Microscopy History, Sample Prep, and Cell Types
History of Optical Microscopy
Key Milestones
- 1611: Johannes Kepler suggests methods for constructing a compound microscope.
- 1655: Robert Hooke publishes Micrographia, introducing the concept of the biological ‘cell’.
- Mid-17th Century: Antonie van Leeuwenhoek builds over 200 simple microscopes (single high-magnification lenses, up to 270x).
- Early 19th Century: Giovanni Battista Amici makes significant improvements by correcting spherical and chromatic aberrations in lenses.
- Late 19th Century: Ernst Abbe
Anatomy of the Orbit, Eyeball, and Mammary Gland
Anatomy of the Orbit
The orbit is the pyramidal bone cavity of the face’s skeleton. It contains and protects the eyeball along with most of the lacrimal apparatus.
Orbit Limits:
- Roof: Frontal and sphenoid bones.
- Medial Wall: Sphenoid, ethmoid, frontal, and lacrimal bones.
- Floor: Maxilla, zygomatic, and palatine bones.
- Lateral Wall: Sphenoid and zygomatic bones.
- Apex: Optic canal.
Orbit Content:
The orbit contains the eyeball, optic nerve, eye muscles, fascia, nerves, vessels, fat, lacrimal glands, and lacrimal
Read MoreHuman Nervous and Excretory Systems
The Excretory System
The excretory system is responsible for removing waste products from the body, primarily nitrogenous waste like urea and creatinine. It filters body fluids (coelomic fluid, hemolymph, blood) through specialized structures. In invertebrates, the basic unit of filtration is the nephridium, while in vertebrates, it’s the nephron.
The human urinary system has two main components:
- Secretory Organs: The kidneys produce urine and perform other vital functions.
- Elimination Pathway: This
Animal Classification: Questions and Answers
3) Progressive Changes in Animal Classification
Answer: Aristotle is known as the father of classification. Then came Carolus Linnaeus, who gave the two-kingdom classification: Plantae and Animalia. After this, Ernst Haeckel proposed the three-kingdom classification: Plantae, Animalia, and Protista. Later, Whittaker introduced the five-kingdom classification: Monera, Protista, Animalia, Fungi, and Plantae.
4) Grades of Organization vs. Symmetry
Answer: Grades of organization describe the types of cells,
Read MoreNucleotides, Monosaccharides, and Polysaccharides
Nucleotides
The nucleotides are formed by the union of one molecule of phosphoric acid and a nucleoside via the hydroxyl group of the fifth carbon (carbon 5′) of the pentose. It is, therefore, a phosphoric ester of nucleoside. The nucleotides are strongly acidic due to the phosphate group that is ionized. Nucleotides are named by adding the term 5′-monophosphate to the name of the nucleoside. Thus, the RNA nucleotides are adenosine-5′-monophosphate (AMP), guanosine-5′-monophosphate (GMP), cytidine-
Read MoreWinemaking Processes: Protein Stability, Fermentation & Sparkling Wine
Identifying Protein Instability in Wine
To differentiate protein instability (protein haze) from other issues like iron casse, perform the following tests:
- Add a few drops of hydrochloric acid to the cloudy wine. If protein instability is present, the cloudiness will likely increase.
- Alternatively, heat the wine to 80°C. If the haze dissolves, it might be tartrate crystals or another deposit. If it persists or increases, protein instability is likely. [Note: Standard tests often involve heating to