Enzyme Catalysis: Mechanisms, Cofactors, and Regulation
Factors in Enzyme Catalysis
Proximity and Orientation
Enzymes act by increasing the effective concentrations of substrates, bringing them closer with appropriate guidance of reactive groups.
Surface Phenomena
The properties of the active site can be considerably different from the surrounding medium and more favorable for a particular reaction to occur.
Strain and Distortion Factors
The presence of groups capable of providing reactive mechanisms of lower activation energy. These act by general acid-base
Read MoreRecombinant DNA Technology: Insulin, Somatropin, and Protein Engineering
Insulin
Insulin is a classic example of a naturally occurring protein produced by recombinant technology. Human insulin was the first recombinant protein commercially produced for therapeutic use. Before the availability of recombinant insulin, diabetic patients relied on insulin purified from the pancreases of pigs and cows, which occasionally resulted in serious immune reactions. Recombinant human insulin has dramatically improved the therapy for diabetes. Human insulin is expressed as a precursor
Read MoreEssential Plant Biology: Processes & Adaptations
Water Absorption in Plants
Plants absorb water primarily through their roots, specifically through tiny, hairlike structures called root hairs. These root hairs significantly increase the surface area of the root, maximizing contact with the soil water.
Mechanism of Water Uptake
The primary mechanism of water absorption is osmosis. Osmosis is the movement of water molecules from a region of higher water concentration (lower solute concentration) to a region of lower water concentration (higher solute
Read MoreEssential Aspects of Animal Cell Culture
Animal Cell Culture Essentials
A well-equipped laboratory is fundamental for successful animal cell culture. Here is a list of essential equipment:
Basic Equipment for Animal Cell Culture
- Sterile Work Area/Cell Culture Hood (e.g., laminar-flow hood or biosafety cabinet)
- Incubator (humid CO2 incubator recommended)
- Water Bath
- Centrifuge
- Refrigerator and Freezer (–20°C)
- Cell Counter (e.g., automated cell counter or hemocytometer)
- Inverted Microscope
- Liquid Nitrogen (N2) Freezer or Cryostorage Container
- Sterilizer
Polymerase Chain Reaction (PCR) Explained
Polymerase Chain Reaction (PCR) is an enzymatic process in which a specific region of DNA is replicated over and over again to yield many copies of a particular sequence.
The most widely used target nucleic acid amplification method is the polymerase chain reaction (PCR).
This method combines the principles of complementary nucleic acid hybridization with those of nucleic acid replication applied repeatedly through numerous cycles.
This method is able to amplify a single copy of a nucleic acid target,
Read MoreAlcohol Metabolism and Forensic Testing
Injury Classification
Injuries are often classified based on severity and type:
Cases with Craniocerebral Injury: These are due to direct collision of a portion of the vehicle on the head or, more frequently, the impact of the head against the ground or other obstacle. They have high mortality.
Cases with Severe Skeletal Lesions of the Trunk: Characterized by the absence of visceral injuries. Most are caused by motor vehicles, whose large kinetic energy and relatively light weight cause their action