Eukaryotic Cell simulation

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## Introduction

__Active and passive transport__ are two processes that help supply nutrients, water, oxygen, and other essential molecules to the body’s cells. Waste products are also eliminated with the help of passive and active transport. They have similar purposes <span id="q1"></span> movements.

---

### Passive transport

The selectively permeable or semipermeable <span id="q2"></span>  membrane, which is the most important feature of the cell, has control over the molecules of the cell. The organization and characteristics of a membrane are responsible for the permeability of the membrane. 

A state of homeostasis within the cell (tissues, organs, and organ systems) is maintained with the help of the cell membrane, which makes the organism stay alive and healthy. The figure below shows that the ions leave or enter the cell as controlled by the membrane.

![Passive Transport](//images.ctfassets.net/4yflszkpcwkt/7DQYVsvQmCeVV3SgaH1iP/721c42b69c9d9d7bd5690d1b688637fe/Passive-Transport.jpg)
[Source](https://microbenotes.com/wp-content/uploads/2019/11/Passive-Transport.jpg)

### Transport across membranes

<span id="q3"></span> molecules like carbon dioxide and oxygen <span id="q4"></span> pass through the phospholipid membrane. In contrast, the membrane does not allow the hydrophilic molecules to pass through because of their water-loving nature. 

Transport proteins help the large molecules like sugar and proteins to pass through the membrane, and hence there is no contact between polar and nonpolar molecules, and the large molecules are moved through large pores. 

Passive transport is one of the ways to pass molecules through phospholipids membrane with no energy input. There are three main types of passive transport- 

- __Diffusion__: It helps the molecules to move from the region of high concentration of molecules to the region of lower concentration. Concentration gradient is the term for the difference between the concentrations of molecules in the two areas.

- __Facilitated diffusion__: It involves the diffusion of solutes through transport proteins. Even though there is an involvement of transport proteins, it is still passive transport because the movement of the solutes is down the concentration gradient.

- __Osmosis__: Diffusion of water molecules through a selectively permeable membrane from higher water concentration to lower water concentration is called Osmosis.

---

### Active transport

Contrary to passive transport, where there is no energy requirement for the movement of molecules and ions are carried down the concentration gradient, active transport pumps molecules against the concentration gradient. Here, energy is required. Energy is used in the form of <span id="q5"></span> to move the molecules against the concentration gradient.

![Active Transport](//images.ctfassets.net/4yflszkpcwkt/2eCH8utkiNytPo0FNmwW7y/0411b96f7837d5aedb14d55464ecf386/Types-of-Active-Transport.jpg)
[Source](https://microbenotes.com/wp-content/uploads/2019/05/Types-of-Active-Transport.jpg)

Transport proteins, also known as protein pumps, transport the small molecules or small ions across a cell membrane, as shown in the figure. The larger molecules (for example-starch) can also be transported actively through the membrane with the help of vesicle transport processes called endocytosis and exocytosis.

### What are endocytosis and exocytosis?

__Endocytosis__: The process of transport of particles from outside the cell to the inside of the cell is called endocytosis. The membrane of the cell folds over the particle, which makes it completely enclosed. The vesicle then pinches off and moves the particle into the cytosol. Endocytosis has two types-

- __Phagocytosis__: A phagocytic vesicle is formed by the plasma membrane, which engulfs the solid material when dissolved in the cell.

- __Pinocytosis__: It occurs when the plasma membrane folds inward to form a channel allowing the dissolved substances to enter the cell. The liquid is encircled with a pinocytic vesicle when the channel is enclosed.

![Three Forms of Endocytosis](//images.ctfassets.net/4yflszkpcwkt/3GbsBR1kPSV7CvUAjnWE0Y/74248c654b66c0cf1bfd6d9b936948f4/Three_Forms_of_Endocytosis.jpg)
[Source](https://www.microscopemaster.com/images/Three_Forms_of_Endocytosis.jpg?ezimgfmt=rs:512x234/rscb25/ng:webp/ngcb25)

__Exocytosis__: When the vesicle fuses with the plasma membrane and releases its content outside the cell, it is called exocytosis. When protein-like substances are produced by the cell for export or when the cell gets rid of a waste product, exocytosis occurs. Newly-made membrane lipids and proteins are moved on the top of the plasma membrane by exocytosis.

---

| Active Transport     | Passive Transport     |
| ---------- | ---------- |
| -Cellular energy is required.       | -Does not require cellular energy.       |
| -Movement takes place from a region of lower concentration to a region of higher concentration of molecules.       | -Movement takes place from a region of higher concentration to a region of lower concentration of molecules.       |
| -It is needed for the transportation of all molecules such as proteins, large cells, ions, etc.       | -It is needed for the transportation of all soluble molecules, including oxygen, water, carbon dioxide, lipids, sex hormones, etc.       |
| -It is a rapid process.       | -It is a comparatively slow process.       |
| -Carrier proteins are required in active transport       | -Carrier proteins are not required in passive transport       |
| -Metabolic inhibitors can influence and might make the transportation stop       | -Transportation is not affected by metabolic inhibitors       |
| -Transpires in a single direction       | -Transpires in multiple directions.       |

---

## Conclusion

- The two biological processes-Active and Passive transport have different types of movement. 

- Energy is required in only one of the two processes i.e active transport. 

- Both the processes transport molecules into the cell by different methods.

---

### FAQs

__1. What are the examples of active and passive transport?__

Phagocytosis, pinocytosis, and sodium-potassium pump are examples of active transport while diffusion, facilitated diffusion and osmosis are examples of passive transport.

__2. What is the difference between active and passive transport?__

Active transport involves the movement of molecules from lower concentration to higher concentration with the use of energy. Passive transport involves the movement of molecules from higher concentration to lower concentration and no amount of energy is required.

__3. What are the four types of active transport?__

Active transport involves endocytosis and exocytosis. Endocytosis is further divided into phagocytosis and pinocytosis.

__4. What are the three types of passive transport?__

Diffusion, facilitated diffusion and osmosis are the three types of passive transport which do not require energy to move the particles.

__5. Is diffusion active or passive?__

Diffusion is a type of passive transport that does not require energy. Diffusion helps the molecules to move from a region of high concentration to a region of low concentration.

__6. Is osmosis a type of active transport?__

No, osmosis is a type of passive transport. It carries out-diffusion of water molecules through a selectively permeable membrane.

*We hope you enjoyed studying this lesson and learned something cool about __Active and Passive Transport__! Join our Discord community to get any questions you may have answered and to engage with other students just like you! Don't forget to download our App and check out our awesome VR room for this guide - we promise, it makes studying much more fun* 😎

## Sources:
1. Passive Transport https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/2.13/primary/lesson/passive-transport-bio/ <https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/2.13/primary/lesson/passive-transport-bio/>Accessed on 3 Dec 2021

2. Active Transport [https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/2.14/primary/lesson/active-transport-bio/](https://flexbooks.ck12.org/cbook/ck-12-biology-flexbook-2.0/section/2.14/primary/lesson/active-transport-bio/) Accessed on 3 Dec 2021

3. Active and Passive Transport - Its Difference [https://byjus.com/biology/difference-between-active-and-passive-transport/#:~:text=Active%20transport%20requires%20energy%20for%20the%20movement%20of,transport%2C%20the%20molecules%20move%20along%20the%20concentration%20gradient.](https://byjus.com/biology/difference-between-active-and-passive-transport/#:~:text=Active%20transport%20requires%20energy%20for%20the%20movement%20of,transport%2C%20the%20molecules%20move%20along%20the%20concentration%20gradient.) Accessed on 3 Dec 2021 

4. Active and Passive Transport [http://www.diffen.com/difference/Active_Transport_vs_Passive_Transport](http://www.diffen.com/difference/Active_Transport_vs_Passive_Transport) Accessed on 3 Dec 2021 


Passive and Active Transport Study Guide


---

## Youtube Video

<iframe width="560" height="315" src="https://www.youtube.com/embed/fDVnKTT8CZE" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

---

## Introduction

Have you ever been having a fun day hanging out with your friends and started wondering what ribosomes and mitochondria are? Well, maybe not (unless you're us). Even so, they’re crucial to the processes of synthesizing <span id="q4"></span> and generating all of the energy you need to hang out with your friends in the first place! They might seem complicated, but we’re here to help you learn all about what they are, what they’re made of, and how they work. Let’s get started!

### Lesson Objectives

- Understand the different components that make up ribosomes and mitochondria.
- Briefly understand the functions of ribosomes and mitochondria.

---

## Ribosomes

__Ribosomes__ are organelles composed of RNA molecules and proteins that carry out the process of protein synthesis. Ribosomes are found both freely floating in the cytoplasm or bound to the <span id="q1"></span>
, and the type of protein they produce depend on their location.

<aside>
😮 Ribosomes that bind to the endoplasmic reticulum give it a bumpy appearance, which is why we call it the rough ER!

</aside>

- Detached ribosomes found freely floating in the cytoplasm translate <span id="q2"></span>to create proteins that will remain in the cytoplasm

- Ribosomes attached to the rough ER generate proteins that will either become part of the membrane or be stored in a small cellular container called a vesicle. 

- Proteins that are to be moved out of the cell are also translated by ribosomes bound to the rough ER. 

<aside>
👯‍♀️ When <span id="q3"></span> or more ribosomes freely floating in the cytoplasm group together on a single strand of mRNA, we call it a polysome.

</aside>

<div class="sketchfab-embed-wrapper"> <iframe title="Ribosomes" frameborder="0" allowfullscreen mozallowfullscreen="true" webkitallowfullscreen="true" allow="autoplay; fullscreen; xr-spatial-tracking" xr-spatial-tracking execution-while-out-of-viewport execution-while-not-rendered web-share width="640" height="480" src="https://sketchfab.com/models/f42a79f90a074fd28b22b383d670a2c0/embed?autostart=1&ui_animations=0&ui_infos=0&ui_stop=0&ui_inspector=0&ui_watermark_link=0&ui_watermark=0&ui_ar=0&ui_help=0&ui_settings=0&ui_vr=0&ui_fullscreen=0&ui_annotations=0"> </iframe> </div>

- Ribosomes are found in both prokaryotic and eukaryotic cells, but they each use a slightly different process to produce proteins. Luckily, we can use these differences to our advantage. We’ve been able to create antibiotics that decimate infections while causing no harm to any human cells–a huge win for our battle against bacteria. 

- Unfortunately, some prokaryotes use these differences to their advantage too, such as the polio virus which is able to attack our translation mechanism and make us sick. While it generally causes mild flu-like symptoms like fever, fatigue, or nausea, in some severe cases it can cause more serious symptoms like paresthesia, meningitis, or even paralysis.

<aside>
🤯 The number of ribosomes in a cell usually depends on the amount of activity that cell undergoes — there are about 10 million ribosomes in a mammalian cell!

</aside>

### Ribosome Structure

As we mentioned before, ribosomes are composed of both RNA and proteins. About 37% to 62% of a ribosome is comprised of RNA, while proteins make up the remainder of its composition.

![image2](//images.contentful.com/4yflszkpcwkt/5kCL1XHFHXu1d2MwG53QUC/de74a53bce073934bce74f17124638b3/image2.jpg)

[Source](https://ccelms.ap.gov.in/adminassets/docs/29112020045732-Ribosomes_Notes_EM_F.pdf)

Ribosomes are divided into two __Subunits__, one large and one small. When not synthesizing proteins, these two subunits remain unattached. During protein synthesis, the two units combine and work together as one to translate mRNA and form a polypeptide chain from amino acids which will eventually become a functional protein.

- First, the __Small Subunit__ binds to a single-stranded mRNA molecule. This mRNA provides the instructions for protein synthesis.

- The small subunit then binds to the large subunit to create what looks like an mRNA sandwich–the large and small subunits on top and bottom and the mRNA in the middle.

- With the instructions provided by the small subunit, the __Large Subunit__ is able to link together amino acids to form a polypeptide chain. This chain will be released into the cytoplasm where it will fold into its final form as a protein.

<aside>
💔 Ribosomes are known to have only a temporary existence as both the sub-units separate after synthesizing the polypeptide. These subunits may be reused later or get broken.

</aside>

- Prokaryotic and eukaryotic ribosomes differ not only in their process of synthesizing proteins, they also differ in size. Prokaryotes have 70S ribosomes made up of 30S and 50S subunits, while eukaryotes have 80S ribosomes made up of 40S and 60S subunits.

<aside>
👉 The values of the ribosomal unit S (Svedberg) depend on the rate of sedimentation that ribosomes undergo during centrifugation.

</aside>

### Ribosome Functions

*__Translate__* instructions on how to produce a protein from a strand of messenger mRNA from the nucleus.

*__Synthesize__* a polypeptide chain by linking together amino acids that are collected from the cytoplasm by transfer ribonucleic acid (<span id="q5"></span>) in a process called peptidyl transfer.

*__Export__* the polypeptide chain into the cytoplasm where it will become a new, functional protein in a process called peptidyl hydrolysis.

---

## 💡 Ribosome Summary

- __Ribosomes__ are organelles composed of both RNA and proteins that carry out the process of protein synthesis.

- Ribosomes either float freely in the cytoplasm or attach to the __endoplasmic reticulum__; the location of a ribosome determines how the protein it synthesizes will be used.

- Ribosomes are composed of two __subunits__, one large and one small.

- The __small subunit__ binds to mRNA and translates its instructions for protein synthesis.

- The __large subunit__ synthesizes polypeptide chains based on the mRNA’s instructions.

- The three main functions of a ribosome are the __translation__, __synthesis__, and __exportation__ of proteins.

---

## Mitochondria

Mitochondria are membrane-bound organelles that generate most of the energy a cell uses to function (if you’ve heard it once, you’ve heard it a thousand times–the mitochondria is the powerhouse of the cell 💪). They look like lima beans with ribbon twisted back and forth inside, and are found floating freely throughout the cytoplasm.

<aside>
👉 Mitochondria were first discovered by Richard Altmann in 1890, except at the time, he called them bioblasts. In 1897, Carl Benda coined the term ‘mitochondrion’ to describe the organelle. (The first one sounds a little bit cooler in our opinion).

</aside>

<div class="sketchfab-embed-wrapper"> <iframe title="Mitrocondria" frameborder="0" allowfullscreen mozallowfullscreen="true" webkitallowfullscreen="true" allow="autoplay; fullscreen; xr-spatial-tracking" xr-spatial-tracking execution-while-out-of-viewport execution-while-not-rendered web-share width="640" height="480" src="https://sketchfab.com/models/32b30ec2ab8c4bbeba44140081a7044e/embed?autostart=1&ui_animations=0&ui_infos=0&ui_stop=0&ui_inspector=0&ui_watermark_link=0&ui_watermark=0&ui_ar=0&ui_help=0&ui_settings=0&ui_vr=0&ui_fullscreen=0&ui_annotations=0"> </iframe> </div>

Two of the four steps that occur during aerobic cellular respiration (the process by which energy is generated in the cell) occur in the mitochondria: the *Krebs Cycle* (or citric acid cycle) and *Oxidative Phosphorylation*.

- In the <span id="q6"></span> cycle__, the mitochondria modifies acetyl CoA to produce precursors for the next step in cellular respiration–oxidative phosphorylation. 

- In __oxidative phosphorylation__, electrons from the precursors from the citric acid cycle are used to produce NADH which is then used by enzymes found in the mitochondrial inner membrane to generate ATP–a form of energy stored in chemical bonds.

![image1](//images.contentful.com/4yflszkpcwkt/7DjaW6PlrhQQT9xYM0OL5p/87b259ecf908e6de566b2162eb20d3b5/image1.jpg)

[Source](https://alevelbiology.co.uk/notes/mitochondria-structure-and-functions/)

<aside>
🏃‍♀️ The more active a cell is, the more mitochondria it has. Sperm tails, muscle cells, and liver cells have up to 1600 mitochondria; microvilli and the oocyte have more than 300,000!

</aside>  

### Mitochondria Structure

The four distinct parts of mitochondria are the *outer membrane*, the *intermembrane space*, the *inner membrane*, and the *mitochondrial <span id="q7"></span>*.

- The __Outer Membrane__ is the gateway to a mitochondrion. It contains protein channels called __porins__ that allow the movement of ions and molecules in and out of the organelle, and is similar in both structure and composition to the plasma membrane of a cell.

- The __Inner Membrane__ contains many components of the electron transport chain along with multiple other enzymes and coenzymes. Transporters such as __proton pumps__ and __permease proteins__ also exist in the inner membrane and regulate the transport of molecules such as phosphate, ADP, and ATP into and out of the matrix.

- The __Intermembrane Space__ sits between the inner and outer membranes and contains the enzymes responsible for citric acid cycle reactions.

- The __Mitochondrial Matrix__ is a gel-like material found within the inner membrane of the mitochondria, and is where the citric acid cycle takes place. It contains ribosomes to produce proteins used by the organelle as well as mitochondrial DNA.

### Mitochondria Functions

*__Energy Conversion__* – the primary function of the mitochondria is to supply energy. It produces ATP, the cell’s energy currency that drives cellular mechanisms.

*__Calcium Storage__* –the mitochondria maintain the ideal concentration of calcium ions for the cell by absorbing calcium ions until they are needed.

*__Programmed Cell Death__* –when cells become old or cease to function, they undergo a process of programmed cell death called __Apoptosis__. Mitochondria assist with this process by deciding which cells need to be destroyed.

*__Additional Functions__* –heat production, steroid synthesis, hormone signaling, cellular metabolism regulation, etc.

---

## 💡 Mitochondria Summary

- __Mitochondria__ are membrane bound organelles primarily responsible for the generation of energy within a cell.

- Both the __Krebs cycle__ and __oxidative phosphorylation__ occur in the mitochondria.

- The mitochondria is formed by 4 distinct parts: the outer membrane, the intermembrane space, the inner membrane, and the mitochondrial matrix.

- The __outer membrane__ regulates the movement of ions and molecules in and out of the mitochondria via porins.

- The __inner membrane__ contains components of the electron transport chain and transporters such as proton pumps and permease proteins.

- The __intermembrane space__ exists between the inner and outer membrane and contains the enzymes responsible for the citric acid cycle.

- The __mitochondrial matrix__ is found within the inner membrane and is where the citric acid cycle takes place.

- __Energy conversion__, __calcium storage__, and __apoptosis__ are all functions of the mitochondria.

---

### FAQs

__1. What is a ribosome?__

A ribosome is an organelle composed of RNA molecules and proteins that carries out the process of protein synthesis.

__2. Where are ribosomes located?__

Ribosomes are either freely floating in the cytoplasm or attached to the rough ER.

__3. What are the functions of ribosomes?__

Ribosomes translate mRNA, synthesize polypeptide chains, and export them into the cytoplasm where they will become a fully functional protein.

__4. What are mitochondria?__

Mitochondria are membrane-bound organelles that generate the energy necessary for a cell to function.

__5. What are the functions of mitochondria?__

Mitochondria are responsible for energy conversion, calcium storage, programmed cell death, and additional functions such as heat production, steroid synthesis, hormone signalling, cellular metabolism, etc.

__6. What is the structure of mitochondria?__

Mitochondria are composed of an outer membrane, intermembrane space, inner membrane, and mitochondrial matrix.

__7. Why is mitochondria called the powerhouse of a cell?__

Mitochondria are called the powerhouse of the cell because they produce the majority of the energy we need to survive. They do this through the process of energy conversion in which they produce ATP–the molecule that drives cellular mechanisms.

__8. How do mitochondria and ribosomes work together?__

Ribosomes are the site or place where protein synthesis takes place. Thus mitochondrial ribosomes or mitoribosomes synthesize proteins inside Mitochondria, which are regulated by the genes found in mtDNA (mitochondrial DNA).

*We hope you enjoyed studying this lesson and learned something cool about __Mitochondria and Ribosomes__! Join our Discord community to get any questions you may have answered and to engage with other students just like you!  Don't forget to download our App and experience our fun VR classrooms - we promise, it makes studying much more fun* 😎

## Sources:

1. The Editors of Encyclopaedia Britannica. “Ribosome | Cytology.” *Encyclopædia Britannica*, 2019, [www.britannica.com/science/ribosome](http://www.britannica.com/science/ribosome). Accessed 10 Nov 2021.

2. Khan Academy. “Nucleus and Ribosomes.” *Khan Academy*, 2018, [www.khanacademy.org/science/biology/structure-of-a-cell/prokaryotic-and-eukaryotic-cells/a/nucleus-and-ribosomes](http://www.khanacademy.org/science/biology/structure-of-a-cell/prokaryotic-and-eukaryotic-cells/a/nucleus-and-ribosomes). Accessed 10 Nov 2021.

3. “Mitochondrion - Role in Disease.” *Encyclopedia Britannica*, [www.britannica.com/science/mitochondrion/Role-in-disease](http://www.britannica.com/science/mitochondrion/Role-in-disease). Accessed 10 Nov 2021.

4. British Society for Cell Biology. (2019). Ribosome | British Society for Cell Biology. Bscb.org. [https://bscb.org/learning-resources/softcell-e-learning/ribosome/](https://bscb.org/learning-resources/softcell-e-learning/ribosome/) 

5. Gahl, W. (2019). Mitochondria. Genome.gov. [https://www.genome.gov/genetics-glossary/Mitochondria](https://www.genome.gov/genetics-glossary/Mitochondria) 

6. Microscope Master. (2019). Ribosomes - Definition, Structure, Size, Location and Function. MicroscopeMaster. [https://www.microscopemaster.com/ribosomes.html](https://www.microscopemaster.com/ribosomes.html) 

7. Mitochondrion – much more than an energy converter | British Society for Cell Biology. (2019). Bscb.org. [https://bscb.org/learning-resources/softcell-e-learning/mitochondrion-much-more-than-an-energy-converter/](https://bscb.org/learning-resources/softcell-e-learning/mitochondrion-much-more-than-an-energy-converter/) 

8. Newman, T. (2018, February 8). Mitochondria: Form, function, and disease. Www.medicalnewstoday.com. [https://www.medicalnewstoday.com/articles/320875#function](https://www.medicalnewstoday.com/articles/320875#function) 


mitochondria

Ribosomes and Mitochondria Study Guide

Prokaryotic and Eukaryotic Cells Study Guide

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## Interactive Simulation
[Launch Eukaryotic Cell Simulation!](https://eukaryoticcell.com)

## Youtube Video

<iframe width="560" height="315" src="https://www.youtube.com/embed/4F3Xr_5LopU" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

*Check out the corresponding VR-based Room on our Inspirit iOS App, which you can download [here](https://apps.apple.com/us/app/inspirit-learn-biology/id1563066201)!*

---

## Introduction

All cells fall into one of two categories: *prokaryotic* and *eukaryotic*. __Prokaryotic Cells__ and __Eukaryotic Cells__ are kind of like fraternal twins–they have a lot of similarities, but they also have some big differences. We place a cell into one of these two categories based on a singular piece of criteria: the presence or absence of a nucleus. Eukaryotes have them, and prokaryotes don’t. 

Now there are a bunch of other characteristics that set them apart from one another, but if you read the title, you know that today we’re only focusing on eukaryotes. These nucleus-having cells are further divided into two categories: *plants* and *animals* (fungi and protists too, but that’s for another day). Once again–fraternal twins. They’re more similar to one another than prokaryotes and eukaryotes, but they still aren’t quite identical.

We’ll begin by going over the features and organelles found in both plant and animal cells: *the nucleus, mitochondria, endoplasmic reticulum (ER), Golgi apparatus, ribosomes, lysosomes,* and *vacuoles*. After that, we’ll touch on the structures that are only found in plant cells: *chloroplasts, the central vacuole,* and a variety of *specialized plasmids*. Let’s start with the nucleus.

![prokaryotic vs eukaryotic cell](//images.ctfassets.net/4yflszkpcwkt/4ChSgSz7FafrsvxhRQjDdz/4be0a03848ab7cdf153bf5e0bef5fdb7/Prokaryotes-vs-Eukaryotes.jpg)

[Source](https://www.sciencefacts.net/prokaryotes-vs-eukaryotes.html)

---

### Lesson Objectives

- Learn about what organelles are present in eukaryotic cells. 
- Briefly understand their structures and functions.

👋 If you want to learn about the organelles of plant and animal cells in more detail, check out are [Cell Structure](https://www.inspiritvr.com/general-bio/cell-biology/cell-structure-study-guide-part-1) and [Plant Cell Structure](https://www.inspiritvr.com/general-bio/cell-biology/plant-cell-structure-study-guide) study guides.

---

### Shared Organelles

---

### Nucleus

Like we discussed, the __Nucleus__ is the organelle that sets eukaryotic cells apart from the prokaryotic ones. Inside the nucleus you’ll find deoxyribonucleic acid (or if you’re short on time, __DNA__). Besides storing DNA, the nucleus controls all of a cell’s activities, including metabolism, growth, protein synthesis, and cell division. It’s composed of 4 parts–the __nuclear envelope__, __nucleoplasm__, __nucleolus__, and <span id="q1"></span>.

![nucleus](//images.ctfassets.net/4yflszkpcwkt/7b16KfxAUZ2GcxEa0BX12W/4d002f2b8a1f8f48e0e9e5a2e6cfd9c2/Nucleus-Structure-Diagram.jpg)

[Source](https://www.sciencefacts.net/cell-nucleus.html)

---

### Mitochondria

__Mitochondria__ are membrane-bound organelles that are composed of an __outer membrane__, __inner membrane__, __intermembrane space__, and mitochondrial <span id="q2"></span>. They generate most of the energy a cell uses to function (we’ll spare you the powerhouse spiel), store calcium, and activate apoptosis if they decide a cell is too old or has ceased to function (no organelle would be complete without a hint of ageism, right?).

![mitochondria](//images.ctfassets.net/4yflszkpcwkt/3xTW0Z7sdKwldo4xknQ85R/6ed7a2463feb85ab73ee3584dc474587/1280px-Animal_mitochondrion_diagram_en__edit_.svg.png)

[Source](https://commons.wikimedia.org/wiki/File:Animal_mitochondrion_diagram_en_(edit).svg)

<aside>
💀 Apoptosis is programmed cell death, making mitochondria the judge, jury, and executioner of a cell.

</aside>

---

### Endoplasmic reticulum (ER)

Up next we have the __Endoplasmic Reticulum (ER)__, an organelle made up by a network of membrane-enclosed sacs called cisternae that attach to the nuclear envelope. __Cisternae__ are formed by the ER’s membrane folding in on itself, making their shape similar to candy ribbon. Each cisterna is shaped kind of like a cup, and the empty space in the middle is called the <span id="q3"></span>. The endoplasmic reticulum is an important manufacturing site for both lipids and proteins, many of which are made for and exported to other organelles. It is divided into two regions: the *rough ER* and the *smooth ER*. Let’s discuss below.

![Untitled 3](//images.ctfassets.net/4yflszkpcwkt/3ZBTrHOq34AUvIcCzk2hGM/56fc2327632cb652f9824b0b7bcc6c36/Untitled_3.png)

[Source](https://images.app.goo.gl/3QEWWSGqzT181Z9M9)

### The Rough ER

The __Rough ER__ is where a cell produces proteins and membranes. It works with ribosomes (we’ll get to those) to make proteins that are destined to be either part of the membrane or released from the cell. Ribosomes translate mRNA and use it to synthesize polypeptide chains. When synthesis is complete, they embed themselves in the rough ER’s membrane and release the chains, which will move to the lumen and fold into their final protein form. Once completed, the proteins are tagged, indicating they are ready for transport to the Golgi apparatus, an organelle that we’ll discuss shortly.

<aside>
😮 Ribosomes that bind to the endoplasmic reticulum give it a bumpy appearance, which is why we call it the rough ER!

</aside>

### The Smooth ER

The __Smooth ER__ is the other region found within the endoplasmic reticulum, distinguished from the rough ER by the fact that there aren’t ribosomes plastered over every inch of it. It’s job is to produce lipids and steroids, both of which are really important for energy storage, membrane structure, and communication. It’s also in charge of calcium regulation. When the nervous system triggers a muscle cell, the smooth ER releases calcium ions that cause the muscle contract. It’s last important job is detoxifying the cell by removing the waste created by both metabolic processes and any drugs in your system.

<aside>
☝️ Steroids can act as hormones, the chemicals that carry messages through your blood to coordinate different functions in your body. This includes controlling your emotions, so if you’re ever feeling extra sad one day, you know which organelle to blame.

</aside>

---

### Golgi apparatus

We mentioned the Golgi apparatus (aka Golgi bodies) when discussing the proteins produced in the rough ER. The __Golgi Apparatus__ is composed of four to eight __Cisternae__ that are not interconnected like they are in the endoplasmic reticulum. It’s essentially a post office, modifying, packaging, and delivering proteins and lipids wherever they need to go in the cell.

![Untitled 4](//images.ctfassets.net/4yflszkpcwkt/4UVAPYrzpbvwI30HvjZTHr/3c9d046dcfb8a98a25d8dab6855ce0e9/Untitled_4.png)

[Source](https://images.app.goo.gl/NGMLdmm7KrkLsMaZA)

---

### Ribosomes

__Ribosomes__ are organelles composed of RNA molecules and proteins that carry out the process of protein synthesis. They have two subunits–one large and one small. When not synthesizing proteins, these subunits remain <span id="q4"></span>. During protein synthesis, the two units combine and work together as one to translate mRNA and form a polypeptide chain from amino acids which will eventually become a functional protein.

![ribosome](//images.ctfassets.net/4yflszkpcwkt/767iVVrRsGT2O81suHl0bJ/1cf69f1f13ee78eb292acf3afbc03fb1/ribosome_lrg_sm_subunits-23b46a3be6354c4eacb550b25fa3c69d.jpg)

[Source](https://www.thoughtco.com/ribosomes-meaning-373363)

👉 To learn more about ribosomes, check out this study guide [here](https://www.inspiritvr.com/!/cell-biology/ribosomes-and-mitochondria-study-guide)!

---

### Lysosomes

__Lysosomes__ are the recycling plant of a cell. They’re filled with tons of enzymes that can (and will) break down any molecule that crosses their path and use their parts elsewhere. All of those enzymes can only function in an acidic environment, which is why lysosomes stay around a pH of <span id="q5"></span>. This is actually a safety mechanism–the pH of the rest of the cell is 7, so if a lysosome were to burst, the enzymes released would cease to function before they had the chance to digest anything else that the cell still needed.

![lysosome](//images.ctfassets.net/4yflszkpcwkt/35cfKHdNGVNWjpRnpkCm2m/cdd9c3465e789984f0ba3c2259932d7b/425618-1.jpg)

[Source](https://cordis.europa.eu/article/id/425618-unveiling-the-regulatory-architecture-of-lysosomal-gene-transcription)

---

### Vacuole

__Vacuoles__ are the storage lockers of a cell. They’re small, membrane-bound sacs containing either fluid or gas (like water or CO2) that are mainly used for storing random materials from the rest of the cell that either need to be used in the future or removed from the cell. Their main functions are removing and storing parts of the cell that have broken down due to age or damage, removing and storing harmful products to protect the cell from damage, and storing water and nutrients like lipids, proteins, and carbohydrates.

![vacuole](//images.ctfassets.net/4yflszkpcwkt/77mJGx76NJgy0PbZeIKYnB/2e6a2b0d6bc0f1d7869043a0f5e5615b/Biological_cell_vacuole.svg.png)

[Source](https://onestudenttoanother.wordpress.com/2014/03/05/vacuole/)

---

### Plant-Specific Organelles

---

### Chloroplasts

__Chloroplasts__ convert solar energy to chemical energy in a process called __Photosynthesis__, during which plants convert solar energy, carbon dioxide, and water into glucose and oxygen. They contain an *outer membrane, intermembrane space, inner membrane, stroma*, and a *thylakoid system*, which is pretty similar to the structure of mitochondria. Both mitochondria and chloroplasts are thought to have evolved through the *endosymbiosis theory*, which is probably why they look so alike.

![Chloroplast](//images.ctfassets.net/4yflszkpcwkt/27XRLKX6Lbxws5XU1zZiRp/c44b29064f6ac02b26d3db79f778471f/stacks-membrane-vesicles-stroma-matrix-chlorophyll-membranes.jpg)

[Source](https://www.britannica.com/science/chloroplast)

---

### Specialized Plastids

There are many specialized plastids found in plants that aren’t found in animals. Today we'll go over about three of the major ones other than chloroplasts: leucoplasts, chromoplasts, and gerontoplasts. 

<span id="q6"></span> are non-pigmented plastids found in the non-photosynthetic parts of a plant (like the roots). They synthesize amino and fatty acids, and store starch, lipids, and proteins.

![chloroplast chromoplast gerontoplast](//images.ctfassets.net/4yflszkpcwkt/7zrwX4pQCTv9tRUnlYZHW0/a946ce7985a18df95568d948e0d58a72/1-s2.0-S0005272815000274-gr2.jpg)

[Source](https://www.sciencedirect.com/science/article/pii/S0005272815000274)

Chromoplasts and gerontoplasts both originate from chloroplasts. In some situations, chloroplasts transform into __Chromoplasts__, plastids that produce and store pigments other than chlorophyll. This occurs during the development of things like flowers, fruits, and the changing leaves when fall comes around. When chloroplasts go into senescence, they become __Gerontoplasts__, plastids that convert the chloroplasts into different organelles to be used within the cell.

---

### Central Vacuole

A vacuole is an organelle that stores and disposes of various substances, and both plants and animals have them. However, instead of the tiny vacuoles found in animal cells, plant cells have one large __Central Vacuole__ surrounded by a membrane called the __Tonoplast__ and filled with a fluid called cell sap. It’s primary purpose is to store water and maintain __Turgor Pressure__, the force exerted by stored water against the cell wall. Turgor pressure changes as water moves into or out of a plant cell via diffusion during osmosis.

![central vacuole](//images.ctfassets.net/4yflszkpcwkt/4LAQAOZQXIDoQXidNbMOS0/ab340f26f18258073551c96fe75c9b88/2000px-Plant_cell_structure_svg_vacuole.svg-58a886443df78c345bf8d009.png)

[Source](https://www.thoughtco.com/vacuole-organelle-373617)

---

## ✅ Conclusion  

The main difference between prokaryotic and eukaryotic cells is that the eukaryotic cells have a nucleus while prokaryotic cells do not. The nucleus, plasma membrane, ribosomes, cytoplasm, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles, and the plant-specific chloroplasts, central vacuole, and specialized plastids are all components of a  eukaryotic cell, each  with its own specific function that  plays a major role in the functioning of the cell.

---

*We hope you enjoyed studying this lesson and learned something cool about the __Eukaryotic Cell__! Join our Discord community to get any questions you may have answered and to engage with other students just like you!  Don't forget to download our App and check out our awesome VR room for this guide - we promise, it makes studying much more fun* 😎

## Sources

1. “Welcome to CK-12 Foundation | CK-12 Foundation.” [https://www.ck12.org/book/cbse_biology_book_class_xi/section/9.4/](https://www.ck12.org/book/cbse_biology_book_class_xi/section/9.4/). Accessed 11 Nov. 2021.

2.  “Eukaryotic Cells | Biology I.” *Courses.lumenlearning.com*, [courses.lumenlearning.com/sanjacinto-biology1/chapter/eukaryotic-cells-2/](https://courses.lumenlearning.com/sanjacinto-biology1/chapter/eukaryotic-cells-2/). Accessed 11 Nov. 2021.


Eukaryotic Cell Study Guide

cell division

The Cell Cycle Study Guide 

Gametogenesis Study Guide

Cytoplasm and Cytoskeleton Study Guide

Sexual and Asexual Reproduction Study Guide

Chromosomes Study Guide

Complete process of photosynthesis Study Guide

Role of Leaves in Photosynthesis Study Guide

Cell Division Study Guide

Chemosynthesis Study Guide

Membrane Proteins Study Guide

Chloroplasts Study Guide

Heterotrophs And Autotrophs Study Guide

Glucose and ATP Study Guide

Diffusion and Osmosis Study Guide

Sodium-Potassium Pump Study Guide

Cell Organization Study Guide

 Nucleus Study Guide

Phospholipid Bilayer Study Guide

Cell Structure Study Guide - Part 2

If we take cars for example, there are so many amazing types and brands! But hidden beneath these differences are a few common components like an engine, the wheels, etc. Something quite similar to our cells too. Here's a quick look at few such irreplacable cell components!

cells

TL;DR Parts of a Cell

We are constantly surrounded by the amazing phenomenon that is GROWTH! A baby, a tree, an animal, not to forget a whale calf that will eventually grow to about 98 feet! Cell division drives this growth wherein one cell divides to form two identical daughter cells. Check out this cheat sheet to know all about it!  

mitosis

TL;DR Mitosis

Here's another quick run through on the important components that make up the variety of cells surrounding us and endow them with powers such as movemment too!

flagella

TL;DR Cell Structure - Part 2

We are constantly surrounded by the amazing phenomenon that is GROWTH! A baby, a tree, an animal, not to forget a whale calf that will eventually grow to about 98 feet! Cell division drives this growth wherein one cell divides to form two identical daughter cells. What is even more fascinating is another unique cell division called meiosis that is essential for this growth to begin. Intrigued? Check out this cheat sheet to know all about it!  

meiosis 

TL;DR Meiosis

Plant cells and animal cells share many common structures, like a nucleus, plasma membrane, and  mitochondria. However, plant cells contain 3 distinct structures that animal cells do not: a cell wall, central vacuole, and specialized plastids (like chloroplasts!). Check out this cheatsheet to learn more about each of these structures and what they do to help a plant cell function.


grass plant cell 

TL;DR Plant Cell Structure

Ribosomes are responsible for the creation of essential proteins in the cell and the mitochondria produce the majority of its energy, two key functions for cellular health and survival. This cheat sheet covers all of the basics of what these organelles are, what they're made of, and what they do to help a cell stay alive and functioning. Check it out!

ribosome

TL;DR Ribosomes and Mitochondria

The cell cycle is the life cycle of a cell. It occurs in two stages: interphase and mitosis. Each of these stages have their own phases during which unique and important processes for cell division occur. Check out this cheatsheet to get the rundown (without all of the reading)!

TL;DR The Cell Cycle

Cells make up the structure of every living organisim on the planet, but what makes up a cell? A group of membrane-bound structures called organelles each perform a special job within a cell to help it stay alive and function (kind of like our organs do for us!). Check out this cheatsheet to get the rundown (without all of the reading).