Cell Organelles and their functions in cells

Introduction 

Cell organelles are specialized structures that act like a digestive system which takes in nutrients, break them down and creates rich molecules for the cell. The specialized/organized structures help turn the energy we take as food into energy that cell can use. The biochemical activity of the cell is known as cellular respiration. The organized structures are the working organelles that keep the cell full of energy. These structures are also known as powerhouse. 

They are present in nearly all human cell and are important for human existence. These structures produce most of our adenosine triphosphate (ATP), which is like the energy currency of the cell. These structures form constituency of eukaryotic cells.

Each cell contains different number of these organized structures. The numbers present depends on how much the cell needs energy. Those that need a lot of energy like thew cell contains a lot, but those that don’t need a lot of energy contain very little. These Microorganisms have the ability to produce more cell organelle as needed and also combine them to make large cell organelle.

Function of Cell organelle 

1. Energy production. cell organelle converts the food we eat into energy form that cell can use. This activity is known as oxidative phosphorylation. cell organelle is the only place oxygen is reduced and eventually broken into water. 

2. Cell death; cell organelle helps to decide which micro-organisms are destroyed, as the micro-organismsbecome old or broken then destroyed and cleared away. Cell death is an essential in life, it’s also known as apoptosis. cell organelle produces cytochrome C, which activate caspase one of the catalysts in wrecking micro-organisms during apoptosis. 

3. Storing Calcium; this ingredient is important in a number of cellular processes like fertilization, blood clotting, thew function and many others. Therefore its critical making it tightly regulated. cell organelle plays a major role in absorption of the above ingredients particles and storing them until when needed. These work very closely with endoplasmic reticulum to limit the amount of the above ingredient in cytosol. 

4. Heat production; in the course of nucleon leak, cell organelle can produce high temperature. Its one of theway the body generates heat by using brownish-yellow tissues, which are found in babies, who have the highest level of it and slowly reduces as they age. 

Structure of Cell organelle 

Cell organelles are small, regularly between 0.75 and 3 micrometer, not visible under microscope unless and are stained. Cell organelles are a small structure within a cell and are made up of two parts; the membrane and the matrix. 

They have two membranes an outer one and an inner one which have different functions. cell organelle is split into different regions which include; 

Outer membrane 

This outer portion include protein known as porins, which forms channels that allows protein to pass through. It also host a number of enzymes. Small molecules can pass through the outer membrane. 

Intermembrane space 

This is the area between the inner and outer membrane 

Inner membrane 

This is where proteins are held. There is no porins in the membrane, therefore, it’s impermeable to most mole. The Inner membrane 

is where most ATP are created. 

Cristae 

These are folds of the inner membrane. Cristae increase the surface area of the membrane hence, increasing the space available for chemical reaction. 

Matrix 

This is the space within the inner membrane. It contains hundreds of catalysts and it’s important in production of ATP. cell organelle DNA is housed here. 

Granules 

They control concentration of particles in cell organelle. Granules contain ribosome which produce protein used by cell organelle. 

Cell organelle are constantly dividing (fission) and bonding (fusion) though oval in shape. Organelles are linked together in every changing network. In sperm cells, cell organelle are spiraled and in mid-piece to provide energy for tail motion. 

The DNA within cell organelle is more susceptible to damage than any related genome, because free radical, which cause damage in DNA are produced when carrying out ATP synthesis. 

Majority of cell organelle disease are due to mutation in nuclear DNA that affect products that end up in cell organelle. The mutation can either be inherited or spontaneous. 

When cell organelle stop functioning, their storage starved of energy. As a general rule micro-organisms that need the highest amount of energy such as the cardiac muscle are affected the most by malfunctioning cell organelle. 

Where Proteins are Made

Many people wonder about the human body and how it works. Here is some information about how protein is made in the cell and a way to understand it in simple terms. 

 Proteins are a series of complex molecules. They are needed by the body in a number of ways. The proteins are needed by the cells to help give them a structure, help with the functions of the cell, and assist with the building of tissues in the body as well as the tissues in the organs. Proteins are made up of units called amino acids. These acids form in a long chain . With this chain, they are able to be attached together. Each contains has 20 amino acids. They can be arranged in a number of different ways and combinations to form the proteins. The arrangement of the amino acids will help determine the structure that the protein. This will also help determine the function that the protein is going to be performed in the body. Different proteins will perform different functions. 

 Proteins are made in the ribosome of the cell. The ribosome is a string of amino acids that are formed together. They are able to use these amino acids to make the proteins. Amino acids work with the mRNA (the messenger ribonucleic acids) and the tRNA( transfer ribonucleic acid) to help make the proteins so the body can use them. 

 In the ribosome, there are two different places where the protein can be made. Protein can be made freely in the cytoplasm and in this case, it would be a soluble protein. Protein can also be made in the endoplasmic reticulum. In order for the protein to be made in the endoplasmic reticulum, a small amount of protein needs to be transferred to this area from the cytoplasm. The proteins that are being made in the cytoplasm are designed to be released from the cell. They will be released into the plasma membrane or they can be released to the Golgi complex. Some of the proteins may end up staying in the cytoplasm. 

 The mRNA is produced in the nucleus of the cell. It is able to mix with the other units in the ribosome. The tRNA is able to link up with the amino acids that are found in the cell. This mRNA will tell the cell how to create each of the amino acids and the tRNA will help to transfer the items that are needed to make these acids. Once this happens the ribosome is able to remove one of the amino acids. This will then be done over and over again with the code for the new proteins and recreation based off of this one amino acid that can be duplicated. Proteins are made of the chains or residue from the amino acids. 

 There are different types of proteins that are formed in the body and each protein has a specific job. Proteins can be used to form antibodies. These will help the body recognize a virus and harmful bacteria. They will help the body fight them off and keep a person from getting sick. 

 Proteins can also be used to make enzymes. Enzymes will help carry out chemical reactions that happen within a cell. There are several hundreds of chemical reactions that can take place and the enzymes help with all of them. Proteins will also help the body make new molecules. It will use the information that is found in the DNA for this reproduction. 

 There are messenger proteins that are also found in the body. These proteins help make hormones and will help the biological process coordination happen between cells of the body and the issues of the organs. Proteins are also needed for the growth hormone to make sure that the body continues to grow and develop. 

 An important job of the proteins is to transport small molecules and other information including atoms in the cells. This will help send messages around the body. 

 Proteins are made in the ribosome of the cells and they can perform a number of function. The body can continue to replicate the production of the proteins and they can be used to help the body stay healthy. 

What is the function of chloroplast ?

Chloroplasts in a cell are the sites where photosynthesis takes place. These sites are however not found in all cells of a body but rather only in the photosynthetic cells such as algae and plant cells. Therefore, you cannot find such cells in bacterial or animal cells. 

Structuring of the chloroplasts 

Those chloroplasts which are featured in higher plants generally are planoconvex or biconvex shaped. Chloroplasts as well can be located in the mesophyll of a cell which is found in the leaves of a plant. For different plants, the shapes of the mitochondria are also different varying from ovoid or discoid to saucer-shaped filamentous shape to spheroid shape. The center of chloroplast is colorless and chloroplasts are vesicular. Some of these sites are structured in such a way that they look like a club whereby the middle zone is thin with ends full of chlorophyll. For algae, the chloroplast is one large site which resembles a stellate plate or rather a spiral band, a network plate. Same cell type has the same number of chloroplast but sizes vary with different plant species. 

Function of chloroplast

The chloroplast has various functions and such include: 

Chloroplast absorbs light energy then converts that energy to biological form of energy. The chloroplasts are important organelles in plant cells as it that allows for process of photosynthesis to happen. Some protists such as algae also have chloroplasts. Each chloroplast contains chlorophyll, which is a green coloring matter, which converts absorbed light energy from sun to chemical energy which can form sugars such as glucose. This is how food is produced in green plants. Therefore, animal cells do not have chloroplast as they obtain food and nutrients from plants. 

The function of chloroplasts which is photosynthesis is divided into two reaction, that is the light and dark reactions. Light reactions occur on thylakoid membranes. These membranes absorb light energy and store it as chemical energy in NADPH form, a form of NADP+ and ATP. This ATP forms that energy used to support dark reactions. That energy is then stored in H+ protons and used later to produce energy in ATP form. Two protein complexes are involved in photosynthesis and they are referred to as photosystems. Therefore, those two photosystems capture light energy and use it to energize those electrons obtained from water and then release energy in those electron transport chain for the mitochondrion. 

Hydrogen ions are then pumped by energy of from electrons obtained from water. A concentration gradient would be created, meaning there would be more hydrogen ions inside thylakoid membrane than in stroma. The hydrogen ions would then go back to stroma against cconcentration gradient through ATP synthase which produces ATP. Since that first photosystem reenergizes depleted electrons from photosystem II which photolyzes water to obtain and energize new electrons. This means that photosystem II occurs first followed by photosystem I. ATP which is needed for the dark reactions is hence produced inside the stroma through a process as well referred to as Calvin cycle. This process is a series of reactions which fix carbon dioxide into Glyceraldehyde-3-phosphate molecules. This reaction uses energy and electrons from ATP and NADPH respectively produced in light reactions. Ironically, in most plants, these processes occur daytime despite being called dark reactions. 

The first enzyme which is used in Calvin cycle is called RuBisCO and it is used for fixing CO2 into five-carbon Ribulose bisphosphate (RuBP) molecules to form 3-phosphoglyceric acid. 3-phosphoglyceric acid is then converted to glyceraldehyde-3-phosphate using ATP and NADPH. Most of glyceraldehyde-3-phosphate molecules are taken back into RuBP to produce more ATP molecules, but one usually leaves that cycle. 

Glyceraldehyde-3-phosphate molecules can combine to form larger sugar molecules called monomers like glucose, galactose, and fructose. These single sugar molecules can also double up to form disaccharides like maltose, sucrose, and lactose. More than two to six monomers combined form oligosaccharides. More than six to a thousand monomers together form polysaccharides such as cellulose and starch. Therefore, this is how food is formed. Carbohydrates are essential for anybody as they are energy-givers, thus it is essential to know how they are formed. Chloroplasts are very vital organelles more so when we are taking about the good health of plants. 

What is mitochondria?

Mitochondria are the plural of mitochondrion. A mitochondrion is a cell organelle found in eukaryotic organisms. The name mitochondrion comes from the Greek word Mitos which means, thread and Chondrion which means granule It has a double membrane and is responsible for the supply of the Adenosine Triphosphate that is used as a chemical energy source. The energy is a result of transformation of the proteins, fats and sugars. 

Mitochondria can be defined as the powerhouse a cell depends on. These are small kind of structures found inside the cell and are composed of a matrix and two membranes. The matrix is responsible for holding some fluid while the membranes allow occurrence of chemical reactions. Mitochondria form part of the eukaryotic cells. Majorly, the mitochondria in a cell are responsible of performing cellular respiration. What this means is that the powerhouse takes nutrients from that cell then breaks those nutrients down so as to produce energy. That energy is all what a cell needs so as to run its normal functions. 

Different cells contain varied numbers of the mitochondria. This number is determined by the much energy that given cell mainly requires. If a cell needs more energy, it will definitely have more of the mitochondria. The cell is able to produce additional mitochondria if it needs more of them. As well, a cell can combine various mitochondria so as to come up with larger mitochondria. 

Functions Of Mitochondria 

Mitochondria generate Adenosine Triphosphate which is used as a chemical energy source. Energy is important for any organism to carry out its functions. This means that mitochondria are very important in the body since they provide around 90% of the energy that is required by the body. 

Other functions of mitochondria include breaking down the harmful waste products to less harmful substances, producing chemicals that the body needs and also the recycling of some waste products. They also help in death of cells. This process is also known as apoptosis. Apoptosis is crucial for both growth and development to take place. The death of some cells ensures that cells do not replicate uncontrollably leading to cancers. This means that mitochondria are targets of the anti-cancer drugs. To convert the food substances to energy, mitochondria require oxygen, in a process called oxidative phosphorylation.

Mitochondria are seen as the cell’s powerhouse. They are different in number according to the needs of the cells. These needs are established by the cell type, tissue and the organism itself. Cells that require more energy have a higher concentration of mitochondria than those that require less energy. Mitochondria can replicate to be adequate when needed by a particular cell. On top of this, they can join together to form one big mitochondria to cater for this same energy requirements. 

Outer Membrane 

The mitochondrion contains both inner and outer membranes which are made of a protein layer sandwiched between two phospholipid layers. It also contains porins. The outer membrane’s task is to enclose the entire to avoid cell death. This occurs when the contents spill outside the cell which causes death of the cell. The inner membrane contains plenty of enzymes that help in conversion of foods intro adenosine triphosphate. 

Inner Membrane 

The inner membrane encloses the proteins in the cell. It is also permeable unlike the external layer. It is a highly impermeable membrane thus molecules require a special kind of transportation to get past it. The inner membrane has folding that are called cristae, which enhance its surface area. 

Matrix 

The space enclosed by the inner membrane is the matrix. It aids in the production of the adenosine triphosphate. It contains plenty of enzymes that yield in conversion of fatty acids as well as pyruvate. The mitochondria can manufacture their own proteins. 

The Cristae 

These are the folding made by the inner membrane. They are many thus increasing surface area for energy productions. They make the inner membrane even five times larger than the outer membrane in some cells.

The mitochondrion is a very crucial organelle without which the human cell cannot survive. They are inherited from the egg that forms the zygote. This means that only the maternal parent contributes to the mitochondria that later replicate as your body grows.

What does Chloroplast do for Plants?

Plant life is very important to our world. Without plants there would be no air, no food and no homes for many plant species. Plants do so much for our world. So, it’s very important that we understand what they are and what they do. One way that we can understand plants is by knowing how they function. This is why we should learn about chloroplast. Keep in mind that chloroplast is not only found in plant life but in algae as well. Keep reading to discover what chloroplast is and how it helps plants to grow and thrive. 

How do plants make food? 

Plants make their own food from the sun through the process of photosynthesis. However, they need certain things to make their own food. Plants must have chlorophyll, light, carbon dioxide, water and nutrients. The chlorophyll is a green pigment in plants. Chlorophyll traps the sunlight’s energy. It then combines the element such as carbon dioxide, water and nutrients into a food substance for plants to consume. This process is called photosynthesis and chlorophyll is critical to this process. 

Chloroplasts are also a part of the photosynthesis process. They are organelles that are contained within the plant’s cells. Chloroplast are important for absorbing sunlight and they also play a role with transforming the elements of water and carbon dioxide into food. 

What is the difference between chloroplast and chlorophyll? 

Chlorophyll is just a green substance that is found in plants. Once again, it is needed to trap the sunlight so that photosynthesis can take place. Chloroplast is a plant organelle which is a specialized part of a cell. In the case of a plant, the organelle known as chloroplast is where the photosynthesis process takes place. The chloroplast contains the chlorophyll that is needed to make the photosynthesis process work. The chloroplast is also a membrane. 

Do humans and animals have chloroplasts? 

No, humans or animals do not have chloroplasts. That is because humans and animals do not need direct sunlight to make food. Instead, they ingest or consume their food from other sources. Most plants just don’t consume other organisms for food. However, there are exceptions to this rule. Some plant species do digest other living things such as insects. Still, these organisms need the photosynthesis process to make food as well. 

What are the functions of chloroplast? 

We already discovered that chloroplasts are the food producers for plant life. Now, we’ll take a look at how these organelles perform other functions that are important to the life of plants. Chloroplast make metabolic energy. They also are developed through the process of endosymbiosis. They even have their genetic systems and they produce themselves through the procedure of cell division. 

Chloroplasts also have the ability to synthesize amino acids, fatty acids and lipid components. They typically do this inside of their membrane as well. This organelle also converts nitrite into ammonia for the purpose of including nitrogen into organic compounds that the plant can use. 

Chloroplast doesn’t just make food for plants it also creates oxygen. As you all know, humans, animals and other types of creatures on the planet need oxygen to live. During photosynthesis carbon dioxide is taken in through chloroplast controlled photosynthetic processes. Once the process is complete, one of the waste materials from this procedure is oxygen. 

Oxygen is actually produced through the chemical reaction when the photosynthesis process takes place. It leaves a plant through its leaves and its then circulated into the air. Keep in mind that plants will grow very well when they have lots of sunlight, water and good soil. These elements are essential to growing lots of food or even super-sized crops. 

Chloroplasts also have the ability to move around a leaf to align themselves with the direction of the sun. Have you ever noticed how plants will usually grow or “move” toward the direction of the sun? Part of this movement happens because chloroplasts are trying to get the best position to take in the most sun. 

Remember, the more light that a plant receives, the more food it can create. So, it is not unusual to see plants repositioning themselves for more light. The chloroplast makes sure that this happens. In closing, chloroplast is an important part of a plant’s system that allows this life form to grow and thrive within its environment. 

What does the Cell Wall Do?

Cells are an important part of any living being. These biological units are small building blocks that allows organic and living matter to exist. Animals, plants, insects, bacteria, fungi and human beings could not exist without cells. Even single-celled microorganisms have a cellular structure. Cells are also made up of macroscopic organisms and they help to form larger systems that make up a living being. Cell walls are also an important part of a cell’s structure for some beings. Keep reading so you can learn about cell walls, what they do and how they function

Most Living Creatures have Cell Walls 

You might have figured this out already, but plants and human cells are different from each other. However, both cell types have a lot in common. Both types have plenty of similarities such as having a nucleus, golgi and various organelles. However, plant cells have cell walls. Human cells don’t have this feature. You can look directly at plant matter to get an idea about how their cell walls look. As a matter of fact, a plant’s cell wall gives its shape and form. It helps a plant to look distinctively different from humans, animals and other creatures within its environment. By the way, plants aren’t the only beings with a cell wall. Other creatures such as fungi, bacteria and protists also have a cell wall. 

Why do plants and most other organisms have a cell wall and not humans or animals? 

The main purpose of a cell wall is to hold the inside systems of a plant or microorganism together. Remember that most living beings do not have a skeleton like people and animals. As a result, they need a cell wall to keep their inside parts from spilling out everywhere. Humans and animals have cell membranes and a skeleton that is used for this purpose. 

Plant cell walls are very common since plant life is all around us. For the sake of keeping things simple we’ll focus on plant cell walls as an example about how they work. Cell walls are made up of substances such as cellulose which are strong fibers. These are commonly used for plants. Bacterial cell walls are made up of peptidoglycan. This strange sounding substance consist of sugar and amino acids. Chitin, proteins and glucan make up the cell walls for fungi. 

There are three parts of a plant’s cell wall and they include middle lamella, the primary cell wall and the secondary cell wall. Most plant cells contain the primary cell wall and the middle lamella. However, not all of them have a secondary cell wall. Just so you will know, the middle lamella is the outer most part of a cell wall. Its purpose is to help cell walls to bind together. The primary cell wall provides the strength and flexibility that a cell wall needs to grow. The secondary cell wall prevents the protective cell wall from over expanding. These three parts of a cell wall help plants to keep their shape and identity within the environment. Other organisms with cell walls don’t have three layers like plants but their walls are just as useful. 

What are the functions of the cell wall? 

The cell wall has many different functions. Regardless of the living organism, a cell wall controls the direction of a cell’s growth. Using plants once again as the example, they help vegetation to withstand pressure from its inner growing parts. As the inner parts grow, they push against the cell wall. Once again, a cell wall keeps a plant’s inside from spilling from outside of the organism. An organism’s cell wall also controls when a cell divides and grows. This is an important function that determines how big an organism will be and what the type of form it will have once its fully grown. 

Cell walls also strongly regulate what will and won’t get into the plant. Cell walls are usually porous. They prevent certain things from getting into a plant and they also keep out other substances as well. Cell walls also allow for communication between a plant’s cells. The wall carries signals from one part of the organism to the next. This allows one part of an organism’s cell to talk to another part of a plant’s system. Viruses and pathogens are also contained by a cell wall. Nutrients and other substances are also contained within this area of the plant. Ultimately, cell walls ensure that certain living creatures can grow and carry out normal life functions that keep organism healthy, alive and thriving.

Article focus: what does cell all do ? | Functions of the cell wall.

What do lysosomes do?

What are Lysosomes?

Lysosomes are known to be the digestive system body cell. They are sac-like structures that hold enzymes which help in the digesting of materials are foreign in the body. Also called suicide bags, these organelles are breaking down and digesting damaged and worn-out cells. 

Definition: Lysosomes are animal cell organelles which are membrane-bound. They possess a phospholipid bilayer on its single outer membrane. The bi-phospholipid layer has one half that avoids water – hydrophobic the other half loves water- hydrophilic. The membrane has enzymes and acids that can decompose and digest macromolecules. 

Creation of Lysosomes 

The lysosomes are made by organelles known as Golgi Bodies or Apparatus. The Golgi apparatus is mostly found in eukaryotic cells. The body of the Golgi apparatus makes vesicles, which bud from the organelle and become the main lysosomes. Secondary lysosomes can also be made through a process called fusion. The fusion process involves combining of vesicles with primary lysosomes in the cell membrane to make secondary lysosomes. 

Lysosomes Structure 

• The outer layer has a single membrane and bi-phospholipid layer which can fuse with different organelles that are membrane-bound.

• It has a spherical shaped structure with a one-micrometre diameter.

• In one lysosome, you can find several enzyme molecules.

• Acid hydrolases which are lysosomes enzymes work best in an acidic environment. The cytosol is an intracellular fluid which surrounds organelles. 

Main advantages of lysosomes 

The general function of lysosomal particles is to break down or break down large molecules. That involves treating worn out and old parts of the cell to recycle its components and make harmful bacteria or toxins safe by breaking them. They process many holes that move inside or outside the cell, which guarantees trouble-free operation. Lysosomes are basically waste disposal units or cell recycling in this sense. 

Self-accusation refers to how the material is divided or digested within the cell. The organelles within the cell fade with time, and when they erode, the lysosome is destroyed, so that the large molecules that make it up can be used to create structures and other organisms. The structures called phagocytes are created, which encapsulate the material to be decomposed. 

The fundamental particles bind to the lysosome fusing them with the lysosome membrane. After this, the pharynx is divided into oneself. While self-involvement refers to the process that leads to the degradation of substances within the cell, the pharynx involves the digestion of contents outside the body of the cell. 

The cellular output is how the cellular material is left via the cell membrane. Energy from the ATP is applied to transfer content that contains an extracellular space. The lysosomes responsible for this process are called secretory lysosomes. 

Gaps that contain a variety of different substances are found outside the cell, and once the cell membrane is absorbed via the cell membrane, it fuses with the gaps and begins to digest them. The extracellular cavities can contain a variety of different compounds. For example, white blood cells are types of macrophages. The cells protect the body of the invaders, killing harmful bacteria or substances. 

Bio-synthesis, the process by which materials are recycled for later use, is mainly done in particles. Lysosomes also destroy dead cells, where their large molecules are collected to produce new organs and cells, in a process known as self-degradation. 

Homogeneous grafts can also include pumpkin and core processes. The hippocampal process is how cells absorb the extracellular fluid and play an essential role in the immune system because it allows immunological monitoring. Endocytosis is how cells can take molecules connected to the outer cell. It is an active form of transport, and cells are disseminated to absorb extracellular molecules. The digested particles are sent to the lysosomes to destroy them. 

Lysosomes defects 

Because lysosomes are an integral part of cell health, they can break down the material and create new ones outside of the elements. Malfunction of lysosomes can lead to problems such as the accumulation of excess sugars or fat. Lysosomal storage disorders generally cause defective genes, and children can inherit one or both faulty genes from their parents. 

Lysosomal storage diseases can kill cells with time, affecting the working of many various organs. Lysosomes are very important for cellular health. If the cell does not contain the lysosomes, it will not be able to break down the components of the old and dead cells, and will not be able to digest and break down the proteins. For these reasons, animal cells depend on their lysosomes. 

Transportation in a Cell – Cars and Crosswalks

Now that most of what a cell does has been discussed, you can learn how things move into and out of a cell. After all, if just anything can get into and out of a cell membrane – the flexible wall that is used to created a border between a cell and what is outside of it – then there would be no point in having a membrane at all. Think of the membrane of a cell like the screen door of a home. It lets air throw a house, but it keeps bugs and small animals from getting in the house without having to have a big heavy door closed all the time. The membrane does something similar for a cell in an effort to balance what is inside and outside of it, but what passes in and out of the membrane isn’t as easy as air. Because of this, we have two different types of transport that allow something to get through a cell membrane. These types of transport are called active transport and passive transport. 

Active transport, as its name suggests, means that it is a type of transport that requires energy. Instead of being able to pass through the cell membrane easily and without effort, things that use active transport need a bit of help getting through because they are too big or complex to fit through the natural channels, or small open spaces, in a membrane. The membrane of a cell is made up of layers of proteins and phospholipids. Phospholipids are lipids, or fats, with phosphate attached to them. The proteins in the membrane of a cell are important in active transport because they are what helps move objects through the membrane in active transport. 

Thinking of these proteins like a car crossing a street will help us understand active transport. The battery of the car is the energy, and the protein is the car itself. The passenger in the car is the object trying to get into the cell, and the street is the membrane of the cell. You use the battery to start the car, and once you’ve done that is moves across the road to take the passenger across the street and into the cell. It sounds very simple! Unfortunately, it isn’t quite that easy. Proteins can only take certain objects across the membrane – a protein that can take sugar across the membrane may not be able to take sodium across. This is also like cars: if the passenger can’t fit in the car, then you can’t use that car to get them across the street. These proteins could be cars, motorcycles, or big trucks. For active transport, the correct protein must match with the correct object, and have the right amount of energy, to cross the membrane. 

Passive transport is much easier. Instead of using a car, the object can just cross the street on its own because it is small and doesn’t need much energy to cross. However, passive transport can be broken down into a few different kinds of transport itself. These different kinds of passive transport are osmosis, diffusion, and facilitated diffusion. Osmosis is passive transport with water only – sometimes it is easier to move water through the membrane instead of objects, so osmosis is used. Diffusion is used for all objects that are moved into and out of a cell through the membrane. But what is facilitated diffusion? As mentioned before, objects that move passively through the membrane can get across on their own. But sometimes it is necessary for them to move faster. Facilitated diffusion uses proteins on a membrane to move these passive objects into and out of the cell more quickly. Think of this like an elderly person getting helped across the street so that they can cross before any cars start moving forward. 

Active and passive transport are both involved in something called the concentration gradient, which is how much of something is on either side of the membrane. If there is more sodium outside of the membrane than inside it, and you need more sodium inside, the sodium could just use passive transport to enter the cell. But if there’s more sodium outside the membrane, and you need to get even more sodium outside, then the sodium would have to go against the grain and use active transport instead. Therefore active transport requires energy – while passive transport goes with the flow, active transport goes against it. 

Top Six Functions of the Cell Wall

A cell wall is a semi-permeable and rigid protective layer that is found next to the cell membrane. It is present in plant cells, bacteria, algae, and fungi. It is important to note that animal cells do not have a plasma membrane. This article emphasizes on the top functions of the cell membrane. 

1. Provide Mechanical Strength 

The cellulose cell wall is made of hard materials such as chitin and other hard components that ensure that it is a sturdy material. It derives its strength from cellulose microfibrils, hence allowing it to exert mechanical strength on the plant. It has a skeletal framework, which is not present in other cell membranes that help it to remain in a rigid and definite shape. 

Cell walls use this definite shape and the hard shells to provide mechanical strength to the plant. Cellulose cell walls are also hardened through lignifications, which is a process of adding lignin to the cell wall hence making it tough while at the same time giving it the structural strength of a woody plant. The strength and rigidity of the whole plant depend on the mechanical strength provided by the cell wall. 

2. Maintaining the Shape of the Cell 

Plant cells, which have cellulose cell walls have a definite shape, which is brought about by the presence of a cell wall. The hard outer shell does not become flaccid when the cell loses water. Mostly, lignin and pectin, which are the major components of the cell wall, maintain a rigid structure that allows the cell to maintain a definite shape. Only the isolated protoplast becomes flaccid after losing water. If plant cells were to lose shape, plants would fall. 

This explains why plant cells have to maintain a definite shape at any given time. It is essential to highlight that animal cells don’t have a distinct shape because they do not have a cell wall. Animal cells become flaccid every time they lose water and bulge after gaining water through osmosis. 

3. Controls Cell Expansion 

For growth to occur in plants, cell expansion is necessary. This happens at earlier stages of plant growth. However, growth and expansion of the cells is a controlled process which takes a more extended period. Cell walls are at the center of the cell growth and expansion. For a young plant, cell walls control turgor pressure from within and prevent any chances of cell bursting. This means that anytime the cells gain water, they will expand, but they will not burst. 

In a mature plant, growth and expansion are not necessary. Lignin is therefore added to the cell wall to prevent any expansion. Lignin makes the cell very hard such that it cannot succumb to the turgor pressure generated from within the cell. Maximum growth has been realized, which explains why growth is not needed. 

4. Controls Intracellular Transport 

Transport of important chemical materials has to take place between cells. However, the transfer of materials from one cell to the other is controlled by the cell wall. Very many substances are transported between the adjacent cells, and all have to pass through the cellulose cell wall. The cell wall allows the movement of the very small ions, molecules, and small protein. However, if the materials under transport are very big or are harmful, the cell wall forms a sieve, which prevents these materials from entering through the cell membrane. 

5. Acts as a Reservoir of Food 

Seeds contain a substantial amount of food that will support the seed during the germination process up to the time when it will start performing photosynthesis. In most cases, most of the food and other nutritional requirements are stored on the cell wall. Other foods form a significant proportion of the cell wall. This explains why the cell wall disappears several weeks after the seed germinates. 

6. Protection 

Protection is one of the primary functions of the cell wall and underlines its importance in plant cells. Fungi, bacteria, virus, and other pathogenic microorganisms will always try to attack the cells for food and other benefits. The cell wall triggers the necessary mechanisms to make sure that these organisms don’t get a chance to attack the cell membrane. Cellulose cell walls are known to have both passive and active defense mechanisms that prevent an attack against plant cells. 

The Eight Critical Functions of the Nucleus

The nucleus is an essential organelle, which is found in eukaryotic cells. This crucial component of the eukaryotic cell carries the better part of the cell's genetic material. This material is organized as deoxyribonucleic acid (DNA) molecules and a variety of proteins to form chromosomes, which are also known as "protein factories". So, what does the nucleus do? 

It should be noted that the nucleus plays more than one essential role in the body. These roles are described as follows: 

1. The Nucleus Controls an Organism's Heredity/Hereditary Characteristics 

In genetics, there is something known as "heredity". This is simply the characteristics we acquire from our parents or people close to us genetically. An example of heredity is to have a certain type of eyes or any other physical characteristic similar to one of your parent's or somebody in your family's. This is controlled by the nucleus. 

2. The Storage of Heredity Material In the Form of DNA strands 

Another important function of the nucleus is the storage of heredity material in the form of deoxyribonucleic acid(DNA) strands. As if that were not enough, the organelle also stores proteins as well as ribonucleic acid (RNA). 

3. The Nucleus Maintains Cellular Metabolism 

In every living organism, there is a set of chemical reactions that take place to maintain life. These reactions are known as "Cellular metabolism". They entail complicated sequences of controlled biochemical reactions referred to as "metabolic pathways". 

Do you know what maintains these complex reactions? It is the very same nucleus, which does so by regulating the synthesis of certain enzymes that power cellular metabolism. 

4. The Nucleus Is In Charge of Cell Division/Growth/Differentiation and Protein Synthesis Processes 

What does the nucleus do apart from the above tasks? Well, the organelle is responsible for cell division/growth/differentiation and protein synthesis processes. All of these processes make sure living organisms are able to grow and develop successfully. 

 5. The Transcription Process Zone for RNA (mRNA) Messengers 

The nucleus provides an optimum environment for the transcription process in which the messenger ribonucleic acids (mRNA) are produced ahead of protein synthesis. For your information, protein synthesis is the process in which protein molecules are produced. 

6. The Exchange of Hereditary Materials Within the Cell 

Another important function of the nucleus is to take part in the exchange of heredity materials within the cell. The hereditary materials we are referring to here are deoxyribonucleic acid and ribonucleic acid. 

7. The Production of Ribosomes 

The nucleolus also produces ribosomes, which are known as "protein factories". These are particles made up of RNA and associated proteins. Their primary tasks are to bind messenger ribonucleic acid and transfer ribonucleic acid to the sites for polypeptides and protein synthesis within the cell. 

8. The Regulation of the Integrity of Genes and Gene Expression 

Again, in genetics, there is something called "gene'' integrity. Living things of the same species generally have a shared genetic profile. Individual organisms in which this profile has not been tampered with are said to have genetic integrity. 

Then there is something else called "gene expression". This is simply the process by which information is taken from a gene and used in the production of a functional gene product. Functional gene products can be proteins, proteins, messenger RNA and small nuclear RNA genes. 

The final important function of the nucleus is to regulate the integrity of genes as well as gene expression. More of this information is covered in advanced genetic. Be sure to check out online sources if you wish to learn more about gene integrity and gene expression. 

Final Thoughts 

Now you know the functions of the nucleus and it is my hope that the next time you are asked to list them, you will pass the exam or assignment. In summary, the nucleus controls an organism's heredity/hereditary characteristics, stores heredity material in the form of DNA strands and maintains cellular metabolism. In addition, it remains in charge of cell division/growth/differentiation & protein synthesis processes and provides the optimum transcription process environment for RNA (mRNA) messengers. Finally, the nucleus helps with the exchange of hereditary materials within the cell, the production of ribosomes and the regulation of the integrity of genes and gene expression.