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

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

Relation Functions in Organisms

Relation functions are those that allow a living being to receive information from the outside or inside, and respond to it in the most appropriate way for their survival.

Components of Relation Functions

Organisms must have the means to receive the stimuli (receptors), systems for processing data (coordination systems), and mechanisms to implement the response (effectors).

Stimuli

Stimuli are changes that occur in the external environment, but also those taking place within their own organism.

External Stimuli

These are changes occurring in the environment that receptors detect. Examples: wind, rain, etc.

Internal Stimuli

These are variations that occur within the body. Examples: temperature self-regulation, urination,...

Cellular Foundations and Body Tissues

Understanding Cell Components

• Cell Membrane: The thin layer that wraps the cell and separates it from the external environment.
• Cytoplasm: The contents of the cell, excluding the nucleus.
• Nucleus: A structure bounded by a double membrane, traversed by pores that allow substance exchange between the nucleus and the cytoplasm. Contains DNA.

Metabolic Processes

• Catabolism: A set of reactions that break down complex molecules to provide energy for cellular activities.
• Anabolism: A set of reactions that build complex molecules from simpler ones, requiring energy.
• Diffusion: Small molecules like oxygen and carbon dioxide freely pass through the plasma membrane.

Cell Specialization and Organization

• Cell Specialization:

Health and Illness

Health: State of complete physical, mental, and social well-being.

Disease: State in which a person's health status is altered by either a physical, mental, or social cause.

Types of Diseases

Physical Diseases

Caused by injury, infection, or a degenerative process of the organism. Their symptoms are recognizable, which facilitates treatment. They are classified as:

• Infectious Diseases: Caused by any pathogen that reproduces within our organism.
• Non-Infectious Diseases: Due to other causes.

Mental Diseases

Caused by a malfunction of the brain, resulting in diminished mental capacity or any alteration of conduct.

Social Ills

Caused by the existence of a social, violent, or educational disadvantage.

Transmission of Infectious Diseases

Common

Embryo Development

Embryo development encompasses the stages from fertilization through the eighth week of pregnancy. During this period, cells divide and differentiate in size, shape, and content, specializing according to the specific tissues and functions they will eventually perform.

Fetal Development

Fetal development covers the period from two months of pregnancy until birth. The fetus floats inside the amniotic sac, receiving oxygen and nutrients through the placenta and umbilical cord.

Human Sexuality

Sexuality evolves throughout a person's life, differing at each age from childhood to old age. It is influenced by society and the evolution of others; sexual behaviors also vary significantly between cultures.

Sexually Transmitted Diseases

Living Organisms: An Introduction

What Defines a Living Being?

A living being, formed by one or more cells, carries out vital operations, including:

• Nutrition: The set of processes by which living things obtain or exchange matter and energy with the environment.
• Relationships: The ability of living beings to perceive changes in the environment and respond to them in the most suitable way for their survival.
• Reproduction: The ability to produce offspring that develop and maintain the characteristics of their parents over time.

Types of Organisms

Unicellular Beings

These organisms consist of a single cell that performs all vital functions. Their shape is highly variable and adapted to their lifestyle.

Colonies

Colonies are groupings of single-celled organisms...

Organelles

An organelle is a small, specialized structure within a cell that performs a specific function. Examples include mitochondria and lysosomes.

Functions of the Cell or Plasma Membrane

1. This structure surrounds the cell, separating it from the external environment.
2. It forms a barrier that allows the cell to incorporate water and nutrients and remove metabolic waste.

Ribosomes

Ribosomes are organelles formed by the combination of different proteins and RNA (ribonucleic acid).

The Golgi apparatus is an organelle that receives immature proteins from the rough endoplasmic reticulum (RER) and releases vesicles containing mature proteins.

• RE: Endoplasmic reticulum
• PER: Ribosomes that have completed the synthesis of a protein

Location and Structure of

Stages of Childbirth

1. Stage of Expansion

This stage involves uterine wall contractions. The pressure from cervical dilation also causes the amniotic sac to rupture, commonly known as the "waters breaking."

2. Expulsion Stage

Contractions last approximately 30 minutes. Once the baby is born, the umbilical cord is tied and cut. The baby's first cry activates the respiratory system.

3. Delivery Stage

Occurring 15 minutes after birth, contractions cause the placenta to detach from the uterine lining for expulsion.

Assisted Reproduction Techniques

Used in cases of difficulty or inability to conceive:

• Artificial Insemination: Introducing semen into the female genital tract, often used for low sperm count or mobility issues.
• In Vitro Fertilization (IVF) and

Understanding Human Reproduction

Human reproduction is a complex biological process that ensures the continuation of our species. It involves the maturation of reproductive organs, the formation of specialized cells called gametes, and a series of intricate cycles leading to fertilization, pregnancy, and birth.

Puberty: The Onset of Reproductive Maturity

Puberty marks the stage when an individual's reproductive organs mature and become functional. In females, it typically begins with the first menstruation.

Male Reproductive System

The male reproductive system is designed for the production and delivery of sperm. Key components include:

• Testicles: Located within the scrotum, these two organs produce sperm and the male hormone testosterone.
• Accessory

Temperature Effects on Water Oxygen

Temperature: The amount of dissolved oxygen in water depends on temperature differences between the surface and deep oceans. These differences create currents that redistribute nutrients and oxygen.

Relations Between Organisms

In a community setting, multiple relationships exist:

• If the relationship occurs between two individuals of the same species, it is called intraspecific.
• If it happens between different species, it is called interspecific.

Competition

Competition occurs when two individuals use the same resource. Intraspecific competition is common because individuals of the same species have similar needs and compete for the same resource.

Cooperation

Cooperation: A type of relationship between individuals...