Natural Sciences & Technology: A Comprehensive Overview
Natural Sciences
Prokaryotes vs. Eukaryotes
Prokaryotes
Smaller than eukaryotes with less organizational complexity. They lack a nuclear envelope and their DNA is located in the cytoplasm.
Eukaryotes
Larger than prokaryotes with greater organizational complexity. They possess a core with a membranous sheath containing abundant DNA.
Types of Nutrition
Autotrophic Nutrition
Organisms with autotrophic nutrition can produce organic compounds from inorganic ones. There are two types:
- Photosynthesis
- Chemosynthesis
Heterotrophic Nutrition
These organisms cannot survive solely on inorganic and organic matter and require other living beings for sustenance. Several types exist:
- Holozoic Nutrition: Feeding on solid organic matter.
- Saprotrophic Nutrition: Consuming decaying organic matter.
- Parasitic Nutrition: Example: Tapeworm.
- Symbiotic Nutrition: Nutrient exchange benefiting both organisms involved.
Photosynthesis and Respiration
Photosynthesis
The fundamental reaction of autotrophic metabolism, where organisms convert solar energy into chemical energy by synthesizing organic matter from other compounds. It involves two phases: light and dark.
Respiration
A complex set of chemical reactions where organic molecules are converted into chemical energy, releasing CO2 and water. Two types exist: aerobic and anaerobic.
Ecological Interactions
- Commensalism: One organism benefits from another without affecting it.
- Inquilinism: One organism seeks shelter in another without causing harm.
- Predation: One organism kills and consumes another for sustenance.
- Parasitism: One organism lives at the expense of another, potentially causing harm.
- Mutualism: Two individuals of different species benefit from their association.
Biotope and Biocenosis
- Biotope: An area with uniform environmental conditions providing a living space for flora and fauna.
- Biocenosis: The set of organisms of all species coexisting in a defined space (biotope) that provides necessary environmental conditions for survival.
- Abiotic Factors: Chemical-physical factors of the environment (e.g., rain, temperature).
- Biotic Factors: Interactions with other species.
Technology
Material Properties
- Cohesion: Strength of atoms when separated.
- Plasticity: The ability of a material to deform permanently under load.
- Malleability: Ability to be deformed into sheets.
- Ductility: Ability to be deformed into wires.
- Hardness: Resistance to scratching.
- Resistance: Ability to withstand forces and loads.
- Elasticity: Ability to return to its original shape after a force is removed.
Metals
Iron
Low density, fragile and brittle in its pure form, but strong when combined with carbon. Adaptable to molding and very hard. Primarily used as steel or cast iron.
Cast Iron
An alloy obtained by mixing iron with fuel. Possesses different properties than steel, notably rigidity and fragility.
Steel
A transformation of iron into a widely used and versatile material.
Aluminum
Gray in color, low density, and high resistance to corrosion. Good conductor of electricity and heat. Soft and easily worked.
Types of Stress
- Tension: Stretching force applied in opposite directions.
- Torsion: Twisting force applied to a material.
- Bending: Force applied to a supported material, causing it to curve.
- Shear: Force applied in opposite directions, displacing a material.
- Compression: Force applied in the same direction, causing a material to shorten and bulge.