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

Atomic Foundations of Life

Democritus and Atomic Theory

• All matter is made of atoms.
• Different types of atoms exist.
• Atoms cannot be broken down.

All matter is composed of atoms. The different types of atoms, known as chemical elements, are organized on the periodic table.

Bioelements: Essential Building Blocks

Bioelements are chemical elements that are essential for life. They are categorized into two main types:

Primary Bioelements: Forming 90% of Living Matter

• C = Carbon
• H = Hydrogen
• O = Oxygen
• N = Nitrogen
• P = Phosphorus
• S = Sulfur

Secondary Bioelements: Comprising 10% of Living Matter

• Na = Sodium
• K = Potassium
• Fe = Iron
• Mg = Magnesium

Essential Biomolecules

Molecular Union of Atoms

Biomolecules are molecules that are integral components of living organisms....

Circulatory System and Blood Components

Blood Cells and Platelets

Red blood cells (RBC): They bind oxygen via hemoglobin and transport it through the bloodstream.

White blood cells (WBC): Defend the body from infectious agents.

Platelets: Involved in blood clotting.

Heart Muscle and Valves

Myocardium: Makes the heart contract and relax.

Mitral and tricuspid valves: Let blood flow from the atria to the corresponding ventricles and prevent backward movement.

Semilunar valves: Prevent backflow of blood into the ventricles.

Capillaries and Circulation Types

Capillaries: Perform exchange of substances between blood and cells.

Pulmonary (minor) circulation: Its function is to facilitate the exchange of respiratory gases.

Systemic (greater) circulation: Transports...

Essential Nutrients and Digestion

1. Nutrients are natural products or substances produced to provide our cells with what they need to live. They can be of two types: inorganic and organic.

6. Changes food nutrients into simple substances that cells can enter.

The Digestive Tract Components

7. The digestive tract consists of:

• Cavity: Mouth (teeth and tongue), pharynx, and esophagus.
• Stomach: Cardia, stomach, pylorus.
• Intestines: Small and large intestine, colon, appendix, blind, rectum, and anus.
• Glands: Salivary, intestinal, gastric, pancreas, and liver.

8. Produces digestive juices and pours them into the digestive tract.

9. These are compounds containing a variety of substances, including digestive enzymes.

10. Proteins are part of the digestive juices;...

Fixism (Cuvier) or fijista theory is a belief that holds that existing species have remained essentially unchanged since they were created, therefore, immutable. The fossil remains of animals would be killed in the biblical flood or by the vagaries of nature (as theories such as vis plastica).
Now become (Lamarck 1809): Progression from simple organisms to complex plants and animals, ultimately reaching humans. "Existence impulse towards perfection" - Cap. of the organisms for adaptability to environmental changes - Principle of use and disuse of organs - Inheritance of acquired characteristics.
Compression Fossils and Printing: This occurs when an organism is caught or parts of it are covered by sediments without decomposing, resulting in...

Lysosome

Found in both cell types, it contains large amounts of digestive enzymes. Function: Intercellular digestion.

Smooth Endoplasmic Reticulum (SER)

Found in both cell types, it consists of two large membranes. Function: Aids in cell division, produces substances, and transports lipids.

Cell Wall

Found in plant cells, this is a rigid, thick structure that surrounds the cell from the outside. Function: Provides protection and is waterproof.

Plasma Membrane

Found in both cell types, it is formed by lipids with integrated proteins. Function: Regulates the selective entry and exit of chemicals and is involved in cell communication and recognition.

Centriole

Found in animal cells, these are two perpendicular cylinders. Function: Involved in cell division...

Topic 4: The Internal Environment

Interstitial Plasma: A liquid that originates from blood that has been filtered through the capillaries.
Blood: The medium for the transport of substances that runs inside blood vessels.
Lymph: A liquid that is formed from interstitial liquid and circulates through the vessels and nodes.

Blood Vessels

• Arteries: Carry blood from the heart to the organs.
• Veins: Carry blood from the organs to the heart.
• Capillaries: The union between veins and arteries.

Blood Functions and Composition

Primary Functions

• Nutrition: Carries nutrients.
• Breathing: Participates in the exchange of gases.
• Excretion: Drives the excretory system regulation.
• Defense: Protects the body.
• Thermal: Plays a role in stabilizing the body temperature.

Blood

Biological Energy Processes

As organisms evolved, their energy requirements became more complex. Fermentation was the appropriate process for simple organisms like yeast, bacteria, and other microorganisms.

Respiration is an oxidation-reduction process: the flow of electrons from hydrogen or high-energy sources (like glucose) to low-energy states (CO2 + H2O). This involves coenzymes and cytochromes (A1, C1, C, A3) that ensure the transfer of electrons through the respiratory chain. Cytochrome A3 (cytochrome oxidase) is the final step in the chain, transferring electrons to molecular oxygen to produce water.

Cellular Respiration

Cellular respiration is the process by which cells oxidize glucose to carbon dioxide and water, releasing energy.

Fermentation:

Milk and Dairy

Provides protein, vitamins, and calcium. Recommended serving: 250 mL of milk and 80g of dairy products.

Meat, Fish, and Eggs

Excellent sources of protein, vitamins, and iron. Recommended serving: 100g of meat and 150g of fish.

Legumes and Potatoes

Offer carbohydrates and protein. Recommended serving: 80g of pulses and 180g of potatoes.

Vegetables

Rich in vitamins, minerals, and fiber. Recommended serving: 125g.

Fruits

Packed with vitamins, fiber, minerals, and carbohydrates. Recommended serving: 125g.

Cereals and Grains

Provide carbohydrates. Recommended serving: 80g of pasta or rice, 50g of bread.

Fats, Oils, and Butter

Sources of lipids.

Carbohydrates

Nutrients that provide energy. Simple sugars, like glucose, are the primary source of cellular...

Meiosis I

Prophase I

In Prophase I, homologous chromosomes synapse to form tetrads, and crossing over occurs in the chiasmata. The nuclear envelope degrades.

Metaphase I

During Metaphase I, homologous chromosomes in tetrads are aligned in the equatorial plane of the cell and held together at the chiasmata (the prior crossover sites).

Anaphase I

In Anaphase I, homologous chromosomes separate and move to opposite poles. The sister chromatids remain attached at their centromeres.

Telophase I

In Telophase I, the chromatids decondense, nuclear envelope reorganization occurs, and cytokinesis takes place.

Meiosis II

Prophase II

In Prophase II, in each of the two cells that formed at the end of Meiosis I, the chromosomes condense again.

Metaphase II

During Metaphase

Divisions of the Nervous System

Central Nervous System (CNS)

The CNS consists of the brain and the spinal cord. Its primary role is processing information and preparing appropriate responses.

Peripheral Nervous System (PNS)

The PNS connects the CNS to the rest of the body and the external environment. It is divided into two main systems:

Somatic Nervous System

This system is built by nerves leaving the brain (cranial nerves) and the spinal cord (spinal nerves).

• Function: Connects the CNS with the rest of the body and the environment.
• Action: Its action is voluntary and conscious.

Autonomic Nervous System

This system is built by nerves and ganglia. Two systems are distinguished: the sympathetic and the parasympathetic.

• Function: Connects the CNS with the