Gel electrophoresis is a technique used to cut and separate DNA fragments due to their size. This technique is vital for modern personalized medication, because this technique can also detect recessive traits of autosomal recessive diseases(genetic diseases). Gel electrophoresis has also been used to detect the identity of a person that carries a recessive trait such as colorblindness or having blue eyes.

So how does this work? DNA is a double helical staircase made up of nucleic acids, and phosphate groups are contained within the nucleic acids. Those phosphate groups are negatively charged and are attracted to positively charged poles. The gel box is a box that is negatively charged on the top portions of the box and more positively charged closer to the bottom of the box and there is a power source connected to both ends. Hence, the system creates an electrical circuit which creates a steady flow of the electrical current traveling from the negative pole,through the agarose gel (the surrounding gel that make up the gel box), and to the positive pole. In this system, there are small indention columns called “walls”, the walls function as a placeholder for the DNA samples. The DNA samples are converted into loading dye called bromophenol-blue. These samples are then injected into the walls with a micro pipette, then the power source is turned on in order to run the current of the system. After the DNA fragments have separated and traveled downwards, away from the negatively charged pole and toward the positively charged pole, the fragments are then observed under UV light with a max range from 300nm to 360nm.

So what is the result from the procedure? When the box is observed under UV light, each sample has been cut into small bands underneath each of the walls. The bands that are closer to the walls are considered to be the large-range bands since the phosphate group from the nucleic acid of that particular DNA sample was attracted to the negatively charged pole itself. The larger bands are considered to carry the dominant traits contained within the DNA. On the other hand, the bands that have traveled further toward the positively charged pole are called short-range bands, and these bands are considered to contain the recessive traits contained within the DNA. In conclusion, gel electrophoresis is vital for research of genetic identification for patients with genetic diseases.

The person who wrote this did this in Lab.

Reference:

https://drive.google.com/drive/folders/0B5yZh40dXqFzNEo2NThOLWhrMXM

Semipermeable vs Selectively Permeable Membranes

The term permeability in biology always refers to membranes. These membranes are made of lipids (phospholipids and cholesterol), integral and peripheral proteins, and carbohydrates (glycolipids and glycoproteins) that all interact with each other to form a barrier between the cell and its environment. The proportion of Carbohydrates, lipids, and fats in membranes vary by cell type and species, but in humans, they are about 50% protein, 40% lipid, and 10% carbohydrates. Cell Membranes are fluid (dynamic in movement) and can regenerate up to a certain degree when damaged. More importantly, cell membranes maintain the electrochemical gradient between the inside of a cell and its environment and can allow smaller charged molecules, water, and metabolic waste to pass in and out of it, making them permeable. This permeability is therefore a vital aspect in maintaining homeostasis.
When referring to membrane permeability there are two types found in living things: semi-permeable and selectively permeable. Both allow molecules and water to move in and out of the cell, as needed to maintain homeostasis. Semipermeable membranes are more simple in function because they are not “picky”, so If molecules are small enough they will pass through the membrane by osmosis, diffusion or following its concentration gradient from an area of higher concentration to an area of lower solute concentration. One example of a semipermeable membrane found in the body would be the tubules of nephrons within the kidney. Blood components like red blood cells, large proteins that are too large to pass through the nephrons will not pass through the tubules, while smaller solutes, Na+, and metabolic waste passes through the kidney to ultimately become filtrate in urine. Patients with renal problems who can’t properly filter blood must undergo dialysis, where an external synthetic semipermeable filter that acts as a membrane is used much like functional kidneys would.
Selectively permeable membranes are more specific (hence the name selective) as to what passes through the membrane, and when. Cell membranes are considered selectively permeable; Some molecules like water can freely pass in and out to regulate solute concentration within the cell, other molecules such as Sodium (Na+), Potassium (K+), carbon dioxide (CO2), hormones and growth factors are regulated. Of course, some molecules are not allowed in at all. Particles that are needed by the cell but cannot diffuse through the membrane on its own can pass through via active transport with the help of integral proteins permanently integrated in the cell wall, and by transport proteins that carry the molecule to wherever it needs to go to be broken down and utilized. The membrane also has pumps that use ATP to expel solutes like Na+ and K+ out of the cell, and receptors (or ligands) that allow for the passage of larger solutes into it.
Though plasma membranes in cells let some molecules like water and sodium pass through freely, they cannot be considered semipermeable because they have a degree of control over what goes in and out to maintain homeostasis. Regulation of this degree can only be done by selectively permeable membranes, and without being selective of what can pass through it the cell would not be able to maintain its inner environment and eventually die.

Semipermeable vs selectively permeable membranes-1e3kmwf

In living organisms, RNA (ribonucleic acid) is transcribed from DNA (deoxyribonucleic acid). They are later transcribed to be expressed into proteins that are needed for structure and repair, metabolic functions, and regulations to include defense. In comparison to DNA, RNA transcripts are single-stranded, shorter in length, contain a ribose sugar backbone instead of Deoxyribose, and use the nitrogen base uracil instead of thymine. RNA is also less stable than DNA and are therefore more susceptible to reacting with its environment. There are 5 different types of RNA that all perform specific functions that relate to protein expression or regulation that include: messenger RNA (mRNA), transfer RNA (TRNA), ribosomal RNA (rRNA), small nuclear RNA (snRNA), and micro RNA (miRNA). Not all types are present in every domain of life, and the amount and rate in which they are produced varies per the needs of the cell.

mRNA is processed from the primary DNA transcript in bacteria and eukaryotes. Their main function after its transcription is to carry the protein encoding message to ribosomes (composed of 60% rRNA and 40% protein) to be translated. They are read in three sets of triplet nucleotide pairs called codons in which three consecutive codons will translate for one protein. In eukaryotes, mRNA is transcribed within the nucleus and exit through nuclear pores to be translated by ribosomes. Prokaryotes do not have nuclei, and its transcription is coupled with its translation while it separates from the primary transcript. Prokaryotic mRNA is also different in that one strand can be polycistronic, or can code for more than one protein. Eukaryotic mRNA must go through RNA processing for translation. Alternatively, eukaryotic mRNA that encodes for one gene can be modified by alternative splicing (removing of introns) to change how it is expressed.

Around 80% of the genes in humans are alternatively spliced. This splicing is done by ribonucleoprotein complexes called spliceosomes which are made of snRNA or scRNA added to proteins. snRNA is present in eukaryotes, whereas scRNA (small cytoplasmic RNA) is found in both prokaryotes and eukaryotes. Some types of scRNA are involved in post-translational modification of proteins that can regulate the protein after its made, or can activate or inactivate them.

rRNA is present in all living cells and is one of the most abundant in mammals. Its primary function is to use the mRNA template to translate an encoded gene and synthesize it into a protein. In both eukaryotes and prokaryotes, the ribosomes are present in the cytoplasm. The rRNA complex within these ribosomes are composed of 1-3 subunits composed of a large subunit (LSU) and up to 2 small subunit (SSU), where eukaryotic ribosomes are larger. Though ribosomes are the site of protein synthesis and establish the right reading frame, it is tRNA that performs the synthesis of the mRNA strand into a functional protein.

tRNA are molecules located within the ribosome. They are composed of nucleotide chains ranging from 70-90 in length. The tRNA carries free-floating amino acids within the cytoplasm along these chains, and “transfer” them to the mRNA-rRNA complex. Attachment of the amino acid to uncharged tRNA is done by an enzyme called aminoacetyl tRNA synthase. Each type of aminoacetyl tRNA synthase enzyme works on only one of the 20 amino acids. Once attached, the tRNA is considered “charged” and the amino acid is attached at the 3’ end. will then travel to the reading frame in the ribosome to the mRNA to be added at its 5’ end in an antiparallel configuration, and therefore are referred to as anticodons.

In conclusion, all types of RNA are involved in some step of protein synthesis. Some types are specific by the type of organism in question, while others (such as rRNA) are present in all living organisms, most likely because RNA evolved over time to make DNA and similarities of RNA can be traced back to life’s origins.

References

Nester’s Microbiology: a human perspective (8th ed.. (2015). ch 4 In A. D. Allen Debra. McGraw Hill, NY: McGraw-hill.
Openstax. (2013). Biology. In Openstax, Biology (p. Ch1.1). Houston, TX: Rice University.

Proteins are one of the most influential macromolecules, and almost all aspects of life involve their use. Proteins are able to carry out specified cellular functions; some catalyze chemical reactions needed to maintain life while others are used for signaling or to coordinate internal cell activities or inter-cellular communication. Proteins are able to form large organic molecules because they are polymers, which are large molecules made up of repeated subunits. Proteins form these linear polymers by combining 20 different amino acids, each with unique chemical characteristics.

The sequences of these amino acids that make up the protein are stored in the DNA  located in the nucleus. The DNA is transcribed into RNA, and translated into proteins. The sequence of bases in RNA determines the order of successive amino acids that will result in new proteins. The formation of proteins occur within the ribosomes, which are large complexes of RNA and protein molecules. The sequence of amino acids in a protein is known as the primary structure that determine how the protein will fold. The interactions between those primary structures form local secondary structures, when the secondary structures interact they form the overall three-dimensional shape or its tertiary structure. These tertiary structures are called polypeptides, some proteins are a combination of these polypeptides forming quaternary structures.

These macromolecules play a vital role in immune defense, energy storage, and structure creation. They can also be used as enzymes to catalyze or speed up chemical reactions. Each enzyme recognizes one or more substrates to catabolize, synthesize, or rearrange their substrates. They can also send messages within cells and across the body. Examples include hormones such as insulin and glucagon that coordinate different body systems. Furthermore, they transport oxygen across the body through hemoglobin. Proteins allow for the wide range functions of life to maintain homeostasis and can become infinitely complex and add to life’s diversity.

Atoms can combine together to form molecules, and chemical bonds are the different forms of attraction between these atoms. The most common forms of chemical bonds are ionic, covalent, and hydrogen bonds. Each chemical bond has its unique attributes that make them strong or weak in a range of situations. Ionic bonds form between ions with opposite charges as electrons are transferred from one atom to another creating a strong bond. An example would a positively charged sodium ion attracted to a negatively charged chloride ion, making sodium chloride. Covalent bonds form between. Non-metal atoms when the electrons in outermost valence shells are shared. They form when hydrogen and chlorine ions combine to form hydrogen chlorideCovalent bonds can be polar or nonpolar. In polar covalent bonds, electrons are unequally shared by the involved atoms, causing slightly positive and slightly negative charges to form in different parts of the molecule. A polar covalent bond example would be the bonding of Hydrogen and oxygen between water molecules. Nonpolar covalent bonds form between two atoms of the same element or atoms that share electrons equally.

Finally, hydrogen bonds occur between a hydrogen atom with a slight positive charge and an electronegative atom of another molecule. Hydrogen bonds are much weaker than ionic or covalent bonds, but become much stronger as many hydrogen bonds form together. Hydrogen bonds give water its unique properties to support life, such as cohesion and adhesion. To summarize, chemical bonds Give atoms the ability to combine into more complicated and diverse structures that make up all known organic and inorganic molecules throughout the cosmos.

Taxonomy is the science of describing, naming, and classifying all living organisms. Taxonomists use genetics alongside behavioral and physical observations to classify all plants, animals, and microorganisms into specific classifications. Taxonomists have so far classified close to 2 million plants, animals, and microorganisms but an estimated 5 to 30 million different species exists on earth. As organisms become more loosely related they progress up an order until the 3 domains of life.  A species is the lowest level in taxonomy, they are classified as a group of organisms that have the capability to breed with one another.  As multiple species become loosely related they are classified as a genus. This trend progresses up a latter from species, genus, family, order, class, phylum, until the 3 domains of life.

The 3 domains of life are Eukaryota, Bacteria, and Archaea. Each domain has specific attributes with Eukaryotes composing life that most people see in their day to day activities. All animals, plants, fungi, and protists are in this domain, they have eukaryotic cells with membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages and contain rRNA that is unique to this domain. Bacteria are prokaryotic cells that are similar to eukaryotes cells but contain no nucleus, lack membrane-bound organelles, and their own unique rRNA. Finally, the domain Archaea is composed of single-celled microorganisms more closely related to eukaryotes over bacteria. Archaean’s inhabit the extreme environments on earth such as deep sea rift vents and extremely alkaline or acid waters.

Shaina Song

What is a Macromolecule?

A macromolecule is a molecule that consists of large biological polymers, and the polymers are made up of smaller molecular subunits called monomers. Their functions are to store energy and/or be used for structure. There are four main classes of macromolecules which are lipids, carbohydrates, proteins, and nucleic acids.

Carbohydrates

Carbohydrates are one of the major macromolecules that are essential for the building blocks of life. They are often called “sugars” and are found in essential everyday needs such as fruits, vitamins, antioxidants, minerals, and more. Carbohydrates, also called saccharides, are molecular compounds made from three elements: carbon, hydrogen and oxygen.  They can function as a source of energy for the body, building blocks for polysaccharides and components of other molecules such as DNA, RNA and ATP. There are three main types of carbohydrates which are Monosaccharides, Disaccharides, and Polysaccharides.

Monosaccharides, known as simple sugars, are the simplest carbohydrates and are also the building blocks from much larger carbohydrates. These simple sugars have a molecular formula (CH2O)n, where n can be 3,5 or 6. The number of carbons within a monosaccharide are classified as trioses (n=3), pentoses (n=5), and hexoses (n=6). If the monosaccharide contains an aldehyde it is called an aldoses. However, if the monosaccharide contains a ketone then it is called a ketoses.

Disaccharides are products of two monosaccharides that’s been reacted. Most sugars are found to be disaccharides rather than monosaccharides. There are three types of disaccharides which are sucrose, lactose, and maltose which were all formed from a specific monosaccharide. Disaccharides tend to be soluble in water, but they are too large to enter through the cell membrane by diffusion.

Polysaccharides are made up of monosaccharides that have been chained together and each building block structure is called a monomer. The properties of a polysaccharide molecule depend on its length, additional side chain units, folding of the chain, and whether the chain is straight or coiled.

Nucleic Acids

Nucleic acids are one of the four major macromolecules that are essential for the building blocks of life. These molecules are called information molecules because they are large molecules that can carry information in the sequence of nucleotides that make them up. This molecular information in is much like the information carried by the letter in an alphabet, but in the case of nucleic acids, the information is in chemical form. The nucleic acid, DNA (deoxyribonucleic acid), is the genetic material in all organisms. It is transmitted from parents to offspring, and it contains the information needed to specify amino acid sequence of all the proteins synthesized in an organism. The nucleic acid, RNA (ribonucleic acid), has multiple functions; it is a key player in protein synthesis and the regulation of gene expression.

Works Cited

“Background on Carbohydrates and Sugars” International Food Information Council Foundation, n.d.Web. 26 Feb. 2017. < http://www.foodinsight.org/Background_on_Carbohydrates_Sugars>

“Carbohydrates” Royal Society of Chemistry, n.d.Web.26 Feb.2017 < http://www.rsc.org/Education/Teachers/Resources/cfb/carbohydrates.htm>

“Macromolecules” Olemiss University, n.d.Web. 26 Feb. 2017 < http://www.olemiss.edu/courses/bisc102/macromol.html>

“Nucleic Acids Encode Genetic Information in Their Nucleotide Sequence” Biology How Life Works,n.d.Web.26 Feb.2017 < https://reg.macmillanhighered.com/Account/Unauthenticated?>

Leeza-Marie Williams

Learning Summation

What is biology?

According to the Norwegian University of Science and Technology, the word biology is derived from the Greek words bios and logos which means life and study, respectively. Simply, biology can be defined as the science of life and living organisms. An organism is a living entity consisting of one cell like bacteria, or several cells such as animals, plants and fungi.

While the definition of biology appears straightforward, biological science can range from the study of molecular mechanisms in cells, to the classification and behavior of organisms, and to how species evolve and interact between ecosystems.

Furthermore, Biology often overlaps with other sciences, for example, biochemistry and toxicology with biology, chemistry, medicine, and even astronomy, to name a few. Biology also interacts with social sciences with regards to the administration of biological resources, developmental biology, biogeography, evolutionary psychology and ethics.

Properties of water

As stated by the website Owlcation, water consists of five properties which are as followed: an attraction to polar molecules, a high-specific heat, a high heat of vaporization, a lower density of ice, and a high polarity.

Firstly, waters ability to attract to polar molecules can be attributed to cohesion and adhesion. Cohesion refers to water’s attraction to other water molecules, whereby, the hydrogen bonds in water hold other water molecules together. Because of water’s cohesiveness, water in its liquid state has surface tension which allows for insects, such as Water Striders, to walk on water. Furthermore, water’s cohesiveness enables it to maintain its liquid state instead of a gas state at moderate temperatures. Adhesion is water’s attraction between molecules of a different substance in which it is able to form hydrogen bonds. Due to water’s adhesiveness, capillary action occurs.

Secondly, high-specific heat is the amount of energy that is absorbed or lost by one gram of a substance to change the temperature by 1 degree Celsius. Since water molecules form many hydrogen bonds between one another, plenty of energy is needed to break down those bonds. Breaking the bonds allows individual water molecules to move freely about and have a higher temperature. If there are many individual water molecules moving about, then, they will create more friction and more heat, which means a higher temperature. The hydrogen bonds between water molecules absorb the heat when they break and release heat when they form, which minimizes temperature changes. Water helps maintain a moderate temperature of organisms and environments.

Thirdly, water’s high heat of vaporization is the other property responsible for its ability to moderate temperature. It refers to the amount of heat energy needed to change a gram of liquid into gas. Just like the properties of having a high specific heat, water also needs an ample amount of energy in order to break down the hydrogen bonds which causes a cooling effect.

Fourthly, when observing water’s density at cooler temperatures, the hydrogen bonds of water molecules form ice crystals because they are more stable and will maintain its crystal-like shape. Ice is less dense than water because of the hydrogen bonds being spaced out and being relatively apart. The low density is what allows icebergs to float and is the reason why only the top part of lakes are frozen.

Fifthly, water is a polar molecule that has a high level of polarity and attraction to ions and other polar molecules. As we already know, water can form hydrogen bonds, which make it a powerful solvent. Water molecules are attracted to other molecules that contain a full charge, like an ion, a partial charge, or polar. Salt is a polar compound that dissolves in water. Water molecules surround the salt molecules and separate sodium from the chloride by forming hydration shells around those two individual ions.

Works Cited:

“What Is Biology at NTNU?” Norwegian University of Science and Technology, n.d. Web. 25 Feb. 2017.

<https://www.ntnu.edu/biology/about-us/what-is-biology>.

“5 Properties of Water.” Owlcation, 13 June 2016. Web. 25 Feb. 2017. <https://owlcation.com/stem/5-

Properties-of-Water>.