Notes, summaries, assignments, exams, and exercises for Biology for Baccalaureate

Origin of Life and Early Biomolecules

Inorganic matter can be transformed into organic compounds under certain environmental conditions (demonstrated by Miller, 1953). Life arises from the existence of organic matter (simple biomolecules) that can evolve into complex biomolecules under favorable environmental conditions.

The Role of Ribozymes and Early Life

Ribozymes (RNA + enzymes) can be replicated, leading to copies identical to the originals. These molecules can evolve into biomolecules such as microscopic algae cells that perform photosynthesis and release primitive oxygen.

Stromatolites are remnants of the oldest fossils found, dating back 3,500 million years ago.

Evolutionary Concepts

Darwin's Theory of Evolution

Since the formation of the...

Key milestones in genetics include:

• James Watson & Francis Crick (1953): Discovery of the helical structure of DNA.
• Gregor Mendel: Pioneering work in Mendelian genetics.
• Genetic Engineering: Development of techniques to manipulate genes.
• Human Genome Project (HGP): Identifying all the genes of a living being.

Steps in Reading the Genetic Code

1. Separation of the two helical chains.
2. Transcription.
3. Using the Genetic Code.
4. Formation of protein-based amino acids.

Genetically Engineered Foods (GMOs)

Genetically engineered foods are obtained through GMOs and were tagged in 2004, with the following exceptions:

• GM foods with less than 0.9% GMO content.
• Products of second or third generations.
• GM foods that use microorganisms for fermentation.

Genetic Engineering

Genetic...

Infection: Pathogen Penetration and Host Response

Infection is the penetration of a pathogen into the body of an animal or plant, causing changes in organs and their functions. It is essential for the microbe to possess pathogenicity (the ability to cause disturbances in the body), which depends on its invasiveness and toxin production. For an infection to develop, the host organism must be receptive to the microbes (i.e., susceptible to invasion).

Organic Defense Mechanisms: Protecting the Body

Nonspecific Defense (External Barriers)

These are the body's first lines of defense, acting as external barriers:

• Structural: Skin and mucous membranes. These are common entry points for pathogens when compromised.
• Mechanical: Tears, urine, coughing, and

Ecosystems: Definition and Characteristics

An ecosystem is a system formed by the interaction between a community and a biocenosis, or physical environmental factors. An ecosystem model for the subject is closed but open to energy, being capable of regulating itself and remaining in dynamic equilibrium over time.

Population Dynamics

A population is comprised of a set of individuals of the same species living in a particular location. There are some factors that prevent a population from reaching its full biotic potential. These can be external or internal to the population:

• External Factors: These may be biotic (predators, parasites, or diseases caused by other agencies competing for a given resource) and abiotic (climate change, food shortages,

Fundamentals of Genetics and Cellular Biology

DNA: Deoxyribonucleic acid is a type of nucleic acid, a macromolecule present in every cell. It contains the genetic information used in the development and functioning of known living organisms and some viruses, and is responsible for hereditary transmission.

Chromosomes and Cell Division

Chromosome: Each of the small rod-shaped bodies of organized chromatin found in the cell nucleus during cell division (mitosis and meiosis).

Mitosis: A process of cell division in which the two resulting cells receive exactly the same genetic information from the parent cell.

Meiosis: A form of cell reproduction where a diploid cell (2n) undergoes two successive divisions to generate four haploid cells (n). This process

Genetic Transcription Process

TRANSCRIPTION: The process of copying a part of the genetic message from its original form (DNA) to another (RNA) that can be used directly for protein synthesis.

Transcription forms a strand of RNA whose sequence is complementary to the DNA template strand. Consequently, its sequence is the same as the non-template DNA strand (with uracil replacing thymine).

Transcription requires:

• A DNA strand serving as template
• Ribonucleotide triphosphates
• Enzymes (primarily RNA polymerase)

Stages of Transcription

Initiation

The RNA polymerase recognizes specific short sequences of nitrogenous bases (promoter) to which it binds. RNA polymerase opens the DNA double helix to allow incorporation of ribonucleotides.

Elongation

Addition of...

Serums and Vaccines

Serums

Serums are artificial preparations containing specific antibodies against a pathogen.

Vaccines

Vaccines are prepared to contain the pathogen that causes disease, but in a weakened, dead, or fragmented state, so it cannot cause damage. This triggers a response similar to a natural infection. The individual is protected against the pathogen if contact occurs later because of the memory cell information.

Pharmacology and Drugs

Drug Control

The control of infectious diseases is managed through drug products. The most important are antibiotics, although they have no effect on viruses (such as the flu).

Definition of a Drug

A drug is an active principle, or a set of them, as part of a pharmaceutical form designed for use in humans...

Protein Synthesis: From Gene to Protein

Transcription: RNA Synthesis

Transcription involves the synthesis of different types of RNA: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). During this process, RNA polymerase reads the base sequence of the DNA template strand, synthesizing an RNA chain through the complementary base pairing of ribonucleotides (adenine, guanine, cytosine, and uracil). Uracil replaces thymine in RNA, so if DNA has Adenine (A), RNA will have Uracil (U); if DNA has Thymine (T), RNA will have Adenine (A); and if DNA has Guanine (G), RNA will have Cytosine (C).

Translation: Protein Formation

Translation is the process of protein synthesis that takes place in ribosomes. Key aspects include:

• mRNA: Information

Factors Affecting Enzyme Activity

pH Effects on Enzyme Function

Enzymes exhibit an optimum pH at which their activity is maximal, characterized by a low K_m (substrate concentration) and maximum velocity. Small variations around this optimum pH value cause a sudden drop in activity. This can be due to the appearance or disappearance of electrostatic forces that alter the spatial structure of the active site, or changes in the charges of the active center and substrate, which affect their binding capacity. If the pH change is very high, the enzyme is denatured and ceases to be functional.

Temperature's Role in Enzyme Kinetics

In general, an increase in temperature increases the rate of chemical reactions. In the case of enzyme-catalyzed reactions,...