Notes, summaries, assignments, exams, and exercises for Biology for Vocational training

Structure and Properties of Nucleotides

Nucleotides (phosphoric esters of nucleosides: nucleoside + phosphate = pentose phosphate linked at C-5) yield nucleosides upon dephosphorylation (nitrogenous base [NB] + pentose via glycosidic linkage).

Nitrogenous Bases and Pentoses

• Pyrimidines (joined via N-1): Cytosine (C), Uracil (U), Thymine (T)
• Purines (joined via N-9, double ring): Adenine (A), Guanine (G)
• Properties of Nitrogenous Bases (NB): Absorption in the UV spectrum (260 nm), weak basic character, planar structures, ability to form hydrogen bonds, and tautomerism (keto-enol and amine-imine).
• Pentose: May be either D-ribose (RNA) or 2-deoxy-D-ribose (DNA).

De Novo Nucleotide Biosynthesis

Origin of Atoms:

• Purines: CO₂, Glycine (Gly), Aspartate (Asp)

Pulmonary Gas Exchange Physiology

Gaseous diffusion: Gas exchange is performed in the alveoli across the alveolar–capillary membrane. Oxygen moves from the air inside the alveoli into the pulmonary capillary blood across this membrane; carbon dioxide moves in the opposite direction. This diffusion occurs while oxygenates blood flows through the pulmonary capillaries and air fills the alveolar spaces.

Transport of Gases

Gases exchanged in the circulation are transported either bound to hemoglobin or dissolved in plasma in small quantities. Hemoglobin binding accounts for the majority of oxygen transport in blood.

Cellular Respiration

Oxygen passes from the capillaries into the cells, and carbon dioxide passes from the cells into the capillaries,...

Radiation Hazards

Ionizing Radiation

Ionizing radiation has the property to affect the resulting field ionization of atoms, which means that electrons are ejected from the atom generator with the resultant production of two ions. They can be natural. The exposure of living tissue to ionizing radiation causes damage to cells, and its effects can be grouped into:

Immediate Effects

These are those that occur when the individual receives a high dose of radiation in a short exposure time. Exposure of the whole body or a large part of it at high doses leads to acute radiation syndrome, which manifests with nausea, vomiting, and other symptoms.

Deferred Effects

These appear years after the radiation exposure. Examples include the development of leukemia...

Head and Neck Anatomy Q&A

• 33. Zygomaticus minor muscle insertion: From the anterior portion of the zygomatic bone to the upper lip.
• 34. Buccal nerve innervation: Posterior and inferior portion of the vestibule, buccal side of the gums of premolars and molars, and skin of the cheek.
• 35. Terminal branches of the infraorbital nerve: Palpebral, nasal, and labial.
• 36. Tensor tympani muscle innervation: Medial pterygoid nerve (branch of the trigeminal nerve).
• 37. Cerebellar peduncles connection: Connects the cerebellum with the brainstem.
• 38. Temporalis muscle insertion: Medial side of the coronoid process.
• 39. Main nerves in the sublingual region: Lingual and hypoglossal nerves.
• 40. Arteries arising from the anterior external carotid: Superior thyroid,

Respiratory System Function

The respiratory system is responsible for gas exchange, where CO₂ is removed from venous blood and atmospheric O₂ is absorbed into the bloodstream.

Respiratory Organs

• Conducting Tubes: These structures clean, heat, and transport atmospheric air into the lungs. This includes the trachea, pharynx, and larynx.
• Lungs: Essential organs where gas exchange occurs.

Nasal Anatomy

• Nostrils: Two cavities in the center of the face serving as the gateway to the respiratory system.
• Nose: An osteochondral prominence located in front of the nostrils.
• Choanae: Posterior nasal orifices.

Nasal Cavity Walls

• Roof: Formed by bone.
• Floor: Composed of the hard palate and soft tissue.
• Septum: Features anterior cartilage and posterior bone.
• Outer Wall: