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

Neurolinguistics: Language and Brain Function

The study of the relationship between language and the brain is called neurolinguistics. Although this is a relatively recent term, the field of study dates back to the nineteenth century.

Since that time, a number of discoveries have been made about the specific parts in the brain that are related to language functions. We now know that the most important parts are located in areas above the left ear.

Anatomy of Language Processing

In order to describe these areas in greater detail, we need to look more closely at some of the gray matter. If we conceptually dissect the brain—removing hair, scalp, skull, disconnecting the brain stem (which connects the brain to the spinal cord), and cutting the corpus... Continue reading "Brain Structures and Language Processing Centers" »

Fundamentals of Biological Processes

Nutrition and Metabolism

Heterotrophic Nutrition

Organisms that obtain organic matter from other living beings through food.

Aerobic Respiration

The process of breaking down the glucose molecule using oxygen.

Fermentation

A process of molecular decomposition that occurs without oxygen (anaerobic process).

Glycogen

A molecule present in animal cells used for energy reserves.

Classification of Heterotrophs

Heterotrophs are classified based on their primary food source:

• Herbivores: Organisms that feed exclusively on plants.
• Carnivores: Organisms that feed on other animals.
• Omnivores: Organisms that feed on both plants and other animals.
• Suspensivores: Organisms that feed on microorganisms and organic matter obtained by filtering

Cellular Motion Structures

Cells can move using either changes in the viscosity of the cytoplasm (pseudopods) or by means of flagella and cilia.

• Pseudopods: These are cytoplasm elongations produced by changes in cytoplasm viscosity, which, in turn, are due to changes in proteins of the cytoskeleton.
• Cilia and Flagella: These are mobile organelles attached to the cell membrane. They consist of a basal corpuscle and a string-like structure that projects out of the cell, composed of the cell membrane and a series of microtubules.
• The Centrosome: This organelle is constituted by two small cylinders positioned perpendicular to each other. Each cylinder is called a centriole, which is made up of nine sets of three microtubules. The centrosome controls

The Organs of Speech

The Lungs

The lungs hold air when we breathe in. We enlarge the chest cavity (in part by lowering the diaphragm). This, in turn, expands the lungs, and air rushes in to fill the vacuum. Breathing out involves the opposite procedure. The chest is contracted, and air is squeezed out of the lungs, passing through the two bronchi (or bronchial tubes), then through the windpipe (more technically the trachea), and finally emerging in the throat.

The Larynx

Before the air reaches the throat, it has to pass through one of the most important speech organs: the larynx. It is at this point that the first possibilities occur for modifying the airstream and generating sound.

The larynx can conveniently be thought of as an irregularly shaped... Continue reading "The Organs of Speech and Sound Production" »

Animal Respiration Methods

1. Cutaneous Respiration (Skin)

Many small, less active multicellular animals respire through their skin. This is possible because the ratio between body surface area and body mass is very large. In larger, more active animals, it is sometimes a complementary method. This occurs in amphibians, where cutaneous respiration supplements lung respiration. In amphibians, gas exchange can be performed through the skin because it is well-vascularized and has large glands that keep it very moist. In some fish, skin breathing can occur via the oral mucosa, intestine, swim bladder, or the epidermis of the fins.

2. Gill Respiration

This is characteristic of aquatic animals. In this type of breathing, gas exchange takes place in the... Continue reading "Animal Respiration Methods Explained" »

Understanding the Human Genome

The study of the human genome involves understanding the complete set of DNA molecules organized into 23 chromosomes. To fully comprehend the information it contains, we must know the sequence of its bases. This knowledge has been instrumental in identifying the human genome. To grasp its immense scale, imagine a library 18 stories high. Current research focuses on deciphering the function of individual genes and how they interact to govern the organization and functioning of the human body.

Benefits of Human Genome Knowledge

Knowing the human genome offers significant advantages. Primarily, it accelerates the identification of disease-causing genes and helps identify individuals who are carriers of diseases. Understanding... Continue reading "Decoding the Human Genome: DNA, Disease, and Future Health" »

Foods Discouraged

• Kitchen and table salt: salt, iodized salt, sea salt, celery salt.
• Meat: salted, smoked and cured.
• Smoked and dried fish, caviar.
• Sausages in general.
• Cheeses in general (Burgos types are allowed, Villalon).
• Bread and biscuits with salt (except for minor amounts of 50 g).
• Olives.
• Soup, instant mashed, diced, chips.
• Packaged vegetable juice.
• Oleaginous fruits, salty.
• Confectionery industry.
• Salted butter, margarine and salt.
• Sparkling water, carbonated beverages in general.
• Seasonings: salt, mustard, pickles, ketchup, meat tenderizer.
• Preserved foods in general.

Foods Allowed

• Meat, poultry.
• Viscera: tongue, kidneys, liver.
• Fresh fish freshwater or sea.
• Eggs.
• Milk, yogurt, Petit-suisse, curd.
• Cheese without salt.
• Unsalted bread and biscuits (up to

Understanding Sensory Receptors

Quimioreceptors: Sensitive to chemicals.

Mechanoceptors: Sensitive to mechanical stimuli, such as pressure and sound.

Photoreceptors: Sensitive to light.

Thermoreceptors: Sensitive to temperature variations.

Nociceptors: Sensitive to intense pressures and are responsible for pain.

Types of Receptors

• Interoceptors: Located inside the body, particularly in the viscera, responsible for collecting information about the internal state of the organism (e.g., hunger and thirst).
• Exteroceptors: Located on the surface of the body, responsible for collecting stimuli from the outside, such as light, sound, and temperature.

Eye Anatomy

Light enters the eye through the cornea, which acts as a convex lens to diverge light rays to a... Continue reading "Understanding Sensory Receptors and Eye Anatomy" »

Understanding Biomass and Ecosystem Productivity

Biomass is the total amount of organic matter contained in living beings. It is usually expressed in units of mass per surface area (e.g., g/m², kg/m²) or mass per volume (e.g., g/cm³, kg/m³).

Ecosystem Productivity

Biomass production, or productivity, is the increase in biomass in an ecosystem over a determined period of time. It can be measured in different units, for example, kg/m² per year.

Key Production Definitions

• Gross Production: The total solar energy converted into organic matter per unit time.
• Net Production: The difference between gross production and respiration (energy used) across all trophic levels.

Ecological Pyramids and Trophic Relationships

Ecological pyramids are graphical... Continue reading "Biomass, Productivity, and Key Biogeochemical Cycles" »

Fundamental Biological Concepts

Energy Acquisition and Matter Cycling

Autotrophic Organisms

They produce organic matter from inorganic matter (mineral salts, water, etc.) using solar energy.

Heterotrophic Organisms

These are organisms that feed on organic material previously produced by autotrophic organisms.

Photosynthesis

This is the process by which plants, algae, and some bacteria use light energy to synthesize organic matter from carbon dioxide and water.

Cellular Respiration

This is the process in which the organic matter synthesized in photosynthesis is broken down to produce necessary energy for the organism.

The Earth and Life's Domain

Biosphere

The surface area of Earth where living matter exists.

Origins of Life and Planetary Components

Where