Important Questions (1 mark): The Fundamental Unit of Life for Class 9

• Option A: Mitochondria - Photosynthesis This is incorrect. Mitochondria are known as the powerhouses of the cell because they generate ATP, the energy currency of the cell, not because they perform photosynthesis. Photosynthesis is carried out by chloroplasts in plant cells.
• Option B: Lysosomes - Powerhouse of the cell This is incorrect. Lysosomes are membrane-bound sacs filled with digestive enzymes that break down waste materials and cellular debris. The mitochondria are known as the "powerhouse of the cell" because they produce ATP.
• Option C: Golgi Apparatus - Packaging and dispatching of materials This is correct. The Golgi apparatus is involved in the storage, modification, and packaging of products in vesicles. It plays a key role in processing and packaging proteins and lipids that are synthesized by the cell.
• Option D: Endoplasmic Reticulum - Storage of DNA This is incorrect. The endoplasmic reticulum (ER) functions as a manufacturing and packaging system. It is involved in the synthesis of proteins and lipids, not in the storage of DNA. DNA is stored in the nucleus of the cell.

The correct option is Option C.
Animal cells are generally smaller than plant cells with their cells ranging from 10-30um in length. Animal cells shape and sizes vary greatly from irregular shapes to round shapes, most defined by the function they perform. Plant cells are larger than animal cells with the cell size ranging from 10um-100um in length.

In eukaryotic cells, most DNA is located in the cell nucleus (though some DNA is also contained in other organelles, such as in the mitochondria and the chloroplast in plants). Nuclear DNA is organized into linear molecules called chromosomes. The size and number of chromosomes varies significantly between species.

Purkinje coined the term protoplam in 1839 for plant sap which is living fluid inside the cell. Initially Dujardin in 1835 observed the living juice inside the animal cell.

Rudolf Virchow famously stated “Omnis cellula e cellula”… “All cells only arise from pre-existing cells. “The parts of the theory that did not have to do with the origin of cells, however, held up to scientific scrutiny and are widely agreed upon by the scientific community today.

Option A: Robert Hooke - Discovered the nucleus
This is incorrect. Robert Hooke is credited with discovering cells in 1665 by observing a thin slice of cork through a primitive microscope. The nucleus was discovered by Robert Brown in 1831.

Option B: Leeuwenhoek - Coined the term 'protoplasm'
This is incorrect. Leeuwenhoek is known for his discovery of free-living cells (bacteria and protozoa) in 1674 using an improved microscope. The term 'protoplasm' was coined by Purkinje in 1839.

Option C: Purkinje - Discovered free living cells in pond water
This is incorrect. Purkinje coined the term 'protoplasm' for the fluid substance within cells. The discovery of free-living cells in pond water was made by Leeuwenhoek.

Option D: Schleiden and Schwann - Proposed the cell theory
This is correct. Schleiden (1838) and Schwann (1839) are known for proposing the cell theory, which states that all plants and animals are composed of cells and that the cell is the basic unit of life.

Therefore, the correctly matched pair is Option D.

The correct option is Option D. 
Golgi apparatus is a cellular organelle which consists of folded and flattened membranes within the cytoplasm.
It helps in modifying, sorting and packaging of proteins for secretion and also helps in the transportation of lipid and forms lysosomes. 
Proteins and lipids synthesised by the endoplasmic reticulum combine with carbohydrates to form glycoproteins and glycolipids.
The hormones produced by endocrine glands is mediated by Golgi bodies.
The complex carbohydrates (mucopolysac­charides, hyaluronic acid and hemicelluloses etc.).
So, the correct answer is 'All of the above'.

The proteins and lipids, essential for building the cell membrane, are synthesized by the rough endoplasmic reticulum (RER). The ribosomes attached to the RER help in this process.

The largest cell in the human body is the ovum or egg cell. It is the largest by volume and is visible to the naked eye. While nerve cells (neurons) are the longest, the ovum is the largest in size and volume.