Trisha Dey

Prokaryotes like all other organisms contain RNA.

So to the question “do prokaryotes have RNA?” yes, they absolutely do. RNA in many forms is essential for protein synthesis in all organisms irrespective of their nuclear organization. Translation i.e the process by which proteins are synthesized is essentially dependant on RNA.

The lack of a nucleus distinguishes prokaryotes from eukaryotes. As a result, prokaryotes lack several RNA molecules that act inside the nucleus. Most long noncoding RNA (lncRNA) and related forms [enhancer RNA or eRNA, circular RNA or circRNA, etc.] are absent in prokaryotes

 Due to the absence of a nucleus and tiny genomes, prokaryotes are left with only brief intragenic regions. The quantity of lncRNA grows as the genome size and noncoding DNA percentage increases. The emergence of lncRNA appears to be a late evolutionary process.

Do prokaryotes have RNA polymerase?

For the process of transcription, prokaryotes do possess Rna polymerase.

Transcription is the process of coding a gene to its respective mRNA. RNA polymerase is the enzyme that converts the gene to mRNA.

Since the prokaryotic gene is small and not as complex as compared to eukaryotes, prokaryotes have a single RNA polymerase to transcribe all their genes. In E. coli, RNA polymerase is a pentamer i.e. it is composed of a total of five polypeptide subunits, of which two are identical.

 The polymerase core enzyme is made up of four subunits, designated by the letters α, α, β, and β′. After a gene is transcribed, these subunits combine, and when transcription is concluded, they dismantle where each component has a distinct purpose.

Do prokaryotes have RNA processing?

Prokaryotes perform processing only for ribosomal RNA and tRNA.

The processing of RNA is a process by which most newly synthesized RNA must go through to become functional. To be transformed to their functional forms, most freshly produced RNAs must be changed in various ways.

Prokaryotic or bacterial mRNA (messenger RNA) is the only exception to this rule as it is not processed but directly translated to protein. However, the first transcripts of both rRNAs and tRNAs have to go through a series of processing activities in both prokaryotic and eukaryotic cells.

Do prokaryotes do RNA processing?

Prokaryotes do perform RNA processing.

Prokaryotes need to process all other RNAs present and produced except mRNA. This includes transfer RNA(tRNA) and ribosomal RNA(rRNA).

The basic processing of ribosomal and transfer RNAs in prokaryotic and eukaryotic cells is actually not very different. Eukaryotes contain a total of four ribosomal RNA types, three of which (the 28S, 18S, and 5.8S rRNAs) are produced by cleavage of the same long precursor transcript known as a pre-rRNA.

Prokaryotes have only three ribosomal RNAs (23S, 16S, and 5S), which are similar to the 28S, 18S, and 5S rRNAs found in eukaryotic cells and are generated from the same pre-rRNA transcript. This also shows that they are similar in function.

Do prokaryotes have RNA splicing?

Prokaryotes essentially do not require to perform splicing.

Splicing is the processing of hnRNA(hetero-nuclear RNA) to convert it into mRNA. It is considered a post-transcriptional step i.e. a step done after transcription and before translation.

The process of converting hnRNA to mRNA involves removing the non-coding parts of the genes also called introns. The coding regains or exons are joined together to form the mRNA.

But this process is unnecessary in prokaryotic cells as the gene itself is very limited in them. Processing the RNA would mean wastage of the cell’s resources, hence the gene itself has only coding regions.

This means that the mRNA is made solely of exons and can be translated to protein as it is.

Do prokaryotes have both DNA and RNA?

In nature most organisms have both RNA and DNA, so do prokaryotes.

 DNA and RNA are equally important for the proper functioning of the cell and its functionalities. They have separate functions and requirements.

While both are nucleic acids DNA is preferred as a genetic material due to its stable structure and chemical composition. While RNA is not as stable it is definitely more versatile.

RNA s can function in more than one way, but mRNA, rRNA and tRNA are all very important for a cell to be able to convert the genes present in their DNA into the proteins they wish to express.

Do prokaryotes have circular RNA?

Some prokaryotes have been found to have circular RNA.

RNA is typically single-stranded and is either intermittently available or simply exist as a polymeric shape to maintain stability. The fact that circular RNA exists is proof of this assumption.

Circular RNA or circRNA in Archeae is typically excised or intricately cut tRNA segments that have formed a circular shape so that they can stably exist. In most Archeae, it appears that no circRNA is produced from coding genes.

Sulfolobus acidocaldarius, an archaeon, has retained several of these circRNAs. In eubacteria, there is almost no circRNA, with just a few intriguing possibilities relating to rRNAs and tRNAs.

Why do prokaryotes only have one RNA polymerase?

Prokaryotic transcription uses one single RNA polymerase for coding all its genes.

RNA polymerase enzyme is what converts the genes in the DNA to mRNA. They occur in all organisms across nature and are essential to protein synthesis. The reason why prokaryotes have a single RNA polymerase compared to the three in eukaryotes is rather simple.

They have a  small chromosome and a very minute amount of genes. Hence to have more than one RNA polymerase to code the genes on one chromosome would be a wastage of the cell’s resources. Also, prokaryotes came into being way before eukaryotes did and hence they are much less complex in organization as compared to the latter.

The same RNA polymerase transcribes all of the genes in prokaryotes. In E. coli, RNA polymerase is a pentamer composed of five polypeptide units, two of which are the same. The polymerase core enzyme is made up of four subunits designated as α, α, β, and β′ with another additional subunit to form the holoenzyme.

A polymerase must have all five subunits to function as a holoenzyme (a holoenzyme is a biochemically active compound comprised of an enzyme and its coenzyme).

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Plasmids can be found in some fungi and higher plants.

Plasmids are small circular DNA fragments that can replicate themselves independent of the nuclear DNA. Across the century, it was believed to be a characteristic of prokaryotic or bacterial cells.

Later scientific studies showed that some eukaryotic cells also contain these self-replicating DNA fragments. Naturally found to be in fungi and some higher plants- the presence of plasmids in animals cells is still unknown.

As to the question “do eukaryotes have plasmids” the most commonly studied ones are those found in unicellular fungi or yeast.

All about plasmids:

• Plasmids are the small circular DNA fragments found outside of nuclear DNA i.e extra-chromosomal.
• They can replicate independently of nuclear DNA in a suitable host.
• They do not contain any form of genetic information.
• Plasmids can range in length from one thousand to a hundred thousand DNA base pairs.
• Till a certain time in scientific exploration, it was considered a feature solely unique to prokaryotic or bacterial cells.
• Later studies showed that plasmids were also found in eukaryotic cells- like in fungi and some higher animals.
• Plasmids carry a minimum of one gene that is beneficial to the host but do not carry any genetic information about the organism as such.
• Though most of them are made of double-stranded DNA, some plasmids can be made of single-stranded DNA or even RNA but the cases are very rare.

Why do eukaryotes have plasmids?

The main function of plasmids in eukaryotes is to clone genes.

Eukaryotic cells are way more complex in structure and composition compared to prokaryotes and so plasmids are strictly restricted to single-celled eukaryotes like yeast.

Yeast cells are more simple due to being unicellular. Scientists know that these plasmids have some functions but, what they are is still unknown. However, scientists have studied and developed these plasmids to clone specific genes that they want to express.

Do all eukaryotes have plasmids?

The appearance of plasmids in eukaryotes is very seldom or rare.

Plasmids were considered to be a feature unique to bacteria but were later discovered in archaea, some single-celled fungi and less than a handful of plant cells.

Eukaryotic DNA organization is very organized and complex. This diminishes the necessity of extrachromosomal DNA. In eukaryotes, extrachromosomal DNA is restricted to mitochondrial DNA and it is not common to see it floating about in the cytoplasm.

Hence eukaryotic cells having cytoplasm is a rarity in nature.

Which plasmid is found in eukaryotes?

Plasmids are found in eukaryotes are the same that is found in prokaryotes.

Plasmids refer to extrachromosomal free circular DNA found in the cytoplasm. Irrespective of the organism the structure or the typical nature of the plasmid does not undergo any major change.

A plasmid of scientific importance found in yeasts is called a 2µ plasmid found in Saccharomyces cerevisiae. It is a 6.3-kilobase plasmid that is extrachromosomal in nature but still occurs in the nucleus. Like chromosomal DNA it is covered by nucleosomes and can initiate replication by itself.

Does eukaryotic DNA have plasmids?

Plasmids are DNA fragments themselves and so DNA cannot contain plasmids.

Eukaryotic chromosomal DNA is conserved and organized. Plasmid DNA in eukaryotes occurs inside the nucleus, though it is extrachromosomal in nature.

Plasmids are DNA fragments themselves are a separate entity from the chromosomal DNA even if they both occur inside the nucleus. In short they are not related or connected to each other in terms of uses or functions.

Do eukaryotic cells have plasmid DNA in the cytoplasm?

It seems that unlike prokaryotes eukaryotic DNA occurs inside the nucleus.

Prokaryotes do not have a nucleus or other membrane-bound organelles. But all the organelles and genetic material in eukaryotes are membrane-bound.

In eukaryotes, the genetic material is practically restricted to the nucleus except for that present in mitochondria. The mitochondria are also membrane-bound, so for extrachromosomal DNA to exist out of the nucleus it must be inside a membrane as well.

Seeing how the cell would consider it a wastage of resources, hence the plasmid DNA is contained in the nucleus as well.

Which eukaryotes have plasmids?

Plasmids in eukaryotic cells are restricted to some single-celled fungi and some plant cells.

Eukaryotic genetics and proteomics is a complex matter and is regulated by a large number of enzymes and mechanisms. Hence the presence of plastids in eukaryotic cells is quite a rarity.

Unlike bacteria, eukaryotes like single-celled yeast and a few plant cells are the only ones discovered to possess plasmids. Before it was considered a feature that differentiated prokaryotes from eukaryotes.

But later it was discovered in archaea and eukaryotes a swell. However, it is a feature more commonly found in parasitic or organisms solely dependant on a host for survival.

Can plasmids replicate in eukaryotic cells?

Plasmids in eukaryotes have the ability to replicate autonomously.

The 2µ plasmid in yeast is covered by nucleosomes just like the chromosomal DNA. The plasmid replication is initiated by the replication enzymes in the nucleus.

The fact that they replicate independently is a truth, but that replication is initiated by the enzymes that initiate replication in the chromosomal DNA. This occurs once every cycle that the cell propagates and host replication enzymes are ample inside the nucleus.

Normal DNA replication is unidirectional but plasmid replication is bi-directional. The site for bi-directional DNA replication is called “autonomous replication sequence” or ARS.

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Fungus (plural: Fungi) cannot photosynthesize so they can be considered heterotrophs.

Fungi unlike algae do not have any photosensitive pigments so they cannot produce food via photosynthesis. Instead, they obtain their nutrition from other sources that is what is said to be heterotrophic.

So the question arises are fungi heterotrophs? Technically they cannot eat like animals, instead, they obtain their nutrition from dead and decaying matter. This is the reason we can find mushrooms growing on dead, decaying matter with ample humidity. This includes the forest floor, on tree trunks and sometimes in the corners of our homes during monsoon.

All about kingdom Fungi:

• Fungi are a separate kingdom in the eukaryote organism structure just like plants and animals. Fungi include all types of yeasts, molds and mushrooms.
• Fungi like animals cannot produce their food, so they have heterotrophic nutrition i.e they depend on other organisms as a source of food.
• Fungi are what we call saprophytic in nature i.e. they get their nutrition from dead and decaying organic matter. They typically do so by secreting their digestive juices into the environment they grow in, and absorbing all the nutrients they can get their hands on.
• So they can live in a symbiotic relationship with other plants or live as parasitic organisms altogether.
• They have cell walls made of chitin a type of hetero-poly glucan.
• Fungi generally reproduce with the help of spores i.e. asexually. These spores can survive the harshest condition.
• For a better survival rate, a fungus can release several thousand of these at once.
• Fungi have special features to facilitate the release of spores. For example mushrooms their gills to store and release their spores into the air and medium.
• Fungi are the molds that appear on spoiled food or leather goods. They can also cause diseases like athlete’s foot.
• There are a lot of beneficial fungi as well- including all the mushrooms that we consume and yeast used in cooking, baking and alcohol brewing.
• Penicillin the first antibiotic was extracted from a fungus called Penicillium.

All fungi are heterotrophic?

Since fungi are unable to synthesize their own food so they have a heterotrophic mode of nutrition.

Plants and algae are called autotrophs as they synthesize their main food source in the form of glucose. Since fungi are unable to perform this function they are called heterotrophs.

Plants and algae are organisms that can biosynthesize their food from inorganic matter- gases, water and sunlight. So they are conventionally termed as autotrophs. All other organisms that depend on other plants and animals for their nutritional needs are called as heterotrophs.

Since no fungi discovered to date have any photosynthesizing pigment in them, hence it can be considered that kingdom fungi consist of heterotrophs only.

How are fungi heterotrophs?

Since fungi are unable to synthesize food and absorb it from organic matter in their environment they are heterotrophs.

The word heterotroph comes from Greek words “hetero” meaning other and “troph” meaning nutrition. This refers to organisms that require other organic sources of nutrition as they are unable to synthesize it themselves.

Fungi can have 3 nutrition sources- saprophytic, parasitic or symbiotic. Saprophytic meaning that they depend on dead and decaying organic matter to survive, This pertains to mould and mushrooms that grow on the forest floor or dead matter.

Parasitic fungi refer to those that depend on living organisms for nutrition and in turn also harm their host. This includes fungi that cause diseases among plants animals and humans. For example, fungi cause diseases like leaf spots and powdery mildew in plants whereas they can cause athlete’s foot and ringworm. All these are highly contagious.

Some fungi can also have symbiotic relations with plants. In these cases, the fungi and the plants both receive the benefits from this mutually beneficial relationship. Mycorrhiza is the homes these fungi make in the root systems or rhizospheres of these plants. They form colonies and supply water and minerals to their hosts and receive glucose molecules as repayment.

Fungi heterotrophic characteristics:

Saprophytic fungi feed on dead and decaying organic matter. They do so by releasing their digestive juices into their environment and sucking up all the digested organic matter using their roots or hyphae. Hence they also work as ecological decomposers.

Fungi grow from the tips of the nodes of the hyphae and the organism itself as parts called mycelia to absorb the digested from matter. The hyphae run under the forest floor or their growing medium like plant runners and spout out mushrooms from every node.

There are fungi like the baker’s yeast(Saccharomyces cerevisiae) that are unicellular and very simple in structure. They usually require a warm and humid environment to grow and activate in. They can obtain all the nutrition they require from something as simple as a sugar solution.

They do not have any special structures, taking up simple monosaccharides and disaccharides by diffusion through their cell wall.

Parasitic fungi can absorb food through their hyphae themselves that they stick against the cells of the host organism. On the other hand, some of them produce special structures called haustoria just for this purpose.

Haustoria are specialized structures that extend and pierce into the host cell itself to absorb nutrition through them.

Conclusion:

Historically fungi once belonged to kingdom Plantae but were segregated as they cannot photosynthesize. They could not be considered plants due to the absence of pigments. But they couldn’t be considered as animals either due to vegetation and spore inducing asexual propagation methods and the presence of a cell wall.

So they were separated into a whole different kingdom. And since they could not photosynthesize their own food they developed ways to obtain nutrition from the environment themselves. So they became heterotrophs i.e. they depended on other organisms whether living or dead to obtain sustenance for themselves.

Humans too used this feature to use them commercially, for example, the Baker’s yeast used in baking and alcohol brewing. They simply obtain their required from the sugars water in bread doughs to produce carbon dioxide that makes the dough rise. This released CO₂  is what gives cakes and bread their fluffy texture.

I breweries yeast obtains sugars from the fruit juices and produce ethyl alcohol and carbon dioxide. This is what in different concentrations gives rise to wine and beer. Hence the heterotrophic nature of fungi can be essentially useful as well.

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Prokaryotes do not have centrioles.

Centrioles are a pair of barrel-shaped cell organelles found in eukaryotic cells- namely in that of animal cells. As prokaryotes are devoid of all cytoplasmic organelles, understandably, they are devoid of centrioles as well.

The question do prokaryotes have centrioles can be makes no sense as they do not need them. Animal cells, which lack cell walls, rely heavily on centrioles. Centrioles are responsible for the formation of microtubules that function as the cell’s skeletal system giving it shape and structure.

Is DNA prokaryotic or eukaryotic?

DNA is neither eukaryotic nor prokaryotic.

DNA or de-deoxyribonucleic acid is the genetic material in most living organisms, both eukaryotic and prokaryotic cells. The DNA structure and shape can differ from organism to organism.

DNA is responsible for containing the genetic material organisms that contain information from one generation to the next. This information includes the structure of the cell, the proteins and biomolecules it needs to synthesize and how to synthesize them. This information is essential to be passed on by an organism from one generation to the next.

The information in DNA regulates how similar a child looks to their parent- their height, blood group, their hair and eye colour, even the diseases that can be genetically passed on. So it needs to be present in all organisms be it eukaryotes or prokaryotes. Even virus has genetic material in the form of DNA or RNA.

Are prokaryotic cells made of DNA?

Technically speaking prokaryotic cells are not made of DNA.

DNA is a biomolecule nothing more or less. Millions of different biomolecules are required to make a cell. DNA is just one of those million biomolecules that are responsible for containing and transferring genetic information.

A living cell means that prokaryotes and eukaryotes all have a cell wall or membrane enclosing some cell matter or cytoplasm which may have some organelles and genetic material present in them.

But prokaryotic cells are not as developed. Unlike eukaryotes, they do not possess any membrane-bound organelles. The DNA is circular and just simply floats around in the cytoplasm.

How is DNA different in prokaryotes and eukaryotes?

It is not the DNA, rather the presentation that is different in eukaryotes and prokaryotes.

Eukaryotic DNA is linear and is housed within the nucleus, which is separated from the rest of the cell by a nuclear membrane. Whereas prokaryotic DNA is circular and just simply floats around in the cytoplasm.

The word prokaryote means that they do not have a true karyon or nucleus. So the genetic material in this case a circular DNA called a nucleoid just floats around in the cytoplasm. Eukaryotes on the other hand have a true nucleus bound by a nuclear membrane to hold its genetic material.

How is DNA stored in a prokaryotic cell?

DNA in prokaryotes are stored in a circular form called a nucleoid.

Normally restricted to the central part of the cell, the circular DNA is called the nucleoid. It is not covered by any membrane and is practically free-floating.

Some prokaryotes also have other DNA fragments out of the nucleoid. These circular DNA fragments are called plasmids. These are characteristically very different from the genetic DNA present in the nucleoid. This plasmid DNA proves to be advantageous in the case of specific environments.

What is unique about the DNA of a prokaryote?

Bacterial DNA is unique in the sense that it has more functions than just being genetic material.

Nucleoid DNA does function in storing of genetic information. But prokaryotes have plasmid DNA as well which has several other functions.

Plasmids are double-stranded circular DNA fragments that exist out of the bacterial nucleoid. The nucleoid contains just a little quantity of DNA, which is in the form of a single molecule, or essentially a single chromosome. Comparing it to humans that have 23 pairs in each cell, the amount of genetic material required for the sustenance of prokaryotes is very minute.

What is the function of DNA in prokaryotic cells?

Unlike eukaryotes, prokaryotic DNA has more functions than just storing genetic material.

In prokaryotes or bacterial the nucleoid DNA contains the genetic material. While the plasmid DNA has other functions.

Plasmid DNA in bacteria is very different from chromosomal DNA. It can be made up of one or more genes. Plasmid DNA is very useful for bacteria in the process of resistance building against anti-biotics. And, through a process known as conjugation, these plasmids may be transmitted from one bacterium to another.

   Scientists often use plasmids in labs as tools for cloning, transferring and manipulating the genes they feel are of economic, medical or scientific significance. For example, this very technology was used for the production of pest and drug-resistant crops through recombinant biotechnology.

What does prokaryotic DNA look like?

The circular nature of prokaryotic DNA seen in the nucleoid and plasmids is similar.

Prokaryotic DNA present in the nucleoid consists only of a single, coiled, circular chromosome. This single chromosome contains a single DNA molecule compactly coiled and kept in place by specific proteins.

Like in eukaryotes prokaryotic DNA also undergoes supercoiling and is kept compact with the help of Nucleoid-associated Proteins (NAPs). But prokaryotes are haploids that is they contain only one strand of chromosome. So they can only reproduce by division, cloning or conjugation.

Do prokaryotes have double-stranded DNA?

Prokaryotes certainly have double-stranded DNA.

The DNA in the nucleoid of bacteria is double-stranded and circular. Double-stranded DNA is more stable and less prone to mutation.

DNA in most organisms except viruses mainly have double-stranded DNA. This implies they can’t mutate as quickly or as easily as viruses.

Do prokaryotes have single-stranded DNA?

Prokaryotes do not possess single-stranded DNA.

Bacteria do not have single-stranded DNA, even if they are premedieval organisms. They have double-stranded circular DNA instead.

Genetic material in the form of single-stranded(ss) DNA in organisms is a very rare occurrence in nature. Due to its unstable structure, it can mutate or malfunction very easily. So ssDNA is only found in certain viruses. But even so, the occurrence is very rare and hard to come by. It is more common to find viruses with ssRNA.

Do prokaryotes have non-coding DNA?

Bacterial cells contain a very minimal 6-14% non-coding DNA.

Non-coding DNA is quite common in eukaryotic DNA, basically 99% of the entire genome. But in the bacterial genome, the fraction is way less. The bacterial genome has only 6-14% of non-coding DNA.

The non-coding section of the genome’s purpose is mostly structural or just unknown. But the bacterial genome is itself a very small molecule, so there isn’t much to stabilize. Where the eukaryotic genome is way more complex and requires regulation so a major portion of it is non-coding in nature.

 This does not mean that the non-coding part of DNA is useless, it’s just that scientists have been unable to decipher its mechanism yet.

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Proteins are polymeric chains made of monomeric units called amino acids.

Amino acids are organically available compounds made of Carbon, Oxygen, Hydrogen and Nitrogen mainly and have some other elements like Sulphur in their side chains. They are called amino acids precisely due to the presence of amino group(−NH₃⁺) and carboxylate group (−CO₂^–).

The human body requires a total off twenty amino acids to function properly. Among these 20 amino acids, there are nine such amino acids that the human body cannot synthesize. They are called essential (monomer of protein examples) amino acids, namely-Methionine, Threonine, Histidine, Valine, Phenylalanine, Isoleucine, Tryptophan, Lysine and Leucine. Since they cannot be synthesized it is very important to obtain them optimally through our diet.

Here are some monomer of protein example:

Essential amino acids:

• Phenylalanine (Phe)
• Valine (Val)
• Threonine (Thr)
• Tryptophan (Trp)
• Methionine (Met)
• Leucine (Leu )

Non-essential amino acids:

• Alanine (Ala)
• Asparagine (Asn)
• Serine (Ser)
• Aspartate (Asp)
• Glutamate (Glu)

Essential Amino Acids:

Phenylalanine:

Abbreviated as (Phe) is the preceding component of various neurotransmitters like- Tyrosine, Dopamine, Epinephrine and Norepinephrine. One of three amino acids with an aromatic ring in its side chain is phenylalanine. Human RBC, precisely haemoglobin is one of the highest sources of Phe.

Valine:

Valine or Val is an aliphatic side-chained amino acid. It is one of the three that has a chain branching to one side of the molecule. Valine functions in muscle regeneration and muscle growth.

Threonine:

Threonine is one of just two amino acids with a polar neutral side chain, meaning it does not ionize under normal circumstances. Unlike humans, microorganisms can synthesize Threonine from Aspartic Acid.

Tryptophan:

Nutritionally essential Tryptophan (Trp) is the second of the three amino acids that have an aromatic side chain. A major component of various substances like- neurotransmitter Serotonin and Vitamin Niacin(Vit B3). Milk is considered an important dietary source of Tryptophan.

Methionine:

An essential amino acid Methionine (Met) is one of the two that have a Sulphur in its side chain. This means that Methionine can ionize even at normal pH. It can be obtained from eggs as egg albumins contain a 5% by weight of Methionine.

Leucine:

Leucine is an essential amino acid also abbreviated as Leu is a major component of human Haemoglobin (15% by weight). Like Valine, Leucine also has a branched aliphatic side chain. Obtained from plants and microorganisms that can synthesize Leucine from Pyruvic acid.

Non-essential Amino Acids:

Alanine:

A non-essential amino acid- which means that humans can synthesize alanine(Ala). It occurs naturally in human muscle in 2 peptides- carnosine and anserine. It is also the constituent of Vitamin Pantothenic acid or Vitamin B5. It is a simple amino acid with a  non-branched aliphatic side chain.

Aspargine:

A non-essential amino acid (Asn) is closely related to Aspartic Acid, which most warm-blooded animals can easily synthesize from aspartic acid itself. It has an amide side-chain, making it one of only two amino acids with one.

Serine:

Serine is the second amino acid with a polar neutral side chain, after glycine. Ser, on the other hand, is not an essential amino acid-like threonine. Most common proteins can be hydrolysed to obtain Serine. Humans can even synthesize simply from glucose, so it doesn’t even require dietary sources.

Aspartate:

Aspartate or Asp is a non-essential amino acid easily obtained from the hydrolysis of normally found proteins. One of the 2 amino acids that have a cationic side chain which means that they are anions in side chains. Hence they can act as Bronsted bases in normal pH.

Glutamate:

Glutamic acid exists in its ionic form as Glutamate. Also has a cationic side chain and exists as Glutamate (Glu) at normal pH. The most abundant neurotransmitter in the vertebrate and human nervous systems. Glutamate is also a precursor of GABA (gamma-Aminobutyric acid).

Proteins:

Proteins are large biomolecules that are the main building blocks of tissues, muscles and organs. Made up of thousands of amino acids monomers, they vary in shape and structure based on the structure and nature of their monomers.

The reason is that based on the nature of their side chains amino acids can be hydrophilic(water-loving), hydrophobic(water-hating), cationic, anionic or neutral. This also changes the nature of the protein they compose, based on which type of amino acids nature plays dominant in greater number.

Proteins are very versatile and have several uses and functions. Antibodies, enzymes and hormones are nothing but proteins that function differently.

Essential and Non-essential amino acids:

As mentioned above a total of 20 amino acids are required for the human system to function perfectly. But they are again classified into 2 types.

Some amino acids are synthesized by the human body itself, so we do not need to go about obtaining them from dietary sources or supplements. These amino acids are called non-essential amino acids. Among the 20 eleven of the amino acids are non-essential.

The rest of the nine amino acids cannot be synthesized by humans (but can be synthesized by plants and microorganisms). So we must obtain them from dietary sources- like plants, meat and milk or supplements to make up for this inability. These amino acids often produce certain vitamins, so their deficiency can lead to the deficiency of the vitamin itself.

CONCLUSION:

Proteins are one of the major biomolecules that make up the human body and amino acids are the smaller blocks that join up to form these proteins. Unlike carbohydrates, proteins cannot be made up of the same type of monomer. Since the amino acids differ from each other in nature based on their stricture and side-chain composition, they inherently modify the structure, shape and nature of the proteins they form as well. So proteins are usually not present in specific shapes and structures.

This ability to change themselves in various pH or media allow them to function as enzymes, vitamins or neurotransmitters. On the other hand, their flexible chains allow them to produce muscles that can relax and contract. So we can say that this versatility of proteins comes from their amino acid monomers themselves.

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The polymers of carbohydrates refer to the long and complex chains of simple sugars that we normally consume in our diet.

Carbohydrates are the primary source of energy in most living organisms. Breaking down glucose to make ATP is the chief source of energy. Glucose is the most common monomer of most carbohydrates, and some other monomers are converted to glucose by chemical changes.

The equation as mentioned above is the simplest chemical reaction to show how glucose is broken down in living organisms to produce the energy required for all bodily functions. This energy is also required to make sure the heart, lungs, brain, and other organs can work nonstop.

Carbohydrates :

Large molecules of sugar are simply called carbohydrates or carbs. Sugars do not always refer to the white sweet table sugar that we eat every day. Carbs are called sugars are mostly broken down to form glucose which is the simplest sugar or its isomers. Since glucose is sweet people usually associate carbs with anything that tastes sweet. Below are listed what are the polymers of carbohydrates that we commonly see and use.

Examples of the commonly used Polymers of Carbohydrates :

Natural complex carbohydrate polymers can be found in both plants and animals. They can be composed of the same type of monomer(homopolysaccharide) or the monomer itself may be complex( heteropolysaccharides). In the latter case, the monomers may be made up of 2 or more different monosaccharides and their derivatives.

These include starch, cellulose, inulin, glycogen xanthan and many more. Here we have discussed a few of them. However, there are a few more basic polymers or disaccharides (made of only 2 monomers). We will discuss them as well.

Examples of simple carbohydrate polymers:

• SUCROSE: Sucrose commonly referred to as table sugar or cane sugar is a disaccharide made of two glucose molecules. This is the most commercially used and available sugar and because of its small and simple structure, it is considered a major cause for weight gain. As a result, in recent years, consumers have begun to replace sugar with healthy alternatives such as stevia and honey. It requires an enzyme called sucrase present in most animals while plaque and cavity-causing bacteria can convert it into a dextran-based compound that they can use.
• LACTOSE: Due to the presence of the disaccharide lactose, milk is inherently sweet. Composed of two monomers -glucose and galactose and requires an enzyme called lactase to hydrolyze. This enzyme is absent in a large population of individuals leading to what is called lactose intolerance. People suffering from this condition are unable to digest any dairy or dairy-based products.
• MALTOSE: Maltose or malt sugar is another disaccharide formed of two glucose molecules. It is found in the majority of grains and pulses and often major components of commercial health drinks.

Examples of Larger polysaccharides:

• STARCH: The reason we wash potatoes and pasta is to get rid of a white powdery substance present in them. This starch is a polysaccharide found in plants that they use to store food by attaching glucose molecules via α(1→4) and α(1→6) glycosidic linkages. This reduces the molecular structure and makes it easier to store. Starch is made of 2 parts amylose (glucose molecules attached via α(1→4) glycosidic bonds) and amylopectin (glucose molecules attached via α(1→6) glycosidic bonds).
• CELLULOSE: Cellulose is a structural polysaccharide made up of hundreds of glucose molecules and is the major component of plant cell walls. They are joined by β(1→4) glycosidic linkages. Herbivores have gut bacteria that can break down cellulose, unlike carnivores and omnivores. Hence in our case, leafy green vegetables act as roughage for good intestinal health.
• GLYCOGEN: Another storage polysaccharide occurring in animals, fungi and bacteria, glycogen is the first source of saved glucose that is hydrolysed in case of unavailability of food. Reserved in the muscles and liver cells and human cells of humans glycogen is structurally glucose units linked together linearly by α(1→4) glycosidic bonds. Branches are connected to the chains from which they branch off by α(1→6) glycosidic bonds between the new branch’s initial glucose and the glucose on the stem chain below.
• CHITIN: Also a large polysaccharide occurring naturally. It forms a major structural component of exoskeletons of insects and crustaceans, cell walls of fungi and invertebrates and fish. Unlike the former polymers, chitin is made up of numerous N-acetylglucosamine(a substituted form of glucose).
• INULIN: Not as commonly heard of, inulin is a storage polysaccharide present in the majority of plants like banana, onions, wheat and garlic. But industrially it is extracted from chicory that is often added to coffee. It’s a fructose polysaccharide made up of many repeating disaccharide units. Inulin producing plants do not store their food reserves as starch anymore.

Dietary sources of carbohydrate polymers:

Carbohydrates are the main source of energy in our diet and most cases comprise the major portion of it too. Across the globe, people obtain their daily carbohydrate needs through different cereals, grains or preparations made of these pulses and grains- rice, bread, pasta or starchy vegetables like potatoes and yams.

But carbs can also be obtained from sweet and unhealthy foods like cakes, chips, soft drinks, chocolates and biscuits.

Good and bad carbohydrates:

The concept of bad and good and carbs rose into question after a majority of the global population was found to have obesity issues due to excessive consumption of fried and junk food items.

Carbohydrates are found naturally in fruits, vegetables, pulses, grains, and cereals called complex carbs. They are long-chain carbohydrate polymers that take a long time to be broken down by the body, allowing the monomers to be absorbed and assimilated optimally.This means it can keep us feeling full for longer.

On the other hand, those in cakes, sweets and fried food consist of carbs made of simple sugars. They are easily broken down and instead of being used up, they get reserved as fat due to its quick assimilation. This makes us feel full at the immediate moments but gives rise to consistent cravings after a short period.  These are the carbs that are the actual cause of unhealthy weight gain and issues related t it.

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