Cell Structure — Set 1
Biology · कोशिका संरचना · Questions 1–10 of 60
Which organelle is responsible for the detoxification of drugs and poisons in liver cells?
Correct Answer: B. Smooth Endoplasmic Reticulum
The Smooth Endoplasmic Reticulum contains enzymes that help neutralize harmful substances. In liver cells, this organelle is highly developed to process various toxins. It also plays a key role in lipid synthesis and calcium storage.
What is the primary function of the nucleolus found within the nucleus?
Correct Answer: B. Ribosome synthesis
The nucleolus is the site where ribosomal RNA is produced and assembled into subunits. These subunits then move to the cytoplasm to facilitate protein synthesis. It is a dense, non-membrane bound structure inside the nucleus.
Which cell structure is primarily composed of a phospholipid bilayer with embedded proteins?
Correct Answer: C. Plasma Membrane
The plasma membrane acts as a selective barrier that regulates the entry and exit of molecules. The fluid mosaic model describes its flexible nature and various functional proteins. It is essential for maintaining the internal environment of the cell.
Which scientist first observed and named the 'cell' while looking at a slice of cork?
Correct Answer: D. Robert Hooke
Robert Hooke coined the term 'cell' in 1665 because the cork structures reminded him of small rooms. He used a primitive compound microscope to make these historical observations. His findings were published in his famous book titled Micrographia.
Which of the following is a characteristic feature of prokaryotic cells?
Correct Answer: C. Absence of nuclear membrane
Prokaryotic cells do not have a defined nucleus, so their genetic material floats freely in the nucleoid. They lack most membrane-bound organelles found in more complex eukaryotic cells. Bacteria and Archaea are the two primary groups of prokaryotes.
Which organelle serves as the primary site for the modification, sorting, and packaging of proteins?
Correct Answer: B. Golgi Apparatus
The Golgi apparatus receives proteins from the endoplasmic reticulum for further processing. It adds chemical tags to ensure proteins reach their correct cellular destinations. It is often compared to a post office or shipping center.
What is the function of the 'Middle Lamella' in plant tissues?
Correct Answer: C. Cementing adjacent cells
The middle lamella is a layer rich in pectin that glues the cell walls of neighboring plant cells together. It provides structural stability and integrity to the overall plant body. This layer is formed during the process of cytokinesis.
Which of these structures is found in animal cells but is generally absent in higher plant cells?
Correct Answer: B. Centrioles
Centrioles are barrel-shaped structures that help in the organization of the spindle fibers during animal cell division. They are located within the centrosome near the nucleus. Most higher plants achieve division without the presence of centrioles.
Which organelle contains its own DNA and is thought to have originated from ancient bacteria?
Correct Answer: C. Mitochondria
Mitochondria possess circular DNA and double membranes, supporting the endosymbiotic theory. This theory suggests they were once free-living prokaryotes that entered a symbiotic relationship. They are responsible for producing ATP through cellular respiration.
What provides the structural framework and allows for the movement of organelles within the cytoplasm?
Correct Answer: C. Cytoskeleton
The cytoskeleton is a network of protein fibers including microtubules and microfilaments. It maintains cell shape and assists in internal transport and cell motility. It is dynamic and can reorganize itself based on the cell's needs.