Essential Concepts in Genetics and Molecular Biology

Genetic Diseases: Hereditary or Not?

No, a genetic disease can be inherited or acquired. A genetic disorder occurs when a normal gene or chromosome undergoes changes, preventing it from performing its normal function. If these changes affect all body cells, the genetic disease is hereditary. For example, most cancers and certain viral diseases like AIDS are not inherited.

Understanding Prenatal Diagnosis

Prenatal diagnosis involves the early detection of genetic diseases in utero. Amniocentesis and Chorionic Villus Sampling (CVS) are common methods of prenatal diagnosis.

What is Amniocentesis?

Amniocentesis is a prenatal diagnostic procedure that involves taking a sample of amniotic fluid, which contains fetal cells in suspension, using a hypodermic needle. This method is used to detect DNA and chromosomal abnormalities, such as Down Syndrome.

Polymerase Chain Reaction (PCR) Explained

The Polymerase Chain Reaction (PCR) allows for the amplification of many copies of a specific gene or DNA fragment from even minute quantities. The process involves denaturing DNA (separating the two strands) and then synthesizing new strands, effectively creating millions of copies.

Key Differences Between DNA and RNA

DNA molecules are typically double-stranded helices, while RNA molecules are generally single-stranded. DNA serves as the genetic blueprint, but it relies on various types of RNA to express this vital information during protein synthesis.

Types and Functions of RNA

• Messenger RNA (mRNA): Carries genetic information from DNA to the ribosomes, specifying the amino acid sequence of proteins. It acts as an intermediary molecule between DNA and protein synthesis.
• Transfer RNA (tRNA): Transports specific amino acids to the ribosome during protein synthesis, matching them to the codons on mRNA.
• Ribosomal RNA (rRNA): Combines with proteins to form ribosomes, the cellular machinery responsible for protein synthesis.

Defining the Genetic Code

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences).

Understanding Genetically Modified Organisms (GMOs)

A Genetically Modified Organism (GMO) is a plant, animal, or microorganism whose genetic material (DNA) has been altered using genetic engineering techniques. They are also commonly known as transgenic organisms.

Benefits and Drawbacks of GMOs

• Advantages:
  • Obtaining food with enhanced characteristics, such as increased nutritional value or resistance to pests and diseases.
  • Accelerated growth rates in crops and livestock.
  • Utilization of bacteria for human benefit, such as in the production of medicines (e.g., insulin) or for treating diseases.
• Disadvantages:
  • Potential for invasion of natural ecosystems by modified organisms.
  • Possible allergic reactions in consumers.
  • Accidental creation of "superweeds" or disease-resistant pathogens due to gene transfer.
  • Concerns about the artificial nature of production, potentially disrupting natural biological processes.

Gene Therapy: Curing Hereditary Diseases

Gene therapy aims to cure hereditary diseases by substituting an abnormal or defective gene with a healthy, functional gene.