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PROKARYOTES AND EUKARYOTES- Part 4 Where do prokaryotes carry out their functions?

As we have seen prokaryotes lack organelles, the tiny little compartments that eukaryotes have that help them carry out all the tasks that keep them alive. We can think of prokaryotes as open concept cells, where there are no walls separating everything inside but there are certainly areas that are designated to special functions.

The nucleoid region as we’ve mentioned is where the genetic information is kept. It’s like having a bookcase set up in the middle of your house to go to and photocopy blueprints from whenever you need to build your cellular ikea furniture.

To build that itty-bitty sofa to make your cell nice and comfy you’re going to need little machines to help you out! Those machines are ribosomes! BUT WAIT! Didn’t we talk about ribosomes when discussing organelles? We sure did! 

But they are NOT organelles, they are sub-cellular components. And that’s because an organelle needs to be an enclosed space with a function. Ribsomes only carry out a function, they’re not a compartment. Ribsomes are special proteins that help you translate genetic language (RNA) into protein language (amino acids). They float around in the cytosol of the prokaryotic cell in their separate large and small subunits, and come together when they need to work. Unlike ribosomes in a eukaryotic cell they don’t have a handy dandy Endoplasmic reticulum (ER) to hang out in though.

ATP synthesis is really cool to look at in prokaryotes too. Unlike eukaryotes which have a mitochondria to make their ATP, the prokaryotic cells rely on their plasma membrane. If you recall ATP is like a rechargeable gift card that the cell uses to ‘pay’ for functions.

As for processes of synthesis and degradation these all occur in roughly the same space.

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PROKARYOTES AND EUKARYOTES- Check In

Let’s now make a short table to summarize the main traits and differences between prokaryotes and eukaryotes. 

Since we can’t make a chart on tumblr we’ll be presenting our information in two nice neat lists. But at home you can always make a nice table, which might make it easier to compare information visually.

We’re not going to include ALL of the differences between the two for now. But you can always add on your own, and later we’ll refer back to these lists and add onto them as we discuss other pieces of information.

For fun, how about you create your own table without referring to your notes and then check in using our notes and your own? Ready? Let’s compare down below!

Eukaryotes:

·       Have a nuclear membrane

·       Have a nucleus

·       Have more than one DNA molecule

·       Reproduce through mitosis

·       Have organelles

Prokaryotes

·       Do NOT have a nuclear membrane

·       Have a nucleoid region

·       Have a single DNA molecule

·       Reproduce through non-mitotic division and binary fission

·       Do NOT have organelles

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PROKARYOTES AND EUKARYOTES - Part 3 Prokaryotes

Prokaryote Characteristics

Comparatively a prokaryotes is less derived this means that it is missing some of the unique characteristics. Let’s see what a prokaryote is missing.

·        Lack organelles. A prokaryote doesn’t have special little compartments inside. Instead all of the chemical processes it needs to carry out are done in the cytosol.

·        Lack a nucleus. Instead of a nucleus, which is a special compartment to store DNA, a prokaryote has a nucleoid. This is a special region of the cell, usually the central one where the genetic information is found. However, there is no membrane that separates the nucleoid from the rest of the cell.

·        Lack linear chromosomes. Prokaryotes only have a single circular chromosome that stores all the information for reproduction

·        Do not carry out mitotic division, prokaryotes reproduce through a special process known as binary fission.

 More on Prokaryotes

Prokaryotes are usually very tiny in comparison to a eukaryote

Prokaryote cells typically have four cell shapes to them: circular (coccus), rod or curved rod and spiral.

Although they do not have organelles, a prokaryote still has a cytoskeleton. The cytoskeleton provides structure and support to a cell, and a means of transportation as molecular motors can walk along them.

Some prokaryotes have a cell wall, this is an extra barrier around the outside of the plasma membrane. 

A plasma membrane is a hydrophobic barrier that all cells have. It’s considered hydrophobic or water averting because it prevents the passage of water soluble molecules. However, it is not completely impermeable, water soluble molecules can still pass but they require special proteins and processes to do so. This membrane is made up of phospholipids and proteins. 

A cell wall however is made out of polysaccharides these are long chains of sugar molecules. The purpose of a cell wall is to provide extra structure and rigidity, as well as protection. If the cell wall is very rigid and hard it is called a capsule but if it is very fluid then it is called a slime layer.

Some prokaryotes have a flagella, which is like a very long tail that extends out from the cell. It whips around very fast and helps the cell move through a liquid environment. The flagella is made out of proteins and it is made out of the plasma membrane.

Some prokaryotes have pilli these are also extensions of the plasma membrane but instead of a tail they look like little hairs. These hair like proteins help the cell attach themselves to things, like cellular Velcro. They also help in binary fission the process of sexual reproduction in bacteria.

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PROKARYOTES AND EUKARYOTES - Part 2 Eukaryotes

Eukaryote Characteristics

Of the three domains, eukaryotes are the most derived. This means they were the newest to evolve and therefore have the most unique traits that have evolved. Traits are the characteristic features that identify an organism.

 For example let’s describe an animal. An animal is a eukaryote, that’s a good start but so are a lot of other things. We can also describe animals as multicellular-but plants and fungi are also multicellular. But if we describe animals as multicellular eukaryotes that ingest their food then we can’t possibly mix them up with anything else.

Now let’s list the traits of a eukaryote:

·       Possess organelles which are little compartments within the cell with specialized functions.

·       Possess a nucleus, we mentioned this before but a nucleus is an organelle that stores genetic information.

·       Possess more than one linear chromosome. A chromosome is a molecule of DNA, it’s a very condensed way of storing all that information.

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PROKARYOTES AND EUKARYOTES - Part 1

Taxonomy is the branch of science that deal with classifying things, in particular classifying living organism. Taxonomy has many different groupings at different levels, but the largest one is called a domain. There are three domains eukaryotes, eubacteria, and archaea bacteria. 

However, there used to be only two eukaryotes and prokaryotes. Why did we switch from two groups to three?

The differences between prokaryotes and eukaryotes are only based on cellular structure. This out dated way of separating cells apart was only based off of what could be observed with the technology available at the time. With newer better technology we can do simply more then look at the appearance or morphology of the cells. For example now we can take in account the genome- the collection of ALL the genetic material in an organism. Now we know that eubacteria and archaea bacteria are separate domains despite having the structure of a prokaryote.

Etymology

Let’s look at the words eukaryote and prokaryote. Eu means true and karyote means kernel, this name “true kernel” refers to the nucleus that is found in eukaryotic organisms. A nucleus is a distinct area in the cell where the genetic material DNA is kept-it’s a distinct area because there is a membrane, the nuclear membrane that separates the DNA from the rest of the cell. 

On the other hand pro means before, therefore a prokaryote lacks a nucleus because these organisms existed before the nucleus evolved.

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This is a literary anthology based on the ideas of paying it forward, and how ti only takes on person to impact an entire community.

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ORGANELLES - Part 12 Specialized Organelles

Some cells like plants cells have specialized organelles that other cells normally do not have. Also the amount of organelles varies between cells types, as some cells will need more of a specific organelle for its function. For example muscle cells will have an abnormally high amount of mitochondria because they need to be able to produce massive amounts of energy all at once.

Cell wall

The cell wall is located outside of the cell membrane and it is an extra casing around the cell to give it protection and structure. The cell wall makes it much harder to enter into a cell or destroy it, as well it helps maintain its structure and function. Plant, bacteria and fungi all have cell walls.

Plant cells make their cell walls out of cellulose a polysaccharide. A polysaccharide is a chain of many (poly) special sugars called saccharides. Since plants are unable to run away from their predators they have cell walls in order to protect themselves and make it harder to eat them.

Cell walls contain many plasmodesmota, these are small holes in the cell wall so that cells can communicate with each other. Think of them like little windows that cells uses to pass very tiny messages in the form of ions to each other. 

Chloroplast

The chloroplast is an organelle found in plant cells that contains the green pigment chlorophyll and is where the process of photosynthesis takes place. Like the mitochondria it is an example of endosymbiosis. Chlorophyll is what gives plants their green colour!

Amyloplasts

An organelle that stores starch, a carbohydrate. 

Chromoplasts

An organelle that stores pigments. You can remember this because chromo refers to colour!

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ORGANELLES - Part 11

Mitochondria – the Mint- shown in orange

Bet you were starting to think we’d forgotten this one didn’t you? Everyone compares the mitochondria to a power plant because it “powers” the cell. But it doesn’t produce energy directly instead it produces energy currency.

Through a process known as cellular respiration the mitochondria makes a molecule known as adenosine triphosphate (ATP). ATP is an adenosine that is bound to three (tri) phosphates. These bonds with phosphate hold potential energy, this means that when the bond is broken energy is released. This is what we mean by energy currency, it’s like the mitochondria is making a whole whack load of gift cards that it hands out to everybody. Then when an organelle need to do something that require energy they cash in the ATP gift card and it becomes an adenosine diphosphate (ADP) card which still has a bit of cash on it but not much. If they chose to use the ADP card it then becomes the adenosine monophosphate (AMP) card, most of the time ADP gets recycled back into ATP.

We mentioned apoptosis the selfless cell suicide process, the mitochondria also plays a role in that as well.

For now we can also mention in passing that the mitochondria is an example of endosymbiosis which is when a larger cell takes in but doesn’t eat a smaller cell. Instead the smaller cell hangs around and preforms a function that is useful to the larger cell in exchange for getting a nice home to live in.

Also with Mother’s Day coming up be sure to thank your mom for your mitochondria-that’s right you only inherit mitochondria from your mother!

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ORGANELLES - Part 10 Peroxisomes

Peroxisomes – The gym – Outlined and sprinkled in purple

Peroxisomes play a big role when it comes to lipids (fats) in the cell. You can think of peroxisomes as a gym because they help a cell breakdown very long chains of fatty acids. Instead of hopping on an exercise bike, they use a special process known as β-oxidation (if you don’t know, β means beta it’s a letter from the Greek Alphabet).

But they also help with the formation of phospholipids so perhaps they aren’t that great of a gym if they’re making fats too!

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ORGANELLES - Part 9 Lysosomes

Lysosomes – Disposal Center – Outlined in dark green

Cells need a way of breaking down undesirable materials including old or useless organelles. The lysosome contains special proteins for breaking down most substances including organelles, substrates and waste products.

These proteins are called hydrolytic enzymes; enzymes are proteins that catalyze reactions, this means they kick start them. Hydrolytic refers to the fact these enzymes are helping with a specific reaction type known as hydrolysis which is the process of breaking apart a bond (lysis), with water (hydro).

Lysosomes play an important role in a process known as apoptosis, this is controlled cell suicide. That’s right cells can kill themselves! If a cell is able to detect that something is wrong with it; for example it is becoming old, cancerous or infected it will go through apoptosis. It’s a very selfless act since the cell is destroying itself in a very controlled way to protect its neighbours from harm. (It is NOT necrosis this is a very destructive form of cell death that is NOT controlled and harmful to a cell’s neighbours)

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ORGANELLES - Part 8 Cytosol

Cytosol – the water bed

Cytosol is the fluid that fills the cell; however it is not just made up of water there are many different ions and other substances found in the cytosol. The cytosol suspends all of the organelles so that they float within the cell. Different cells have different contents in their cytosol for a different intracellular environment, this could be because of what the cell’s role is or what it’s outside environment-extracellular environment is like.

!!! Remember an organelle has to have a function AND be a compartment! Because of this, cytosol is a sub-cellular component!!!

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Factors - Part 3 Continued...

Strategy Three: Decompose and Recompose

This one is very similar and overlaps with Find a Friendly Multiple. This strategy involves the idea of composing numbers, which just means the different ways we can represent a number, which are many!

For example the number five, we can represent it in letters five, in Arabic numerals 5, Roman numerals V, as 4+1, 3+2, 20/4, and many, many other ways.

For this strategy we can rearrange how we’ve composed our number sentence. And we can do this in many ways. I’ll show some methods down below:

          Split ‘em up then add ‘em up

For this method: split the number that’s giving you grief, in this case 9, into two or more integers that are easier to work with. Then, add together the products of these numbers to get the overall product.

          Example: 9 X 12 = 108

                                  9 = 3 + 6 therefore (3 X 12) + (6 X 12) = 9 X 12

                                              3 X 12 = 36, and 6 X 12 = 72.

                                              36 + 72 = 108  It worked!      

                      Alternatively, 12 = 2 + 10 therefore (9 X 2) + (9 X 10) = 9 X 12

                                              9 X 2 = 18, and 9 X 10 = 90

                                              18 + 90 = 108 It still works

As shown in this example it doesn’t matter which number you decompose, and what is the best choice is to choose the numbers that are the easiest for you to work with. Some people might find the first method easier and others the second. With 9 and 12 there are many ways you could approach this, but there’s no point in listing all of them.

How about taking a moment and trying three other ways you could have solved this problem using this method?

          Maintain Balance in the Force

This method is a little harder to grasp as it involves some more complicated shuffling of your numbers around. In this method I will apply some sort of change to either the multiplicand or the multiplier and then do the inverse to the other number.

                      For example:  9 X 2 = 18

3 is an easier number to work with than 9, so I will divide 9 by 3 and then multiply 2 by 3.

                                           (9/3) x (2 X 3) = 3 X 6

                                           3 X 6 = 18, and 9 X 12 = 18

How about trying this with a few other integers?

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Factors - Part 3

9, 18, 27, 36, 45, 54,63, 72, 81, 90, 99, 108, 117, 126, 135, 144, 153, 162, 171, 180, 189, 198…

What are these? Why the multiples of nine!

When I was small I always found the 9 times tables the hardest to remember, the others from 1-12 I could spout with ease but these ones always had me stumped. Since the previous post was on general tips and tricks for factoring I decided to focus in on the number I found the hardest. Some of these will only be applicable to nine, but others you can modify to help with other numbers.

Strategy One: Add the Digits!

This is the strategy mentioned in my previous post, for determining if 9 is a factor of any given integer. It’s very simple. Just take all of the digits in the number and add them together. If the sum is a number divisible by nine then the number itself is too!

Examples:

           333: 3+3+3=9 therefore this number is divisible by 9!

           1234: 1+2+3+4= 10 therefore this number is NOT divisible by 9.

Go ahead and try this on all of the multiples of nine listed at the top!

Strategy Two: Multiply by 10 and subtract! (Find a Friendly Multiple)

This is the strategy I used for many years to find multiples of 9. This method involves multiplying your integer by ten, and then subtracting the integer from the resulting product. In this case the product of our integer multiplied by 10 is our friendly multiple because it’s one that is easy to find.

           Examples:

                       8 X 10= 80 then, 80 – 8 = 72  Therefore, 8 X 9 = 72

What I like about this strategy is its flexibility to be applied to other numbers. For instance, for people who struggle with 12 times tables, I tell them to simply add the integer twice to the product of the integer multiplied by ten. 

However, you don’t have to use 10′s times tables. 

Let’s say you’re struggling with the 6 times tables. You can change your friendly multiple to the product of your integer by five. Then all you have to do is add your integer to the friendly multiple and ta-dah, you know what 6 multiplied by your integer is.

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Factors - Part 2

 Listed below are some quick checks you can do to check divisibility. These divisibility tests will help you with identifying factors!

 0’s: What are you trying to do? You can’t divide by zero!

1’s: Every number is divisible by one AND itself!

 2’s: If the number is even, as in it ends in 0, 2, 4, 6 or 8, then it’s divisible by 2.

3’s: if the sum of the digits in the number is equal to a number divisible by three, then the number itself is divisible by 3.

Examples: 45 and 46, 4+5=9 therefore 45 is divisible by 3, but 4+6=10 therefore 46 is NOT divisible by three.

6’s: if the number is divisible by 2 and 3, then it is divisible by 6.

9’s: if the sum of the digits in the number is equal to a number divisible by nine, then the number itself is divisible by 9.

Examples: 45 and 46, 4+5=9 therefore 45 is divisible by 9, but 4+6=10 therefore 46 is NOT divisible by nine.

I have some other tips for nine’s times tables, and will make a full post on them later.

5’s: if the number ends with 5 or 0 it is divisible by 5.

10’s: if the number ends with 0 it is divisible by 10.

 In fact for any number that ends with a zero be it 100 or 10,000,000,000 as long as the number of zeroes in the number you are trying to find factors for is the same or higher then the number you are trying to determine is factor, then that number is a factor.

For example 10,000 has 4 zeroes and 100 has 2, therefore 100 is a factor of 10,000.

 Another tip, even numbers can only multiply to even numbers, therefore they will NEVER be the factor of an odd number.

 When I need to factor a number, and begin to write out it’s factors I make sure that every factor I write has it’s partner. Unless the number is a square, there should be an even number of factors listed. So, if I write that a number is divisible by two I make sure I write whatever number two has to be multiplied by.

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Factors - Part 1

So recently I’ve been getting questions in my classes and at tutoring on factoring, and if I have any tips for tricks for tutoring. Listed in the following posts are some quick checks you can do to check divisibility.

Before we get into various tips and tricks, let’s clarify some terms:

Multiples: The product of any chosen number multiplied by an integer. Which is a really fancy way of saying any number you get by multiplying a number of your choice.

           Example: 2, 4 and 8 are the first three multiples of two.

Factors: These are the numbers that result by dividing any chosen integer. Or another way too look at it is the numbers that can be multiplied together and produce any chosen integer.

I like to think of them as the opposite of a multiple, since the multiple would be the result of multiplying the two factors together.

           Example: We know 8 is a multiple of 2. Therefore 2 is a factor of 8                                       because I can multiply 2 by 4 (another factor) to get 8.

I like to associate multiples with multiplication and factors with division, that’s how I keep the two terms clear in my head. Multiples sound like multiply, and factors sounds like fractions. 

Fact Families: A group of numbers connected to each other by math facts. This applies to ANY math operation. 

             Example 3, 2, and 1 can be a fact family because 3 - 2 = 1, or 1+2 =3...

However, sometimes people like to think of fact families as the collection of ALL of the factors of a number.

Divisible: a number is divisible by another number if it can be divided WITHOUT remainders.

Product: the answer to a multiplication sentence. 

                Example: 12 is the product of 3 x 4

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ORGANELLES - Part 7 Cytoskeleton

Cytoskeleton – Highways – only centriole is shown in black outline

The cytoskeleton is responsible for maintain the cells shape and giving it structure, but it also acts as a high way for moving things around the cell and during replication plays a very important role two.

Earlier we mentioned that cyto means cell, so it literally is the skeleton of the cell. But unlike our skeleton, a cell can disassemble and reassemble their skeleton. Their skeleton is also made of three different elements. We’ll give a brief overview of them here, but discuss them all in great detail later.

Microfilaments are the smallest of the three and they are made up of a globular protein known as actin. They have their own molecular motor known as myosin. Micro means small and filaments are also very tiny so that is how you can remember these elements as the smallest. When we talk about muscles they will become important, muscles are important for ACTION and so they are made of actin. They also play a role in making the cleavage furrow or the site where two cells separate during division (mitosis).

Intermediate filaments are the intermediate sized ones, they aren’t the biggest but they also aren’t the smallest. There are many different types and the type that a cell has is related to what the role of the cell is. They give the cell’s skeleton its rigidity and anchor the organelles in place.

Microtubules are the largest of the three, you can remember this because they are tubes not filaments, like the other two types. They are made up of a protein subunit called tubulin. We mentioned dynein and kinesin earlier, these molecular motors walk along the microtubule. These microtubules also make up structures called cilia and flagella.

!!! Like we mentioned before with the ribosome, this is NOT an organelle. Organelles are compartments with functions. This is a sub-cellular component!!!

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ORGANELLES - Part 6 Vesicles

Vesicles - Delivery Vans – shown in light blue outline

Vesicles are formed from the invagination of a membrane, this is when the membrane folds in to make a little bubble and then pinches off. Vesicles are usually formed to carry something between the various components of the cell.

For example in nerve cells they store neurotransmitters to be released through a process called exocytosis. Exocytosis is when the vesicle fuses with the plasma membrane an releases its contents outside of the cell. Exo means outside and cyto refers to cell.

Plant cells are known for having extremely large vesicles that take up the majority of their cells that store water and nutrients to support the cell.

Single cellular fresh water organisms also have specialized vesicles for collecting and disposing of water. This is because these organisms are constantly taking in water and need to get rid of it before they die. These vesicles are referred to as contractile vesicles.

Vesicles however don’t move on their own and instead rely upon special molecular motors that walk along the cytoskeleton to get to and from their destination. These motors are called dynein and kinesin.