains the DNA

Color the animal cell below 


Color the organelles these colors: 

Nucleus – red 

Ribosomes – brown 

ER – blue 

Vacuole – purple 

Lysosome – orange 

Mitochondria – yellow 

Golgi body - blue


So far, you have looked at four organelles that you can find 

in both plant and animal cells: the nucleus, ribosomes, “ER”, 

and mitochondria. Every eukaryotic cell uses these small 

structures to stay alive. But there are many more for you 

to study... 

In this chapter, you are going to look at three more 

organelles that can be found in both plant and animal cells: 

Lysosome (“lie-so-so-m”) 

Golgi body (“goal-gee”) 

Vacuole (“vack-u-ol”) 

In addition, you are going to explore one more organelle 

that you would never find in an animal cell: 

Chloroplast (“klor-o-plasts”) 

In the last chapter you were asked to think of the cell as a 

business... you have a boss, messages being sent, and ways 

to deliver these messages. 

Most businesses work 

with other businesses, 

don’t they So how 

does a cell work with 

other cells


The ribosomes have a hard time sending out their protein 

messages to other cells on their own. So, the ribosomes 

use another organelle... 

...the Golgi body. 

The Golgi body acts like a “packing station” by 

wrapping up proteins into a bundle. This “packing station” 

collects a large group of messages into a bundle and sends 

them outside of the cell. When the bundle reaches another 

cell, the bundle releases its protein into the new cell. 

Please do not 

confuse the 

Golgi body 

With the “ER”! 

The Golgi body 

sends bundles of 

protein messengers 

outside of the cell. 

The “ER” can only send messages within the same cell! 

But every business has some kind of waste


So how does a cell get rid of its waste 

Getting rid of waste is the job of the lysosome. Think of 

this organelle as the “garbage disposal” of the cell. 

Whenever you put garbage in the garbage disposal, it 

breaks it apart into smaller pieces. When the pieces are 

small enough, it gets flushed down the drain! A lysosome 

does the same thing with the waste inside a cell. 

Inside this 

organelle you 

will find 

enzymes that 

break down 

the waste that 

is trapped in 

the cell. 

Remember that enzymes are chemicals that your body uses 

to do all kinds of things...including breaking down your 

waste into smaller, more usable pieces. 

Most businesses store their materials somewhere. 

How does a cell store its materials


Plant and animal cells store extra water and nutrients in an 

organelle called a vacuole. The vacuole is known as the 

“the warehouse” of the cell. 

The vacuoles inside animal cells are not very large. There is 

no need for an animal cell to have a large vacuole because an 

animal can always eat more food! 

In plant cells, the vacuole is much larger! A plant cannot 

pick up a cheeseburger and fries whenever it gets hungry. 

So the plant must store as many nutrients as it can.


A little review... 









Sometimes, these messages (proteins) are delivered 

faster by traveling on the “ER” (the highway). 

Other times, these proteins are sent outside of the cell 

after they are bundled up in the Golgi body (packing 

station).


If any extra protein, nutrients or water is needed to be 

stored, it goes into the vacuole (the warehouse). 

When there is any waste that the cell makes, it goes to the 

lysosome (garbage disposal) to be broken down into 

smaller pieces. 

Now, let’s take a look at an organelle that 

you will never find in an animal cell! 

Chloroplasts 

(“klor-o-plasts”) 

Chloroplasts are special organelles that can be found in 

plants and many organisms in the Protista and Eubacteria 

kingdoms.

What makes chloroplasts so special 


Chloroplasts contain a chemical called chlorophyll (“klor-ofill”). 

Chlorophyll soaks up as much sunlight as possible. 

What does it do with all of the sunlight 

It takes a lot of energy to keep a plant growing. The sun 

provides a huge amount of energy to the plant to make its 

food! 

Chlorophyll uses sunlight, nutrients and water to make their 

own food. This is called photosynthesis. 

And since a plant cannot pick up a cheeseburger when it 

gets hungry, it has to make its own food to stay alive! 

If you do not believe me, 

try putting a plant into a 

dark closet. Without 

any light reaching its 

leaves, you are certain 

to find a dead plant 

wilting by your coats in a 

couple of days!


By the way, if you ever wondered why plants almost always 

look green, it is because green is the color of chlorophyll. 

The next time you look at a leaf on a tree, all of the green 

that you see is coming from chlorophyll! 

Also... 

Plant cells have a special way to protect themselves by 

using… 

Cell walls 

Plant cells have cell walls. 

So do most organisms 

from the kingdom fungi 

and a few organisms from 

the kingdom Eubacteria. 

The cell wall is a stiff 

structure that surrounds 

the cell and protects it 

from harm. 

In addition to protecting the cell, the cell wall also gives an 

organism the ability to remain stiff, like the trunk of a 

tree! Cell walls connect to each other just like a brick wall! 

This gives plants and fungi a strong body that does not 

break in half during a windstorm and can straighten up 

when it gets knocked down!


In the next chapter, you 

are going to explore 

what makes a plant cell, 

animal cell and bacterial 

cell the same...and what 

makes them different!


Animal cell 

ribosomes 

nucleus 

vacuole 

ER 

cell 

membrane 

lysosome 

golgi 

body 

mitochondria 

cytoplasm


Plant cell 

vacuole 

nucleus 

Golgi 

body 

ER 

chloroplast 

cytoplasm 

mitochondria 

cell membrane 

lysosome 

ribosomes 

cell wall


Unscramble the words below: 

1. odgoyilgb ________________________________ 

2. cotahllpros ________________________________ 

3. ouecalv ________________________________ 

4. yhrplhlcolo ________________________________ 

5. llcaewll ________________________________ 

6. yoosesml ________________________________ 

Write the definitions for each word: 

1. ______________________________________________ 

2. ______________________________________________ 

3. ______________________________________________ 

4. ______________________________________________ 

5. ______________________________________________ 

6. ______________________________________________




_____ Lysosome 

1) an organelle that stores extra 

water and nutrients 

_____ Golgi body 

2) an organelle that gets rid of the 

waste inside a cell 

_____ Vacuole 

3) special organelles that contain 

chlorophyll 

_____ Cell wall 

4) an organelle that wraps up proteins 

into a bundle inside a cell 

_____ Chloroplast 

5) a chemical found inside chloroplasts 

that uses sunlight to make food 

for the cell 

_____ Chlorophyll 

6) a stiff structure that surrounds a 

plant cell and protects it from 

harm


Color the plant cell below 

Color the organelles these colors: 

Nucleus – red 

Lysosome – orange 

Ribosomes – brown Mitochondria – yellow 

ER – blue 

Golgi body - blue 

Vacuole – purple 

Chloroplast - green


In the past two chapters, you have explored the organelles 

that can be found in both plant and animal cells. You have 

also learned that plant cells contain an organelle that is not 

found in animal cells. Don’t forget... plant and animal cells 

are eukaryotic because they have organelles! 

But what about the prokaryotic cells 

If you remember from chapter 29, bacterial cells are 

known as prokaryotic. Each prokaryotic cell is one 

organism that does not have any organelles!! 

Even though bacteria do not have any organelles, 

they still have the same needs as any other 

organism: 

They must use food to keep them alive. 

They must be able to 

grow. 

They react to 

changes in the 

environment 

They must reproduce 

They must use air to 

survive


And… just like eukaryotic cells, every bacteria has a 

membrane which holds in the gooey fluid called cytoplasm. 

However, the DNA (“the boss”) that is inside a bacteria 

is not protected inside a nucleus… 

...it just floats around in the cytoplasm! 

Ok...so how do bacteria survive without any 

organelles 

First of all, prokaryotic cells are protected the same way a 

plant cell is protected... with a cell wall! The cell wall 

surrounds the bacteria and keeps the bacteria safe. 

In addition, many bacteria can move with the help of a tail 

known as 

flagella. 

The 

flagella of a 

bacteria looks 

like a long whip 

that helps to 

push the 

bacteria through 

a liquid…just like 

the tail of a fish!


How do bacteria get their food 

Well, they can always move with the help of their flagella 

to where the food is. But some bacteria do not have 

flagella! These bacteria must be able to get the nutrients 

it needs in order to survive. One way that the bacteria can 

do this is to make its own food...just like a plant cell! 

That is right! Some bacteria can make their own food, 

just like plants do. 

In these bacteria, sunlight is used by its chlorophyll to go 

through photosynthesis. in bacteria, photosynthesis can 

take place anywhere inside the gooey cytoplasm!!! 

Aarrghhh!!! 

There is so 

many things 

to learn! 

How can I 

make it 

easier to 

remember


The following table may help you 

understand all of these cells a little better: 

Plant 

cell 

Animal 

cell 

Bacterial 

cell 

DNA YES YES YES 

Cell membrane YES YES YES 

Cytoplasm YES YES YES 

Nucleus YES YES NO 

Ribosomes YES YES NO 

“ER” YES YES NO 

Mitochondria YES YES NO 

Lysosome YES YES NO 

Golgi body YES YES NO 

Vacuole YES YES NO 

Cell wall YES NO YES 

Chloroplast YES NO NO 

Chlorophyll YES No Some do


You started off looking at 

“everything in the world” 

which is known as the 

environment. 

Since the 

world is such a huge place, 

scientists break it down into 

sections called biomes. Each biome is different from the 

others. Each of these biomes contain so many different 

organisms, scientists have placed them into six different 

groups called kingdoms. Within each kingdom there are 

thousands of different species of organism. 

Each 

species is a group of similar organisms that you can find 

anywhere in the world. 

When you get a group of similar organisms living in one 

place, you call this group of organisms a population. 

Since each population is a group of similar organisms, 

we need to look closely at each one! 

Most organisms (except for bacteria!) use organs to stay 

alive. These organs are made up of tissues. Tissues are 

nothing more than a large group of cells! And, you have 

been learning that eukaryotic cells are all made up of 

organelles that work together to keep the cell alive.


If you were to put these words in order from largest to 

smallest, this is what it looks like: 

Environment 

Biomes 

Kingdoms 

Species 

Populations 

Organisms 

Organs 

Tissues 

Cells 

Organelles 

You can pat yourself on the back! You 

have learned quite a lot this year! 

But you are not done yet. In the next unit, you are 

going to explore how you can keep yourself healthy 

and happy!


Fill in the blanks with the correct words 

from the bank at the bottom of the page. 

A ____________ ____________ a 

____________ ____________ 

____________ that ____________ to 

____________ the bacteria through a 

liquid. 

Word Bank: 

flagella 

is 

long 

helps 

tail 

push 

whip-like


Fill in the blanks in the following table. You 

may write “yes” or “no” 

Plant 

cell 

Animal 

cell 

Bacterial 

cell 

DNA YES YES 

Cell membrane YES YES 

Cytoplasm YES YES YES 

Nucleus YES NO 

Ribosomes YES YES 

“ER” YES NO 

Mitochondria YES YES 

Lysosome YES NO 

Golgi body YES YES 

Vacuole YES NO 

Cell wall 

Chloroplast YES NO 

Chlorophyll YES No Some do


Unit Eight review 



_____ 

_____ 

_____ 

_____ 

_____ 

_____ 

Mitochondria 

ER 

Vacuole 

Nucleus 

Golgi body 

Lysosome 

1. the largest organelle in a plant 

or animal cell; contains the Dna 

2. an organelle that gets rid of 

the waste inside a cell 

3. an organelle that turns 

nutrients into energy for the 

cell 

4. an organelle that wraps up 

proteins into a bundle inside a 

cell 

5. organelle that sends protein 

messages to other organelles 

6. an organelle that stores extra 

water and nutrients


Fill in the missing boxes with “yes” or “no”. 

Plant 

cell 

Animal 

cell 

Bacterial 

cell 

DNA 

Cell membrane 

Cytoplasm 

Nucleus 

Chloroplast 

Cell wall 

Be certain to go over your definitions for the test!

Cell Basics

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