Notes, summaries, assignments, exams, and problems for Biology

Part A: Multiple Choice

• What is the monomer of a protein?
  Answer: c) Amino acid
• A scientist adds Lugol's iodine solution to an unknown clear liquid, and it instantly turns deep blue-black. What biomolecule is present?
  Answer: b) Starch
• Why does an enzyme cease to function after being exposed to an extremely high temperature?
  Answer: c) The enzyme denatures, altering the shape of its active site.
• Which of the following functions as a micronutrient in the human body?
  Answer: b) Iron (Mineral)

Part B: Structure Identification & Fill-in-the-Blanks

1. Peptide bond
2. Protein
3. Starch
4. Glycogen

Part C: Metabolic Roles and Protein Folding

While carbohydrates provide the raw chemical energy (calories) for the body, micronutrients (vitamins and minerals) act as essential... Continue reading "Biochemistry and Enzyme Function Assessment" »

Metric Conversions and Temperature

Metric Units

• 1 m = 100 cm = 1000 mm
• 1 kg = 1000 g
• 1 L = 1000 mL

Conversion Direction:

• Right: Moving the decimal to convert from bigger to smaller units.
• Left: Moving the decimal to convert from smaller to bigger units.

Temperature Standards

• Water freezes at 0°C.
• Water boils at 100°C.

Biomolecule Identification Tests

Protein Test (Biuret)

• Positive: Pink or purple
• Negative: Blue

Starch Test (Iodine)

• Positive: Black or purple
• Negative: Yellow or brown

Sugar Test (Benedict’s)

• Green: Low concentration
• Yellow: Medium concentration
• Red/Orange: High concentration
• Blue: None

Lipid Test (Brown Paper)

• Positive: Greasy or translucent
• Negative: Opaque

Cellular Processes and Enzymes

Diffusion and Osmosis

• Hypertonic: Water moves out; the cell shrinks.

Q — Classify antihistaminic drugs and their therapeutic uses.

Classification of Antihistamines and Therapeutic Uses

1. Introduction to Antihistamines

Antihistamines are drugs that block or reduce the effects of histamine, a chemical involved in allergic reactions, gastric acid secretion, and neurotransmission. They are primarily classified based on the histamine receptor subtype they act on:

• H₁ receptor antagonists (H₁ antihistamines)

• H₂ receptor antagonists (H₂ blockers)

• H₃ and H₄ antagonists (experimental/limited clinical use)

2. Classification of Antihistamines

A. H₁ Receptor Antagonists (H₁ Blockers)

1. First-Generation H₁ Antihistamines

• Cross the blood–brain barrier → cause sedation

• Have anticholinergic and antiemetic effects

Examples:

• Diphenhydramine

• Chlorpheniramine

• Hydroxyzine

• Promethazine

• Dimenhydrinate

• Meclizine

2.

Mendel's Laws of Inheritance and Genetic Crosses

Mendel's Laws of Inheritance

1. Law of Segregation: Each parent contributes only one of their two alleles for a specific trait to their offspring.
2. Law of Independent Assortment: Alleles for different traits are passed down independently of one another during gamete formation.
3. Law of Dominance: When an organism inherits two different alleles for a trait, the dominant allele will be expressed in the phenotype, masking the effect of the recessive allele.

Analyzing Monohybrid Inheritance

Case Study: Earlobes (Monohybrid Cross)

The results of the cross show:

• Mr. Jones: aa (Attached earlobes, recessive)
• Mrs. Jones: Aa (Free earlobes, heterozygous dominant)

Their children exhibit the following genotypes and phenotypes:... Continue reading "Genetic Inheritance: Mendel's Laws, Crosses, Ratios, and Probability" »

Differential Diagnosis of Oral Ulcers and Vesiculobullous Lesions

Classification by Number and Etiology

• Single Ulcers: Traumatic, Tuberculosis (TB), Primary Syphilis.
• Multiple Ulcers: Recurrent Aphthous Stomatitis, Herpetic Stomatitis, Erythema Multiforme, Pemphigus Vulgaris.

Classification by Location

• Keratinized Mucosa: Recurrent Intraoral Herpes, Mucous Membrane Pemphigoid, Major Aphthous Ulcers.
• Non-Keratinized Mucosa: Minor Aphthous Ulcers, Herpetiform Ulcers.

Classification by Clinical Features

• Ulcers Causing Scarring: Major Aphthous Ulcers, Mucous Membrane Pemphigoid Ulcers, Tertiary Syphilis.
• Painless Ulcers: Tuberculosis (TB), Primary Syphilis, Tertiary Syphilis.
• Painful Ulcers: Primary Herpetic Gingivostomatitis, Recurrent Intraoral Herpes,

Introduction to Histology

Tissues are groups of similar cells specialized to carry out a specific function.

• Histology: The study of tissues.
• Cytology: The study of cells.

There are 4 primary types of tissues in the human body: Epithelial, Connective, Muscle, and Nervous.

Epithelial Tissue Overview

Epithelial tissue covers organs and lines cavities to form barriers; these tissues absorb, secrete, and excrete substances.

• Glandular Tissue: Secretes substances needed by the body.
• Characteristics: Avascular, high mitotic rate, tightly packed, possesses a basement membrane and one free surface.

Extracellular Matrix: All material outside of and between non-living cells.

Classification of Epithelial Tissue

Epithelial tissues are classified by shape: Squamous,

The Human Digestive System

Definition: The digestive system is a network of organs and tissues that work together to perform digestion.

Digestion: Digestion is a complex process that involves the breakdown and absorption of nutrients from ingested food.

Composition: This system consists of the Gastrointestinal (GI) tract, accessory organs, and various digestive processes.

The Gastrointestinal (GI) Tract

The GI tract is a long, hollow tube extending from the mouth to the anus, including the esophagus, stomach, small intestine, and large intestine.

Accessory Organs

The accessory organs include the liver, gallbladder, pancreas, and salivary glands.

• Functions: Produce digestive enzymes, produce saliva, and produce bile.

Main Functions of the Digestive System

1. Ingestion:

Anatomy and Physiology Fundamentals

Anatomical Terminology

• Anatomical Descriptors
  • Anterior — at or near the front of the body
  • Posterior — at or near the back of the body
  • Midline — imaginary vertical line dividing the body equally
  • Lateral — farther from the midline
  • Medial — nearer to the midline
  • Superior — toward the head or upper part of a structure
  • Inferior — away from the head or lower part of a structure
  • Superficial — close to the surface of the body
  • Deep — away from the surface of the body
  • Proximal — near the origination of a structure
  • Distal — farther from the origination of a structure
  • Contralateral — on the opposite side
• Anatomical Planes
  • Sagittal — body divided into left and right halves by a vertical plane passing through

Circulatory System

Deoxygenated blood from the body returns to the right atrium of the heart through the superior and inferior vena cavae. The right atrium contracts, pushing the blood through the tricuspid valve into the right ventricle. The right ventricle contracts, pumping the deoxygenated blood through the pulmonary valve into the pulmonary artery. The pulmonary artery carries the deoxygenated blood to the lungs, where it picks up oxygen and releases carbon dioxide through the process of gas exchange. Oxygenated blood returns from the lungs to the left atrium of the heart via the pulmonary veins. The left atrium contracts, pushing the oxygenated blood through the mitral valve into the left ventricle. The left ventricle contracts, pumping... Continue reading "Understanding the Circulatory and Reproductive Systems" »