Notes, summaries, assignments, exams, and exercises for Biology for Secondary education

Human Tissue Types: Location and Function

Epithelial Tissue: This tissue is found on the body's exterior surfaces, lining internal cavities (such as blood vessels), and in glands. Its cells are directly linked, without any intermolecular substance between them. The primary function is to coat and protect the body's exterior and internal cavities.

Connective Tissue: Located around organs, tendons, ligaments, in the dermis of the skin, and bone marrow. It consists of several cell types and connects other organs, muscles, and bones. It also fuels the dermal tissue and generates red blood cells.

Adipose Tissue: Found under the skin and around certain organs (like the kidney or heart). It is composed of round cells that store fat. Its functions include...

The M-Bo makes noise due to: air inflow, low oil, or worn parts.

The M-Bo warming indicates: very high pressure, high speed, or poor refrigeration.

The B does not flow due to: base oil, clogged filter, or pump failure.

• Leaks at the pump or motor worn parts
• Leaks in the body
• Bad tightness

The M-Bo does not revolve due to: little flow, internal leakage, improper loading, or unsuitable engine.

Breaking parts can occur due to: pressure excess, stiffness due to lack of fluid, or abrasives not retained.

If the M rotates slower than the flow that arrives, it may be due to: leaks, low pressure input, or high temperature.

Wear excesses of B and M can be caused by: abrasives, excess or no viscosity, or high pressure.

For the v/v regulatory pressure:

• Regulator does

Meiosis: Diploid to Haploid Cell Division

Meiosis is a specialized cell division mechanism that produces haploid daughter cells (n) with distinct genetic combinations from a single diploid cell (2n). It involves two consecutive divisions: Meiosis I (the first meiotic division) and Meiosis II (the second meiotic division).

Essentially, Meiosis transforms one diploid cell (2n), which has already duplicated its genetic material, into four genetically different haploid cells (n) through these two divisions. Without meiosis, gametes would retain the same chromosome number as somatic cells. Consequently, after each fertilization event, the resulting zygote would have double the necessary chromosomes. This highlights the crucial role of meiosis in maintaining...

Cell: Basic Unit of Life

1_Celula: The fundamental unit of structure and function in living organisms, forming the lower portion of the material that meets the functional vitales.

2_Difference: Variations arise from differing degrees of specialization. While all cells share a similar chemical composition and structure, some remain undifferentiated, specializing for specific functions.

3_Structures: All cells possess a plasma membrane, a cytoplasmic matrix, and genetic material, enabling self-replication and transmission of species characteristics.

Cell Types: Eukaryotic and Prokaryotic

4_Eukaryotic: Cells with a true nucleus and various organelles enclosed by a plasma membrane. Prokaryotic: Cells lacking a nucleus, with the plasma membrane as the...

Touch

The skin is the largest organ of our body, composed of two layers:

• Epidermis: The outer layer is formed by epithelial tissue. The outer cells are dead and continuously shed as flakes and dandruff.
• Dermis: The inner layer, formed by connective tissue, provides elasticity to the skin. The dermis contains numerous blood vessels and tactile receptors.

Smell

The inside of the nostrils is lined by a mucosa called the pituitary gland. Two regions can be distinguished:

• Red pituitary: Occupies the lower part, has several blood vessels that warm the incoming air.
• Yellow pituitary: Occupies the upper part, contains numerous olfactory receptors.

Taste

At the top of the tongue are numerous projections called taste papillae. These contain sensitive cells (chemoreceptors)...

Endocrine System

The endocrine system is formed by cells and glands that secrete specific hormones. These hormones are effective messengers that regulate various bodily functions through feedback mechanisms.

Endocrine Glands

Pituitary Gland

Anterior Lobe

• GH (Somatotropin)
• ACTH (Adrenocorticotropin)
• TSH (Thyroid Stimulating Hormone)
• PRL (Prolactin)
• FSH (Follicle-Stimulating Hormone)
• LH (Luteinizing Hormone)

Posterior Lobe

• Vasopressin (ADH - Antidiuretic Hormone)
• Oxytocin

Hypothalamus

The hypothalamus controls the neurohypophysis through nerve fibers and releases or inhibits pituitary factors.

Adrenal Glands

Cortex

• Glucocorticoids: Regulate carbohydrate and protein metabolism and inhibit the immune response.
  • Cortisol
  • Corticosterone
• Mineralocorticoids: Regulate Na-

Skeletons: Types and Functions

Exoskeletons

External systems support proportionally less weight than endoskeletons of the same size, which is why larger animals such as vertebrates have internal skeletal systems.

Key developments in exoskeletons are found among arthropods and some invertebrates, where the exoskeleton forms a shell or outer structure that protects the internal organs.

Given the limitations on animal growth imposed by exoskeletons, species with this feature have evolved various solutions. Most molluscs have calcareous shells that grow along with the animal, maintaining a consistent growth morphology. Other animals, such as arthropods, shed their old exoskeleton to grow, a process known as "molting." The new...

The Digestive System

Functions of the Digestive System

The digestive system performs the following vital functions:

• Breaks down food into molecules the body can use.
• Absorbs molecules into the blood and carries them throughout the body.
• Eliminates wastes from the body.

Types of Digestion

There are two main types of digestion:

• Mechanical Digestion: Foods are physically broken down into smaller pieces.
• Chemical Digestion: Chemicals produced by the body break foods into their smaller chemical building blocks. Most chemical digestion occurs in the stomach.

Key Components and Processes

Saliva

Saliva is the fluid released when your mouth waters. It is produced by salivary glands and plays an important role in chemical digestive processes.

Teeth

• Incisors: Central

DNA Replication: The Biological Mechanism

DNA replication is the essential process by which a cell creates an exact copy of its DNA prior to cell division (mitosis or meiosis). This critical event occurs during the S phase of the cell cycle.

Initiation: Unwinding the DNA

• Helicase: An enzyme that unwinds and separates the double helix by breaking the hydrogen bonds between nitrogenous bases, creating a "replication fork."
• Single-strand binding proteins (SSBs): Bind to single strands of DNA to keep them separated and prevent the helix from re-forming.
• Primase: Adds short RNA primers to the single-stranded DNA template. These primers are necessary for DNA polymerase to begin adding nucleotides.

Elongation and Synthesis

• DNA Polymerase III: Adds complementary

Ecosystem

An ecosystem is a community of plants and animals (living things) that interact with each other and their natural surroundings, including non-living things such as rocks, water, and air. Each ecosystem is sustained by a flow of energy through it and the recycling of nutrients within it.

Community

When plants and animals live together, they form a community.

Photosynthesis

Photosynthesis is the process in which plants absorb CO₂ from the air and convert it into sugar using the sun's energy.

Biomes

Biomes are large ecosystems at the global scale where the climate and vegetation are uniform.

Xerophytic Plants

Xerophytes are plants that have adapted by altering their physical structure to survive in harsh climates. These plants exhibit several...