LIPID IN LIFE

Fats can be classified into 3 types namely saturated fats, unsaturated fats, and trans fats.

Each has a chemical structure and different shapes. At room temperature, saturated fats and trans fats such as butter is solid whereas unsaturated fats are usually liquid, such as vegetable oil.

The three types of fats also have different effects on cholesterol levels in the body.

Properties of saturated fats and trans fats bring much LDL cholesterol in the blood that cause plaque stick to the blood vessels that eventually disturb the circulatory system and supplies the oxygen in the body.

Therefore, both types of fats are often called bad fats. Unlike the saturated fats that carries less cholesterol and fat in the blood. Now let us identify each type of fat.
 

Saturated Fat

Saturated fat is easily recognizable from its waxy solid and are found in animal products such as red meat, butter, or milk. In vegetable material, saturated fats can be found in coconut oil and palm oil.

Saturated fat has properties that can disturb the body which can thicken the blood so easy to stick to the walls of blood vessels due to clot which of course can disrupt blood circulation in the body.

Saturated fats are also easily attached to the walls of blood vessels and can lead to hardening of the arteries. Due to impaired blood circulation and oxygen, other diseases such as heart disease, high blood pressure, and stroke often attack people who love to eat foods high in saturated fat.
 

Unsaturated Fats

This type of fat is usually liquid at room temperature, but can turn into a solid if stored in the refrigerator. Commonly found in plant materials such as vegetable oils (olive oil, sunflower oil, sesame oil, soybean oil, nuts) and avocado. Also found in fish, fisheries.

This type of fat known as good fats because it is a good chance that its cholesterol content of LDL less than that contained in saturated fats. According to experts this type of fat can increase the antibodies in the body, lowering LDL cholesterol, and lower the risk of heart attack.

Unsaturated fats can be categorized into two types namely monounsaturated fats (mono-unsaturated fatty acids) and polyunsaturated fats (poly-unsaturated fatty acids). Monounsaturated fatty acids can be found in olive oil, peanut oil, and canola oil, avocados, and most nuts. Meanwhile, polyunsaturated fatty acids can be found in corn oil, sunflower seed oil, and soybean oil.

Unsaturated fatty acids have carbon double bond atoms are easily decompose and react with other compounds, to obtain a stable composition in the form of saturated fatty acids. The more the number of double bonds that (poly-unsaturated), the easier it is to react / change the oil.

Oils with unsaturated fatty acids better consumed directly without being processed / heated first. When used for cooking, can be used for stir-fry cooking because heat does not last long. If used for frying, unsaturated fatty acids it is easier to form trans fats are dangerous because it is easy to react. In addition, their use should not exceed 4 grams a day.
 

Trans Fats

Trans fats come from unsaturated fats undergo partial hydrogenation compaction techniques that cause changes in the chemical bonding configuration of the fat. Consequently, unsaturated fats are generally liquid, a solid and more durable.

The real goal is to help the vegetable oils that are unsaturated become more stable so it is more resistant to rancidity reactions and remain solid at room temperature.

Although derived from unsaturated fats that are good, trans fat is changed in character since the last hydrogenation. This type of fat to be no different because of its saturated fat increases LDL cholesterol and lower LDL cholesterol. The product of one form of trans fat margarine widely used in daily life.

PROTEIN AS A TRANSPORT TOOL IN LIFE

Transport Proteins

Carrier Molecules

The next broad category of proteins we will consider are the carrier molecules or transport proteins. These transport proteins are often globular proteins. They are generally tightly packed with polar side groups on the outside to enhance their solubility in water. They typically have nonpolar side groups folded to the inside to keep water from getting in and unfolding them.
Serum albumin is one example. It transports water-insoluble lipids in the bloodstream.

Hemoglobin

Hemoglobin is another example. It carries oxygen from the lungs to the tissue. Myoglobin performs a similar function in muscle tissue, taking oxygen from the hemoglobin in the blood and storing it or carrying it around until needed by the muscle cells.
Hemoglobin and myoglobin also have similar structures. Myoglobin contains 151 amino acid residues plus a heme group to bond to oxygen. Hemoglobin has four similar chains, two with 141 residues and a heme group and two with 146 residues and a heme group. The molecular weight of hemoglobin is about 64,500 and can carry four oxygen molecules.
It is important that hemoglobin can bond to oxygen under certain conditions. But it is equally important that hemoglobin can release oxygen under other conditions. The ability of hemoglobin to bind oxygen is sensitive to several factors. They include pH, temperature, concentrations of O₂ and CO₂, and even the number of oxygen molecules already bound. It seems that when oxygen binds to hemoglobin, the structure of the hemoglobin changes slightly in a way that makes it better at binding to more oxygen, thus enhancing its ability to carry more oxygen.

Oxygen Binding Curve

This graph relates the ability of hemoglobin to bind oxygen to the concentration or the partial pressure of oxygen. (It is also found in Example 9 in your workbook where you will be able to read the details of the labeling on the axes.) The vertical axis shows the fraction or percentage of hemoglobin molecules that are saturated with oxygen. The horizontal axis shows the partial pressure of oxygen gas, a measure of how much oxygen is available in the air.
The partial pressure as used here is not a direct measure of the concentration of the oxygen in the blood. Instead, it refers to the aqueous concentration of oxygen that would be in equilibrium with gaseous oxygen having the stated partial pressure. If that makes no sense to you, don't worry about it. But if you wondered how a solution can have a partial pressure, it doesn't, and that is the explanation.
When the partial pressure of oxygen is high, virtually all of the hemoglobin molecules have oxygen molecules bound to them. The partial pressure of oxygen in the lungs is about 100 mm Hg (shown by the pencil), which is in the region just to the right of the steep portion of the curve.
When the partial pressure of oxygen is very low, virtually none of the hemoglobin molecules have oxygen molecules attached.
In the region near the steep part of the curve (at about 40 mm Hg) a very small change in the partial pressure of oxygen will cause a very large change in the fraction of hemoglobin molecules that bind oxygen. Compare the values on one side of the pencil to the values on the other.

The partial pressure of the oxygen in the body tissues is about 40 mm Hg or less, which is partway down the steep part of the graph. Thus, in the lungs, virtually all of the hemoglobin bonds to oxygen and the blood becomes rich in oxygen, turning a characteristic red color. When the blood reaches active body tissue, the hemoglobin releases a fair amount of its oxygen because of the low partial pressure of oxygen in the tissue and it turns the blue color characteristic of venous blood. Hemoglobin generally retains about half to three-quarters of its oxygen in venous blood, rather than giving it all to the cells under normal conditions. The value of this is that some reserve oxygen is available from the hemoglobin when strenuous exercise depletes the cellular oxygen to even lower partial pressures.
Hemoglobin can be used as an example to point out how important the conformation of a protein is. The shape and the functional groups must be such that they will attract oxygen molecules, but not nitrogen molecules (which are four times more abundant in air than are oxygen molecules), and not water molecules, and not sugar molecules, and so on. Ironically, another molecule, carbon monoxide, will bind to hemoglobin 200 times more readily than oxygen. That makes carbon monoxide very dangerous. Not only does the hemoglobin that has bonded to carbon monoxide not have oxygen to give to the cells, it cannot easily get rid of the carbon monoxide to be able to get some oxygen.

Sickle Cell Hemoglobin

The disease sickle cell anemia points out another important aspect of protein structure. As you know, the primary structure of a protein determines the secondary structure which determines the tertiary structure and the quaternary structure, which in turn determines the function of the protein.
In sickle cell hemoglobin the sixth amino acid residue is valine instead of glutamic acid.
That's it. That's the difference.
The consequence is that when the hemoglobin releases its oxygen, it reacts with other such proteins in a way that causes the shape of red blood cells to change. The red blood cells change to a sickled shape which does not readily pass through capillaries and thus causes a number of problems.

Linus Pauling, who helped uncover the alpha-helix primary structure of proteins, refers to diseases such as this as "molecular diseases." The change of a single amino acid in a protein, by the way, does not always have such a drastic effect on the function of the protein.

Cytochromes

Another quite different group of carrier molecules is the group known as the cytochromes. These are the electron carrier proteins that operate in the electron transport chain which is part of the respiration process. They carry electrons from the hydrogen atoms freed in the citric acid cycle to waiting oxygen molecules. At the end of that process, the hydrogen and oxygen combine to form H₂O. The energy released in this series of reactions is stored by using it to convert ADP to ATP.

"Inhibition" of Carrier Proteins

Carrier proteins can be affected by what can be called competitive inhibition.
For example, hemoglobin is a carrier protein that transports oxygen from the lungs to muscle tissue and other cells. However, carbon monoxide molecules compete with oxygen for the binding sites on the hemoglobin molecule. If they are present in high enough concentration, they prevent sufficient oxygen from getting to the tissues and the organism dies.
Cyanide is another poison that affects respiration. It acts by inhibiting the cytochrome proteins that are an integral part of the electron transport system in respiration.

ORGANIC COMPOUNDS OF LIFE

Chemical compounds of living things are known as organic compounds because of their association with the organism. Organic compounds, which are compounds associated with life processes, is the subject of organic chemistry. Among the various types of organic compounds, four main categories were found in all living things: carbohydrates, proteins, and nucleic acids.
The four compounds have been discussed in my previous blog post entitled macromolecules. In a blog post ORGANIC COMPOUNDS OF LIFE I am talking about the biosynthesis of proteins.

Following is a discussion of protein biosynthesis

PROTEIN

Protein (the root of the Greek word protos meaning "most important") are complex organic compounds of high molecular weight which are polymers of amino acid monomers are connected to each other by peptide bonds. Protein molecules containing carbon, hydrogen, oxygen, nitrogen and sometimes sulfur and phosphorus.
Protein is one of the bio-macromolecules essential role in living things. Every cell in our body contains protein, including the skin, bones, muscles, nails, hair, saliva, blood, hormones, and enzymes. In most tissues of the body, protein is the second largest component of the water. An estimated 50% of the dry weight of cells in the liver tissue and consists of meat protein. While the woven around 20% fresh meat.
Protein is found in many kinds of food, ranging from nuts, seeds, meat, poultry, seafood, beef cattle, to dairy products. Fruits and vegetables provide little protein. The selection of protein sources should be wise, because a lot of high protein foods are also high in fat and cholesterol. The function of the protein itself can be broadly divided into two major groups, namely as a structural material and as a machine that works on the molecular level.
Several structural proteins, fibrous proteins, serves as a protective, for example, a and b-keratin found in skin, hair, and nails. While there are other structural proteins that function as an adhesive, such as collagen. Protein may play functions as a structural material because, like other polymers, proteins have long chains and may also undergo cross-linking and others. Additionally protein can also serve as a biocatalyst for the chemical reactions in the system of living things. This macromolecule metabolic control pathways and complex time to maintain the viability of an organism. A metabolic system would be disturbed if the biocatalyst who played in it were damaged.

PROTEIN SYNTHESIS

The stages in the synthesis of proteins, can be divided into two, namely transcription and translation. Both transcription and translation, each divided further divided into three phases, namely initiation, elongation, and termination.
Transcription
Transcription is the synthesis of RNA using DNA as a template. DNA serves as the architect who designed the pattern of proteins while RNA preparation will be the ambassador as the carrier of genetic information in the form of code or the genetic code codons.
RNA transcription results one is m RNA that would serve as a template protein. Will set up a series of bases of mRNA codons (3 bases is a series that co-exist on a single mRNA that encode amino acids). Genetic Message mRNA translated into a series of amino acids based on the genetic code.
• Things to know in the transcription process:
o Promoter site, is the starting point for the process of transcription in which promoter is a nucleotide sequence that is recognized by transcriptase / RNA polymerase enzyme and a stick and start the process of transcription. On the promoter encountered three important points relating to the process of transcription, namely:
- Initial cue point, an area that shows sigma factor. That tells us that there are pieces of DNA downstream to be transcribed busi
- The area of ​​attachment, found somewhere downstream area sticking transcriptase enzyme composed of seven base pairs of the consensus sequence are sometimes often called Pribnow box (base pairs AT) AT-rich ps bs easier denatured (easier to open the double helix strands) than ps bs GC.
- The starting point of transcription, DNA is first transcribed nucleotides into RNA nucleotides. At this sticking point transkripstase be closely associated with DNA and Ribonuleotide will get to pair up with thread mold. The starting point is usually (90%) is a base Purines
• The enzyme RNA polymerase, is often referred to as RNA transcriptase to distinguish RNA in charge Replikasi.Enzim process is often used as a model organism. This enzyme is composed of a complex structure (composed of + 15 subunit - subunit) called Holoenzim active. Holoenzim consists of the core enzyme and the factors σ (sigma).
- Enzymes core: catalyzes the synthesis of RNA
- Factor σ (sigma): Recognizing early signs transcription template DNA found on another thread.
- Sub units - sub-units are not united by covalent bonds but with the secondary bond
• Antisense (-) strand. DNA is a double strand in the transcription of the DNA thread would be a mold / template. Meanwhile, the other thread will be a companion thread (thread antipararel) for Print thread. Nucleotide sequences of RNA synthesized is anti-parallel thread to thread with thread mold or companion. Thread mold called Antisense strand (-). Threads that are not used as a mold called Antisense strand (+).
• Terminator. Nucleotide sequences of DNA which suggests that transcription must end. All the terminator on prokaryote containing polidrom series, just before the point of closing. Polidrom are two sets of couples mounted inverted nucleotide by nucleotide sequences are separated by a small distance. The point of the cover is AT base pairs. Terminator will produce RNA with structures at the ends form hairpin formed by the pair between nucleotides repeated antipararel reversed. Besides, it also formed thread / chain poly U. Thread hairpin serves to reduce speed or stop working before the end of the transcription transcriptase.
• Terminology / Stage transcription
o Initiation
o elongation
o Termination
1. Initiation
The process of attachment of RNA polymerase to the promoter complex site.
2. Elongation
After the initiation process subunit σ (sigma factor) will break away and RNA synthesis followed by Core enzymes (enzymes that do not contain a factor sigma) using thread mold towards 51-31 and requires four kinds of nucleosides (ribonukleosida 51trifosfat) are: r-ATP, r-CTP, GTP-r, r-UTP.
3. Termination
Transcription lasted until the invention of signs to stop. Signs that simple termination is part of a sequence of DNA bases called palidrome GC and followed by a section of DNA rich in AT bases. When the genome does not contain palidrome then use protein Rho termination.
 Translating
Translation is the process of translating the genetic code by tRNA to the amino acid sequence. Translations into three stages, namely initiation, elongation, and termination. All of these stages require protein factors which help the mRNA, tRNA, and the ribosome during translation. Initiation and elongation of the polypeptide chain also requires some energy. This energy is provided by GTP (guanosine triphosphat), a molecule similar to ATP.
1. Initiation
The initiation phase occurs when the three components, namely mRNA, a tRNA containing the first amino acid of the polypeptide, and the two ribosomal subunits. mRNA from the nucleus to the cytoplasm out in coming by the ribosome, and mRNA into the "gap" in the ribosome. When mRNAmasuk to the ribosome, the ribosome "reads" incoming codon. Readings were taken for each of three base sequence until completed. For the record ribosomes that comes to reading codons are usually not just one, but multiple ribosomes known as polisom form a series of similar skewers, where tusuknya is "mRNA" and the meat is "ribosomnya".
Thus, the codon reading can take place sequentially. When I read the ribosome codon (eg kodonnya AUG), tRNA anticodon UAC and carrying the amino acid methionine to come. tRNA into the ribosome gap. Ribosomes are here serves to facilitate the specific attachment between tRNA anticodon with mRNA codons during protein synthesis. Ribosomal subunits constructed by protein-protein and ribosomal RNA molecules.

2. Elongation
In the elongation phase of translation, amino acids are added one by one in the first amino acid (methionine). The ribosome continues to shift so that more incoming mRNA, codon II to read. For example, codon II UCA, which immediately translated by tRNA codons AGU means carrying the amino acid serine. In the ribosome, which first entered methionine coupled with serine dipeptide form.
The ribosome continues to shift, reading codons III. Suppose III GAG codon, immediately translated by the CUC anticodon carrying the amino acid glycine. tRNA into the ribosome. Coupled with the amino acid glycine dipeptide that has been formed to form tripeptida. So forth the process of reading the genetic code took place in the ribosome, which translates into a form of amino acids to be assembled into a polypeptide.
MRNA codon on the ribosome to form hydrogen bonds with the anticodon of tRNA molecules had entered carrying the correct amino acid. MRNA molecules that have been releasing amino acids will return to the cytoplasm to reproduce the transport of amino acids. RRNA molecules of large ribosomal subunits function as enzymes, which catalyze the formation of peptide bonds that combine a polypeptide that extends to the newly arrived amino acids. 

   

3. Termination
The final stage is the translation termination. Elongation continues until the ribosome reaches a stop codon. Base triplet stop codons are UAA, UAG, and UGA. No stop codon codes for an amino acid but acts signal to stop translation. Polypeptides formed then "processed" into proteins.