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Steroids and Bile Acid: Lipid Metabolism

Lipid metabolism is the process by which lipids are synthesized and degraded in cells. In this article, important lipids discussed are bile salts, cholesterols, steroids and ketone bodies. Also covered in this article are the structures and functions of these types of lipids. The biosynthesis and metabolism of these lipid molecules are also covered in this article.

Biotechnology: Analytical Techniques

Biotechnology is an emerging field that allows scientists to use analytical techniques to study the structure and function of biomolecules. Protein purification is an all but mandatory step for studying macromolecules; but this task is not necessarily easy. Several experimental methods, deductive logic, and even a little bit of luck make this possible. Here you'll read about some of the methods.

RNA: Basic Knowledge

Ribonucleic acid (RNA) is a polymeric molecule, which is implicated in different biological roles such as coding, decoding, expression of genes and regulation. Biological reactions within cells are catalyzed by some RNA molecules, which control gene expression and communicate responses to cellular signals. The structure of RNA is similar to that of DNA, but there are some differences between them.

Metabolic Regulation

Integration of cellular metabolism is controlled by insulin and the opposing actions of glucagon and epinephrine. When food is available in abundance, or when the body needs to make stored energy available, changes in the circulating levels of these hormones allow the body to respond accordingly. This discussion of metabolic regulation will be tailored to fit two scenarios, the fed and fasted states, and highlight how metabolite flux is modulated by the direct activating or inhibiting of enzymes, or by inducing or repressing their transcription in the nucleus.

Energy, Enzymes and Metabolism

Metabolism is the sum of both catabolism (pathways that break down molecules for generation of cellular energy) and anabolism (pathways that build macromolecules using cellular energy). Here, we will discuss metabolism with regards to the Laws of Thermodynamics, Enzymology, and go over some of the major metabolic pathways utilized by organisms to perfectly prepare you for upcoming exams.

The Cell Cycle: Regulation, Apoptosis, Mitosis and Replication of DNA

This article explains the semiconservative replication of DNA and the role it plays in the cell cycle. The phases of the cell cycle and mitosis (prophase, metaphase, anaphase, and telophase) as well as the regulatory mechanisms associated with cyclins and their antagonists are all relevant topics in medical exams.

Gene Mutations and Repair Mechanisms of the Human Cell

Mutations are associated with diseases and defective genes. Mutated genes are actually the cause of many diseases, although they are also necessary. Without permanent change in the genome, evolution is not possible, and purely static DNA would prevent any development. DNA is also the only molecule of the cell that is repaired. The information stored in the DNA is so important that the energy expended by repairing it is worthwhile. The cell must find the correct balance between the loss of evolution by mutation, and evolution by mutation.

DNA Transcription and Translation – From Gene to Protein

Transcription and translation convert a gene into protein. During this process, the genetic information of a gene, the DNA, is converted into RNA so that protein may be realized later on. This article will provide you with exam-related information regarding this process, thus preparing you ideally for the upcoming exams.

Gluconeogenesis – The Body's Own Sugar Production

Gluconeogenesis, which is the body's own synthesis of glucose, confronts some students who just studied glycolysis with the question: Why? Why build up sugar again which has already been split up into its components? However, this metabolic pathway is more than just a reversal of glycolysis; in fact, it is essential to human life. Therefore, the following article will present you a comprehensive overview of the processes of gluconeogenesis, so that you will be able to score with this extensive knowledge in your next biochemistry exam.

Glycolysis

In biochemistry, glycolysis is very important. The knowledge of energy supply is of great significance for medical training. This also applies to the regulation of carbon hydrate deficiency and excess. Even the formation and utilization of lactate plays an important role in this. Physicians who supervise not only people with weight problems but also athletes have to deal with this subject on a daily basis. Glycolysis comprises more than sugar metabolism. In all professional areas, energy metabolism is an important subject. This article enables you to gather extensive knowledge concerning energy metabolism of human beings which will help you to master your medical exams.

Enzymes – Biocatalysts of Metabolism

With the help of catalysts, chemical reactions are accelerated and the entire human metabolism is thereby brought in momentum. Everything about the various biocatalysts and their classification can be found here.

Biochemistry for Physicians: Cholesterol Metabolism

Cholesterol (Greek for: ‘gall’ and ‘solid’) is a media star: For decades, no other biochemical substrate draws as much attention as cholesterol has. But what are the hard pre-clinical facts? How is cholesterol synthesized and degraded in the human body? How is cholesterol metabolism regulated? The following article presents you with useful information that will aid you in your exam preparation.

Preclinical Biochemistry: Fat Mobilization, β-Oxidation and Ketone Body Metabolism

Fats or fatty acids represent an important energy source for the human body. Thus, intake, storage and degradation have to be strictly regulated. Fatty acid synthesis is also possible, which is of little significance in industrial countries, but is vital for a body with too little fat intake.

The Chemistry of Lipids

The term ‘lipids’ describes a hotchpotch of heterogeneous structures; yet they all have two things in common: they are fatty, and high in energy. Lipids do not dissolve in water, or only do so partially – which means they are lipophilic or hydrophobic (they do, however, dissolve well in solvents) – and they are all made from energy-rich units of activated ethanoic acid, so-called acetyl-CoA units. These two properties, plus the way lipids appear in many different forms, means they are destined for a variety of important functions within the human body. In addition to other things, they constitute building materials, message-carriers, and combustible materials. You can read about the properties, structure and functions of lipids below.

Triacylglyceride Metabolism

Triacylglycerides are a group of insoluble compounds that serve as energy reserves in the body. Their storage occurs in adipocytes, which are built up or depleted in response to the constantly changing energy demands of the cell. Both of these processes are under tight hormonal regulation. This discussion will also include the absorption and transport of fatty acids, as well as the production of ketone bodies.

Signal Transduction and Hormones

What makes the difference between a human being and a fungus? A fungal network can be split in the middle – and both halves will survive and grow further. This does not happen if a human being split since our faculties and vital functions are spread over several locations within our organism. Our cells are specialized and organized into organs. The system only works if the organs work together and communicate. Hormones are the messengers in this communication system. The most important ones, the hormone receptors, and the signal cascades, are explained in the following article.

Metabolism of Amino Acids

The biochemical processes that form part of the amino acid metabolism all support the synthesis and breakdown of amino acids. In the following article, the three most important reactions of the metabolism, i.e. transamination, deamination and decarboxylation, are explained in a compact overview, providing you with the perfect preparation for your upcoming exams.

The Liver – The Central Organ of Metabolism

The liver (Latin: Iecur, Greek: Hepar) is the generalist among all organs – acting universally as center of metabolism, storage unit, detoxifying- and excreting organ. Medical staff is frequently confronted with diseases such as liver cirrhosis, hepatitis and fatty liver. Therefore, anatomical and biochemical knowledge of the liver is part of every medicine student`s basic training. Read this compact overview on structure, functions and diseases of the liver.

Amino Acids

Amino acids are the simplest unit of a protein. It has distinct structural characteristics that is responsible for the different types of interaction it can make inside the body. It is important to study the structure of amino acids as the functioning of proteins is highly affected by the type of amino acids it is comprised. In this article, the structural features and properties of an amino acid will be discussed. Also included in this article are the classification of the amino acids based on the side chain it have. Given focus also in the article is the ionization of amino acids.

Ketone Body Synthesis

Ketone bodies are an important energy source for our bodies during periods of fasting. They provide the brain, the myocardial muscles and the skeletal muscles with energy whenever our body has to live off its reserves. The following article addresses the synthesis and degradation of ketone bodies, their impact on the pH-level of the blood, as well as their clinical relevance with regard to diabetes - all of which is based on pre-med biochemistry knowledge.

The Urea Cycle – A Biochemical Cycle

The daily protein turnover of a human being is approximately 300 g. Amino acids contain nitrogen atoms, which need to be eliminated by the body without developing too much toxic ammonia. Here, urea comes into play as an appropriate end product of protein degradation. The steps of synthesis in the urea cycle (also: ornithine cycle), which occurs in the liver, should be well understood. By the way, the urea cycle was first described in 1932 and is therefore the first described cyclic metabolic pathway.

Fructose – Transport, Degradation and Biosynthesis

Fructose is a carbohydrate that naturally occurs in fruits and is included in /the form of sucrose in many other foods. While congenital disorders of the fructose metabolism and fructose intolerance are relatively rare, numerous clinical trials have proven a correlation between increased fructose uptake and disorders such as the metabolic syndrome and the non-alcoholic fatty liver disease.

Citric Acid Cycle – The Hub of Metabolism

As the final stage of food utilization, the citric acid cycle is primarily responsible for many anabolic and katabolic processes of the human body. As the ‘hub of metabolism’, it is a very popular subject in medical examinations. The following article will help you to better understand its functions, the different reaction steps, and their regulation.

Normocytic Anemia: Sickle Cell Anemia (Sickle Cell Disease)

Sickle cell anemia leads to sickling of red cells during hypoxia. This can cause blockage in blood vessels with a range of clinical problems. Treatment is with red cell transfusions and hydroxycarbamide.

Lipid Metabolism: Fatty Acid Metabolism

Lipids are organic molecules that are composed of the elements carbon, hydrogen and oxygen, with the hydrogen to oxygen ratio greater than 2:1. They are highly hydrophobic because of having a long hydrocarbon chain. This family of compound includes fats, waxes, steroids and phospholipids. This article focuses more on the metabolic processes involved in processing fats and fatty acids.

Nucleotide Metabolism – Purines and Pyrimidines

Nucleotide metabolism results in the synthesis of the four nucleotides that form DNA. These are further divided in two categories: purines and pyrimidines. Their construction and degradation takes place in a progression of single steps, while different enzymes and cofactors are involved in the process. Beside degradation, there is also a form of reprocessing purine and pyrimidine nucleotides, defined as Salvage-pathways.

Biochemical Pathways: The Pentose Phosphate Pathway

Both glycolysis and its parallel metabolic, the pentose phosphate pathway, start with the breakdown of glucose, i.e. glucose-6-phosphate. Divided into two distinct phases, the pentose phosphate pathway generates NADPH and pentoses, which can be used in other metabolic pathways. The pentose phosphate pathway is a small, but very important biochemical pathway physicians should be aware of, as, for instance, the metabolic disorder glucose-6-phosphate dehydrogenase deficiency (G6PD) may impart a distinct selective advantage against malaria.

Bilirubin and Biliverdin Reductase

Bilirubin is a yellow compound that is the product of the catabolism of ageing heme. It can be used to determine abnormality in liver functions as characterized by yellowing of skin and eyes. In this article, we will discuss about the biochemistry of bilirubin. Specifically, how the compound is synthesized and what are the important enzymes used in the synthesis of this biomolecule.

Introduction to Vitamins

Vitamins are the organic compounds which are required in small quantities for normal growth, reproduction and maintenance of the human body. They are different from other organic food stuff because they do not go through the degradation processes to provide energy, and do not enter the tissue structure. Moreover, several B vitamins act as a coenzyme in various metabolic reactions of the body. Vitamins are also different from hormones as they are not produced by the body and have to be taken through diet. They are classified on the basis of their biological and chemical activity.

Biochemistry for Physicians: Cholesterol Metabolism

Membrane Lipid Metabolism

Lipids are a large and diverse group of naturally occurring organic compounds that have relatively very low solubility in water and higher solubility in non-polar organic solvents. Different types of lipid molecules include fatty acids, fats, oils, waxes, phospholipids, eicosanoids, steroids etc. The focus of this article is on two types of lipids namely glycerophospholipids and sphingolipids. Specifically, the article emphasizes on the synthesis of these two types of lipids.

Steroids and Bile Acids: Mevalonate Pathway and Receptor-mediated Endocytosis

Lipid is one of the biomolecules important to humans. They serve a number of purpose in human metabolism. In absence of carbohydrates, acetyl CoA does not enter the TCA cycle, instead, are processed to form ketone bodies, cholesterol, steroid hormones, and bile acids. This article focuses on the metabolism of these four compounds.

Hemoglobin and Movement of Oxygen

Hemoglobin is the iron-containing metalloprotein that is responsible for oxygen transport in vertebrates. It is present in the blood and functions mainly to carry oxygen from the lungs to the other parts of the body, and carbon dioxide from the body to the lungs for eventual elimination. This article will focus on the basic structure and function of hemoglobin.

Precursor of Thyroid Hormones

Tyrosine is one of the amino acids that play a big role in a number of physiological processes. They are precursors for some hormones and neurotransmitters needed by the body for metabolic functions. In this article, the chemistry of tyrosine will be discussed. The article will answer how it is metabolized to produce the different hormones and neurotransmitters.

Porphyria — Symptoms and Treatment

Porphyria is a group of disorders that arise from a buildup of chemicals that are involved in the production of porphyrin in the human body. The porphyrins are important as these are essential components of the hemoglobin that carries oxygen to the organs and tissues of the body. When there is a high level of porphyrins in the body, different symptoms or manifestations related to porphyria show.

Porphyria — Classification and Diagnosis

Porphyrias are a group of metabolic disorders, at the bottom of which lies a disturbance in the synthesis of the heme. Thereby, in most cases it is about a hereditary enzyme defect. The disease patterns differ depending on the affected enzyme; one clinically differentiates between acute and non-acute forms. In particular, a physician should also be aware of the two most common forms of overall rare diseases as an important differential diagnosis. Below is thus an overview of the clinical manifestations, diagnosis and treatment options of the porphyria.

Biochemistry – Board-Style Questions 49 questions 10 free
Enzymes and Enzyme Kinetics 01:23 h / 15 videos 15 free

Enzymes and Enzyme Kinetics 1 article 1 free

Enzymes and Enzyme Kinetics 20 questions 20 free
Amino Acid Metabolism 03:13 h / 36 videos 7 free

Amino Acid Metabolism 9 articles 9 free

Amino Acid Metabolism 84 questions 18 free
Vitamins 01:20 h / 12 videos 4 free

Vitamins 1 article 1 free

Vitamins 17 questions 10 free
Hormones and Signal Transduction 01:16 h / 11 videos 3 free

Hormones and Signal Transduction 1 article 1 free

Hormones and Signal Transduction 27 questions 5 free
RNA and the Genetic Code 01:42 h / 16 videos

RNA and the Genetic Code 2 articles 2 free

RNA and the Genetic Code 30 questions 0 free
Carbohydrate Metabolism 02:13 h / 27 videos

Carbohydrate Metabolism 7 articles 7 free

Carbohydrate Metabolism 40 questions 0 free
Analytical Techniques in Biotechnology 00:23 h / 3 videos

Analytical Techniques in Biotechnology 1 article 1 free

Analytical Techniques in Biotechnology 5 questions 0 free
DNA Replication and Repair 00:35 h / 7 videos

DNA Replication and Repair 2 articles 2 free

DNA Replication and Repair 12 questions 0 free
Metabolic Control 01:12 h / 17 videos

Metabolic Control 7 articles 7 free

Metabolic Control 17 questions 0 free
Lipid Metabolism 01:05 h / 14 videos

Lipid Metabolism 9 articles 9 free

Lipid Metabolism 25 questions 0 free
Purine and Pyrimidine Metabolism 01:14 h / 13 videos 4 free

Purine and Pyrimidine Metabolism 1 article 1 free

Purine and Pyrimidine Metabolism 22 questions 4 free

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