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Pleiotropy: Definition, Mechanism, and Examples
Continue ReadingPleiotropy Definition
Pleiotropy is a phenomenon that occurs when a single gene affects several characteristics of living creatures. Pleiotropy can be caused by a gene mutation. Marfan syndrome, a human genetic disease affecting the connective tissues, is an example of pleiotropy.
The eyes, heart, blood vessels, and bones are all often affected by this illness. Pleiotropy is produced by a mutation in a human gene that causes Marfan Syndrome.
What is Pleiotropy?
Pleiotropy is derived from the Greek pleio, which means “many,” and trepein, which means “influence.” Pleiotropy is the state of having numerous effects.
It is a term used in genetics to describe a single gene that controls or influences several (potentially unrelated) phenotypic characteristics. In pharmacology, it’s a characteristic of a medication that causes it to have extra (positive) effects in addition to the ones it was designed to have.
It is demonstrated in molecular biology by cyclic AMP in a cell, which has a range of effects via controlling a protein kinase, which impacts a variety of other proteins.
Is Cystic Fibrosis an Example of Pleiotropy?
One of the most frequent examples of pleiotropy is cystic fibrosis, which is a hereditary disease. Lung infections are common with this condition. The digestive system and other organs in the body might be affected by this condition. Cystic fibrosis is caused by a mutation in the “cystic fibrosis transmembrane conductance regulator gene,” which prevents the gene from functioning properly.
Is Albinism a Pleiotropy?
Albinism is caused by a pleiotropic gene produced by a tyrosinase (TYR) gene mutation. The afflicted person’s body produces less melanin as a result of the mutation.
Pleiotropic genes are genes that influence the behaviour and functions of several genes with unrelated characteristics. On occasion, such qualities have been seen to be extremely similar in nature, while in other situations, they have been noted to be very unlike.
Pleiotropic characteristics are a term used to describe the issues caused by pleiotropic genes.
Effect of Genes on Traits of Humans
The phenotype refers to the physical characteristics of a person, such as body shape, height, colour, physique, and height. A trait governed or controlled by a single gene is known as a single gene trait. It may be difficult to determine the presence of pleiotropic characteristics until the gene is subjected to mutation.
Mutations are alterations in DNA sequences that occur relative to one another. The point mutation is the most frequent form of gene mutation, which is further divided into silent mutations, nonsense mutations, and missense mutations.
The character of the qualities is generally determined by the two alleles, which are the variation forms of a gene, according to diverse publications. The combinations of particular alleles dictate the synthesis of proteins that derive the process of phenotypic trait development, whilst the DNA sequence of the gene is altered by the mutation that occurs in the gene.
As a result, alterations in the gene segment sequences cause the proteins to stop working. As a result, the progression in the mutation will affect all accessible characteristics that are connected to a single attribute in the pleiotropy process.
Pleiotropy in Genetics
Pleiotropy was first proposed in biology by Gregor Mendel, a well-known geneticist well known for his groundbreaking work on pea plants. He tried purple-flowered plants and white-flowered plants in a series of trials.
Colorful blooms and leaf axils are always visible on plants with coloured seed coats, he observed. An axis is the portion of the plant that connects the stems to the rest of the plant.
He noticed that, although the seed coats were colourless in nature and had no colour in their axis, the pea plants, which were the focus of the study, invariably had white blooms.
After reviewing his findings, it was determined that the colour of the plant’s axil and the seat coat are the most crucial elements in determining whether the plant would produce white or purple flowers. Today, similar findings are attributed to the phenomenon of pleiotropy, in which a single gene contributes to numerous phenotypic characteristics.
Pleiotropy may be caused by a number of different processes, including development pleiotropy, gene pleiotropy, and selectional pleiotropy.
The focus of gene pleiotropy is on the functionality of a specific gene, and this type of pleiotropy is also known as molecular gene pleiotropy. The functions of a characteristic are generally determined by the number of traits and biochemical components influenced by the gene.
The biochemical parameters include the number of enzyme reactions performed by the gene’s protein products. In the evolution of pleiotropy, the major focus is on mutations and their relative influence on a variety of characteristics. It has been shown that single-gene alterations have a broader influence on numerous other potential characteristics.
Furthermore, illnesses involving mutational pleiotropy are defined by deficits in many organs that disrupt the proper functioning of multiple bodily systems. The last process that causes pleiotropy is selectional pleiotropy, which focuses on the impact of gene mutations on the number of distinct fitness components.
The method by which an organism transmits its genes from one generation to the next through sexual reproduction is typically governed by the fitness of the organism. Selectional pleiotropy is frequently concerned with the effects of selection on naturally occurring characteristics.
Polygenic vs Pleiotropy
Many people confuse the meanings of polygenic inheritance with pleiotropy, which is a common finding. The main difference between the two is that pleiotropy occurs when a single gene influences several traits, whereas polygenic inheritance occurs when a single trait is regulated by many distinct genes, such as skin colour.
Pleiotropy vs Epistasis
Understanding the idea and meaning of epistasis, as well as its relationship to pleiotropy, is also critical.
Epistasis refers to the interplay of several genes in influencing phenotypic results.
Pleiotropic gene research is important in biology because it helps researchers understand how specific genes are frequently implicated in genetic diseases. Pleiotropy may be found in abundance throughout nature.
Pleiotropic disorders include fruit flies with vestigial genes, poultry with frizzle characteristics, the process of pigmentation and deafness in cats, pleiotropic sickle cell diseases in humans, and phenylketonuria (commonly known as PKU).
Pleiotropy Examples
Pleiotropy is influenced by both direct and indirect pleiotropy, as evidenced by instances found in numerous literature research.
For example, if a blind mouse is born as a result of changes in a single gene, the odds are quite high that the blind born mouse will struggle with visual learning tests, showing that a single gene is implicated in many pathways.
As a result, there are numerous examples of both direct and indirect pleiotropy, some of which are discussed in further detail in the sections below.
i. The Vestigial Gene and Fruit Flies
Vestigial genes are important in the development of the wing of the fruit fly Drosophila. If these flies are homozygous for the recessive version of the vestigial gene, they have small wings and are unable to fly in the proper manner (VG). As a result, the vestigial gene is pleiotropic, resulting in the fruit fly drosophila’s wings not developing.
Other indirect impacts of pleiotropy in fruit flies include a reduction in the number of eggs present in the ovaries of the flies, a shift in the location of the bristles on the scutellum of the flies, and a shorter life span of the flies. The wings of the first bee are not entirely formed, as opposed to the fully developed wings of the second bee.
ii. Deafness and Pigmentation in Cats
Deafness is present in around 40% of cats with white hair and blue eyes, according to reports. Although this information is intriguing because we have most likely never paid attention to these cats throughout our lives.
It was discovered early on in the research that white cats with one blue eye and one yellow eye were blind in one eye, which was typically the blue eye, but it was subsequently shown that this occurrence of blindness does not necessarily apply to all cat breeds.
Waardenburg syndrome is a human disease that is comparable. Pleiotropic genes are involved in this disease in cats, producing not just deafness but also colouring issues. The goal of the study was to figure out how hearing capacity and the pigmentation process are linked.
Pigmentation has a critical function in regulating fluid flow in the ear canals, according to the findings, which were conducted on mice. Those who lacked pigmentation also lacked the flow of fluids through the ear canals, causing them to rupture and eventually lead to deafness.
iii. Frizzle Traits of Chickens
Pleiotropic genes cause the hens to express a variety of genes. Walter Landauer and Elizabeth Upham discovered in 1963 that hens with the dominant frizzle gene generate feathers that curl all over their bodies rather than laying flat against their skin.
This impact was linked to the genes’ phenotypic effects. Furthermore, it was discovered that these frizzle characteristics induced a variety of alterations in the hens, including aberrant body temperatures, high blood flow rates, high metabolic rates, and increased digestive capacity.
Furthermore, as compared to typical wild eggs, the hens with pleiotropic characteristics produced fewer eggs, affecting their reproduction rates.
iv. Marfan Syndrome
The Marfan syndrome is a hereditary disease that causes problems with tissue connections. The eyes, heart, bones, and blood arteries are the most commonly affected parts of this condition. People who suffer from these disorders generally have long, slender bodies with long legs, arms, fingers, and toes, and the Marfan syndrome can cause mild to severe damage.
The symptoms of the condition differ from one family to the next, and they also differ by age, with some experiencing minor symptoms and others experiencing life-threatening problems. Cardiovascular problems include aortic aneurysms, aortic dissections, and valve abnormalities.
Eye difficulties, such as lens dislocations, retinal issues, and early-onset glaucoma, commonly known as cataracts, are, on the other hand, extremely essential.
v. Sickle Cell Disease
The most frequent kind of pleiotropy that affects humans is sickle cell disease, which is caused by a condition that causes irregularly shaped red blood cells, whereas normal red blood cells have a biconcave, disc-like shape and contain large amounts of haemoglobin.
Red blood cells in the blood are primarily responsible for binding tissues and transporting oxygen to all accessible cells. Sickle cells are most commonly caused by mutations in the beta-globin gene. As a result, irregularly shaped blood cells cluster together, creating a block in the veins and eventually stopping blood flow in the veins.
This obstruction causes a slew of health issues as well as harm to critical human organs, including the heart, brain, and lungs.
vi. Phenylketonuria
Phenylketonuria, or PKU, is another frequent type of pleiotropy, which causes mental impairment, hair loss, and changes in skin colour or pigmentation. The majority of these illnesses are caused by a significant number of mutations in a single gene on a chromosome.
These genes are involved in the synthesis of phenylalanine hydroxylase enzymes. These enzymes are responsible for breaking down the amino acid phenylalanine, which we obtain via protein digestion. Pleiotropy causes the nervous system to be harmed when the amount of amino acids rises owing to pleiotropy.
Other diseases induced by phenylketonuria include intellectual impairments, cardiac issues, developmental delays, and seizures. Classic PKU is the most prevalent kind of PKU, and it usually affects infants. The prevalence of these disorders varies depending on where you live.
In the United States, one out of every ten thousand newborns is affected by this illness. The good news is that doctors can diagnose PKU in newborns based on their early symptoms, allowing them to begin therapy early and save the youngsters from the disease’s devastating consequences.
Antagonistic Pleiotropy
Antagonistic pleiotropy is a theory offered to explain senescence or biological ageing that can be ascribed to natural selection of specific pleiotropic genes.
Natural selection may prefer an allele that has a detrimental influence on the organism if it also provides beneficial aspects of antagonistic pleiotropy. Furthermore, natural selection favours genotypes that improve reproductive fitness early in life but induce biological ageing later in life.
The sickle cell, where the Hb-S allele mutation of the haemoglobin gene gives varied advantages and drawbacks for their survival, is the most typical example of antagonistic pleiotropy.
The homozygous for the Hb-S allele, which has a couple of Hb-S alleles of the haemoglobin allele, has a shorter lifespan due to the negative effects of sickle cell traits, whereas the heterozygous traits, which usually have one normal allele and a single Hb-S allele, are highly resistant to malaria and do not have the same negative symptoms.
Furthermore, it may be deduced that the frequency of the Hb-S allele is higher in geographical areas with higher malaria transmission rates. Lethal alleles are those that result in the death of the individual who has them.
Generally, they are the result of gene mutations that are highly important for an individual’s development and growth. A dominant, recessive, or codominant allele can exist. An individual with the AB blood type possesses both alleles, i.e. allele A and allele B. This is an example of a codominant allele.
Pleiotropy Summary
Pleiotropy is a characteristic that demonstrates that several genes have many phenotypic effects, which may be summarised from the preceding explanation. Pleiotropy may be caused by a number of different processes, including development pleiotropy, gene pleiotropy, and selectional pleiotropy.
The focus of gene pleiotropy is on the gene’s functionality, whereas the focus of development and selectional pleiotropy is on mutations and their relative influence on numerous characteristics, and the effect of gene mutations on the number of distinct fitness components, respectively.
Pleiotropic gene research is important in biology because it helps researchers understand how particular genes are involved in a variety of genetic disorders. Pleiotropy is implicated in a number of genetic diseases that have been reported in the literature.
Deafness and pigmentation in cats, the prevalence of frizzle features in cats, Marfan syndrome in humans, sickle cell disease, phenylketonuria (PKU), albinism, Austin, and schizophrenia are only a few examples of pleiotropic qualities.
Pleiotropy Citations
- Evaluating the potential role of pleiotropy in Mendelian randomization studies. Hum Mol Genet . 2018 Aug 1;27(R2):R195-R208.
- Pleiotropy and Specificity: Insights from the Interleukin 6 Family of Cytokines. Immunity . 2019 Apr 16;50(4):812-831.
- What Is Antagonistic Pleiotropy? Biochemistry (Mosc) . 2019 Dec;84(12):1458-1468.
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Arboreal: Definition, Types, and Examples
Continue ReadingArboreal Definition
The word arboreal originates from a Latin word, which means like trees. Thus, it is associated with the trees and the words related to it are arborary, arborous and others.
Arboreal locomotion occurs when the organism residing in the trees show movement such as jumping, swinging and walking and is thus termed arboreal locomotion. As they reside on trees, their body has been adapted in that way, such as their tail, claws or their legs.
Arboreal Animals
Animals which reside on trees are called as arboreal animals, their whole life they lodge on the trees where all their daily activities are carried out such as hunting, mating, sleeping as well as leisure. Their offspring also reside on the trees however as they are very small, these juvenile are most susceptible to tumble down.
Parrots, cat, squirrel, lizards, insects, monkeys, chameleon, koalas, and sloths are the example of arboreal animals, however there are other animals who stay on land but can climb trees such as goats and leopards, where leopards get on the tree so that their prey cannot be taken by other animals.
These arboreal animals form the forest ecosystem and will be seen in such ecosystem, and more specifically in the tropical forests. Arboreal animals reside on trees to protect themselves and their family from scavengers on the land, however there are chances of them tumbling down.
Thus they have acquired certain adaptations such as they make their nests or their habitat at the peak of the trees and those animals which are huge in size will reside in the middle portion of the tress and will hide in the branches and leaves when they feel they could be hunted.
Challenges for Arboreal Animals and Adaptations
There are various problems which could be faced by the arboreal animals such as falling down which results in mishap. Other challenges are looking for food and storing them as well and protection and various daily activities they carry out.
Other problems could be inappropriate weather conditions resulting in loss of habitat as the branches fall of and balancing, walking on tiny branches and other obstacles are some of the issue. Although these problems are overcome as they have stayed on trees for a long duration, thus adapting to it.
i. Gravitational Balance
Center of gravity is responsible for the movement in animals, thus resulting in no friction. When cow walks it does not use both the legs at the same time it uses alternate legs, thus, the center of gravity is from side to side. Other examples of animals with excellent center of gravity are dogs, giraffe, buffalo and elephants.
However, the opposite is that of arboreal animals, i.e., they have low center of gravity which is due to small length of legs. Thus, they can maintain their balance and avoid tumbling down from tress due to center of gravity being low.
ii. Membranes for Gliding
Trees might have spaces between, thus arboreal animals have made gliding adaptations which is due to patagia, which is a membrane allowing sliding found between the legs. As it is flexible, they can jump from one branch to the other and will not fall down but glide in such scenario. These membrane contract and expand but does not possess weight on them.
In animals such as flying frogs, snakes, squirrels, mice and geckos possess this membrane as well, where they glide but not fly. Smallest gliding animal is the flying mouse and they possess the membrane between their knees and their elbows. While gliding it requires its tail and is a rodent.
iii. Body Structure
As arboreal animals spend their whole life on their tree, they have acquired some adaptation such as the gliding membrane, swinging and brachiation. Brachiation is the ability of the arboreal animals to shift from one branch to the other which is seen in monkeys, apes, lemur and other primates.
Other adaptations are long arms which helps them to swing and move from branches to branches and the gaps present between the trees. 35miles/hour is the monkey’s speed. The wrist of arboreal animal can move freely which helps to catch hold off the branches while moving and swinging.
Arboreal animals have prehensile tail and the most classic example are the monkeys, where tail provides support, helps in jumping, swinging, moving, snatching. To prevent from tumbling down and getting bruised, these animals have grip in their feet so that they can hold the branches very firmly and their fingers lack hair thus providing a grip when they hold branches.
Example are squirrel which have easily rotatable ankles, thus can move both the sides very quickly. Other adaptations are shorter feet, thumb, spine, nails and long fingers and forelimb. Some arboreal animal have adhesive feet and its example are tree frogs and salamander.
Arboreal animals are usually small which has various pros like low center of gravity, less weight and more stability. The exception are orangutans which are around 300 pounds in weight and reside in tropical forest.
Arboreal Locomotion
Arboreal locomotion occurs when the organism residing in the trees show movement such as jumping, swinging and walking and is thus termed arboreal locomotion. As they reside on trees, their body has been adapted in that way, such as their tail, claws or their legs.
The adaptations are long arms which helps them to swing and move from branches to branches and the gaps present between the trees. Many times, when they fight and play, they don’t tumble because of the adaptations made by the body and their locomotion which prevents from falling when they have skipped a branch and are about to fall.
The type of locomotion varies from animals to animals such as concertina locomotion is seen in snakes.
Arboreal Examples
The examples of Arboreal animals residing in the tropical, subtropical area are:
a) Orangutan: They are found at the peak of trees and don’t come down very often. Their feet and hands are not considered separate as they both can perform the same functions like swinging, climbing, snatching and etc.
b) Tree Kangaroo: They reside in the New Guinea tropical rainforest and are actual arboreal staying on trees. Tree kangaroo also reside on the peak and have human speed when on the land. The features of kangaroo are strong forelimbs and legs. Their jump is quite excellent as they possess the ability to jump 30 feet down from one tree to the other.
c) Sunda Flying Lemur: Lemur are agile during night, thus sleep in day at the top or in the holes of the tree and requires all its four leg to obtain a hold on the tree’s branches. To climb they using hoping where they spread their legs and jump.
Sunda colugo and Malayan colugo are the other names of the lemur. It does not stay on the ground and has gliding membrane which is present from the neck to the toes, thus making gliding very smooth.
Arboreal Citations
- Positional behavior and body size of arboreal primates: a theoretical framework for field studies and an illustration of its application. Am J Phys Anthropol . 1992 Jul;88(3):273-83.
- Hindlimb suspension and hind foot reversal in Varecia variegata and other arboreal mammals. Am J Phys Anthropol . 1997 May;103(1):85-102.
- Fomitopsis officinalis: a Species of Arboreal Mushroom with Promising Biological and Medicinal Properties. Chem Biodivers . 2020 Jun;17(6):e2000213.
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ATP and ADP: Definition, Formation, and Examples
Continue ReadingATP and ADP Definition
The source of energy for the organism is the ATP, which is required to various biological processes. When the body requires ATP to meet the requirement, that ATP is broken down to ADP where the energy released is used by us to sustain life.
There are 3 phosphate molecule and one adenine molecule which forms the ATP.
ATP to ADP Energy Release
As the ATP molecule consist of 3phosphate molecule and an adenine molecule, thus when ATP is converted to ADP, a phosphate molecule is lost in this process.
The reaction can be written as ATP → ADP + Pi
Thus, this reaction results in energy released which is used by the cells to perform the biological process. Thus, to obtain more energy foods that are rich in glucose can be administered and broken down to obtain food.
However, in absence of such condition, mechanism exist to produce energy. This is the reversal of the ATP synthesis process, which requires energy and reuses the ATP molecule.
The reaction is ADP + Pi → ATP.
Glucose and ATP
The amount of ATP required by the cells is in huge numbers, thus they are synthesized within the cell and as the cells are in millions thus, ATP synthesis is also required in huge numbers.
To synthesize ATP, glucose is required which is obtained from the food we consume and the other foods provide the raw material to synthesize ATP. Through the respiration process, glucose is metabolized and energy is produced.
Respiration and ATP Formation
Within plants and animals, through the respiration process ATP is formed. However, plant have photosynthesis through which they synthesize food. Some substrates are required for the synthesis of ATP.
Respiration process occurs in aerobic condition and requires three steps and they are Glycolysis, Kreb’s cycle and Cytochrome system.
ATP and ADP Citations
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Plasmolysis: Definition, Mechanism, and Examples
Continue ReadingPlasmolysis Definition
Plasmolysis is the process in which cells lose water in a hypertonic solution. The reverse process, deplasmolysis or cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external osmotic pressure and a net flow of water into the cell.
What is Plasmolysis?
Plasmolysis can be divided into two words, where plasma means matrix and lysis means loosening. The desiccation of the cell’s protoplast due to loss of water, which occurs at a distance from the plant, is called as Plasmolysis.
Thus, voids are seen between the plasma membrane and the cell wall. Convex and concave are the two plasmolysis types.
Shrinking of protoplasm whereas, concave pockets are formed by plasma membrane in concave plasmolysis, however there exist common places between the protoplasm and cell wall. With hypotonic solution, the situation can be reversed for concave plasmolysis.
From the cell wall, protoplast has separated itself and the cell is now of spherical shape and this convex protoplast, which cannot be reversed.
Crenation is seen in animals, which is nothing but plasmolysis, and the cells are contracted, however plants does not contract because of the cell wall, thus possess concave pockets or are circular.
Plasmolysis vs Cytolysis
Plasmolysis and cytolysis are separate as the cell ruptures due to the amount of water present in the cell, more than the cell can hold and this happens when the cell comes in contact with a hypotonic solution and the water keeps on entering the cell more than the limit of the cell, resulting in cytolysis. This is seen in red blood cell, which explodes but does not happen in plants as they turgor pressure and cell wall.
Due to variation in osmotic pressure and movement plasmolysis and cytolysis occurs. In plasmolysis water exits from the cell due to hypertonic environment, whereas in cytolysis water moves inside due to hypotonic conditions. Thus, they are the opposite of each other.
Plasmolysis vs Turgidity
Due to variation in osmotic concentration of solutes in the solution and movement plasmolysis and turgidity occurs. In plasmolysis, the water is thrown out of the cell, whereas in turgidity, there is influx of water. Thus, contraction of cell takes place due to plasma membrane and protoplasm gets isolated from cell wall and the opposite of this occurs in turgidity.
Turgidity takes place when cell is placed in hypotonic solution and plasmolysis occurs when there is hypertonic condition. Thus, turgor pressure elevates in turgidity and drops in plasmolysis. Thus, the plants in turgidity stands straight and bend down in plasmolysis.
Plasmolysis vs Flaccidity
In plasmolysis, the water is thrown out of the cell, due to hypertonic environment. Thus, contraction of cell takes place where, plasma membrane and protoplasm gets isolated from cell wall. Due to absence of water between the plant and the surrounding, turgor is lost, thus flaccidity occurs. Such a cell is neither contracted nor expanded.
However, these processes quite resemble each other as water is lost and they start to bend down which is the plant. Both these conditions can be normalized once the cell is near the hypotonic environment.
Plasmolysis Process
Appropriate solute concentration and pressure in the plant is maintained by the vacuole, whose work is osmoregulation. Water diffuses into the cell when there is variation in solute or water concentration. The movement of water from a region of high water to a region of low water is called as Osmosis. Water will always move to a region which has a greater number of solutes, when referring to solute.
Turgor pressure can be kept under control if salt and water amount is maintained. To maintain the structure of plants, water molecules possess pressure which will move them towards the plant cell, thus maintain structure.
Thus, plant turgidity is very vital, as it limits the water amount and takes up only the required amount of water and if this turgor pressure is imbalanced or damaged then the plant will not be able to stand through in isotonic environment, which means when the concentration of solute within the environment and the cell is similar.
Such a cell is called plasmolyzed and is no more turgid and can be called as a flaccid cell. Hypertonic is those that has more salt than water, and in such a hypertonic condition, cell will release water and this process is plasmolysis and the cell is in plasmolyzed condition.
However, this process can be over turned by de-plasmolysis and if the water is effluxed continuously it would lead to cytorrhysis, where the wall of the cell is disintegrated. Plasmolysis is performed in lab when cells ae exposed to sugar or salt in high concentration. However, this process does not happen in the environment.
Concave vs Cconvex Plasmolysis
The desiccation of the cell’s protoplast due to loss of water, which occurs at a distance from the plant, is called as Plasmolysis. Thus, voids are seen between the plasma membrane and the cell wall. Convex and concave are the two plasmolysis types.
Shrinking of protoplasm whereas, concave pockets are formed by plasma membrane in concave plasmolysis, however there exist common places between the protoplasm and cell wall. With hypotonic solution, the situation can be reversed for concave plasmolysis, by de-plasmolysis.
From the cell wall, protoplast has separated itself and the cell is now of spherical shape and this convex protoplast, which cannot be reversed. Plants produce wax and control stomata so that water is not released.
Plasmolysis Examples
Plasmolysis is performed in lab where cells are exposed to sugar or salt in high concentration. However, this process does not happen in the environment. However, some examples are flooding of coastal areas with elevated salt content and when they are left unprotected to chemicals such as weedicides.
Plasmolysis Importance
In plasmolysis, the water is thrown out of the cell, due to hypertonic environment. Thus, contraction of cell takes place where, plasma membrane and protoplasm gets isolated from cell wall. Voids are seen between the plasma membrane and the cell wall.
From the cell wall, protoplast has separated itself and will signal the plant to start absorbing water and stop further loss of water, which is the backup plan of plasmolysis until cytorrhysis has arrived, which will eventually disintegrate the cell wall and finally apoptosis.
Plasmolysis Citations
- The biophysics of the gram-negative periplasmic space. Crit Rev Microbiol . 1998;24(1):23-59.
- Salt stress or salt shock: which genes are we studying? J Exp Bot . 2013 Jan;64(1):119-27.
- Significance of plasmolysis spaces as markers for periseptal annuli and adhesion sites. Mol Microbiol . 1994 Nov;14(4):597-607.
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Competition: Definition, Structure, and Examples
Continue ReadingCompetition Definition
As the word itself means to compete. When living organism in same species or different species compete for supplies such as food, territory, habitat, power and mating partners it is called as Competition.
It is a type of interaction that occurs within organism in the environment. As the number of organism exceeds than the environment can take care, thus for the survival they need to fight against each other for limited assets.
There are two types of Competition; Intraspecific and Interspecific. In Intraspecific competition, organism of the same species are rivals of each other and is called as Intra-specific.
Example is when the plants of same species are in close proximity for each other, they will fight for obtaining nutrients from the soil, water and sunlight and thus to survive they will adapt themselves in ways such as distorting, increasing in length and evolving with huge roots are some of the example.
The fight which occurs between different organism of different species can be termed as Interspecific competition. An example is, in plants where in the rice field, weeds are also grown.
In animals, the fight could be because of food such as between leopards and lion. Other types of competition are exploitation ad interference competition.
Competition Citations
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Concentration: Definition, Structure, and Examples
Continue ReadingConcentration Definition
Within a solution, the total sum of the solute present in it is termed as Concentration. Amount of solute upon the amount of solvent can determine the concentration. Concentration states the amount of the product present and its value.
Thus, the amount of solute present in a particular solution is called as the Concentration and can be found out by the number of solute to the number of solvent within a solution.
Purification, solution dissolution and dissemination are the possible ways of concluding the amount of solute.
Concentration in various field has various meaning, in pharmacology it determine the value of pharma product. Isolating, desiccating of the active compound and condensation are the possible methods to determine the concentration of a product.
Concentration Citations
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Diploid: Definition, Structure, and Examples
Continue ReadingDiploid Definition
The word diploid originates from a Greek word, which can be broken into two word “di” meaning two and “ploidy” means the chromosome set present within the cell. thus, diploid means there are two set of similar chromosome, each coming from the parent cell.
The chromosome are similar as they possess traits which are obtained from the parent and similar case is seen in humans, where they obtain genes from parents. As diploid means two set of chromosomes, haploid comprises of one set of chromosome.
Example of haploid cell are sex cells which come together and form a zygote which is diploid. Example of diploid cell are somatic cell. thus, humans have 2 cell types and they are; somatic and sex cell. the chromosome number is “2n” in diploid and “n” in haploid.
Ploidy
Depending on the number of set of chromosome present, they can be categorized. This is called as ploidy. Those are termed as polyploidy which contain either three set or more than that.
In silkworms, there are 10,48,576 ploidy, whereas in human it is deadly and can result in complication in the pregnancy and has to be terminated. Visibility of an extra chromosome can result in a condition which is aneuploidy observed in humans, resulting in disorder such as trisomy 21 or Down syndrome, trisomy 18 or Edwards syndrome and trisomy 13 which is Patau syndrome.
In monosomy, chromosomes are absent, example is Turner syndrome, where female lack chromosome or is dysfunctional. Polyploidy occurs in plants and not in higher animals. Example are African frog, potato, rat in which polyploidy is observed.
In heptaploid, seven chromosome sets are observed. In hexaploidy six sets of chromosomes, five set of chromosomes in pentaploidy, four sets in tetraploidy, three sets in triploidy, in diploid two sets of chromosome and in haploid one set of chromosome.
Humans have a pair of 23 chromosomes, thus 2n = 46. These 23 can be further divided into 22 somatic cell and one sex cell. all the cells in the human body are diploid except the sex cell which consist of egg and sperm and are haploid, with 23 chromosomes. However, these sex cells when fuses they form a zygote which is diploid. Thus, the chromosome number remains stable.
For the formation of sex which are haploid, meiosis occurs and when these sex will tur to diploid after which they will undergo mitosis. Meiosis takes place to form four daughter cell, with each daughter having half chromosome from the parent cell. formation of two daughter cell, where each one contain similar chromosome number. Example are the bees, ants which are developed from meiosis and are known as haploid organism.
Haploid cell possess one chromosome set, whereas the diploid has two sets. Diploid cells further undergo mitosis and haploid cells are formed by meiosis. Example of diploid are somatic cell and that of haploid are sex cells. The daughter cells formed in meiosis are not similar to the parent, whereas in mitosis daughter cells are identical. Eggs and sperm are haploid and skin cells are diploid.
Diploid Examples
There are 23 pair of chromosomes in human which means 46 chromosome in total. Earthworm possess 18 chromosome pair and dogs have 39 chromosome pair, thus 78 chromosomes. There is just a single chromosome in E. coli, animals cannot change from haploid through diploid but plants ae capable to do so and is called as alternation of generation. Example is during gamete formation, plants are haploid and during spore production, diploid. Viruses are also diploid as they possess two RNA.
Biological Importance of Diploid
It is said that there are high mutations probability in diploid than in haploid which is because of more chromosome, thus doubling it in diploids. Although these mutations will affect those diploid cells which are surviving through difficulty, but diploids have better thriving rate than the haploid, thus if a haploid cell gets mutated it comes into action at that possible time and in diploid, they are effective when they are heterozygous.
Mutations can be hold on to in haploids than in diploids, thus diploids are quite adapted when changes are occurring due to mutation, however, haploids are better adapted when changes are due to natural selection.
Diploid Citations
- Diploid sperm and the origin of triploidy. Hum Reprod . 2002 Jan;17(1):5-7.
- Physiological polyspermy: Selection of a sperm nucleus for the development of diploid genomes in amphibians. Mol Reprod Dev . 2020 Mar;87(3):358-369.
- Unzipping haplotypes in diploid and polyploid genomes. Comput Struct Biotechnol J . 2019 Dec 9;18:66-72.
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Humans are Omnivores? Diet and Evidence
Continue ReadingHumans are Omnivores
There are various misbelieves about the diet of a human, some say they are herbivores, consume plant-based diet and some say they are complete carnivores, eating animal’s flesh. Thus, to prove this various scientist have undergone research and have found that humans are actually omnivores, feeding on both. This fact was proved by Dr. McArdle, a primatologist and anatomist.
Taxonomy and Diet
The myth that humans are complete vegetarians have been arisen due to lack of certainty about the diet and the taxonomy. Carnivores can be specific to a particular diet or can eat various flesh, thus belonging to carnivores.
The diet cannot be just classified into herbivores or carnivores but insectivores are those which eat insects, frugivores which consume fruits, gramnivores eat seed and nuts, whereas folivores consume leaves.
He concluded by saying that every organism has a particular function and those functions are also found in other species.
Omnivores
Omnivores are said to be those organism, that are both herbivores as well as carnivores, which is a type of adaptation accomplished by them. Thus, to thrive in the environment they have acquired this type of adaptation and feed on whatever is available.
This adaptation is seen only in animals and humans have the freedom to choose what they want to consume. However, in animals a few characteristic have been seen such as modified teeth which can also be an adaptation.
Great Apes and Their Diet
Species differ from each other in their food characteristic, is said by Dr. McArdle. Animals that consume fruits are the apes, however there are other types of apes which also eat fruit but differ in the habits and the habitat, example gibbons and siamangs.
There are other animals that are on plant-based diet but does not eat much fruit are the gorilla and orangutans which have not been viewed eating non-vegetarian food. A comparison was done to identify the link between the primate’s diet and their size. It was found out that the tiniest species fees on insect, called the insectivores and the one which is the hugest is an herbivore.
Thus, it determines the amount of food consumed according to the size and the food available on the basis of the location. Organism that quite resemble the humans in their habits, physiology, characteristic and the genetics are the chimpanzee, which hunt the prey to feed themselves.
Evidence that Humans are Omnivores
a) Archeological Records: From the records it has been very evident that since the ancient times humans have been killing other animals to obtain food and they are potential carnivores. Thus, humans are omnivores.
b) Anatomical Features: There are features that humans have similar to omnivores on the basis of their body. Example are mice, pigs, rodents and others. Although omnivores do not have vats where food is broken down by microflora, but is present in deer and cattle and there are sacs found in animals such as monkey, rhinos and horses, and sharp teeth, but humans do not possess such features. However, humans have other features.
c) Jaws and Teeth: One of the most important feature of omnivores that are humans are the teeth which have canines which are quite small due to cranium enlargement and small size of the jaw. However, in animals the canines are huge as they help to prove their dominance as well as to eat their food. In humans the canine and premolar and molar are enough to break the food.
d) Intestines: The most tedious digestive system is of herbivores due to the presence of various compartments, then the carnivores and omnivores. As the plant-based diet is quite rigid, thus breaking it is more complex in nature. Thus, they possess more organs for digestion to occur. The easier to broken one are the carnivores, whereas the omnivores are in between the herbivore and carnivore, not complex as well as not easy. Those plant substances that cannot be broken by humans are thrown out of the body.
Thus, humans are omnivores and have the freedom to choose the type of diet, however in animal it is an adaptation made by them for survival.
Humans are Omnivores Citations
- Vegetarian diets : nutritional considerations for athletes. Sports Med . 2006;36(4):293-305.
- Nutritional considerations for vegetarian athletes. Nutrition . Jul-Aug 2004;20(7-8):696-703.
- Vegetarian and Omnivorous Nutrition – Comparing Physical Performance. Int J Sport Nutr Exerc Metab . 2016 Jun;26(3):212-20.
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Polysaccharide: Definition, Structure, and Examples
Continue ReadingWhat is Polysaccharide?
Polysaccharide are chains of carbohydrate that are connected to each other by glycosidic bond and consist of repeating carbohydrate to form a long chain. The term polysaccharide can be broken into words, where poly means many and saccharide means various sugars.
Thus, it means a group of various sugars consisting around 10 moieties. These carbohydrate moieties, are the biomolecules which are made up carbon, hydrogen and oxygen. Carbohydrates can be categorized in two; simple and complex.
Carbohydrates forms the structure and are the energy source. Carbohydrates that can be easily broken down, to provide energy are termed as simple carbohydrate, whereas those that require time to be broken down, however does not interfere with the increment of sugar level and are fibrous in nature are called as complex carbohydrates.
Example of simple carbohydrate are glucose and that of complex carbohydrate are chitin, glycogen and cellulose.
Polysaccharide Characteristics
a) The formula for polysaccharide are Cx (H2O) y.
b) The ration of carbon to hydrogen to oxygen is 1:2:1.
c) Polysaccharide do not dissolute in water.
d) They are less active and are present in condensed form.
e) In taste they aren’t pleasing.
f) They cannot form crystals
g) They are white in color on isolation.
The polysaccharide can be heterogenous and its structure will be branched or linear depending on the polysaccharide it forms. On the basis of sugar molecules, oligosaccharide and disaccharide differ from polysaccharide, where 2 sugar molecules are the disaccharide and more than that sugar moieties are called as oligosaccharide, however they aren’t huge like the polysaccharides.
Polysaccharide Dehydration Synthesis
Dehydration means water is been worn out of a molecule, in polysaccharide it happens when to a sugar molecule another molecule gets attached and results in the expulsion of water molecule. Another way for synthesis to occur is when the sugar molecule attach to the other molecule, they are in a condensed form and water is expelled.
Polysaccharide Hydrolysis
Hydrolysis is the exact reversion of condensation, where a water molecule is lost. In hydrolysis water molecule gets used. To form a monosaccharide from polysaccharide it is known as saccharification. Enzymes such as maltase, pancreatic and salivary amylase break down the sugar molecule, such as the enzyme acting on starch is salivary amylase, resulting in the formation of maltose.
In the small intestine, further the digestion of carbohydrate will take place. In the small intestine, when the partly digested sugar molecule reach, pancreatic juice is released by the pancreas, which will further degrade them into small sugars.
There are enzymes present on the borders of intestine, which will take up the simple sugars with the use of transporters and through the passive transport will reach the capillaries and will be moved to organs such as liver, where it will serve as reserves for glycogen or it could also synthesize ATP.
The enzymes are found on the border of intestine are sucrase, lactase, maltase and isomaltase. These polysaccharide will be attacked at the 1-6 linkage and will form maltose, which will further be cleaved by the enzyme maltase forming glucose, explicitly two molecules.
If instead sucrose or lactose would be present then the respective enzyme sucrase and lactase would act on it. Only those sugar molecules which reach the large intestine, which cannot be absorbed and will be colonized by the microflora in the intestine anaerobically and release gases and fatty acid which are utilized by the body and the gases are released when we fart.
Glycogenesis
From glucose the formation of glycogen is known as the glycogenesis, which would occur when there is huge amount of glucose in the liver and the muscles. Large glucose chains are formed from small glucose molecule, and in the glycogenesis process from those sugar molecules which are present in the cell, glycogen is formed. These molecules when have to be utilized are again broken into glucose by the glycogenesis process.
Glycogenolysis
The metabolization of glycogen is known as glycogenolysis. From the glycogenolysis process, glucose is formed, where from the glycogen a glucose molecule is cleaved and forms glucose-1-phosphate and then again forms glucose-6-phosphate to proceed with the glycolysis. Glycogenolysis takes place in the liver.
Glycosylation
The attachment or linkage of a protein, organic molecule or a biomolecule to the glycan is known as glycosylation. For example, in O linked glycosylation, the O glycan is linked to the oxygen of amino acid such as tyrosine, threonine and etc.
Another example is N linked glycosylation where the N glycan is linked to nitrogen atom of another amino acid which is asparagine. There are various example such as Sulphur linked glycan, Phosphorous linked glycan, Carbon linked glycan and others.
Polysaccharide Classification
When the polysaccharide is formed from a single type of sugar it is called as Homopolysaccharide. Heteropolysaccharide is made up of various sugar molecules. These are two types of polysaccharide classification on the basis of the type of sugar present.
There are two types of polysaccharide and they are Storage polysaccharide and Structural polysaccharide. On the basis of their name is their function.
Structural polysaccharide are like chitin, cellulose which forms the structure of a certain animal. Example is to make the exoskeleton of animals, chitin is required.
Storage polysaccharide are those stress various sugar molecules serving as the reserves. For example, the storage of glycogen in animals in its simple form.
Polysaccharide Example
There are various polysaccharide such as cellulose which is made up of glucose molecules chains in a linear array. Another polysaccharide is glycogen which is formed in liver and muscle and comprises of glucose in a branched chain and is a storage polysaccharide in animals.
Another polysaccharide is Starch which connects glucose moiety to each other by glycosidic bond. A polysaccharide with nitrogen is the chitin, which is a structural polysaccharide that forms structure in various organism. Other example are Zylan, fucoidan, arabinoxylan, galactomannan and others.
Biological Importance of Polysaccharide
The major energy source is the carbohydrates, which are taken up by animals to produce ATP. Example using the substrate level phosphorylation, from glucose ATP is produced. However excess amount of glucose can result in diabetes and similarly excess of fructose can could result improper absorption from small intestine.
Thus, to prevent that fructose is relocated to large intestine where it will be colonized by the micro-flora. In plants, they function as storage polysaccharide, such as storage of glucose in the starch form, which will used by plants to prepare food.
Glycogen is stored in animals, where it can be broken into glucose to meet the energy requirements. In animals, they also form the skeleton and covering of various organism and have industrial applications as well.
Polysaccharide Citations
- Biological activities and pharmaceutical applications of polysaccharide from natural resources: A review. Carbohydr Polym . 2018 Mar 1;183:91-101.
- Polysaccharide of Ganoderma and Its Bioactivities. Adv Exp Med Biol . 2019;1181:107-134.
- Natural Polysaccharide Nanomaterials: An Overview of Their Immunological Properties. Int J Mol Sci . 2019 Oct 14;20(20):5092.
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Skeletal System: Definition, Structure, and Examples
Continue ReadingSkeletal System Definition
The major role of the skeleton is to provide structural support and protection, and it is made up mostly of bones, cartilage, ligaments, and tendons.
An organ system (or simply a system) is a collection of organs that work together to achieve a certain purpose. The integumentary system, lymphatic system, muscular system, nervous system, reproductive system, urinary system, respiratory system, skeletal system, and immunological system are the organ systems in humans and other animals.
The skeletal system is a set of organs that act as the structure for an organism’s body. Other structures such as bones, cartilage, ligaments, and tendons are produced in the connective tissues.
The skeleton refers to all of an organism’s bones and cartilage. It might be either an exoskeleton or an endoskeleton. The skeletal structures of an endoskeleton are located within the body.
An exoskeleton is a form of skeleton that exists outside of an organism’s body. An endoskeleton is found in most animals. The skeleton in humans is of the endoskeleton type, with 206 bones.
The smallest bones are located in the middle ear, whereas the femur is the biggest bone. Crabs, shrimp, insects, and a variety of other invertebrates have exoskeletons.
Skeletal System Citations
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