Glycolysis

The above shows an important cycle that occurs in all humans. It is vital for life and if it did not occur then we would all die. When glycolysis occurs, it is that it extracts energy from glucose and converts it into pyruvate with the production of a relatively small amount of ATP. Glycolysis can be carried out anerobically (in the absence of oxygen) and is thus an especially important pathway for organisms that can ferment sugars. For example, glycolysis is the pathway utilized by yeast to produce the alcohol found in beer.

Glycolysis occurs in the cytosol.

Video Review 2

This video deals with the endosymbiotic theory and it explains it using pictures with each cell being a character. It is a fun way in which to learn the concept of the endosymbiotic theory but it is not as descriptive as it should be. This video makes it seem that the only evidence of this theory is in DNA when in reality DNA is not the only explanation that can be given. Also later on in the video it is said when the cells which depicts mitochondria and chloroplasts enters the larger cell they can become multicellular and form plants and animals. Now this is not entirely true because if it were true then animals would possess chloroplasts also. However we all know that this is not the case. I would not recommend using this video as a reliable source of information but it is somewhat useful in understanding a very basic concept of this theory.

Video Review 1

This video on the fates of pyruvate was made by my biochemistry teacher, Jason Matthew, and I thought I should at least review one of his videos. The fates of pyruvate is part of the topic glycolysis and is a topic that had given me some difficulty. However after watching this video the three fates of pyruvate along with the reactions of converting pyruvate to ethanol, lactate or acetal-CoA can be learnt very easily. This video explains everything mentioned before at level one studies sufficiently. The video is detailed but it is not to detailed to the extent where viewers can become lost in what is being said. In other words, this video is so simple that a person who knows nothing about the fates of pyruvate could watch this video and at least have some understanding of pyruvate’s three fates. Even though this video is very informative it mainly appeals to year one students and any further information on the topic is not discussed here as year one students are not required to know more than what is stated here. This makes it useful to year one students but for students who would like to know more on the topic, at the end of the video further information can be briefly given on what is to be learnt at further levels to appeal to other students above year 1. If this was done then this video would appeal to a much wider audience and more students would be educated on the topic to a comfortable extent.

PUBLISHED PAPER 2: PANCRIATIC DYSFUNCTION AND PROTEIN MALNUTRITION

Proteins are made up of chains of amino acids known as polypeptides and are essential for proper nutrition of the human body. However, what if one’s diet lacked proteins severely? What would this result in? The answer is simply this protein deficiency would eventually lead to a dysfunction in the functioning of the pancreas. But how would this affect the body and what about this dysfunction is induced by this lack of proteins?

 

Now what exactly is the purpose of the pancreas? The pancreas is a vital organ in the body that performs two functions, an exocrine function and an endocrine function. The exocrine glands of the pancreas produce enzymes important to digestion which aid in the digestion of fats, carbohydrates and proteins. The endocrine function of the pancreas consists of the islet cells that make and release hormones directly into the bloodstream. The two main hormones that are put into the bloodstream are insulin, which lowers blood sugar, and glucagon, which raises blood sugar. Maintaining this blood sugar level is a very important job of the pancreas.

Now that we understand how important the pancreas is imagine what would happen if this organ was dysfunctional. This could cause serious harm to a person’s health if a dysfunction of the pancreas occurs. This is where proteins come in as their deficiency seems to be linked to pancreatic dysfunction.

 

IVAN PAVLOV

The effect of dietary protein on pancreatic function in animals was investigated as early as the end of the nineteenth century by the scientist, Ivan Pavlov, who noted that diet influences pancreatic secretion. The first report published on the topic of the long term effects of protein deficiency in humans described a syndrome known as kwashiorkor. This syndrome caused vomiting and undigested food in stool at large amounts in individuals that had an adequate calorie intake which lacked protein in the diet. An additional study showed that kwashiorkor might be resultant from pancreatic dysfunction.

In a study on animals, the enzyme kinase mTOR which is able to regulate cell growth by integrating diverse nutritional and mitogenic signals and is located in the pancreas was used to aid in this investigation. The phosphorylation state of a upper target (with respect to the diagram above) kinase of mTOR, AKT, as well as two lower targets of mTOR (with respect to the diagram above) which are S6K1, the ribosomal protein, and 4E binding protein 1 (4E-BP1 which is the eukaryotic initiation factor) was made to determine whether changes in dietary protein intake had any effect on mTOR signalling in the pancreas.  This study showed that the phosphorylation of AKT Ser⁴⁷³, an indicator of AKT kinase activity, was not affected by a protein deficiency. However, the phosphorylation of S6K1 and 4E-BP1 was decreased to a significant extent in the pancreas of animals (mice) fed protein deficient chow in a comparison over four days.  Therefore this study clearly shows that protein deficiency has an effect that causes a dysfunction in the pancreas. 

In conclusion the proper functioning of the pancreas is compulsory for good health and when it comes down to it pancreatic dysfunction is no laughing matter. I suggest balancing your diet with a sufficient amount of proteins to avoid pancreatic dysfunction and also in order to stay healthy and happy. 

REFERENCES

1. Pavlov IP. The work of digestive glands. C Griffin and Co.; 1910.

2. Williams CD. A nutritional disease of childhood associated with a maize diet. Arch Dis Child.1933;8:423–433

3. Shamji AF, Nghiem P, Schreiber SL. Integration of growth factor and nutrient signaling: implications for cancer biology. Mol Cell. 2003;12:271–80. [PubMed]

4. Arsham AM, Neufeld TP. Thinking globally and acting locally with TOR. Curr Opin Cell Biol.2006;18:589–97. [PubMed]

5. Alessi DR, Andjelkovic M, Caudwell B, Cron P, Morrice N, Cohen P, Hemmings BA. Mechanism of activation of protein kinase B by insulin and IGF-1. Embo J. 1996;15:6541–51. [PMC free article][PubMed]

 

 

 

 

 

PUBLISHED PAPER 1: ENZYMES CURING CANCER

We all know that enzymes are biological catalysts that speed up chemical reactions by providing an alternate pathway with lower activation energy. We also know that enzymes are essential to human life as they speed up chemical reactions in the body that are to slow to occur on their own, meaning human life could not exist without these enzymes. However what if enzymes were more important than just speeding up chemical reactions? What if they were capable of curing diseases, but not just any disease, what if enzymes had the capability of curing cancers? 

The method whereby enzymes can aid in curing cancer is called suicide gene therapy and is relatively new in the anti-cancer approach. It was suggested years ago in 1986 by Moolten. In addition to this, Moolten also proposed what is known now as the bystander effect. This bystander effect is now widely recognized because it is responsible for the success of suicide gene therapy. The definition of the bystander effect states that the effects of cytotoxic effects from transfected cells to non-transfected neighbouring cells such that complete tumor regression is observed when only little tumor cells is transfected successfully.  

This method is preferred as it has minimum harmful effects as compared to standard cancer treatments such as radiation, surgery and chemotherapy.

 

Cancer is caused by mutations which occur in the body and can also be caused by external factors such as ultraviolet light (UV Rays). The method of gene suicide therapy is carried out whereby the suicide gene encodes an enzyme with the unique ability to activate an impotent prodrug. Once the suicide gene is expressed in the transfected cell, an appropriate prodrug is released and is converted into cytotoxic compound by the action of the suicide gene product. 

The above maps out the process of gene suicide therapy and this prove that enzymes are capable of many amazing things besides the catalysis of chemical activities in the human body. So in conclusion appreciate enzymes as they are a major part in keeping you and me alive and don’t forget the value of these spectacular protein molecules.

REFERENCES

1. Relling MV, Rubnitz JE, Rivera GK, et al. High incidence of secondary brain tumours after radiotherapy and antimetabolites. The Lancet. 1999;354(9172):34–9. [PubMed]

2. Kaldor J, Day N, Pettersson F, et al. Leukemia following chemotherapy for ovarian cancer. N Engl J Med. 1990;322(1):1–6. [PubMed]

3. Curtis R, JB, Stovall M, et al. Risk of leukemia after chemotherapy and radiation treatment for breast cancer. N Engl J Med. 1992;326(26):1745–51. [PubMed]

4. Travis LB, Curtis RE, Glimelius B, et al. Bladder and kidney cancer following cyclophosphamide therapy for non-Hodgkin’s lymphoma. J Natl Cancer Inst. 1995;87(7):524–31. [PubMed]

5. Travis LB, Holowaty EJ, Bergfeldt K, et al. Risk of leukemia after platinum-based chemotherapy for ovarian cancer. N Engl J Med. 1999;340(5):351–7. [PubMed]

6. Moolten FL. Tumor chemosensitivity conferred by inserted herpes thymidine kinase genes: paradigm for a prospective cancer control strategy. Cancer Res. 1986;46(10):5276–81. [PubMed]

7. Greco O, Dachs GU. Gene directed enzyme/prodrug therapy of cancer: historical appraisal and future prospectives. J Cell Physiol. 2001;187(1):22–36. [PubMed]

 

 

 

 

 

BLOG EXAM QUESTIONS

1.Which of these bacteria is the smallest?

a.Dialister Invisus

b. Dialister Succinatiphilus

c. Dialister Micraerophilus

d. Dialister Pneumosintes

2. (i) Every 24^th glucose residue forms a branch, alpha(1-6)

(ii) Every 10^th glucose residue forms a branch, alpha (1-6)

(iii) Glucose polymer with mainly alpha (1-4) linkages

(iv) Highly branched structure permits rapid glucose release from stores.

Which of the above applies to amylopectin?

1. (i), (ii) and (iv)
2. (i) and (iii)
3. (ii) and (iv)
4. (i), (iii) and (iv)

Protein mutation-Sickle Cell Anemia

Sickle cell anemia is a congenital form of anemia characterized by abnormal blood cells having a crescent shape. It is caused by a mutation in the base sequence of hemoglobin.

The above shows both the normal base sequence of hemoglobin and the mutant base sequence of hemoglobin.

The above shows a mutant sickle cell hemoglobin (left) compared to a normal cell hemoglobin (right) 

The goal of treatment of this disease is to manage and control symptoms. Patients with sickle cell disease need ongoing treatment, even when they are not having a painful crisis. It is best to receive care from health care providers and clinics that take care of many patients with sickle cell anemia. Folic acid supplements should be taken as it is needed to make new red blood cells. Treatment for a sickle cell crisis includes; blood transfusions (may also be given regularly to prevent stroke), pain medicines and an abundance of fluids. Other treatments for sickle cell anemia may include; Hydroxyurea (Hydrea), a medicine that may help reduce the number of pain episodes (including chest pain and difficulty breathing) in some people and antibiotics to prevent bacterial infections, which are common in children with sickle cell disease. Treatments that may be needed to manage complications of sickle cell anemia include; Dialysis or kidney transplant for kidney disease, counseling for psychological complications, gallbladder removal in people with gallstone disease, hip replacement for avascular necrosis of the hip, surgery for eye problems, treatment for overuse or abuse of narcotic pain medicines and wound care for leg ulcers. Bone marrow or stem cell transplants can cure sickle cell anemia. However, they are currently not an option for most patients. Sickle cell anemia patients are often unable to find well-matched stem cell donors. People with sickle cell disease must reduce their risk of infections. This includes receiving certain vaccinations, including: Haemophilus influenzae vaccine (Hib), Pneumococcal conjugate vaccine (PCV) and Pneumococcal polysaccharide vaccine (PPV).

An amino acid is an organic compound containing an amino group (NH₂), a carboxylic acid group (COOH) and any of various side groups, especially any of the 20 compounds that have the basic formula NH₂CHRCOOH, and that link together by peptide bonds to form proteins or that function as chemical messengers and as intermediates in metabolism. A protein is any group of complex organic macromolecules that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are composed of one or more chains of amino acids. Proteins are fundamental components of all living cells and include many substances, such as enzymes, hormones, and antibodies, that are necessary for the proper functioning of an organism. They are essential in the diet of animals for the growth and repair of tissue and can be obtained from foods such as meat, fish, eggs, milk, and legumes. 

   

Above shows a typical amino acid

The above shows a typical alpha helix of a protein. 

Disaccharides, Oligosaccharides and Polysaccharides

Disaccharides are two monosaccharides covalently linked together. Some disaccharides are; 

Maltose which is formed from two glucose molecules,

Lactose (milk sugar) formed from beta glucose and beta galactose,

Sucrose (table sugar) formed from glucose and fructose.

An oligosaccharide a few monosaccharides covalently linked.

The above shows some types of oligosaccharides and their structures.

A polysaccharide is a polymer consisting of chains of monosaccharide units.

The above shows three polysaccharides; 1) amylose, which is unbranched and is a glucose polymer with alpha (1–>4) linkages. 2) Amylopectin which is a glucose polymer with mainly alpha (1–>4) linkages but also has branches formed (at every 24 residue) by alpha (1–>6) linkages. The branches produce a compact structure and provide multiple chain ends at which enzymatic cleavage can occur. 3) Glycogen is the glucose storage polymer in animals and is similar to the structure of amylopectin but it has more alpha (1–>6) branches (evry 10 glycosyl residues). The higher brancehed structure permits rapid glucose release from glycogen stores.

Monosaccharides

Monosaccharides are simple sugars with multiple -OH groups and based on the number of carbons present (3,4,5,6) a monosaccharide is a triose, tetrose, pentose. hexose respectively.                                                                                                               

The above shows a triose sugar

The above shows a tetrose sugar

The above shows a pentose sugar

The above is a hexose sugar

Monosaccharides can also be classified as aldoses and ketoses where aldose sugars posses an aldehyde group at one end and ketose sugars posses a keto group usually at carbon 2.

Above shows D-Glucose, an aldose sugar.

Above shows D-Fructose a keto sugar