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

Biological Anthropology: The Theory of Evolution

From Fixism to Evolution

During the 19th century, the only accepted theory to explain the origin of humans and other species was fixism, which claimed that all species were originally created fully formed and complete, remaining unchanged to the present day. In essence, species were considered immutable.

Fixism had two primary approaches:

• Creationist: A higher being created the different species from the beginning.
• Naturalist: Nature, through natural processes, produced the various species.

At present, it is an accepted scientific fact that all animal and plant species are the result of the evolution of ancestral species.

1. The Theory of Evolution: Lamarck

The first scientist to propose a comprehensive...

Cells are the basic structural and functional units of life. Living cells contain structures called membranes, and they carry genetic material (DNA and RNA) capable of self-replication and of directing the synthesis of their proteins. Plant cells, animal cells and other eukaryotes are the result of the evolution of prokaryotic organisms similar to current bacteria. The precursors of eukaryotic cells are urcariots, which lost their capsule, increased in size, incorporated internal structures and developed a membrane system and a consistent cytoskeleton.

The Endosymbiotic Theory

The endosymbiotic theory (proposed by Lynn Margulis) holds that the urcariota could have engulfed bacteria, which became endosymbionts that constituted organelles within...

Theories on the Origin of Life

Panspermia

Panspermia suggests that life forms originated elsewhere in the universe and were transported to Earth.

Oparin and Miller's Hypothesis (Abiogenesis)

The Oparin-Miller hypothesis posits that under the conditions of the primitive Earth, simple biomolecules could spontaneously generate simple organic molecules.

Historical Views and Evolutionary Dating

Fixism and the Static Universe

The ideas of Aristotle and Plato, often incorporated into Christian thought, supported a fixed, static universe (Fixism).

Molecular Clocks

Molecular clocks are used to calculate the evolutionary proximity of species. This method is based on the principle that the genetic difference between two species depends on the time elapsed since...

Types of Transplants

• Autotransplant: Donor and recipient are the same patient. Used for tissues or organs such as skin portions or bone.
• Isotransplant: Donor and recipient are identical twins. No rejection occurs.
• Xenotransplant: Donor and recipient are distinct species (e.g., using pig heart valves in humans). There is a risk of rejection.
• Allogeneic Transplant: Donor and recipient are of the same species but genetically different. This is the most common type, and there is a risk of rejection.

Immune Rejection Problems

Our immune system distinguishes self from foreign. If it locates foreign tissue, it attempts to destroy it. This is of great importance when dealing with viruses and bacteria, but it also applies to donor tissue. It is crucial that...

Proteins

Proteins are polymers of amino acids, also known as polypeptides. They are essential biomolecules, as nearly all life depends on them.

Protein Structural Levels

Proteins can have thousands of amino acids, and therefore, their thousands of atoms can adopt a wide variety of positions. Importantly, a protein consists of thousands of amino acids linked one after another through peptide bonds, forming long linear chains. However, the final spatial structure of a protein is not a linear chain; it adopts a specific three-dimensional form in space, which is essential for its function.

Primary Structure

Consists of the amino acid sequence of a protein. It is the most basic and arguably the most important level of structural organization.

Secondary

Key Concepts in Health and Disease

Risk Factor

A risk factor is any circumstance or detectable characteristic in a group of persons related to the probability of developing or producing disease.

Public Health

Public health involves the application of the scientific method to problems of health and disease, considered as a subject for the community.

Preventive Medicine

Preventive medicine is a branch of medicine dealing with preventing, on the individual, family, or population group level, the appearance, development, and maintenance of disease, based on the knowledge of medical science.

Disease

Disease is a physical or mental disorder that causes alterations in the normal functioning of the body, whether at the physical or mental level.

Pathology

Pathology...

Active Transport Across Cell Membranes

Active transport enables certain types of proteins within the cell membrane to move substances. This process consumes energy, typically provided by ATP molecules, allowing transport against a concentration gradient.

The Sodium-Potassium Pump

The sodium-potassium pump is a transmembrane protein that actively transports sodium ions (Na+) out of the cell and potassium ions (K+) into the cell. This counter-gradient transport exhibits ATPase activity, meaning it breaks down ATP to power the movement. For every three Na+ ions pumped out, two K+ ions are pumped in, consuming one ATP molecule. This action generates potential differences across the membrane, contributing to the membrane potential. This potential is...

Glycolysis

Glycolysis: glucose + 2 ADP + 2 Pi + 2 NAD+ → 2 ATP + 2 pyruvate + 2 NADH + 2 H+

Step 1

Hexokinase phosphorylates glucose, keeping it inside the cell. This is a coupled reaction, making it spontaneous.

Step 2

Isomerisation.

Step 3

ATP coupling makes the non-spontaneous reaction spontaneous (PFK).

Step 4

Lysis.

Step 5

DHAP is converted to G3P by TPI.

Step 6

G3P dehydrogenase catalyses a redox reaction: NAD+ → NADH + H+.

Step 7

Phosphoglycerate kinase catalyses substrate-level phosphorylation of ADP, and the payoff phase repays the ATP debt.

Step 8

The phosphate is moved from C3 to C2 via phosphoglycerate mutase.

Step 9

Enolase dehydrates the substrate to form enol, forming PEP.

Step 10

Pyruvate kinase catalyses second-level phosphorylation of ADP,...

Applications and Skills

Comparison of Water and Methane Thermal Properties

Water and methane are small molecules with similar covalent structures, yet their physical properties differ significantly due to water's polarity.

Since water is polar, it has stronger intermolecular attraction (hydrogen bonds) and therefore has a much greater specific heat capacity, latent heat of vaporization, melting point, and boiling point.

Water as a Coolant in Sweat

• Water is essential to living organisms.
• Water

The Locomotor System

The locomotor system is made up of the skeletal system and the muscular system.

The Skeletal System

The skeletal system is formed by bones and joints.

Purpose of the Skeletal System

• To serve as an internal framework for our bodies.
• To protect organs and internal tissues.
• To provide anchorage support for muscles.
• To manufacture blood cells.
• To serve as a reserve store of calcium and phosphorus.

Bones

Bones are organs composed of compact bone tissue on the outside and spongy bone tissue at the core. To avoid friction, the ends of our bones are covered with cartilage. The holes in the spongy bone tissue are filled with bone marrow. There are two types: red bone marrow, in which blood cells are produced, and yellow bone marrow, which...