Stem Cells, Genetic Engineering, and Infectious Diseases
Stem Cells and Transplants
ITEM 5. Who can donate? Usually, a person in a situation of brain death, or *encephalic* death. A person who has died and whose brain has stopped functioning, but whose heart is still beating artificially, can have their organs transplanted, as they are in perfect condition. In some types of transplants, the donor may be a living person (skin, bone marrow, kidney, etc.).
Immune Rejection
Our immune system can distinguish self from foreign. If white blood cells detect something
Read MoreHuman Body: Functions, Systems, and Anatomy
Living Things vs. Non-Living Things
Living things possess life and include animals, bacteria, and algae. They move, reproduce, and nurture relationships. These are the three vital functions.
- Heterotrophic Animal Nutrition
- Autotrophic Plant Nutrition: Photosynthesis
- Fungi: Heterotrophic nutrition (they are not plants because they acquire food by absorption, not ingestion)
All plants adapted to the air environment (not water) have a root, stem, and leaf. However, moss does not, as it represents an evolutionary
Read MoreOrigin and Evolution of Life: From First Cells to Biodiversity
Theories on the Origin of Life
First Theories
- Creation: This myth is the basis of most religions. In them, some sort of creative force acts on matter, such as land or rocks. For a long time in the West, the Genesis account was accepted literally.
- Spontaneous Generation: In ancient Greece, it was believed that life appeared spontaneously whenever adequate conditions were met. Aristotle synthesized the ideas about spontaneous generation. The theory of spontaneous generation prevailed for over two thousand
Understanding Molecular and Cellular Cloning Techniques
Molecular Cloning
Molecular cloning is used in a wide variety of biological experiments and practical applications, ranging from fingerprinting to large-scale protein production. In practice, to amplify any sequence in a living organism, the sequence to be cloned must be linked to an origin of replication, which is a DNA sequence.
Key Steps in Molecular Cloning:
- Transfection: Introduces the formed sequence within cells.
- Selection: Selects the cells that have been successfully transfected with the new
Animal and Plant Cell Structure: A Detailed Comparison
Animal Cells
Animal cells are surrounded by an outer membrane, called the cell or plasma membrane. This membrane surrounds the protoplasm. The protoplasm of a cell is made up of the nucleus and the surrounding cytoplasm. Many of the reactions in a cell take place in the cytoplasm.
Plant Cells
Plant cells are enclosed by a rigid cell wall made of cellulose. Cellulose is a strong structural carbohydrate (or polysaccharide) and is the main component in paper and cotton wool. The cell wall gives the cell
Read MoreChemical Agents in the Workplace: Health and Safety
Comparison of Chemical Agents
- Fiber and Particle: A fiber has a diameter of less than 1/3 of its length.
- Gases and Vapors: Gases are substances whose state is a gas under high pressure and temperature. Vapors come from solids or liquids under normal conditions and are now acting on the vapor pressure or temperature.
- Mists and Fogs: Mists have a size between 0.01 and 10 microns, are produced by condensation of a gaseous state, and fog condensation and disintegration of a liquid. Its size is between