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

Understanding Circulation and Blood Disorders

Pulmonary and Systemic Circulation

Pulmonary Circulation: Circulation through the lungs.

Systemic Circulation: Circulation to the rest of the body.

Vena Cava: Carries deoxygenated blood.

Coronary Heart Disease

Coronary Heart Disease: Refers to any disease that results in blockage of the coronary blood supply to part of the heart's muscular wall. The blockage causes partial deprivation of oxygen to the affected part and may result in the death of muscle cells.

Effects of Coronary Heart Disease

If a large part of the heart is affected, the person may die instantly. If a small region is affected, it may recuperate.

Atherosclerosis

Atherosclerosis: The most common form of hardening of the arteries. It begins...

The Structure of DNA and the Human Genome

In 1953, James Watson and Francis Crick established the molecular structure of DNA. The genetic information of a living organism's cells is stored in chromosomes. The complete set of this genetic information is called the genome.

The Human Genome

The human genome sequence was published in 2003. It consists of 23 pairs of chromosomes and contains approximately 20,000 protein-coding genes. These genes make up only about 2% of the entire genome. The remaining 98% of the DNA, which includes introns, is non-coding. This portion was once referred to as "junk DNA," but its functions are still being studied.

DNA Composition

DNA is a molecule composed of two chains, forming a double helix. Each chain is made of many...

Food Chains and Trophic Levels

Living beings require material and energy, obtained from nutrients in food, to perform vital functions such as nutrition, relationships, and reproduction. Living things are classified into three groups or trophic levels:

• Producers: These are autotrophic organisms that produce organic matter from inorganic substances. Most are photosynthetic, using sunlight to convert water, mineral salts from the soil, and carbon dioxide from the atmosphere into organic material. This level is formed by plants, algae, and certain bacteria.
• Consumers: These are heterotrophic organisms that feed on organic matter from other living beings. Consumers are categorized into types:
  • Primary Consumers: They feed on producers. Herbivores are

How Infectious Diseases Spread

Infectious diseases can spread through various means:

• Water: Consuming water contaminated with feces from humans or animals.
• Food: Eating fruits and vegetables irrigated with contaminated water or improper food handling.
• Animals: Through disease vectors. For example, the Anopheles mosquito transmits malaria.

Stages of Infectious Disease Development

The development of infectious diseases involves several stages:

• Infection: The organism enters the body.
• Incubation Period: The time from infection to the appearance of symptoms.
• Period of Manifestation: The disease is fully manifested, with symptoms like fever and pain.
• Period of Decline: Symptoms subside due to the immune system and medications.
• Convalescence: The patient recovers

Differences Between Living and Non-Living Things

Living things exhibit several defining characteristics:

• They are made of cells and perform the three vital functions: relationship, nutrition, and reproduction.
• They are composed of essential biomolecules: carbohydrates, lipids, proteins, and nucleic acids.

Cell Theory Fundamentals

Cell Theory establishes three core principles:

1. All living things are made up of cells.
2. Cells are formed from pre-existing cells.
3. A cell performs the three vital functions (relationship, nutrition, and reproduction).

Cell Types and Structure

Cell Types

• Prokaryotes: These are the most primitive cells and do not have a defined nucleus.
• Eukaryotes: These cells possess a nucleus where the genetic material is stored.

Basic Structure

Renal Physiology and Homeostasis

Appellative or conative: focuses on the receiver. Function of office and asks.

1. Fundamental Nephron Processes

The two fundamental processes that occur in the nephron for urine production are:

• The leakage of toxic components from the blood to be eliminated through the urine.
• The reabsorption of fluids and salts.

2. Maintaining Body Water

Maintaining body water refers to the regulation of the gain and loss of body water.

3. Critical Homeostatic Functions

The most critical homeostatic function that occurs in the body is the regulation of the chemical composition of body fluids.

4. Glomerular Filtration

Glomerular filtration involves the elimination of toxic products from the blood, as well as the control of the volume and...

Respiratory System Anatomy and Function

Oxygen (O₂) intake transforms into ATP. The respiratory pathway includes the nostrils, pharynx, larynx, trachea, bronchi, bronchioles, and alveoli.

• Nares (Nostrils): The yellow region is associated with smell, while the reddish region warms the air.
• Choana: The communication hole between the nasal fossae and the nasopharynx.
• Bronchioles: These allow CO₂ output through the lungs.
• Alveoli: The primary site for gas exchange.

Upper and Lower Respiratory Tracts

The upper respiratory tract consists of the mouth, pharynx, and larynx. The pharynx is divided into the nasopharynx, oropharynx, and laryngopharynx.

• Larynx: A cartilaginous structure connecting the pharynx with the trachea; it is responsible for phonation.
• Epiglottis:

The Brain and Consciousness

The Cerebellum

Phases of Infectious Diseases

All infectious illnesses typically follow three phases:

• Incubation: The time that elapses between infection and the appearance of disease symptoms.
• Overt Disease: Symptoms and signs of the disease are clear.
• Convalescence: The phase when the pathogens are completely eliminated. The body recovers lost health and repairs damage.

Prevention of Infectious Diseases

Prevention involves two main approaches:

• Following healthy lifestyle habits.
• Vaccination: The introduction of killed or weakened microorganisms into a healthy person's body, prompting the immune system to produce antibodies against the specific disease.

Treating Infectious Diseases

Treatment often involves chemotherapy, which is the use of chemical substances. There...

The Biological Function of Reproduction

The primary function of reproduction is to create new individuals, ensuring the survival of the species. Unicellular organisms usually reproduce through the division of their single cell.

Reproduction in Animals

Reproduction in animals can be classified as sexual, asexual, or alternating.

Asexual Reproduction in Animals

Asexual reproduction involves no gametes and requires only a single individual, known as the progenitor. The resulting beings are genetically identical to the parent. Key mechanisms include budding and fragmentation.

Fragmentation

The parent organism is divided into pieces, and each piece develops to produce a new individual. Fragmentation can be:

• Spontaneous: A normal mechanism of reproduction.