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

Fundamentals of Genetics and Heredity

Genes: Units of Heredity

Genes are the fundamental units of heredity.

Mendel's Experiments on Inheritance

To test his hypotheses, Mendel crossed pure strains differing in a single character (e.g., tall or dwarf plants, green or yellow seeds—up to seven different traits). He approached the problem quantitatively and with patience.

For each variety studied, he found, surprisingly, that the first generation (F1) were all identical. All offspring resembled one character from the father or the mother.

After crossing the F1 generation with each other, he found that the grandchildren (F2) were not all identical.

He also noted that if the parents differed by more than one character, each character is transmitted independently

Invertebrate Classification

• Porifera: Sponges living on the seabed; reproduce sexually and asexually.
• Cnidarians: Jellyfish and corals with radial symmetry; bag-shaped bodies; reproduce sexually and asexually.
• Annelids: Earthworms requiring moisture; reproduce sexually.
• Echinoderms: Starfish with radial symmetry and bodies covered in calcareous plates.
• Mollusks: Soft-bodied organisms, often with a CaCO3 shell; reproduce sexually.
• Myriapods: Centipedes with an external chitin skeleton; breathe via gills or tracheae; reproduce sexually.

Protein Biochemistry

Proteins are organic macromolecules formed by C, O, H, N, and S. They are composed of 20 different amino acids, where the R-group determines the variation. Amino acids are linked by peptide bonds....

Earth's Biosphere and Ecosystems

The biosphere of the Earth is established by living organisms within a thin layer where energy comes from the sun. An ecosystem is formed by a community of living organisms that occupy a given space, the relationships established between them, and the physical environment.

Key Ecological Concepts

• Ecotone: Areas that limit ecosystems.
• Habitat: The area that presents the physicochemical conditions required for a population to properly function.

Components of an Ecosystem

Landforms are part of the ecosystem, which is part of the ecosphere. The components include:

• Biocenosis: The community of living organisms.
• Biotopo: The physical environment.

Biotopo Components

These include:

• Characteristics of the substrate: The support

James Watson: Pioneer of Molecular Biology

James Watson, a U.S. biochemist and geneticist, received the Nobel Prize in Physiology or Medicine in 1962. This prestigious award recognized his groundbreaking work in discovering the double-helix molecular structure of deoxyribonucleic acid (DNA) and its profound significance as a signaling molecule of heredity. Watson also directed the Human Genome Project from 1988 to 1992, resigning to protest the possibility of patenting genes. He is widely considered one of the fathers of modern molecular biology.

Early Life and Education

Watson pursued his studies in his hometown and at Indiana University. In 1947, he obtained the equivalent of a degree in Zoology, and in 1950, he earned his doctorate in Zoology...

Carbohydrate Digestion and Enzyme Action

Digestion begins in the mouth, where salivary amylase converts starch polysaccharides into smaller fragments: dextrin, maltose, and glucose. In the stomach, amylase is denatured, but a slow hydrolysis of polysaccharides continues through the action of hydrochloric acid.

In the small intestine, pancreatic amylase from pancreatic juice supplements the action of salivary amylase. There are also other enzymes in the juice to hydrolyze other polysaccharides. Intestinal juice contains enzymes that convert disaccharides into monosaccharides: maltase, lactase, and sucrase, which respectively hydrolyze maltose, lactose, and sucrose. There are also enzymes that convert various monosaccharides into glucose, the main...

Human Fertilization and Biological Development

Fertilization is the union of one egg and one sperm. This crucial event occurs within the female genital tract, specifically in the fallopian tube. The result of fertilization is the formation of the zygote (the fertilized egg cell).

Understanding Biological Development

Biological development is the set of changes that occur in any living being throughout its life. Development is typically divided into two main phases:

• Prenatal Development: The period ending at birth.
• Postnatal Development: The period beginning at birth and continuing for the remainder of life.

Key Stages of Embryonic Development

Implantation: A Critical Milestone

Implantation is the process where the embryo attaches to the uterine wall....

Bacteria: Structure, Morphology, and Function

Bacteria are microorganisms that can be organized into two main groups: Archaebacteria (often found in extreme conditions) and Eubacteria (more frequent). According to morphology, they can be classified as:

• Bacilli (rod-shaped)
• Cocci (spherical)
• Vibrios and Spirilla (curved or spiral)

Bacterial Components

Key parts of a bacterium include:

• Capsule: Provides a protective function.
• Cell Wall:
  • Gram-Positive (+): Characterized by a lipid bilayer and various layers of peptidoglycan. Stains purple/blue.
  • Gram-Negative (-): Characterized by two lipid bilayers and a thinner layer of peptidoglycan. Stains pink/red.
• Plasma Membrane: Contains invaginations called mesosomes, which are involved in metabolic reactions and

The Rhinencephalon and Limbic System

The rhinencephalon is a structure related to the sense of smell. In humans, it has evolved into an area responsible for instinctive motor activity, autonomic and visceral functions, behavior, emotions, and memory. It forms the beginning of the limbic circuitry, a complex formation that occupies the inner surface of the cerebral hemispheres, with its end at the cingulum.

Klüver-Bucy Syndrome

First described in 1930, Klüver-Bucy syndrome results from a bilateral temporal lobectomy. Its symptoms include:

• Visual agnosia
• Hyperorality
• Hyperphagia
• Hypersexuality
• Flattening of emotions (emotional blunting)

MacLean's Theory on the Limbic System

MacLean's theory suggests that the limbic system is primarily related to the...

Vertebrates vs. Invertebrates

Vertebrates: are generally larger than invertebrates and possess a bony or cartilaginous internal skeleton. This skeleton includes a spine composed of bones or cartilages called vertebrae.

Invertebrates: lack a spine and internal skeleton. They exhibit either radial or bilateral symmetry, undergo metamorphosis to reach adulthood, and their bodies are formed by true tissues.

Mammals: Key Characteristics

Mammals are characterized by:

• The presence of hair on their bodies.
• The ability to regulate their body heat (homeothermy), making them warm-blooded animals.
• Internal fertilization and viviparous reproduction (live birth).
• Pulmonary respiration.
• Double-loop blood circulation with a heart divided into four chambers.
• A skeleton