Biochemistry & Health: Core Concepts and Clinical Insights

Posted on Aug 21, 2025 in Medicine & Health

Biochemistry Fundamentals

Biochemistry is the study of the chemical processes and substances that occur within living organisms.

Scope of Biochemistry

1. Drug Design and Development: Biochemistry is used to understand the structure and function of biomolecules such as enzymes and receptors, which are important targets for drug development. Biochemists use this knowledge to design and develop new drugs that can bind to these targets and modulate their activity.
2. Biotechnology: Biochemistry is used to develop biotechnology products such as vaccines, diagnostic tests, and gene therapies. Biochemists use techniques such as recombinant DNA technology and protein engineering to create these products.

Qualitative Tests for Carbohydrates

1. Fehling’s Test: Reducing sugars reduce the copper ions present in the Fehling solution to give a red precipitate.
2. Formation of Osazones: When reducing sugar is heated with phenylhydrazine, yellow crystalline compounds called osazones are formed. For example, D-Glucose + Phenylhydrazine → Glucose Osazone (Yellow crystal) + Phenylhydrazine + H₂O.
3. Reduction: The carbonyl group of sugar can be reduced by a variety of reagents, such as hydrogen and platinum, to an alcohol. Such carbohydrate derivatives are called alditols. Important examples are sorbitol, glycerol, and ribitol.

Diseases Related to Carbohydrate Metabolism

Diabetes Mellitus

It is a group of metabolic disorders characterized by hyperglycemia. Hyperglycemia in diabetes mellitus is due to a defect in insulin action, insulin secretion, or both. The term “Diabetes” comes from the Greek word “Siphon,” implying that a lot of urine is made. The second term, “Mellitus,” comes from the Latin word “Mel,” which means Honey.

Diabetes mellitus is broadly classified into two categories:

1. Type 1 Diabetes
2. Type 2 Diabetes

Type 1 Diabetes

• It is characterized by an absolute deficiency of insulin due to the destruction of beta-cells of the pancreas.
• A chronic condition in which the pancreas produces little or no insulin.

Symptoms of Type 1 Diabetes

• Increased Thirst
• Frequent Urination
• Hunger
• Fatigue

Dehydration and Water’s Role

Understanding Dehydration

Dehydration refers to a condition where the body lacks sufficient fluids to carry out normal physiological functions. It can occur when the body loses more fluids than it takes in, leading to an imbalance in the body’s electrolytes.

Causes of Dehydration

1. Inadequate Fluid Intake: The most common cause of dehydration is not drinking enough fluids. This can occur if a person is not thirsty or if they are unable to access water.
2. Excessive Fluid Loss: Dehydration can also occur if the body loses too much fluid through sweating, urination, or diarrhea.
3. Medical Conditions: Certain medical conditions can also cause dehydration, including diabetes, kidney disease, and fever.
4. Medications: Some medications can cause dehydration as a side effect.

Oral Rehydration Therapy (ORT)

Oral rehydration therapy (ORT) is a simple and effective way to treat dehydration. It involves drinking a solution of water, salts, and sugar to replace fluids and electrolytes lost due to dehydration. ORT is often used to treat dehydration caused by diarrhea, vomiting, and other illnesses that cause fluid loss. ORT is recommended by the World Health Organization (WHO) as the first-line treatment for dehydration. It can be given at home or in a healthcare setting and is suitable for all age groups.

ORT solution can be made by dissolving the following in one liter of clean water:

• 6 level teaspoons of sugar
• 1/2 level teaspoon of salt

The solution should be sipped slowly over a period of four to six hours. If vomiting occurs, the solution should be paused for 10 minutes and then restarted.

Functions of Water in the Body

• Carrier of Food Nutrients: Every nutrient in soluble form in water is carried from intestines to tissues through blood.
• Constituent of Body Fluids: Water is the major constituent of all liquids of the body, such as blood, urine, sweat, and lymph.
• Regulates Body Temperature: Water helps to regulate and control body temperature. Heat is produced when food is burnt for energy. Water is evaporated through respiration and sweat, and body temperature is maintained normal. Body’s heat is lost through the skin, lungs, urine, and feces.
• Protection of Delicate Organs: Water surrounds organs like the lungs, heart, and brain, protecting them from outer injury. Thus, it provides security to these organs and thereby to human beings.

The human body is roughly 60% water.

The primary hormone that regulates water retention in the body is antidiuretic hormone (ADH), also known as vasopressin.

Advanced Biological Technologies

DNA Technology

DNA technology is the use of various methods to manipulate, analyze, and modify DNA (deoxyribonucleic acid), which is the genetic material that carries the instructions for the development and function of all living organisms. DNA technology has revolutionized many fields of biology, including genetic engineering, molecular biology, and biotechnology.

One of the most common uses of DNA technology is genetic engineering, which involves the manipulation of an organism’s DNA to add, delete, or modify specific genes. This technology has allowed scientists to create genetically modified organisms (GMOs) with desired traits, such as resistance to pests, increased yield, or improved nutritional content.

Examples of DNA Technologies

• DNA cloning
• Polymerase chain reaction (PCR)
• Gel electrophoresis
• DNA sequencing

Biotechnology in Environmental Conservation

1. Pollution Control and Remediation

   • Bioremediation: Biotechnology utilizes microorganisms and plants to clean up pollutants like oil spills and hazardous waste. For example, bioremediation uses microorganisms to degrade oil and convert it into harmless substances.

2. Resource Management and Sustainable Agriculture

   • Sustainable Agriculture: Biotechnology can improve crop yields, reduce the need for chemical pesticides and fertilizers, and promote soil health.
   • Phytoremediation: Plants are used to absorb and remove pollutants from soil and water.

3. Biodiversity Conservation

   • Genetic Rescue: Biotechnology can help preserve endangered species by enhancing their genetic diversity and restoring degraded habitats.

Industrial Biotechnology Applications

Industrial biotechnology can produce a wide range of products (chemicals, materials, food and beverages, biofuels, and biodrugs) from bio-based raw materials. It can reduce environmental impact by using biomass as an alternative to fossil resources for manufacturing bioproducts, biofuels, and biopolymers.

Biotechnology in Medical Science

• Gene Therapy

  • Replacing Defective Genes: Gene therapy aims to correct genetic defects by introducing functional genes into cells to treat genetic disorders.

• Tissue Engineering

  • Regenerative Medicine: Tissue engineering involves creating tissues and organs in the laboratory for transplantation, offering a potential solution for organ failure and tissue damage.

Clinical Diagnostic Tests

Kidney Function Tests

1. Blood Tests: Blood tests that measure levels of creatinine and blood urea nitrogen (BUN) are commonly used to assess kidney function. Creatinine is a waste product that is produced by muscle metabolism and excreted by the kidneys, while BUN is a waste product of protein metabolism. Elevated levels of creatinine and BUN in the blood can indicate decreased kidney function or kidney damage.
2. Urine Tests: Urine tests that measure levels of protein and albumin are commonly used to assess kidney function. Albumin is a protein that is normally present in the blood, but not in the urine, while proteinuria is the presence of excessive amounts of protein in the urine. Elevated levels of protein and albumin in the urine can indicate decreased kidney function or kidney damage.
3. Glomerular Filtration Rate (GFR): GFR is a measure of the rate at which blood is filtered by the kidneys. It is calculated based on a person’s age, sex, and blood creatinine levels. A GFR of less than 60 mL/min/1.73m² for more than 3 months indicates chronic kidney disease.

Clinical Significance of Kidney Tests

• Urine Output: This is a measure of how much urine is produced over a certain period of time. Low urine output can indicate poor kidney function.
• Glomerular Filtration Rate (GFR): This is considered the most accurate measure of kidney function. It is a measure of how well the kidneys are filtering waste from the blood. GFR can be estimated through blood tests that measure levels of creatinine, a waste product produced by muscles.

An increased serum creatinine level generally indicates a potential issue with kidney function.

Liver Function Tests

Routine liver function tests are performed to assess the liver’s health and function. These tests include:

1. Alanine Transaminase (ALT) and Aspartate Transaminase (AST): These tests measure the levels of liver enzymes in the blood. High levels of ALT and AST are indicative of liver damage.
2. Alkaline Phosphatase (ALP): This test measures the levels of ALP in the blood. Elevated levels of ALP may indicate liver or bone disease.
3. Bilirubin: This test measures the levels of bilirubin in the blood. High levels of bilirubin may indicate liver disease or hemolytic anemia.

Clinical Significance of Liver Function Tests

1. Detection of Liver Disease: Liver function tests can help detect liver disease in its early stages, before symptoms appear.
2. Monitoring of Liver Function: Liver function tests are used to monitor the progress of liver disease and assess the effectiveness of treatment.
3. Diagnosis of Liver Injury: Liver function tests can help diagnose liver injury caused by drugs, toxins, or infections.

High bilirubin levels, also known as hyperbilirubinemia, generally indicate issues with the liver, bile ducts, or red blood cell breakdown.

Function of the Liver

The liver’s functions include filtering the blood, producing bile for digestion, metabolizing nutrients, and detoxifying harmful substances.

Components of a Lipid Profile Test

A lipid profile test typically includes total cholesterol, HDL (high-density lipoprotein) cholesterol, LDL (low-density lipoprotein) cholesterol, and triglycerides.

HDL stands for high-density lipoproteins. It is sometimes called the “good” cholesterol because it carries cholesterol from other parts of your body back to your liver.

Nutritional Requirements

Recommended Dietary Requirements for Calcium

Good sources of calcium include dairy foods like milk, yogurt, and cheese, calcium-fortified foods (such as soy products), and, to a lesser degree, some leafy green vegetables and nuts and seeds.

Recommended Dietary Requirements for Iron

• Adult man: 10 mg/day
• Menstruating woman: 18 mg/day
• Pregnant and lactating woman: 40 mg/day

Iron can be found in both animal and plant-based foods. Animal sources like red meat, poultry, and seafood are rich in heme iron, which is easily absorbed by the body. Plant-based sources like beans, lentils, spinach, and fortified grains contain non-heme iron.

Dietary Requirement for Zinc

The dietary requirement for zinc varies based on age and gender, with adults generally needing 11 mg/day for men and 8 mg/day for women. The Tolerable Upper Intake Level (UL) for adults is 40 mg/day.

Best Sources of Zinc

The best source of zinc is oysters, but it’s also plentiful in red meat and poultry. Other good sources of zinc include other kinds of seafood, nuts, whole grains, breakfast cereals, and dairy products.

Classification of Minerals

Minerals are classified into macrominerals and trace minerals:

• Macrominerals: You need larger amounts of macrominerals. They include calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfur.
• Trace Minerals: You only need small amounts of trace minerals. They include iron, manganese, copper, iodine, zinc, cobalt, fluoride, and selenium.

Iodine Deficiency and Goiter

Iodine deficiency is the most common cause of goiter. Consuming a diet that includes fish, dairy, and a healthy amount of iodized table salt prevents these types of goiters.

Blood Cell Analysis

Erythrocytes: Abnormal Cells and Their Significance

Red blood cells (RBCs) or erythrocytes are the most abundant type of blood cells in the human body, and their main function is to transport oxygen from the lungs to the body tissues and to carry carbon dioxide from the tissues back to the lungs. The shape of RBCs is an important characteristic that can provide information about a person’s health status. A medical professional can evaluate the shape and size of RBCs as part of a complete blood count (CBC) test to diagnose and monitor blood disorders. Some abnormal shapes of RBCs include:

1. Normal RBCs: Normal RBCs have a biconcave shape with a flattened center, which increases their surface area for efficient gas exchange. Normal RBCs are essential for oxygen transport and carbon dioxide removal.
2. Sickle Cell-Shaped RBCs: Sickle cell-shaped RBCs have a crescent or sickle shape and are characteristic of sickle cell anemia, a genetic disorder that affects the production of hemoglobin. These abnormal RBCs can cause blockages in the blood vessels, leading to pain, organ damage, and other complications.
3. Schistocyte-Shaped RBCs: Schistocyte-shaped RBCs have an irregular shape and are fragmented due to physical damage, such as from trauma or mechanical heart valves. These abnormal RBCs can cause hemolysis, anemia, and other blood disorders.
4. Target-Shaped RBCs: Target-shaped RBCs have a central dark spot surrounded by a lighter ring and an outer dark ring. Target-shaped RBCs can be caused by iron deficiency anemia, liver disease, thalassemia, and other conditions.
5. Ovalocyte-Shaped RBCs: Ovalocyte-shaped RBCs have an oval or elliptical shape and can be seen in various blood disorders, including hereditary elliptocytosis, thalassemia, and myelofibrosis.
6. Tear-Drop-Shaped RBCs: Tear-drop-shaped RBCs have a teardrop or pear-shaped appearance and can be seen in various blood disorders, including thalassemia, myelofibrosis, and other conditions.

Cellular Components and Biochemical Tests

Mitochondria

Mitochondria are often referred to as the “powerhouse of the cell.”

Ribosomes

The role of ribosomes is to serve as the site of protein synthesis in the cell.

Ninhydrin Test for Protein

The Ninhydrin test is a chemical reaction used to detect the presence of amino acids and proteins.

Sudan III Test for Lipids

The Sudan III test is a method for identifying lipids, particularly in stool samples, used to detect fat malabsorption (steatorrhea).

Fatty Acids

Fatty acids are building blocks of fats in the body and food, crucial for energy storage, cell function, and other vital processes.

Millon’s Test for Tyrosine

Millon’s test is a chemical test used to detect the presence of tyrosine.

Molisch’s Test for Carbohydrates

Molisch’s test is a chemical test used to detect the presence of carbohydrates in a solution.

Nonessential Amino Acids

Nonessential amino acids are those that our bodies can produce, even if we do not get them from the food we eat. Examples include:

• Alanine
• Arginine
• Asparagine
• Aspartic acid
• Cysteine