Genetics, Evolution, and Solar System: A Comprehensive Overview

Genetics

Core Concepts

Genetics is the study of biology that focuses on genes and biological inheritance related to characteristics.

Chromosomes are components that appear as cylindrical or rod-shaped bodies during cell division: mitosis and meiosis.

Genetic engineering involves manufacturing techniques.

The world lives thanks to bacteria and other antibiotic substances they produce. These products prevent the growth of bacteria and fungi.

Cellular Biology and Cloning

Stem cells and blastocysts are cells in the body with no specialized function. They can multiply while maintaining that state and can be transformed into over 200 cell types in an adult individual. They are fundamental.

Cloning:

• Therapeutic cloning: Obtaining stem cells to regenerate tissues for internal use or to repair damaged tissues without rejection problems.
• Reproductive cloning: In humans, achieving embryos with the same DNA and other assisted reproduction techniques like cytoplasmic sperm microinjection into the ovule. After selecting 3 embryos, they are implanted into the womb.

Children à la carte: Selection based on diseases; artificial.

Children specimen: Vaginal insemination of sperm.

Chromosomes and DNA

Chromosomes: The number of chromosomes in a species is maintained during sexual cell formation because it is reduced by half. The complete set of sorted chromosomes is called a karyotype. There are 23 pairs of chromosomes in humans.

DNA contains the genetic information used in the development and functioning of living organisms and some viruses, responsible for hereditary transmission.

A gene is a particular sequence of nucleotides on one side of the DNA ladder of a chromosome.

A genotype is the genetic content of an individual in the form of DNA.

Gene therapy: Transplanting genes between people to repair defective genes, not only for diseases but also for conditions like cancer. Viruses are used to bind to infected cells and make copies of the genes integrated into viral and human chromosomes.

Current Theory on the Origin and Evolution of the Solar System

Nebular Theory

The solar system originated from a nebula or cloud of gas and dust that collapsed due to gravity. Some parts with higher density collapsed to form the nucleus and a protoplanetary disk. The gas and dust temperature were high. Dust particles collided and grew in size. Larger objects continued cooling and accreting more material. Strong solar winds cleared the remaining gas.

Origin of Earth

Orbiting planetesimals gave rise to the planet. Earth had high temperatures initially, followed by collisions with other planetesimals. Finally, a large asteroid collision caused an explosion of materials.

Structure of Earth

• 0-500km: Atmosphere (troposphere, where auroras occur)
• 30km: Crust
• 14km: Hydrosphere
• Up to 2900km: Mantle
• 2900km-6370km: Core

Planets and Celestial Bodies

Defining Planets

Planets have sufficient mass to form a nearly spherical shape and have cleared their orbital neighborhood.

Dwarf planets have a similar spherical shape but share their orbital neighborhood.

Minor bodies are lighter and may not have a spherical shape.

The Milky Way Galaxy

Sunlight takes 8 minutes to reach us. Looking far away is looking into the past. If we see a star 500 light-years away, we see it as it was 500 years ago.

The Milky Way is abundant with stars immersed in a whitish halo. It includes various types of galaxies: elliptical (E), lenticular (S0), and spiral (S).