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

The cell is the fundamental unit of life. Every living organism consists of at least one cell. It is a body with volume that converts energy and is capable of transferring genetic information.

Cellular Structure and Components

The cell's shape depends on its outer envelope, the essential cell membrane. Cell organelles are specialized structures, analogous to the organs of the body, each having specific roles crucial for cell maintenance.

Key Organelles and Their Functions

The following organelles perform many of the most important functions required for cell maintenance and operation:

• The Nucleus

  Controls protein synthesis in the cytoplasm by sending molecular messengers.

• Cytoplasm

  The volume covers the entire cell, excluding the nucleus. It hosts

Postnatal Maturation and Age Assessment

1 Bone Age (Skeletal Maturity)

Ossification begins in the womb and continues throughout the first two decades after birth. For radiological assessment, small areas (commonly the hand) are imaged to minimize exposure and potential risks. Through the study of ossification it was determined that:

• Girls' bones ossify earlier than boys'.
• The two sides of the body mature symmetrically.
• The genetic component is of great importance in bone maturation.

2 Dental Age

Dental age is the study of emergence of teeth (primary and permanent) and its comparison with established standards. This index assesses the degree of calcification and eruption of teeth as indicators of jaw and dental development. Important distinctions include:...

Comparative Animal Physiology and Anatomy Systems

Circulatory and Vascular Systems

Diffusion in unicellular and multicellular organisms occurs across vascular diffusion channels (1 mm). Sponges utilize cavities and choanocytes, while cnidarians possess a digestive respiratory cavity known as the gastrovascular cavity, featuring one pore and ciliary cells. Flatworms utilize a similar cavity with two pores acting as a gastrovascular unit of fluid flux.

Circulatory System Types

• Open System: Found in arthropods and mollusks (hemolymph), featuring arteries and veins.
• Closed System: Specialized vascular systems containing blood and lymph, operating with afferent and efferent vessels.

Respiratory Pigments and Fluids

• Hemocyanin: Found in mollusks and arthropods.

Lymphedema Clinical Presentation

• Increased limb volume:
  • Worsens during the day and is lower at night.
  • Decreases with elevation.
• Lower extremity involvement:
  • Often respects the sole of the foot.
  • Typically begins in the ankle.
  • Can progress to resemble an elephant's foot (elephantiasis), which is usually painless.

Temporal Clinical Classification of Ischemic Stroke

Transient Ischemic Attack (TIA)

• Episode of focal neurological deficit, short-term.
• Total recovery within 24 hours.
• No cerebral parenchymal necrosis.
• Current definitions often include standard imaging tests.

Reversible Ischemic Neurological Deficit (RIND)

• Neurological deficit lasting 24 hours and less than 4 weeks.

Established Stroke

• Focal neurological deficit remains unchanged since its onset.

Progressive

Antidepressant Drugs

• Tricyclic Antidepressants (TCAs): Ending in -line or -mine
• Selective Serotonin Reuptake Inhibitors (SSRIs): Fluoxetine, Paroxetine, Citalopram, Fluvoxamine, Sertraline, Nefazodone
• Monoamine Oxidase Inhibitors (MAOIs): Phenelzine, Moclobemide

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

1. Salicylic Acid Derivatives: Aspirin, Diflunisal, Fosfosal (+ codeine for dentalgia)
2. Acetic Acid Derivatives: Indomethacin, Tolmetin, Ketorolac, Diclofenac
3. Propionic Acid Derivatives (Widely used in dentistry): Naproxen, Ketoprofen, Ibuprofen
4. Nicotinic Acid Derivatives: Clonixinate lysine
5. Oxicam Derivatives: Piroxicam
6. Pyrazolones: Dipyrone (Metamizole)
7. Selective COX-2 Inhibitors: Rofecoxib, Celecoxib

Glucocorticoids

• First Generation: Cortisone, Prednisone,

Antidepressants

Tricyclic Antidepressants (TCAs) have a core of condensed 3-rings, a side chain, and amine ends. The introduction of oxygen and nitrogen in the core and the branched side chain are associated with antidepressant action, and the introduction of halogens increases this action. These drugs are well absorbed orally but have low bioavailability. They can also be administered intramuscularly. They tend to bind to plasma proteins and are easily metabolized. TCAs are typically administered twice a day.

Adverse Reactions:

• Cardiovascular: Hypotension, palpitations, tachycardia.
• Anticholinergic: Dry mouth, constipation, urinary retention, nasal congestion, blurred vision (glaucoma).
• Neurological: Confusion, hallucinations, tremors of the hand

Antiparasitic Drugs

• Albendazole: a-tubulin inhibitor. Used for neurocysticercosis, ascariasis, and other helminth infections. Possible side effects: abdominal pain, increased liver enzymes/fat, anorexia, somnolence, and erythema multiforme.
• Praziquantel: increases calcium permeability in parasites. Used for cysticercosis, schistosomiasis, and taeniasis. Possible side effects: abdominal pain, nausea, headache, dizziness, and meningismus.
• Suramin, nifurtimox: inhibit enzymes (oligopeptidases) in trypanosomes. Used for trypanosomiasis. Possible side effects: nephrotoxicity, neurotoxicity, and fever.
• Chloroquine: concentrates in parasite food vacuoles and inhibits heme polymerization and DNA synthesis. Long half-life (30-60 days). Used for malaria.

Tooth Number Anomalies: Agenesis and Hyperdontia

Tooth number is determined by excess or defect. When referring to missing teeth, the term is agenesis. Conversely, having more teeth is known as supernumerary or hyperdontia. Heredity plays a significant role in these anomalies.

Impact of Premature Tooth Loss

Premature tooth loss can alter the perimeter and symmetry of the dental arch. This can be caused by caries, root resorption, and iatrogenic factors. If a tooth is lost, a space maintainer or eruption guide is necessary to keep the antagonist in normal occlusion.

Consequences in Permanent Dentition

In the case of permanent dentition, loss involves:

• Shortening of the arch
• Tilting of adjacent teeth during eruption
• Deviation of the dental midline

Iatrogenic...

Bacterial Structure and Protective Layers

Capsule

The capsule is a structure composed of viscous carbohydrate substances. It plays a protective role against phagocytosis and the attack of antibodies.

Bacterial Cell Wall

The bacterial cell wall is formed by peptidoglycan and other substances. It is a rigid wrapper that supports the strong osmotic pressure to which bacteria are subjected.

Pathogenic Neisseria Species

Gonococcus (Neisseria gonorrhoeae)

Clinical manifestations:

• Men: Urethritis with thick, yellowish pus, painful urination, and dysuria.
• Women: Pelvic inflammatory disease (PID), salpingitis, endocervicitis, and secretions characterized by yellow mutism.

Pathogenesis

Bacteria with daughter cells are virulent. They affect the mucosa of the genitourinary...

Proteins: Structure, Function, and Classification

Proteins are complex molecules made up of amino acids. They perform various essential functions in the body, such as:

• Structural Support (e.g., collagen)
• Enzymatic Activity (e.g., lactase)
• Transport (e.g., hemoglobin)
• Defense (e.g., antibodies)

Classification of Proteins

Proteins are classified based on their structure and function.

Classification Based on Structure

• Fibrous Proteins: (e.g., collagen)
• Globular Proteins: (e.g., enzymes, antibodies)

Classification Based on Function

• Enzymes
• Hormones
• Structural Proteins
• Transport Proteins
• Defense Proteins

The Urea Cycle and Ammonia Removal

The urea cycle is a series of biochemical reactions that occur in the liver to remove excess ammonia from the body. This process...