Explanation

• The first compound microscope is believed to have been invented around 1590.
• It was developed by the Dutch spectacle makers Hans Janssen and his son Zacharias Janssen.
• Their invention used two lenses to magnify tiny objects.

Additional information:

• Galileo Galilei – 1609 improved the microscope design
• Robert Hooke – 1665 observed cork cells and wrote Micrographia
• Antonie van Leeuwenhoek – 1674 discovered microorganisms
• Joseph Jackson Lister – 1830 improved modern compound microscope

Last verified on 13-03-2026

Explanation

• Glucose is a simple sugar (monosaccharide) and a primary source of energy for cells.
• Its chemical formula is C6H12O6.

Additional information:

• Fructose: C6H12O6 (same formula as glucose, different structure)
• Galactose: C6H12O6
• Ribose: C5H10O5
• Deoxyribose: C5H10O4
• Sucrose (disaccharide): C12H22O11

Last verified on 13-03-2026

Explanation

• The spleen is not part of the digestive tract; it is part of the lymphatic system and helps in blood filtration and immune response.

Additional information:

Main components of human digestive tract:

• Mouth – ingestion and initial digestion
• Oesophagus – food passage
• Stomach – protein digestion
• Small intestine – nutrient absorption
• Large intestine / Colon – water absorption and feces formation

Last verified on 13-03-2026

Explanation

• Hydrochloric acid (HCl) is produced in the stomach, not the liver.
• The Right lobe, Hepatocyte, Common bile duct are directly associated with the liver.
• The liver is involved in bile production, metabolism, and detoxification.

Last verified on 13-03-2026

Explanation

• Mitochondria are known as the powerhouse of the cell.
• They are the site of cellular respiration, where glucose is converted into ATP (energy).
• Mitochondria have a double membrane and their own DNA and ribosomes.
• They provide energy for all cell activities.

Last verified on 13-03-2026

Explanation

• Filtration is not part of digestion; it occurs mainly in the kidneys for removing waste from blood.

Additional information:

Main functions of the digestive system:

1. Ingestion – taking in food
2. Propulsion – swallowing and peristalsis
3. Mechanical processing – chewing and churning
4. Chemical digestion – breaking down molecules with enzymes
5. Absorption – nutrients absorbed into blood or lymph

Last verified on 13-03-2026

Explanation

• Chromosomes are thread-like structures inside the nucleus that carry genetic material (DNA).
• They determine an organism’s hereditary traits.
• Humans have 46 chromosomes arranged in 23 pairs.

Last verified on 13-03-2026

Explanation

• The diaphragm of a microscope controls the amount of light passing through the specimen.
• In humans, the iris regulates the amount of light entering the eye through the pupil.

Additional information:

• Eyepiece → Lens of eye (focuses image)
• Stage → Retina (holds specimen/image for observation)
• Light source → Pupil (allows light to enter)
• Objective lens → Cornea & Lens (magnifies object)

Last verified on 13-03-2026

Explanation

• Meiosis is a special type of cell division that produces four daughter cells from one parent cell.
• These cells are haploid (n), meaning they contain half the number of chromosomes.
• Meiosis is essential for sexual reproduction and genetic variation.

Last verified on 12-03-2026

Explanation

• Bacteria are prokaryotic organisms, meaning they do not have a true nucleus.
• Their genetic material (DNA) is not enclosed in a membrane-bound nucleus.
• Instead, the DNA is present in a region called the nucleoid within the cytoplasm.
• Therefore, bacterial DNA is found floating in the cytoplasm of the cell.

Additional information:

• In contrast, eukaryotic cells (plants, animals, fungi) have DNA enclosed inside a nucleus.

Last verified on 11-03-2026