Notes, summaries, assignments, exams, and problems for Biology

What is Atherosclerosis?

Atherosclerosis, literally meaning hardening of the arteries, is a degenerative disease characterized by narrowing of the arteries. Deposits of lipids, fibrous cells, muscle cells, cholesterol crystals, and calcium build up on the artery walls. This process develops slowly.

When narrowing of the arteries prevents blood flow, it leads to ischemia (lack of blood supply to the tissues).

Understanding Atherosclerosis Development

• Atherosclerosis is a widespread condition, although there are notable differences in incidence based on geography, race, and sex.
• Although the term "atherosclerosis" is relatively modern, traces of artery hardening have been found in mummies from the Fifteenth Dynasty of Egyptian pharaohs (dating back

1. Health and Disease

1.1. Definitions

Health: A state of complete physical, mental, and social well-being, not merely the absence of disease.

Disease: A change in health status, i.e., a temporary or permanent loss of physical, mental, and social well-being.

Quality of Life: The comfort level, happiness, and satisfaction in a person that allows them to act and feel positively about their lives. This depends on their physical and mental health, their level of independence, and social relationships. One of the main indicators is life expectancy at birth.

1.3. Genes, Lifestyle, and Health

There are genetic diseases due to alterations in the genome (e.g., Down syndrome, hemophilia, or certain types of diabetes).

In other cases, the genotype determines... Continue reading "Health, Disease, and Infectious Diseases: A Comprehensive Overview" »

Uric Acid Stones: Causes, Treatment, and Diet

Uric acid stones are associated with the production of acidic urine.

Treatment for Uric Acid Stones

• Increase fluid intake.
• Increase urine pH to 6.0-6.5.
• Adopt a diet rich in alkaline-forming foods, supplemented with citrate or bicarbonate.

Dietary Considerations for Uric Acid Stones

Acid-Forming Foods (Potentially Acidic Residue)

• Meat: Beef, fish, game, seafood.
• Dairy: Eggs, cheese.
• Fats: Bacon, walnuts, Brazil nuts, hazelnuts.
• Grains & Baked Goods: Flour, bread (especially whole wheat), cereal, biscuits, pasta, rice, cakes.
• Vegetables: Corn, lentils.
• Fruits: Blueberries, plums.

Alkaline-Forming Foods (Potentially Basic Residue)

• Dairy: Milk and milk products, cream, whey.
• Fats: Almonds, chestnuts, coconut.
• Vegetables:

Types of Illness

There are several types of illness:

• Physical illness: Caused by injury, infection, or a degenerative process of the organism.
• Mental illness: May result from a malfunction of the brain.
• Social diseases: Can be caused by the existence of a violent social environment.

Defining Health and Illness

Health is a state of complete physical, mental, and social well-being. Illness is the state in which a person's health is disturbed.

Violence: Impact on Health and Society

Violence is a detrimental social issue, often originating in childhood. It negatively influences health, potentially harming or causing the death of loved ones, family members, or neighbors.

Understanding Infectious Diseases

Infectious diseases are caused by pathogens (such as... Continue reading "Foundations of Health: Diseases, Risks, and Well-being" »

Population Autoregulation

A population is constituted by a set of individuals of the same species living in a given location. Environmental resistance is a set of factors that prevent a population from reaching its maximum biotic potential. These factors include:

• External factors: These may be biotic (predators, parasites) or abiotic (climate change, food shortages, disasters, etc.).
• Internal factors: Increasing population density adversely affects individuals.

There are two forms of reproduction strategies:

• r strategists: These are simple organisms with very high biotic potential. They have many offspring with no parental care. Consequently, only a few manage to survive and reach adulthood. The population size remains relatively stationary (e.g.

1. How Viral Structure Affects Digestive System Impact

The structure of a virus, particularly its capsid and genetic material, significantly influences its ability to infect and impact the digestive system. These structural characteristics are crucial for classifying viruses into clinical and subclinical categories based on their pathogenic potential.

2. Digestive System Viruses: Transmission Methods

Viruses affecting the digestive system can be transmitted through several common mechanisms:

• Common Vehicle Transmission: Via contaminated food and water.
• Fecal-Oral Transmission: Direct or indirect contact with infected feces (e.g., Hepatitis A).
• Direct Contact: Physical contact with an infected person or contaminated surfaces (e.g., some forms of Herpes

Industrial Composting Processes

Compost is created through a biological process, relying on aerobic fermentation (with air). This technique ensures hygienic processing of organic waste into a homogeneous substance easily assimilated by the soil. The process involves a microbial population, including bacteria, actinomycetes, and fungi (responsible for 95% of the activity), as well as algae, protozoa, and cyanophytes.

Suitable Organic Materials for Composting

• Plants from the garden or orchard
• Adventitious herbs or "weeds" (before they seed)
• Poultry manure and bedding
• Lawn clippings (in thin, dried layers)
• Organic food remains
• Napkins and tissues (unprinted and uncolored)
• Haircuts (undyed)
• Raw wool or old mattresses (in small, mixed layers)
• Wine, vinegar,

Bryophyte Nutrition

Bryophytes have no true tissues or organs such as roots, stems, or leaves. Nutrients pass directly from cell to cell by diffusion or active transport. Bryophytes require permanently moist environments for transport. Their structure is not equivalent to higher plants; mosses and liverworts have a false root, or rhizoid, which serves only for attachment, and leaf-like structures where photosynthesis occurs. They do not possess true stems, and their cells lack lignin, meaning the plant has no conducting or support systems. Nutrients move very slowly. Because they lack roots to absorb water and conducting tissues to transport it, they must absorb water directly from the air through their photosynthetic areas.

Cormophyte Nutrition

Cormophytes... Continue reading "Plant Nutrient Acquisition: Bryophyte and Cormophyte Strategies" »

Fundamentals of Genetics and Heredity

Deoxyribonucleic Acid (DNA)

DNA is the inherited material that carries genetic information in all living organisms, passed down from generation to generation. A DNA molecule is composed of nucleic acid nucleotides.

Nucleotides are formed by three essential components:

• A phosphate group.
• A pentagonal ring sugar (Deoxyribose).
• A nucleobase (nitrogenous base).

In DNA, there are four basic types of nitrogenous bases: Cytosine (C), Guanine (G), Thymine (T), and Adenine (A).

DNA Replication: Ensuring Genetic Continuity

The information contained within the sequence of DNA bases is the foundation of inheritance for every species. This information must be transmitted intact from cell to cell to ensure the continuity of that... Continue reading "DNA, Genes, and Chromosomes: Core Concepts of Heredity" »

The Human Ear: Structure and Function

The ear is the organ that allows us to capture sound, which consists of vibrations and waves. Audition has two essential characteristics: intensity and tone. Intensity depends on the amplitude of the sound waves, and tone depends on the number of waves received per second.

Parts of the Ear

• External Ear: Includes the pinna (or auricle) and the external auditory canal. The pinna captures sound vibrations, which are then transmitted to the middle ear. The auditory canal contains ceruminous glands that produce wax for protection, hygiene, and cleanliness.
• Middle Ear: Starts with the tympanic membrane (eardrum), which vibrates upon receiving sound waves. These vibrations are transmitted to the ossicles (three small