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

Key Concepts in Enzymes, Cellular Respiration, and Genetics

1. Free Energy Curve

In a catalyzed reaction, the enzyme lowers the activation energy required for the reaction, making it proceed more quickly. The free energy curve for the catalyzed reaction is shifted to the left compared to the uncatalyzed reaction.

2. Components in a Chemical Reaction

• Reactants: A and B
• Products: C and D (catalyzed)

3. Factors Affecting Enzyme Function

• Temperature: Enzymes have an optimal temperature; deviation can denature them.
• pH: Enzymes function best within a specific pH range.
• Substrate Concentration: Up to a point, increasing substrate concentration increases enzyme activity.

4. Definition of an Enzyme

Enzymes are biological catalysts that accelerate chemical reactions... Continue reading "Enzymes, Cellular Respiration, and Genetics: Key Concepts" »

Barrera especifica: Acciones que realiza el sist. inmunitario que se pone en funcionamiento cuando el organismo no ha podido evitar la invacion del agente patogeno. hace que la persona adquiera inmunidad. FAGOSITOS.
Barrera inespecifica: son iguales para todos los agentes patogenos y actuan de forma indiscriminada frente a cualquiera de ellos.
1º barrera: evita entrada de germenes. estructural-piel-mucosas-lagrimas-saliva-jugos gastricos-secreciones acidas.
es inespecifica----> intenta que ninguna noxa ingrese, no deja memoria inmune.
2º barrera o respuesta inflamatoria: impide que las noxas que ingresan causen infeccion.(inflamacion-dolor-rubor-color)
Sangre->globulos blancos o leucocitos= fagocitan cualquier noxa.
             ... Continue reading "Barrera." »

Cellular Immunity

Cellular immunity involves two main types of lymphocytes: T lymphocytes and B lymphocytes. It also involves non-T, non-B cells. This system effectively destroys:

• Foreign cells
• Tumor cells
• Virus-infected cells
• Cells infected by intracellular pathogens

T Lymphocytes

T4 Lymphocytes

T_H Lymphocytes: These cells stimulate other T cells and B lymphocytes.

T_D Lymphocytes: These cells increase the number and activity of macrophages.

T8 Lymphocytes

T_C Lymphocytes: These cells destroy target cells.

T_S Lymphocytes: These cells regulate and suppress excessive or inappropriate immune responses. They deactivate lymphocytes once antigenic agents are controlled.

A phagocyte captures a foreign element, digests it, and presents it as an antigen-presenting... Continue reading "Understanding Cellular and Acquired Immunity: Types, Mechanisms, and Pathologies" »

Neck Anatomy

The head and neck join the upper chest. The neck comprises skin, fibrous muscles, major vascular elements, lymph nodes, organs (cervical larynx, cervical trachea), and glands (thyroid and parathyroid).

The skeletal neck includes the cervical spine.

• Platysma (2): Thin ring from the superclavicular zone to the face, deep chin.
• Sternocleidomastoid (2): Lateral neck, from the thorax to the temporal and occipital mastoid bones.
  • Origin: Lower insertion and command of the sternum and below the clavicle.
  • Lateral/External: External jugular vein, ending with the subclavian, used for serum.
  • Medial/Internal: Vasculo-nervous bundle, primitive carotid artery, internal jugular vein, neurogastric nerve.
  • Double Innervation: Branches of the nerve cord and

Acute Renal Failure (ARF)

Signs

ARF is often asymptomatic. However, some common signs include:

• Oliguria: Urine output of less than 400 ml per day
• Increased nitrogen products in the blood
• Electrolyte and acid-base abnormalities

Classification of Acute Renal Failure

1. Pre-renal ARF

This type accounts for 55% of cases. It is characterized by a deficiency in kidney perfusion, which decreases the glomerular filtration rate (GFR). There is no frank damage to the renal parenchyma initially.

Features of Pre-renal ARF:

• Often reversible
• No initial damage to the renal parenchyma
• Prolonged deficiency can lead to ischemia and acute tubular necrosis
• The renal tubules and loop of Henle are most affected by ischemia

Phases of Pre-renal ARF:

• Extension phase: Swelling occurs,

Mammals

• Females have breasts that produce milk to feed their young.
• The body is covered with hair.
• Body temperature is constant.
• Young are born alive.
• Examples: Prototherians (e.g., the platypus), marsupials (e.g., kangaroos), and eutherians (e.g., insectivores, bats, primates, cetaceans, carnivores, Perissodactyla, and Artiodactyla).
• Temperature: Mammals maintain a constant body temperature, typically between 38 and 40 degrees Celsius, regardless of whether they live in hot or cold climates.
• Reproduction: Mammals reproduce viviparously with internal fertilization. They lay eggs without nutrient reserves, which are implanted and developed in the womb. The placenta provides nourishment and oxygen to the developing fetus and facilitates the excretion

Cellular Respiration Explained

Respiration is the process in which glucose and oxygen are transformed inside the cell into water, carbon dioxide, and energy.

The goal is to transform glucose and oxygen into energy.

Gases involved are oxygen, which we use, and carbon dioxide, the result.

It happens inside the cell in the mitochondria.

Defining Metabolic Rate

Metabolic rate is an average of the amount of energy that a person needs. While sleeping, we spend energy in circulation, for development, breathing, and protection. We spend energy because the body is working constantly.

Function of the Breathing System

In breathing, gases are exchanged. Oxygen goes from the air to the blood, and carbon dioxide goes from the blood to the air.

Lining of the Respiratory

Neurons: The Basic Unit of the Nervous System

A neuron is the basic unit in the nervous system. It is a specialized conductor cell that receives and transmits electrochemical nerve impulses. A typical neuron has a cell body and long arms that conduct impulses from one body part to another.

Three Different Parts of the Neuron:

• The cell body
• Dendrites
• Axon

Types of Neurons

• Multipolar neurons have one axon and several dendrites. These are common in the brain and spinal cord.
• Bipolar neurons have one axon and one dendrite. These are seen in the retina of the eye, the inner ear, and the olfactory (smell) area.
• Unipolar neurons have one process extending from the cell body. The one process divides with one part acting as an axon and the other part functioning

Cancer Treatment Modalities

The basis of cancer treatment lies in the elimination of tumors through surgery, chemotherapy, immunotherapy, and radiotherapy.

Chemotherapy

Chemotherapy is anticarcinogenic. Certain drugs act directly on DNA, such as oxaliplatin, anthracyclines, and cyclophosphamide. Others, like taxanes and vinblastine, interact with mitotic spindle formation. Common side effects can include hair loss or effects on leukocytes.

Immunotherapy

Immunotherapy is based on the stimulation of the immune system to trigger a response against tumors. Approaches include the use of interferon alpha, which can reduce tumor growth; vaccines using antigens present in cancer cells to stimulate immune defense; and monoclonal antibodies.

Radiotherapy

Radiotherapy... Continue reading "Cancer Treatment Methods and Surgical Procedures" »

Economic Entomology

It refers to the study of all aspects of insects that are related in a way or another with human activity involving the economic, ecological and social.

Ecology of Insects

Species: A group of individuals who share common characteristics, can interbreed and produce fertile offspring under natural conditions.

Population: Group of organisms of the same species that occupy a certain space at a given time.

Community: A group of populations of several species of plants or animals that share a certain time regardless.

Ecosystem: Habitat where biotic and abiotic factors interact to exchange energy and matter in a continuous cycle.

Agroecosystem: Artificial system manipulated by man but stable in nature.

Ecological Niche: Resources that... Continue reading "Economic Entomology: Insect Ecology and Pest Management" »