Zoology MCQs for NEET — Practice Questions with Answers

Mitochondria are known as the powerhouses of the cell because they generate ATP (adenosine triphosphate), which is the primary energy currency of the cell. Through the process of oxidative phosphorylation, mitochondria convert energy stored in nutrients into ATP, which is then used by the cell to perform various functions.

Ribosome synthesis takes place in the nucleolus, which is a prominent sub-nuclear structure that is not bound by a membrane and resides within the cell nucleus. The nucleolus is responsible for producing and assembling ribosome components.

The mitochondria are often referred to as the 'powerhouse of the cell' because they generate most of the cell's supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.

The Electron Transport System (ETS) occurs in the inner membrane of mitochondria. This membrane contains the proteins involved in the electron transport chain and ATP synthesis.

The cytoskeleton is a complex network of protein filaments and tubules that extends throughout the cytoplasm of eukaryotic cells. It is primarily made up of microfilaments (actin filaments), intermediate filaments, and microtubules, all of which are proteinaceous in nature.

In higher plants, the cell wall is primarily composed of cellulose. Cellulose is a polysaccharide consisting of a linear chain of glucose molecules. It provides structural support to the plant cells and is the most abundant organic polymer on Earth.

Rudolf Virchow, a German physician, and pathologist, proposed that new cells arise from preexisting cells through cell division. This concept is encapsulated in his famous dictum 'Omnis cellula e cellula,' which means 'every cell from a cell.' This idea is fundamental to the cell theory.

The fluid mosaic model of the cell membrane was proposed by Singer and Nicolson in 1972. According to this model, the cell membrane is a fluid combination of phospholipids, cholesterol, and proteins. The proteins float in or on the fluid lipid bilayer like boats on a pond.

The flagella of eukaryotic cells exhibit a 9+2 arrangement of microtubules. This means that there are nine doublets of microtubules arranged in a circle around two central microtubules. This structure is crucial for the movement of the flagella.

Microtubules are made up of tubulin proteins. Tubulin is a globular protein that polymerizes to form the hollow tubes that make up the microtubules. These structures are essential for various cellular processes, including cell division and intracellular transport.