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

There are eight fundamental characteristics of the structure of animals that distinguish this group from other groups of living things. These features are:

1. Animals are multicellular. This means that all individuals belonging to the animal kingdom consist of more than one cell, no matter what species they belong to.

   This feature clearly separates the animals from protozoa. Protozoa are a group of unicellular organisms (composed of a single cell) that were formerly classified in the animal kingdom but are now classified in a different group, the kingdom Protozoa, also known as Protista or Protoctista.

2. Animals are eukaryotic. All animals have true cells with nuclei and different organelles in the cytoplasm that perform specific functions. Deoxyribonucleic

Genetic Variations

All individuals within a population possess unique characteristics that distinguish them from one another. These individual differences are called variations and result from an individual's genetic makeup and environmental influences.

Types of Variations:

• Genotype: These are inherited differences passed from parents to offspring and are contained within an individual's genes.
• Phenotypic and Environmental: These variations result from the interaction of genes with the environment. In most cases, the phenotype does not fully express the genotype.

Gene Pool

Each individual in a population carries a unique combination of genes. The gene pool represents the sum of all genes within a population.

Populations evolve through changes in their... Continue reading "Understanding Genetic Variations, Gene Pools, and Stem Cells" »

Vital Functions of Living Beings

Vital functions refer to the specific actions that support life. There are three main functions:

1. Nutrition: Living beings obtain the matter and energy necessary to sustain life through this function.
2. Interaction: Living beings relate to their surrounding environment through this function.
3. Reproduction: Individual living beings are produced; this ensures the perpetuation of the species.

Biomolecules: The Building Blocks of Life

Biomolecules are the fundamental components of living organisms. They are mainly composed of carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus.

Organic Biomolecules

Organic molecules are exclusive to living beings. There are four main types:

1. Carbohydrates (Saccharides)

   These are the most

Health and Disease

Until recently, health was defined as "the absence of disease." However, the World Health Organization (WHO) has developed a more comprehensive definition. Health is a state of complete physical, mental, and social well-being.

Disease, on the other hand, is the state in which a person's health is altered, whether due to physical or social causes. We can distinguish three types of diseases:

• Physical diseases: Produced by injury, infection, or a degenerative process in the body. They are classified into:
  • Infectious diseases: Caused by a pathogen that reproduces within our body.
  • Non-infectious diseases: Due to other causes.
• Mental illness: Caused by a malfunction of the brain, resulting in a decline in mental capacity or some alteration

These measures are designed to protect individuals from electrical hazards. They can be implemented at the facility or personal level. Protection must be provided against direct contact (accessible parts or insulation failure) and indirect contact from arcing. Measures must also be taken to prevent power surges or over-current, high voltage drops, burns due to overloading, etc.

Protection Against Direct Electrical Contacts

These measures are designed to prevent the risk of contact with live parts (according to Standard 20460-4-41):

• Protection by insulation of live parts: This must be an insulator that can only be removed by destroying it; lacquer varnish is not sufficient.
• Protection by barriers or enclosures: All equipment and connections must

Breathing Process

Breathing: The process of obtaining energy in which we inhale oxygen and exhale carbon dioxide.

Respiratory System

Processes:

• Nostrils: Air enters through the two nostrils. Hair inside warms the air. The interior is lined by:
  • Pituitary Mucosa: Mucus-secreting glands capture dust and moisten the air.
  • Pituitary Yellow: Mucosa has nerve endings that detect odors.
• Pharynx: A duct that connects the nostrils, oral cavity, larynx, esophagus, and middle ear. Muscles and elastic fibers direct air into the trachea.
• Larynx: Formed by cartilage. The mucosa of the larynx has folds that form the vocal cords.
• Trachea: Composed of cartilage and lined by ciliated epithelium that produces mucus. This removes impurities from the outside through the cough

Fetal Development Stages

Overview

Fetal development primarily involves rapid body growth, tissue differentiation, and the formation of organs and systems. The fetal period is marked by significant growth, especially in the final weeks.

Viability

Fetal viability refers to the ability of a fetus to survive outside the uterus (after premature birth). Fetuses weighing less than 500g at birth typically do not survive. With postnatal care, some fetuses born weighing less than 500g may survive. Many term pregnancies with low birth weight result from intrauterine growth retardation (IUGR). The majority of fetuses born weighing between 1500g and 2500g survive but may experience complications. Prematurity is a common cause of morbidity and perinatal death.... Continue reading "Fetal Development Stages: A Comprehensive Guide" »

Seasonal Isolation

Response:

Species: The name given to each of the groups that divide the sexes, i.e., the limitation of the generic in a particular field of morphology. In biology, a species is the basic unit of biological classification.

Variations: These are the distinctive features that occur in individuals of the same species. These changes or differentials in characteristics of individuals relate to those who show up. Even though their heredity plays an important role in the transmission of hereditary or genetic characteristics, there is no chance, or a very remote one, that there are individuals the same as those around us.

Adaptation: A biological adaptation is an anatomical structure, physiological process, or behavioral trait of an organism... Continue reading "Understanding Biological Species and Genetic Concepts" »

Gases, Vapors, and Associated Risks

A gas is matter neither liquid nor solid at room temperature and normal atmospheric pressure, expanding to fill any container. A vapor is the gaseous state of a substance typically solid or liquid. Fumes result from volatilization or sublimation. Gases and vapors diffuse freely, remaining mixed with air.

Lead Poisoning

Metabolism

Inhaled lead is 40-60% retained in the lungs, entering circulation. Ingested lead absorption is about 10%. Blood lead distributes to liver, kidneys, brain, and bone. Elimination occurs via respiratory tract, gastrointestinal system (bile, feces), urine, and generalized discharges (colic).

Pathological Effects

• Hematologic: Altered metabolism via enzyme changes and metabolite accumulation.

Intramuscular Drug Administration and Receptor Binding

Explains what a circuit is: a drug that is administered intramuscularly until it reaches the receptor. It exits the bloodstream through the capillary endothelium, traveling through the interstitial fluid, and crosses the cell membrane of its target cells.

Morphine Effects in Elderly Patients

Explains why an old man, who is administered morphine in doses equal to a middle-aged person, may be at increased risk of sleepiness, even after the drug's effects should have worn off. The elderly, like children, have decreased hepatic activity, so the drug takes longer to metabolize and be disposed of by the body, which can cause drowsiness in the case of morphine.

Drug Molecule Characteristics for Barrier