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

Nervous System Actions: Reflexes and Voluntary Acts

Reflex acts are fast and automatic, and do not involve conscious brain processing. These acts occur when a quick response is needed.

Neurons Involved in Reflexes

• Sensory neurons: Come from the skin and their axons enter the spinal posterior roots.
• Interneurons: Synapse with sensory neurons and transmit nerve impulses to other neurons.
• Motor neurons: They leave the spinal cord by the anterior roots and reach muscles, causing contraction and reflex.

Voluntary acts are varied, changing, and more elaborate than reflexes, involving the cerebral cortex.

Autonomic Nervous System

Also called the involuntary nervous system, it is responsible for the proper regulation and coordination of internal organs.

Types

Carnitine: An Essential Nutrient

Carnitine is a nutrient synthesized in the liver, kidneys, and brain from two essential amino acids: lysine and methionine. Carnitine is responsible for transporting fatty acids into the mitochondria, cellular organelles responsible for energy production.

Some individuals need carnitine supplements to maintain normal metabolism, which indicates that carnitine should be considered an essential nutrient.

Carnitine Deficiency

Carnitine deficiency is classified into two major groups: systemic deficiency (rare) and myopathic (more common). The systemic form affects the whole body, while the myopathic form affects only muscle tissue.

Causes of Carnitine Deficiency

Known causes of carnitine deficiency include:

• Deficiency

Population, Community, and Ecosystem

A population is a group of individuals of the same species living in a specific area. A community is a set of populations inhabiting the same area. The biotope is the physical environment occupied by a community, characterized by specific environmental conditions. An ecosystem encompasses both the community (biocenosis) and the biotope, including the interactions of organisms with each other and their environment.

Habitat and Optimal Conditions

A habitat is the specific environment where an organism finds the necessary conditions for life. Optimal conditions, regarding a given environmental factor, are the values at which a species thrives, reproduces effectively, and experiences high offspring survival.... Continue reading "Understanding Ecosystems: Species, Niches, and Interactions" »

In the early 1990s, research on the human being began with the Human Genome Project. In April 2003, the entire nucleotide sequence of the human genome was completed. Today, we know that:

• Our haploid genome (all 23 different chromosomes that we possess) contains 3,000 million pairs of nitrogenous bases, which equates to about 30,000 genes.
• 99.9% of these genes are the same in all people: the differences between us do not represent more than 0.1% of the genome.
• 90% of the genome has no known coding function, which does not mean it has no function, such as gene regulation or various biological controls. It is thought that some of this DNA may correspond to genetic remains of our ancestors.

Applications of the Human Genome Project

The practical applications... Continue reading "Decoding the Human Genome: Applications and Biotechnology" »

Biotic Relationships

Biotic relationships are the interactions among living organisms in an environment. There are two main types of biotic relationships:

Interspecific Relationships

Interspecific relationships occur between organisms of different species. These include:

• Mutualism: A relationship where both species benefit. Example: Bees pollinating flowers.
• Commensalism: A relationship where one species benefits, and the other is unaffected. Example: Beetles feeding on mammal excrement.
• Inquilinism: A specific type of commensalism where one organism uses another for housing.
• Parasitism: A relationship where one species (the parasite) benefits at the expense of the other (the host). Example: Cochineals feeding on cacti.
• Predation: A relationship where

Non-Infectious Diseases

In addition to diseases caused by microorganisms, other diseases are caused by different reasons:

a) Diseases Affecting the Functioning of the Equipment

These include circulatory diseases, which affect the respiratory tract (such as asthma or bronchitis), and those that affect bones or joints (osteoarthritis and osteoporosis).

b) Cancer

This occurs when certain cells, for reasons not yet fully clarified, undergo a metamorphosis that makes them divide rapidly and uncontrollably. As a result, it creates a mass of abnormal cells, called a tumor, which causes the destruction of nearby tissue.

c) Deficiency Diseases

These are caused by a poor diet lacking in certain nutrients. Examples include vitamin deficiency or anemia.

d) Traumatic

Cloning:
Is to obtain multiple copies of a gene (gene cloning) or get genetically identical (cloned organisms).
Gene cloning can get identical copies of a gene of interest introduced into a body:
1. DNA fragments with restriction enzymes and isolating the gene.
2. Bacterial vector is obtained.
3. Recombinant DNA is formed with the participation of a ligase enzyme.
4. Is introduced into the host cell.
5. You select the desired clone cells are produced.

The cloned animals can be achieved by separating embryonic cells or implanting a nucleus into an egg that has been removed theirs.
Process cloning of a sheep:
1. Immature egg is removed from a sheep and removed its nucleus.
2. Is replaced by the egg nucleus from a somatic cell from... Continue reading "T.7 (2nd)" »

Dental Pathology & Caries Vocabulary

• Pathology: The study of the effects of disease as seen in the structure and function of the body.
• Pathogen: Any organism capable of causing disease.
• Etiology: The study of the causes of disease, including all factors that may be involved in its development.
• Clinical Data: A collection of information gathered about a patient's disease.
  • Symptom: A subjective experience reported by the patient.
  • Sign: An objective finding observed by a clinician (e.g., blood pressure, swelling).
• Diagnosis: The identification of a disease through scientific evaluation of its physical signs, symptoms, medical history, laboratory tests, and other procedures.
• Prognosis: The predicted outcome of a disease, based on the patient's condition

Human Body Systems: Core Functions

The human body relies on several interconnected systems to maintain life and process energy.

The Digestive System

This system is responsible for taking in solid and liquid foods, preparing and transforming them so that nutrients can be distributed to every cell in the body.

The Respiratory System

The respiratory system captures the oxygen necessary for cells and removes carbon dioxide produced during cellular metabolism.

The Circulatory System

The circulatory system transports nutrients and oxygen to cells and removes waste substances.

The Excretory System

This system expels the waste products of cellular metabolism, which are carried by the circulatory system, outside the body.

Components of the Digestive Tract

The... Continue reading "Understanding the Mechanics of Human Digestion and Metabolism" »

What Is Embryonic Development?

Embryonic development includes the processes from the formation of the zygote to the birth of the new individual. After fertilization, the zygote undergoes many cellular changes and becomes a developing organism, called an embryo. Depending on the species, embryonic development takes place in three main ways:

Viviparous Development

• The embryo develops inside the female body where it receives nourishment and protection.
• In this case, the embryo grows inside an organ in the abdomen, called the uterus.
• A special organ, called the placenta, feeds the embryo through the umbilical cord.
• Embryonic development ends with birth. This is typical of mammals.

Oviparous Development

• The embryo develops inside an egg, normally outside