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

Human Body Systems: Core Functions

The human body relies on several interconnected systems to maintain life and process energy.

The Digestive System

This system is responsible for taking in solid and liquid foods, preparing and transforming them so that nutrients can be distributed to every cell in the body.

The Respiratory System

The respiratory system captures the oxygen necessary for cells and removes carbon dioxide produced during cellular metabolism.

The Circulatory System

The circulatory system transports nutrients and oxygen to cells and removes waste substances.

The Excretory System

This system expels the waste products of cellular metabolism, which are carried by the circulatory system, outside the body.

Components of the Digestive Tract

The...

Blood Composition

Blood composition: Blood is a connective tissue made up of plasma and different cells. Blood is known as the "sanguine tissue."

Plasma: Plasma is a liquid that makes up about 90% of blood. It contains a variety of dissolved substances: proteins, carbohydrates, lipids and mineral salts (such as O₂, CO₂ and nitrogen). Plasma without some proteins (such as fibrinogen) is called serum. When blood solidifies it forms a coagulum (clot).

Blood Cells

Red blood cells or erythrocytes: Biconcave cells that lack nuclei, are flexible and deformable. They contain hemoglobin, which transports oxygen and carbon dioxide.

White blood cells or leukocytes: Cells with a large nucleus that come in 5 types: neutrophils, eosinophils, basophils, monocytes...

The Human Respiratory System

The respiratory system is responsible for gas exchange, capturing oxygen from the air and delivering it to the blood, while the blood collects carbon dioxide to remove it from the body.

Key Respiratory Functions

• Airway: Collecting ducts where air is oxygenated.
• Lungs: The site of gas exchange between blood and air.
• Cellular Respiration: A process where combustion occurs in food to obtain energy.

Air Conditioning and Vocalization

The air entering the lungs must be clean, moist, and warm. Mucus is responsible for moistening the air and trapping dust and microbes. Additionally, the vocal cords vibrate to produce sounds as air passes through, which are then modified by the language, lips, and teeth.

Anatomy of the Respiratory

Anatomy and Functions of the Human Brain

The brain is the largest organ of the Central Nervous System (CNS) and is divided into several parts, each with specific functions. Its structure is organized into lobes:

• Frontal Lobe: Located at the front of the brain, it is responsible for functions such as thinking.
• Parietal Lobe: Positioned behind the frontal lobe, it is responsible for processing sensory information related to touch, temperature, and pain.
• Temporal Lobe: On the sides of the brain, it is essential for sound processing.
• Occipital Lobe: At the back of the brain, it specializes in visual processing.

Key Brain Structures

• Cerebellum: Located at the lower back of the brain, its main function is to coordinate muscle movements.
• Medulla Oblongata:

Prokaryotic Cells: Bacteria

• Bacteria capsule: The outer jelly-like layer.
• Bacteria wall: The rigid structure that maintains cell shape.
• Fimbriae: Multiple short appendages used to attach to surfaces.
• Flagellum: A long appendage used for movement.
• Plasmid: A small ring of DNA.
• Ribosomes: Organelles that synthesize proteins.
• Nucleoid: The area where genetic material is concentrated.
• Cell membrane: A selective barrier.
• Cytoplasm: Everything inside the cell excluding the nucleus.

Eukaryotic Cells: Animal Cells

• Mitochondrion: Produces energy for the cell.
• Cell membrane: A selective barrier.
• Cytoplasm: Everything inside the cell excluding the nucleus.
• Nucleus: The site where ribosomes are made.
• Cytoskeleton: A network of protein filaments in the cytoplasm.
• Ribosomes:

Laboratory Exam Questions

Cell Functions and Observations

2) Write down the function of the parts that you see in the sample. Intense blue?

• Cell membrane: Separates the inside and outside of the cell, and controls what goes in and what goes out.
• Nucleus: Contains the genetic information and the nucleolus, where ribosomes are produced.
• Cytoplasm: A gel-like fluid where organelles are located.
• Mitochondria: Organelles that break down sugars and produce energy.

Yes.

3) Which part of the cell stains the most?
The cytoplasm.

4) Do you see any organelles? Why?
No, because they are so small.

5) What are the small blue dots in the samples?
Organelles.

Levels of Biological Organization

• Atom: Consists of the atoms of the chemical elements that make up living things.

Key Biological Terms

• Notochord: A flexible rod to which muscles are attached.
• Agnathans: The most primitive fishes that lack a jaw.
• Air bladder: An internal sac that fills with gas to regulate buoyancy and depth.
• Tadpoles: Aquatic larvae that emerge from eggs laid in the water.

Mammals

Mammals are endothermic vertebrates. While many live on land, some are aquatic or adapted for flight.

• Body: Covered with hair for temperature regulation and camouflage.
• Mammary glands: Produce milk for offspring.
• Limbs: Share anatomical patterns adapted to their specific environment.
• Physiology: Possess teeth and breathe using lungs.
• Reproduction: Internal fertilization.

Types of Mammals

• Monotremes (e.g., platypuses): Oviparous, possess a leathery beak, and lack teeth.
• Marsupials

The Spinal Bulb

The spinal bulb (medulla oblongata) is an extension of the spinal cord. It consists of grey matter surrounded by white matter. There are neural pathways that carry information, and these pathways cross; thus, the right side of the brain receives information from the left side of the body, and the left side of the brain receives information from the right side of the body.

Functions of the Spinal Bulb and Hypothalamus

It performs different functions, including:

• Regulating the process of sleep.
• Regulating visual and auditory reflexes.
• Regulating blood pressure.
• Coordinating communication between the cerebrum and other parts of the brain.

It contains an important part called the hypothalamus, which controls the pituitary gland, which in...

Lipids: Characteristics and Classification

Lipids are diverse substances characterized by their insolubility and oily appearance. They are categorized into three main groups:

• Fats: Energy-dense molecules. Depending on their chemical composition, they are classified as saturated fats (mostly of animal origin) or unsaturated fats (mostly of plant origin, often liquid and referred to as oils).
• Membrane lipids: These form the structures of cell membranes and organelles, such as phospholipids and cholesterol.
• Lipids with regulatory functions: These include certain vitamins (A and D) and sexual hormones.

Proteins: Structural Building Blocks

Proteins are essential structural molecules, comprising about half of the dry weight of our cells. They are formed...