You might be asking yourself, what exactly is glycosylation? Glycosylation is the adding of a glycoside (sugar) to a protein. This process occurs in the endoplasmic reticulum (ER), while the polypeptide is still being biosynthesized and is partially unfolded. This suggests that glycosylation plays a role in protein folding and stability. Glycosylation is one of the most common and important protein modifications.
(The image above shows O-linked glycosylation)
This article basically talks about the process of glycosylation and its glycoproteins. A glycoprotein is formed when a membrane associated carbohydrate is exclusively in the form of oliogsaccharides covalently attached to proteins. Glycoproteins consist of proteins covalently linked to a carbohydrate.
This article explains how scientists have designed a special enzyme that rids the process of human immunodeficiency virus (HIV), which inserts its genetic material into host DNA. When testing the mutated enzyme (Tre recombinase) on cultured human tissue, it snipped HIV DNA out of chromosomes. Scientists suggest that treatment with similar enzymes could potentially remove infected cells of the virus.
(This picture shows the modified a bacterial enzyme, which is shown as red scissors, that will remove HIV DNA, gray double helix, from infected cells)
First off, why is HIV harmful? Well the articles states that HIV infects the immune system's disease-killing T cells; it does this by converting its genome into double-stranded DNA and using the enzyme integrase to embed that DNA into a T cell's genome. Scientists have adapted bacterial DNA-cutting enzymes for adding and subtracting genes from mice and other multicelled organisms. From this creation, they speculate that they could reverse the process of HIV.
This article basically talks about what type of diseases can occur if proteins are folded defectively or if the cell’s quality control apparatus fails. In order for proteins to properly function, all of its necessary components must be correctly compartmentalized. This article also presents ways for therapeutic intervention.
One type of disease that can occur from conformational errors is cataracts. Conformational diseases are disorders in which the structure of the fundamental protein mutates, leading to the aggregation and deposition of abnormal proteins. Cataracts is when there is clouding in the lens of your eye.
The major structural protein in the lens is crystallins, which form complex protein-protein interactions with each other. There are several types of crystallins, such as α-Crystallins, which act as molecular chaperones to prevent the aggregation and precipitation of the crystallins. β-Crystallins contain aggregates that range in size from dimers to octomers. A major lens protein is αB-Crystallin because it has a structural role in maintaining the transparency of the lens and confers protection to cells against thermal, osmotic, and oxidative damages.
αB-Crystallin's non-lenticular function is to bind irreversibly to denaturing proteins, thus preventing the formation of large light-scattering aggregates. This function is significantly important in the lens because it prevents cataracts from occurring. Proteins are prone to denaturation and aggregation and are subjected to osmotic and oxidative stresses over the lifetime of the organism.
(The image above shows two neurons; one is a healthy neuron and the other a neuron affected by TSD. In the healthy neuron (top) lysosomes act as the waste processing center of the cell. In Tay-Sachs disease, genetic deficiencies hamper with lysosome enzymes that break down fatty cell products, which build up and destroy the cell.)
You might be asking yourself what exactly is Tay-Sachs disease? Well Tay-Sachs disease (TSD) is a fatal genetic (runs through the family) lipid storage disorder in which harmful quantities of a fatty substance called ganglioside GM2 build up in tissues and nerve cells in the brain. This condition is caused by the absence of a vital enzyme, beta-hexosaminidase A.
Tay-Sachs disease occurs in infants and progressively damages the central nervous system as they age. A baby with TSD appears to develop normally for the first few months, but then there is a relentless deterioration of mental and physical abilities. The child gradually becomes blind, is unable to swallow, and has inefficient pulmonary function. Unfortunately, there is no cure or treatment for TSD and the average life expectancy is 3-5 years of age.
This condition is particularly high among people from Eastern European and Jewish descent. Patients and carriers of TSD can be identified by a receiving a blood test to measure beta-hexosaminidase A activity. In order to have an affected child, both parents must carry the mutated gene. In such instances, there is a 25% chance with each pregnancy that the child will be affected with Tay-Sachs disease.
In this blog post I will only be discussing proteins and nucleic acids. But don't fret! I will explain the structure of protein, nucleotides, and the difference between DNA and RNA.
First off....what is a protein? Well proteins are polymers that are found in ALL cells and play crucial roles in most processes of life. Proteins have various functions throughout the body. However, the function of a certain protein is determined by its structure. Some of these proteins include (not all are listed below):
Antibodies: involved in defending the body from antigens (foreign invaders); destroy antigens by immobilizing them so that they can be destroyed by white blood cells
Enzymes: speed up biochemical reactions (often referred to as catalysts)
Structural: fibrous, stringy proteins that provide support
Hormones: messenger proteins which help to coordinate certain bodily activities by sending signals between cells
Storage: store amino acids
The structure of proteins is viewed through four levels: primary, secondary, tertiary, quaternary. These levels basically break down the folding of a protein into a 3-Dimensional structure. The protein structures are very important because they DETERMINE the FUNCTION of the protein!
Primary Structure is referred to as the sequence of amino acids. Proteins are large polypeptides of defined amino acid sequence. The sequence of amino acids in each protein is determined by the gene that encodes it. The gene is transcribed into a messenger RNA (mRNA) and the mRNA is translated into a protein by the ribosome.
Secondary Structure is a local regularly occuring structure that is mainly formed through hydrogen bonds between backbone atoms. There are two types of basic secondary structures: alpha helix and beta-pleated sheets. Alpha helix and beta-pleated sheets determine the protein's characteristics and are preferably located at the core of the protein.
Tertiary Structure is the 3-D shape of a single polypeptide. It includes all secondary structures and any interactions involving amino acid side chains. For single polypeptide chains, this is the final level of structure.
Quaternary Structure involves the association of two or more polypeptide chains into a multi-subunit structure. These types of proteins are called multimeric proteins, while individual polypeptides are called protein subunits.
Nucleic acids are biological molecules essential for life because they are responsible for the storage, expression, and transmission of genetic information. Nucleic acids are broken down into two classes: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA molecules store genetic information coded in the sequence of their monomer building blocks. Molecules of RNA are involved in decoding the info from DNA. They decode this information into instructions for linking together a specific sequence of amino acids to form a polypeptide chain.
Both DNA and RNA are polymers that consist of linear sequences of repeating monomers. A single monomer is a nucleotide, and is made up of a phosphate group, five-carbon sugar (ribose or deoxyribose), and a single/double ring of carbon and nitrogen atoms (known as a base).
DNA forms a double helix, consisting of two strands of nucleotides coiled around each other. The nucleotides in DNA have deoxyribose and are presented in four different ways. It is composed of the purine bases, adenine (A) and guanine (G), and the pyrimidine bases, cytosine (C) and thymine (T). The purine bases have double rings of carbon and nitrogen, while the pyridine bases have a single ring.
RNA differs slightly from DNA because it has a single strand of nucleotide rather than a double. Unlike DNA the sugar in RNA has ribose and the pyrimidine base of thymine is replaced. In RNA this base is the pyrimidine base of uracil (U); the other bases remain the same in both nucleic acids. There are different forms of RNA, including messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). But these types of RNA shall be discussed in a later chapter (so you will just have to wait and see what they really are)!
II. Useful Materials:
This video is a song about functional groups. It differentiates between the different types of functional groups. I think the song is super catchy and fun, meaning you should listen too it! Trust me, you will not regret it!
In my previous blog post, I posted a video from this guy, who explained the chemical basis of life. Well now I found another video from the same person. In this video he is basically giving a brief overview of chapter three. He talks about isomers, functional groups, proteins, and a lot more! I enjoy watching his videos because they are very useful and also helps me study as well.
This article from Pubmed talks about how to treat dyskinesias, which is caused from levodopa. Levodopa (L-Dopa) is an amino acid that is the metabolic precursor of dopamine, and is converted in the brain to dopamine to treat Parkinson's disease. A side effect of L-Dopa is dyskinesia (the inability to control muscles). Dyskinesia can occur in several forms; most often uncontrolled flailing of the arms and legs or chorea, rapid motions that can affect the limbs, face, tongue, mouth, and neck. Anyways, this article basically explains the common surgical targets used to treat LID and the appropriate selection of patients with LID for surgery.
In 1961 a drug called thalidomide was discontinued for several reasons. Thalidomide was a drug prescribed for pregnant women who had morning sickness. It was discovered that this drug causing severe deformities in developing fetuses. About 10,000 children, worldwide were affected from thalidomide!
This article is basically about the reasons why thalidomide caused those
problems for the fetus. The primary cause for thalidomide's effect to cause fetal malformations is due to a protein called cereblon. Researchers from the Tokyo Institute of Technology proved this reason by using zebra fish and chick embryos. They presented that thalidomide binds to cereblon, causing pectoral fin mutations in the zebra fish and complete absence of forelimbs in the chicks. The researchers concluded that thalidomide exerts these effects by inhibiting cereblon function, because overproduction of cereblon prevented the malformations. However, the normal function of cereblon is still unknown.
(The picture above is the chemical structure of thalidomide: 2-(2,6-Dioxo-3-piperidinyl)-
Have you ever wondered how we are made up? Past our outer epidermis we, and all other living organisms are composed of matter. Matter is anything that has mass and occupies space. Within our matter, there are atoms, which are the basic building blocks of matter. I cannot even count how many atoms there are in the human body; lets just say there are a lot!
Atoms consist of protons and neutrons, which are located in the center of the atom called the nucleus. Atoms also have electrons, which are not confined to a single space in the atom; these regions are called orbitals that occupy energy shells. Protons have a positive charge, while electrons have a negative charge and the neutrons are neutral. The protons and electrons create the atom because their opposite charges attract with one another.
Depending on the atom, some can have one or more shells. The first shell of an atom can hold two electrons and every shell after the first can hold up to eight electrons. The electrons in the outermost shell are called valence electrons. Some atoms can easily share electrons, while others have a more difficult time. Electronegativity is the chemical property that describes the tendency of an atom to attract electrons.
There are many types of atoms and each specific type of atom is called an element. You might be asking what elements are we made of? Well the human body is mainly composed of four elements: oxygen, carbon, hydrogen, and nitrogen! There are other elements that humans are composed of but these are the four primary elements in our body. Each element is assigned a certain atomic number(which is the same number as the number of protons in that atom) to recognize it from other elements. Then there is the atomic mass, which is the average mass of atoms in an element.
When a molecule(two or more atoms bonded together) contains two or more different elements it is called a compound. For example, when two hydrogen atoms bond with an oxygen atom it forms...WATER (H2O)!!!
Atoms can form several types of bonds, depending upon the specific types of atoms involved. NOTE: These are not all of the types of bonds that atoms can make, just some of them.
Covalent Bond: bond in which one or more pairs of electrons are shared by two atoms
Polar Covalent Bond: bond in which a pair of electrons is shared between two atoms, but the pair is held more closely by one atom
Non-polar Covalent Bond: bond in which a pair of electrons is shared equallybetween two atoms
Double Bond: bond in which atoms share two pairs of electrons
Hydrogen Bond: bond in which a hydrogen atom of one molecule is attracted to an electronegative atom
Ionic Bond: bond between two ions(atoms with an electric charge) with opposite charge
Now that I covered mostly everything about atoms and molecules, we can talk about the liquid properties of living organisms, such as WATER! Have you ever wondered what life would be like without water?!?! Let me tell you this, it would not be fun! Since the human body is composed mostly of water (60-70%), even a few days without it would be crucial.
A solution is a homogeneous mixture composed of two or more substances. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent for chemical reactions in all living organisms is... you guessed it, water!
Depending on the type of bond of molecules, they can be either hydrophobic(water-fearing) or hydrophilic(water-loving). Molecules that have ionic/polar covalent bonds are hydrophilic, while molecules that have non-polar covalent bonds are hydrophobic.
A substance that is dissolved in water can either release or absorb hydrogen ions. When a substance releases hydrogen ions it is called an acid. When a substance absorbs hydrogen ions it is called a base. A substance's concentration of H+ is determined on a pH scale, which measures the acidity or basicity of a solution. The lower the pH the more acidic the concentration is; the higher the pH the more alkaline (basic) the concentration is.
Anyways, this is pretty much everything that we covered in class for chapter two. And remember, for every living organism there is always a CHEMICAL BASIS for life!
II. Useful Materials:
This video is about a science teacher going over the chemical basis of life. He goes over pretty much everything covered in chapter two of our biology textbook. I think this video is very helpful because not only is he talking you through the chapter but there are also pictures and diagrams to help you better understand. He even teaches you some helpful ways to remember important facts. Overall, this video was a useful material to study from, even teaching me new things as well.
When it comes to studying through each chapter, I like to use flash cards as a study technique. Quizlet is a website that has online flash cards that you can use to study. You can even print out the flash cards so you can take them and study where ever you go! Each flash card gives you a definition/question and the answer. I think this is a helpful website if you need help remembering definitions or just want to quiz yourself.
As I posted on my blog before, this article talks about how scientists have been researching how isotopes in someone's hair can track where that person may be living.
Scientists have been researching how isotopes in someone's hair can track where that person may be living. Water makes up more than half of an adult human's body weight; through several metabolic processes, some of that water is broken apart and the basic atoms are incorporated into body tissues, fingernails, and hair. Hair consists of keratin, which is a stable protein, meaning that most of its hydrogen and oxygen atoms are not lost to the environment.
(Researchers have generated maps that show the predicted average hydrogen (top map) and oxygen (bottom map) isotope levels in human hair across the United States.)
According to James R. Ehleringer, an environmental chemist at the University of Utah, any variations in the concentrations of hydrogen and oxygen isotopes in water should be recorded in the hair because much of the water that people consume comes from the area where they reside. Researchers suggest that about 27% of the hair's hydrogen and 35% of its oxygen come from local tap water. Overall, about 86% of the hair samples have hydrogen and oxygen isotopes that derive from the isotopic designation of the local water. However, definite proof of a person's region of residence may not always come from concentrations of hydrogen and oxygen because the concentrations may represent the isotopic signature of groundwater in several regions. Regardless, this brand of research may not always have clear evidence but it will reduce the amount of questions to help you eventually find the answer.
You might be asking yourself, what exactly is glycosylation? Glycosylation is the adding of a glycoside (sugar) to a protein. This process occurs in the endoplasmic reticulum (ER), while the polypeptide is still being biosynthesized and is partially unfolded. This suggests that glycosylation plays a role in protein folding and stability. Glycosylation is one of the most common and important protein modifications. 
