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

Reptile Skin

Dry, thick skin covered with scales prevents moisture loss and protects against predators. Due to their specialized skin, reptiles are entirely dependent on lungs for gas exchange.

Reptile Skeleton

Legs are located under the body, not out to the side like in amphibians. This allows for better support and easier movement on land, increasing their chances of catching prey and avoiding predators. Claws on their feet allow for grasping.

Reptile Heart

Most reptiles have a three-chambered heart, but some (notably crocodilians) have a four-chambered heart. This separates oxygenated blood from deoxygenated blood, enabling more O2 to reach body tissues. This supports the higher level of energy use required by land animals.

Reptile Reproduction

Reptiles...

Evolutionism

According to biology, fixism maintained that the existing living species were independent and immutable and that they had always existed with the same basic characteristics.

From the works of Lamarck and Darwin, evolutionism emerged. It holds that the universe and life in all its manifestations, and therefore all species, are the result of change and adaptation. This theory is called evolution and argues that species living today come from others who have disappeared, and these in turn from another, until reaching the first living organisms. For evolution, all living creatures belong to a single large family that has developed over Earth's history.

Early Evolutionary Theories

Scientists disagree on:

• The mechanisms causing species diversification.

Vegetative Reproduction in Plants

Vegetative reproduction is a form of asexual reproduction in plants. A part of a single individual, a cell (e.g., spores), or a group of cells (fragmentation) develops into a duplicate of the progenitor. The offspring are identical to each other and identical to their preserved vegetative progenitor. Plants always have embryonic tissues, the meristems, which consist of totipotent cells. Therefore, they have a great capacity for regeneration, and asexual reproduction is common.

Structures Involved in Asexual Reproduction

• Stolons: Stems that run parallel to the ground, which occasionally produce roots and new stems and leaves. Example: Strawberries.
• Rhizomes: Underground stems that occasionally produce roots and

Bread Fabrication via Yeast Fermentation

Bread is produced through fermentation by the yeast Saccharomyces cerevisiae, which generates ethanol (alcoholic fermentation). The ethanol evaporates during cooking, while carbon dioxide creates tiny bubbles that result in the typical spongy texture of bread. The yeast dies due to the heat.

Wine and Beer Manufacturing

This process also utilizes Saccharomyces cerevisiae for alcoholic fermentation. In the case of wine, yeast is found naturally on the skin of grapes. Beer production requires a series of steps:

• Malting: Roasting germinated barley seeds (malt).
• Brewing: Addition of hops to the fermentation product.

Cheese Fabrication

Cheese is produced through fermentation by lactic acid bacteria (e.g., Lactobacillus,...

Toxins

• Toxins:

• Main Routes of Transmission of Infectious Diseases and Examples

In any infectious disease, a pathogen must pass from a healthy host to another to become a new host. Transmission can occur through:

• Transmission by direct contact: injuries, sexually, via parental (mother to fetus). Examples:

Autoclave (Moist Heat Sterilization)

The autoclave is a device used in hospitals for moist heat sterilization. It effectively destroys spores, fungi, bacteria, and viruses. It maintains a temperature of 120 ºC for 15 to 30 minutes, depending on the size and nature of the load.

Autoclave Components and Operation

The autoclave features a reservoir with thick stainless steel walls and a tight-fitting lid. Key components include:

• A pressure gauge indicating the internal pressure and temperature.
• A safety valve that opens automatically if the pressure reaches a dangerous level, preventing explosion.
• A bleed valve (or purge valve) through which steam is released.
• A tank containing water up to a certain level, which is heated by electric heat, gas, or other

Understanding Immunity: Types, Disorders, and Hypersensitivity

Types of Immunity

• Natural Passive Immunity

  This process involves the body receiving antibodies without producing its own. Antibodies are transferred through the placenta during embryonic development or via breastfeeding until the infant's immune system fully develops.

• Active Natural Immunity

  Antibodies are formed naturally when the body comes into contact with a pathogen. The individual develops immunity after exposure to the disease.

• Active Artificial Immunity

  The body produces its own antibodies through vaccination. Vaccines contain attenuated or killed pathogenic organisms that stimulate the immune system to create active immunity without causing the disease.

• Passive Artificial Immunity

  This

Genomic Mutations

These are variations in the number of chromosomes.

Euploidy

These are alterations in the normal chromosomal number.

• Monoploidy or Haploidy: There is only one chromosome of each pair (n).
• Polyploidy: Organisms containing more than one complete set of chromosomes, such as triploid (3n) or tetraploid (4n).

Aneuploidy

Affected individuals have one chromosome more or less than their normal allocation.

• Trisomies: The carriers have an extra chromosome.
• Monosomies: Individuals lacking one chromosome from a pair of homologues.

Mutagenic Agents

These are physical, chemical, or biological agents that increase the rate of spontaneous mutation in a species.

Physical Mutagens

• Ionizing Radiation: X-rays and gamma rays can cause chromosome breakage and

Nerve Structure

• Nerve: Formed by neurons.
• A typical neuron has a body with a nucleus and extensions:

- Axon: The longest extension that carries the nerve impulse from the cell body to dendrites or the body of another neuron.

- Dendrite: Shorter and more numerous extensions that receive nerve impulses from other neurons and lead them to the cell body.

Each neuron can contact different cells simultaneously to send and receive information throughout the body.

Helper Cells

These cells provide protection and support:

• Schwann cells: Produce myelin, which covers axons in the central and peripheral nervous systems, providing insulation and accelerating nerve impulses.
• Astrocytes: Provide nutritional support and connect neurons to blood vessels.
• Microglia: Responsible

The Process of Insemination

Insemination is the process by which male gametes (sperm) are transferred to meet the female gametes (egg). This contact is necessary for fertilization to occur, resulting in the formation of the zygote. Insemination can be external, internal, or artificial.

Types of Insemination and Fertilization

The method of insemination varies widely across the animal kingdom, often dictating where fertilization takes place:

• External Insemination and Internal Fertilization

  In aquatic animals, sperm are released into the water and swim until they move inside the female body where fertilization occurs. A simple case of this is observed in Porifera (sponges).

• External Insemination and External Fertilization

  Females release eggs into the