Notes, summaries, assignments, exams, and exercises for Biology for Baccalaureate

Carbohydrates: Bonds and Structures

O-glycosidic bond:

• Maltose: Known as malt sugar, it is a product of starch or glycogen hydrolysis. It consists of two molecules of α-D-glucose linked by an easily hydrolyzable monocarbonyl bond and possesses reducing properties.
• Lactose: The sugar found in mammalian milk, formed by the union of β-D-galactose and α-D-glucose. It has a free reducing end.
• Sucrose: Common table sugar extracted from sugar cane and beet. It involves a linkage between glucose and fructose and is non-reductive.
• Cellobiose: Does not exist in a free state in nature; it results from the hydrolysis of cellulose. It has reducing properties and is hydrolyzed with difficulty.

Cellulose

Cellulose is a linear polymer of β-D-glucose molecules....

Mitosis: Nuclear Division and Cell Reproduction

Mitosis is nuclear division followed by cytokinesis, producing two identical daughter cells. The process involves five main stages: Prophase, Prometaphase, Metaphase, Anaphase, and Telophase.

While often discussed alongside mitosis, Interphase is technically not part of mitosis itself. Interphase includes the preparatory stages of the cell cycle:

• G1 (Gap 1)
• S (Synthesis)
• G2 (Gap 2)

Interphase: Preparation for Division

The cell is engaged in intense metabolic activity in preparation for mitosis (the next four phases that lead to and include nuclear division). Chromosomes are not clearly discernible in the nucleus, although a dark spot called the nucleolus may be visible. The cell contains a pair of centrioles...

Chemical Evolution

Chemical evolution refers to evolution-based chemical processes, not biological ones, including the changing of simple inorganic compounds into complex organic compounds. According to Oparin, this process could result in two important characteristics of living organisms:

1. Living matter is mostly composed of complex organic molecules. Chemical evolution must have produced these molecules from smaller building blocks.
2. Systems of organic molecules in organisms are surrounded by a capsule or exist as separate units. These units are the cells that form all living things. Encapsulation of materials was necessary for the emergence of life.

Biological Evolution

Biological evolution refers to the origin of life, development, and subsequent...

Developmental Biology: Protostomes vs. Deuterostomes

In protostomes, the mouth is formed from the opening of the gastrula. In deuterostomes, the anus is formed from the opening of the gastrula.

Marsupials (Metatheria)

Marsupials (Marsupialia) or metatherians (Metatheria) are an infraclass of mammals. They are characterized by a short gestation period in the mother's womb, completing much of their growth while clinging to the mammary glands inside a pouch, or marsupium.

Epithelial Tissues

Epithelial tissues are characterized by continuous layers of cells covering surfaces such as the skin epidermis and internal cavities. Their primary functions include protection, secretion, and absorption.

• Cell Shape: Flat, cylindrical, or cuboid.
• Layering: Simple

Toxoplasmosis: The Zoonotic Infection

Zoonosis caused by the intracellular protozoan Toxoplasma gondii (Apicomplexa). It is one of the most widespread infections in nature. Forms of presentation of T. gondii include:

Tachyzoite

Shaped like a bow and is 4 to 6 mm in length. This is the form in which the parasite multiplies actively during the acute phase of infection.

Cyst

These are round or elongated and are 20 to 200 m.m. Inside are the bradyzoites. They are located in tissues, primarily the CNS, muscle, and eye. They are present in the chronic stages of infection, appearing induced by the host immune response.

Oocyst

It is rounded, is 10 mmy and has two sporoblasts. In the external environment, it is eliminated through the stool of the cat. Environmental...

1. The Mediterranean Diet

The Mediterranean diet is considered highly healthy because it provides a wealth of fiber-rich carbohydrates, essential vitamins, and healthy fats derived from olive oil and fish.

2. Understanding the Influenza Virus

a) Viral Infections

The flu is a viral infection that causes annual epidemics.

b) Viral Mutation

The human influenza virus is constantly changing due to the accumulation of genetic mutations. When these mutations alter the surface molecules of the virus, the antibodies previously produced by our body cannot neutralize the new variant.

c) Antigenic Shifts

Every few decades, the human influenza virus acquires drastic changes. When this occurs, the resulting virus possesses completely new antigens against which there...

Chronic Venous Insufficiency and Varicose Veins

Varicose veins are caused by venous stasis, edema, and congenital weakness of the vein wall collagen. Symptoms are aggravated by prolonged standing, pregnancy, puberty, and heat, and include heaviness, tiredness, edema, induration, pain, and nocturnal cramps. Advanced cases may show trophic changes such as skin discoloration, hair loss, thinning of the skin, nail alterations, and ulcers.

Thrombophlebitis and Venous Thrombosis

Superficial venous thrombosis (thrombophlebitis) is caused by venous stasis, hypercoagulability, endothelial injury, and the consequences of surgery. It is characterized by a painful course, edema, induration, increased skin temperature, redness, and, when infected, bacterial...

Genes, Lifestyle, and Health

Genetic diseases arise from alterations in the genome, where a genetic defect is the direct cause of the condition. Examples include Down syndrome, hemophilia, and certain types of diabetes. In other cases, the genotype does not directly determine the disease but creates a predisposition to it.

Environmental Risks and Health

Diseases are classified by location or cause, influenced by factors within the body, lifestyle habits, and the sociocultural environment.

Physical Environmental Aggressors

• Ionizing Radiation: Energy that modifies the structure of matter, potentially altering cellular health. Sources include natural ultraviolet rays, gamma rays from minerals, and artificial sources like nuclear waste.
• Noise Pollution:

The quality of life of a person is defined as their degree of prosperity, happiness, and satisfaction, which allows them to act and feel life in a positive way.

Genes, Lifestyle, and Health

The health of a person is the result of the interaction between their genotype and the environment in which they develop and live.

• There are genetic diseases due to alterations in the genome.
• In other cases, the genotype does not directly determine the presence of the disease, but rather a predisposition to it.
• A group of diseases related to genetic diseases are caused by certain congenital disorders produced during embryonic development, such as Down syndrome.

Environmental Chemical Attacks

These are divided into two main groups:

Air Pollution

This is caused especially...

Composition of living matter

Living matter is composed mainly of water and carbon (about 98% in the original estimate). It also contains elements such as iron, selenium, sulfur and potassium.

Autotrophs and heterotrophs

Autotroph: an organism that produces organic matter from inorganic matter (minerals, water and other substances) using solar energy.

Heterotrophic organism: an organism that feeds on organic matter produced by autotrophs.

Chemosynthesis and energy

Chemosynthetic organisms obtain energy from chemical reactions with other elements; these reactions may also yield oxygen or other products depending on the chemistry.

Origins of carbon and water

Carbon originates from inside the Earth, where it accumulated when the planet was formed. The...