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

Zika is a mosquito-borne disease transmitted by the same mosquito that carries the dengue virus. There have also been cases of transmission through sexual intercourse.

Transmission

Most people get Zika from a mosquito bite. Mosquitoes become infected when they feed on the blood of a person already infected with the virus, and when they bite others, they can transmit the virus. Other forms of transmission include:

• A pregnant woman can pass the Zika virus to her fetus during pregnancy or at the time of birth.
• Zika can also be transmitted through sexual intercourse and blood transfusion.

Symptoms

Zika can cause incomplete brain development in fetuses. Common symptoms include fever, rash, joint pain, and conjunctivitis.

Prevention

To reduce the risk of

SPERMATOZOA 

Food and Essential Nutrients

Food is our source of nutrients. Nutrients are biomolecules our body needs to sustain vital functions. They are the chemical components of food, the building blocks and energy sources our cells require to live.

Basic Nutritional Requirements

• Energetic: Some nutrients are broken down in mitochondria to extract energy.
• Structural: Some nutrients are building blocks of body structures.
• Regulatory: Some nutrients are necessary in small quantities to regulate body metabolism.

Carbohydrates (Glucids)

Biomolecules present in bread, cereals, potatoes, pasta, etc. They provide energy to cells, and some of them must be consumed on a regular daily basis.

Simple and Complex Glucids

Simple Glucids (Sugars)

Sweet taste, small molecules.... Continue reading "Essential Nutrients and Their Role in Health" »

Receptors

Internal receptors perceive changes inside the body, such as a rise in blood pressure. External receptors perceive stimuli in the external environment.

Types of Receptors

• Mechanoreceptors: Perceive mechanical stimuli (pressure).
• Thermoreceptors: Perceive changes in temperature.
• Chemoreceptors: Detect chemical substances in the air, water, etc.
• Nociceptors: Perceive pain stimuli.
• Photoreceptors: Light sensitive.

Nervous System

The nervous system analyzes internal and external stimuli perceived by receptors, generating responses. It carries out this function through nerve impulses transmitted by cells called neurons. This system coordinates fast, short-lived responses (e.g., muscle contraction).

Endocrine System

The endocrine system is made up... Continue reading "Sensory Systems and Nervous Coordination" »

Sensory receptors are responsible for perceiving infortion, which they convert into a nerve impulse. The nerve impulse travels to the brain and produces a feeling.

Biogeographical Evidence

Isolated groups evolved in different ways.

Molecular Evidence

The higher the molecular similarities, the closer their evolutionary relationship.

Coevolution

Coevolution is the process by which two species mutually influence each other during their evolution.

Lamarckism

Lamarckism is the theory of inheritance of acquired traits, explaining that animals develop the structures and organs they need in order to adapt to the environment they live in, and these new characteristics are transmitted to offspring.

Darwinism

Darwinism posits that there is competition between the individuals of a species, known as the struggle for existence. Individuals whose characteristics help their survival are favored over those who are poorly adapted... Continue reading "Understanding Evolutionary Processes and Species Development" »

Antioxidants and Exercise

Key antioxidants include Vitamin C, Vitamin E, Carotenoids, Glutathione (GSH), and Coenzyme Q10 (Q10).

Enzymatic Antioxidant Systems

• Superoxide Dismutase (SOD)
• Catalase
• Glutathione Peroxidase

Functions of Antioxidants

• Neutralize free radicals by donating electrons (e-) and hydrogen ions (H+).
• Decrease lipid peroxidation both at rest and after exercise.
• Note: Supplementation may not necessarily decrease overall oxidative stress markers.
• Note: Vitamin E supplementation does not appear to decrease neutrophil count after exercise.

Benefits and Roles of Oxidative Species

• Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS) are important for cellular development, function, and as stimuli (cellular messaging) – involved

Two Main Circuits of the Cardiovascular System

Pulmonary Circulation

Pulmonary circulation refers to the circulation of blood in which deoxygenated blood is pumped from the heart to the lungs and oxygenated blood is returned back to the heart. Pulmonary circulation only occurs between the heart and the lungs.

Systemic Circulation

Systemic circulation refers to the circulation of blood in which oxygenated blood is pumped from the heart to the body and deoxygenated blood is returned back to the heart. Systemic circulation occurs between the heart and the entire body.

Pericardial Sac

The pericardial sac is the outermost layer of the heart. It surrounds the heart and protects it.

Heart Valves

Atrioventricular (AV) Valves

The AV valves prevent backflow into... Continue reading "The Cardiovascular System: Pulmonary and Systemic Circulation" »

The Endocrine System

The endocrine system is a set of organs and tissues responsible for secreting hormones. It is distributed throughout the body, similar to the nervous system. However, the endocrine system uses chemical substances instead of nerve impulses.

Types of Hormones and Glands

• Pituitary: Located in the head.
  • Growth hormone: Stimulates the growth of all body tissues, especially the skeleton.
  • Thyroid-stimulating hormone: Regulates the production of thyroid hormones.
• Testes: Male gonads.
  • Testosterone: Stimulates the production of sperm and the development of secondary sexual characteristics.
• Thyroid: Located in the neck, in front of the trachea.
  • T3 and T4: Increase cell metabolism, oxygen consumption, protein synthesis, and glucose utilization.