Biological Organization, Cell Structure, and Nutritional Health

Biological Organization and Cellular Structure

Levels of Biological Organization

These levels grade the complexity of organization based on specific goals.

• Subatomic Level

  Particles corresponding to the atoms that make up protons, neutrons, and electrons.

• Atomic Level

  Composed of atoms, which are the smallest constituents of matter.

• Molecular Level

  Molecules that result from the binding of different atoms.

Chemical Components of Life

• Inorganic Molecules: Found in both living matter and inert substances (e.g., water and mineral salts).
• Organic Molecules: Exclusively found in living matter (e.g., carbohydrates, lipids, proteins).

Structural Levels of Life

• Cellular Level

  The first biotic level that is alive. Examples include epithelial, muscle, and osseous cells.

• Tissue Level

  A set of specialized cells with the same function and origin.

• Organ Level

  Organs are formed by different tissues accustomed to performing a particular function.

• System and Apparatus Level

  A system is a set of organs performing a specific function, often composed of the same type of tissue. An apparatus corresponds to a different set of organs with specific functions involved in various, higher-level functions.

• Organismal Level

  The overall function of the living being. Organisms include both unicellular and pluricellular (many cellular) entities.

Types of Cells

• Prokaryotic Cell

  Cells without a nucleus (kernel) and not limited by a single membrane.

• Eukaryotic Cell

  The nucleus is surrounded by a nuclear membrane. In contrast, in prokaryotes, this membrane is absent, and the nuclear material is scattered throughout the cytoplasm.

Understanding Nutrition, Diet, and Related Disorders

Fundamentals of Nutrition

• Nutrition Defined

  The set of processes by which an organism obtains matter and energy necessary to produce its own substances and perform vital functions.

• Food

  The solid and liquid substances that constitute our diet, essential for our nutrition.

• Nutrients

  Chemical substances obtained from food. They are categorized into two types:
  • Inorganic Nutrients: Water and mineral salts.
  • Organic Nutrients: Carbohydrates, lipids, and proteins.

• Diet

  The set of solid and liquid substances consumed as food throughout the day.

Healthy Eating and Imbalances

The Balanced Diet

A diet is considered balanced (or equilibrated) when it provides all necessary types of food and sufficient quantities of energy and nutrients to cover the body's daily energy expenditure. A balanced diet includes three main functional groups:

1. Energy Foods
2. Plastic (Building) Foods
3. Regulator and Trainer Foods

Nutritional Disorders

• Undernutrition

  Caused by the lack of essential nutrients, mainly due to an inadequate diet or lack of food.

• Obesity

  Excess body fat, which usually involves high body weight. Causes may include hereditary factors or endocrine disorders, but the most common cause is excessive consumption of high-energy foods.

• Anorexia Nervosa

  Characterized by an intense fear of weight gain and a distorted perception of one's own body, which causes the person to judge themselves as fat even when their body weight is below normal.

• Bulimia Nervosa

  Characterized, like anorexia, by preoccupation with weight and body figure. In this case, the person may eat excessively (binge) even when not hungry, often in secret.

Apparatus Involved in Nutrition

The apparatus involved in nutrition typically include the Digestive, Respiratory, Circulatory, and Excretory systems.