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

The Central Nervous System: Brain and Spinal Cord

The Central Nervous System (CNS), comprising the brain and spinal cord, receives information to process and control bodily functions.

The Brain

Located within the braincase, the brain is divided into two hemispheres. Its outermost part, the gray matter, has convolutions (gyri) and grooves (sulci). This area receives information and develops responses. The innermost zone is white matter.

The Cerebellum

Situated below the brain, the cerebellum is also divided into two hemispheres and features convolutions. It coordinates movements such as walking and maintains balance.

The Medulla Oblongata (Bulb)

This vital part links the encephalon with the spinal cord. It controls automatic bodily functions, including...

Cellular Foundations of Life

Cell Theory Principles

The Cell Theory was set forth in 1860. According to this theory:

• All living things are composed of cells.
• Cells are the basic units that constitute the structural and functional basis of life.
• Every cell comes from another existing cell through cell division.

Plasma Membrane Function

The plasma membrane encloses the cell, provides structural integrity, and facilitates the exchange of substances with the external environment.

Cytoplasm: Cell's Internal Environment

The cytoplasm is the space between the plasma membrane and the nucleus. It contains various structures and other organelles, such as the cytoskeleton.

The Cell Nucleus: Control Center

The nucleus is the area of the cell bounded by the nuclear...

Porifera and Cnidarians: Structure

Porifera (sponges) and Cnidarians (anemones, corals, and jellyfish) are simple, aquatic invertebrates.

Porifera (Sponges)

• Mostly marine, some freshwater species
• Bag-shaped body with pores that communicate with the atrial cavity
• The atrial cavity connects with the exterior through the osculum
• High capacity for regeneration

Cnidarians

• Anemones, corals, and jellyfish (all marine), hydra (freshwater)
• Radial symmetry
• Soft body with a single opening surrounded by tentacles
• Stinging cells (cnidocytes)
• Gastrovascular cavity that functions as a stomach
• Carnivorous
• Two forms:
  • Polyps: Tubular, bag-shaped with the opening at the top
  • Medusae: Umbrella-shaped, actively swim or float in the water

Worms: Platyhelminthes, Nematodes, and Annelids

Worms...

The Respiratory System: Air Circulation and Gas Exchange

The respiratory system is responsible for circulating air.

Components of the Respiratory System

• Upper Tract: Pharynx.
• Lower Tract: Bronchioles.
• Air Entry: Nose and Mouth (air passes to the pharynx).
• Trachea: Flexible tube, kept open.
• Larynx: Funnel-shaped structure with internal hard walls. Note: The text states 'No vocal strings.'
• Lungs: Located in the thoracic cavity, protected by ribs, resting on the diaphragm.
• Bronchi: Two main bronchi branch into increasingly thin bronchioles.

Alveolar Gas Exchange (Interchange)

Gas exchange occurs easily across the surface of the alveoli. Alveoli are thin-walled and surrounded by blood capillaries.

• Oxygen (O₂) from the air passes into the blood.
• Carbon Dioxide

The Relations Function

Living beings perceive information from the external environment and their body. This information consists of stimuli that can be positive or negative. This process occurs in three steps:

• Reception of the stimulus: By specialized structures or bodies.
• Integration of information: Information is processed, and a response is generated through the nervous system.
• Execution of the answer: This is carried out through muscle movements and physiological changes caused by hormones.

Function of Reproduction

• Asexual: Requires only one individual to produce more descendants.
• Sexual: Needs the intervention of two individuals, called germ cells, which are specialized.

Diversity and Classification of Living Things

The variety of creatures inhabiting...

Mendel's Experiments with Pea Plants

Mendelian genetics refers to the laws of inheritance discovered by Gregor Mendel through his work with pea plants. He studied specific characters, including:

• Seed color (Yellow vs. Green)
• Seed surface (Smooth vs. Wrinkled - implied, though not explicitly stated in the original text)

In his first cross, Mendel bred purebred yellow-seeded plants with purebred green-seeded plants. The resulting first filial generation (F1) consisted of 100% plants with yellow seeds.

Conclusions from Initial Crosses

• Each individual carries two hereditary factors (now called alleles) for each character, one inherited from each parent.
• In an individual carrying alleles for both yellow and green seeds, the yellow allele dominates over

Pulmonary Ventilation and Gas Exchange

Pulmonary ventilation: This is the mechanism through which the air in the lungs and the respiratory tract is renewed. It allows air to flow in and out of the lungs. Ventilation is carried out through two respiratory movements: inhalation and exhalation. The diaphragm and the intercostal muscles mainly participate in these movements. By contracting and relaxing, these muscles produce changes in the volume of the lungs.

Inhalation

This is the movement that allows air to enter the lungs.

1. The diaphragm contracts, increasing the vertical diameter of the thoracic cavity.
2. The external intercostal muscles contract. The diameters of the thoracic cavity increase.
3. The lungs, which are elastic, expand.

Exhalation

This is...

NSAIDs: Therapeutic Groups

NSAIDs are categorized into three primary therapeutic groups:

• Analgesic
• Antipyretic
• Anti-inflammatory

Classification of NSAIDs

A. Nonselective COX Inhibitors (Traditional NSAIDs)

• Salicylates: Aspirin
• Propionic acid derivatives: Ibuprofen, Naproxen, Ketoprofen, Flurbiprofen
• Anthranilic acid derivative: Mefenamic acid
• Aryl-acetic acid derivatives: Diclofenac, Aceclofenac
• Oxicam derivatives: Piroxicam, Tenoxicam
• Pyrrolo-pyrrole derivative: Ketorolac
• Indole derivative: Indomethacin
• Pyrazolone derivative: Phenylbutazone, Oxyphenbutazone

B. Preferential COX-2 Inhibitors

• Nimesulide, Meloxicam, Nabumetone

C. Selective COX-2 Inhibitors

• Celecoxib, Etoricoxib, Parecoxib

D. Analgesic-Antipyretics (Poor Anti-inflammatory Action)

• Para-aminophenol

1. Homeostasis and Ecology

• 1(a) Maintaining constant internal conditions.
• 1(b) 250 hours.
• 1(c)(i) A.
• 1(c)(ii) Fertilisers from farms run off into rivers. This causes algal growth. Less light penetrates, reducing photosynthesis. Pesticides kill organisms.
• 1(d)(i) Low FSH: eggs do not mature.
• 1(d)(ii) Low LH: no ovulation.
• 1(e)(i) Less water is absorbed into the blood. Water moves by osmosis because water potential remains higher in the blood.
• 1(e)(ii) Mutation. Only resistant bacteria survive. They reproduce and pass on the allele.
• 1(f)(i) Denitrifying bacteria convert nitrate to nitrogen gas. This reduces algal growth, so there is more oxygen in rivers.
• 1(f)(ii) Roots absorb water. More transpiration occurs, leading to slower water flow and less runoff.