Notes, summaries, assignments, exams, and exercises for Biology for Secondary education

The Endocrine System

The endocrine system consists of a set of glands that produce hormones to regulate and coordinate various bodily activities. Glands respond to stimuli by producing hormones and releasing them into the bloodstream, where they travel to reach their destination: target cells, which they stimulate or inhibit.

The Neuroendocrine System

The endocrine system is regulated by the nervous system, particularly the hypothalamus. Located beneath the cerebral hemispheres, the hypothalamus is part of the nervous system but also functions as an endocrine gland. It releases neurohormones that control the pituitary gland, which in turn produces hormones that act on other glands. These hormones exert effects on target cells and provide feedback...

Mycolic Acids

Mycolic acids are beta-hydroxy acids with branched, very long chains. They form a unique component of the bacterial cell wall skeleton, specifically associated with peptidoglycan (PG) and arabinogalactan.

Properties Conferred by the Cell Wall (AFB)

• Appearance: Waxy consistency of colonies in Petri dishes.
• Liquid Growth: Forms clumps in liquid media.
• Waterproofing: Provides high resistance to desiccation and antibacterial agents, including detergents, oxidants, acids, and bases.

Cellular Components

Nucleoid

Represented by the bacterium's chromosome, consisting of circular, single-stranded DNA.

Plasmid

Extrachromosomal genetic elements (DNA) with self-replicating capacity.

Spore

Spherical or ovoid refractile structures included within the vegetative...

Understanding Diet and Health Conditions

Essential Dietary Concepts

• Balanced Diet: Consuming the correct nutrients in the appropriate proportions for optimal health.
• Malnutrition: A condition occurring when either too much or too little of a nutrient is consumed, leading to health problems.
• Kwashiorkor: A severe form of malnutrition caused by insufficient protein intake, primarily affecting children and leading to poor growth and development.
• Myocardial Infarction (Heart Attack): Occurs when a part of the heart's wall dies due to lack of blood supply.

Obesity and Associated Health Risks

• Causes of Obesity: Primarily results from consuming too much fat and calories.
• Health Complications: Obesity is a significant health problem, contributing to conditions

Types of Illness

There are several types of illness:

• Physical illness: Caused by injury, infection, or a degenerative process of the organism.
• Mental illness: May result from a malfunction of the brain.
• Social diseases: Can be caused by the existence of a violent social environment.

Defining Health and Illness

Health is a state of complete physical, mental, and social well-being. Illness is the state in which a person's health is disturbed.

Violence: Impact on Health and Society

Violence is a detrimental social issue, often originating in childhood. It negatively influences health, potentially harming or causing the death of loved ones, family members, or neighbors.

Understanding Infectious Diseases

Infectious diseases are caused by pathogens (such as...

Plasma Membrane

Structure

The plasma membrane is a flexible and deformable thin envelope that surrounds all cells.

Function

Its mission is to limit the cellular content, but it allows the passage of substances.

Cell Wall

Structure

The cell wall consists of cellulose fibers (a carbohydrate) that confer high resistance and prevent its distortion. This is why plant cells have fixed and often polyhedral forms. Sometimes, the cell wall is covered with a waxy substance that waterproofs it.

Function

It protects the cell and determines its shape, allowing the exchange of substances through pores.

Cytoplasm

The cytoplasm is the internal environment of the cell, where various organelles are suspended.

1. Hyaloplasm

   Structure

   The hyaloplasm is formed by a viscous fluid

Carbohydrates: Primary Energy Source

Carbohydrates are chemical compounds of oxygen, carbon, and hydrogen, synthesized by plants through the action of solar energy. Sugars are found in bread, grains, fruits, and vegetables.

They serve as the first major energy substrate, providing between 50% and 60% of the total energy necessary for movement and basic functions. They are also essential to feed the brain.

Fats (Lipids)

Fats (lipids) consist of hydrogen, oxygen, and carbon that form a chain, categorized as saturated or unsaturated fatty acids.

Sources of Fats

• Saturated Fats: Meat, eggs, and dairy.
• Unsaturated Fats: Olive oil or sunflower oil.

Fats are indispensable; they serve as an energy source, help regulate body temperature (Tª), and transport...

Cell Theory Fundamentals

• The Cell as the Structural Unit: All living beings are composed of one or more cells.
• The Cell as the Functional Unit: Cells perform all metabolic processes essential for life.
• All Cells Arise from Pre-existing Cells: Cells originate from the division of other cells.
• The Cell as the Genetic Unit: Cells contain the hereditary information of all living beings.

Biological Levels of Organization

Abiotic Levels:

• Subatomic Particles: Elementary particles that form atoms.
• Atoms: The smallest part of a chemical element.
• Molecules: A combination of two or more identical or different atoms.
• Macromolecules: The union of several molecules.
• Organelles: The union of supramolecular structures forming a complex cellular structure with a determined

Understanding the Human Genome

The study of the human genome involves understanding the complete set of DNA molecules organized into 23 chromosomes. To fully comprehend the information it contains, we must know the sequence of its bases. This knowledge has been instrumental in identifying the human genome. To grasp its immense scale, imagine a library 18 stories high. Current research focuses on deciphering the function of individual genes and how they interact to govern the organization and functioning of the human body.

Benefits of Human Genome Knowledge

Knowing the human genome offers significant advantages. Primarily, it accelerates the identification of disease-causing genes and helps identify individuals who are carriers of diseases. Understanding...

Infectious Disease Transmission Routes

• Air: Tuberculosis, diphtheria, cholera.
• Water and Food: Typhoid, salmonellosis, trichinosis.
• Animal Vectors: Malaria, sleeping sickness.

Infection and Infectious Agents

Infection results from the establishment and multiplication of microorganisms within the body. Microbial infection follows these four phases:

1. Colonization of the cell surface.
2. Penetration of defensive barriers.
3. Invasion.
4. Propagation and production of abnormalities in tissues and organs.

Bacterial Diseases and Toxins

Bacterial toxins are substances produced by bacteria, either secreted externally or retained within the bacterial cell.

• Tuberculosis: Spread through the air; causes serious pulmonary injury.
• Cholera: Transmitted via contaminated water and

Mental and Neurodegenerative Disorders

Schizophrenia typically appears after adolescence. It is a personality disorder in which individuals fail to distinguish the real from the imaginary world, often experiencing delusions and obsessions. Dementia involves the gradual loss of mental capacity and intellectual functions. This includes senile dementia (occurring at 80 years or older) and presenile dementia (occurring before the age of 80).

Neurodegenerative Diseases

Neurodegenerative conditions are caused by neuronal destruction or dysfunction in determined Nervous System (SN) areas. Common types include:

• Parkinson's: This affects nerve cells in the substantia nigra (nucleus niger). These neurons control involuntary movement and muscle coordination.