Cellular Organisation, Biomolecules, and Cell Division: MCQ Test
Test your comprehensive knowledge of cell structure, biomolecules, and cell division processes, suitable for competitive exams, based on the provided learning materials.
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1. Which theory emphasized the unity underlying the diversity of life forms, focusing on cellular organisation?
The cell theory emphasized the unity underlying the diversity of forms, specifically the cellular organisation of all life forms.
2. Who first saw and described a live cell?
Antonie Von Leeuwenhoek first saw and described a live cell.
3. In 1838, Matthias Schleiden, a German botanist, made which key observation contributing to cell theory?
In 1838, Matthias Schleiden observed that all plants are composed of different kinds of cells which form the tissues of the plant.
4. Theodore Schwann (1839), a German Zoologist, reported that animal cells had a thin outer layer. What is this layer known as today, and what unique characteristic did he note for plant cells?
Theodore Schwann reported that animal cells had a thin outer layer, known today as the 'plasma membrane.' He also concluded that the presence of a cell wall is a unique character of plant cells.
5. The statement 'Omnis cellula-e cellula' was first explained by whom, giving the cell theory its final shape?
Rudolf Virchow (1855) first explained that cells divided and new cells are formed from pre-existing cells ('Omnis cellula-e cellula'), modifying the hypothesis of Schleiden and Schwann to give the cell theory a final shape.
6. Which of the following is NOT a characteristic of prokaryotic cells?
Prokaryotic cells lack membrane-bound organelles and a well-defined nucleus.
7. The semi-fluid matrix that occupies the volume of the cell in both prokaryotic and eukaryotic cells, and is the main arena of cellular activities, is called the:
In both prokaryotic and eukaryotic cells, a semi-fluid matrix called cytoplasm occupies the volume of the cell and is the main arena of cellular activities.
8. Identify the smallest cells known, which are only 0.3 µm in length.
Mycoplasmas, the smallest cells, are only 0.3 µm in length.
9. Which of the following is a characteristic shape of bacteria?
The four basic shapes of bacteria are bacillus (rod like), coccus (spherical), vibrio (comma shaped) and spirillum (spiral).
10. In prokaryotic cells, what are the small circular DNA molecules found outside the genomic DNA, which can confer unique phenotypic characters like antibiotic resistance?
Many bacteria have small circular DNA outside the genomic DNA, called plasmids. These confer unique phenotypic characters, such as resistance to antibiotics.
11. Mesosomes, which are characteristic of prokaryotes, are essentially infoldings of the cell membrane. Which of the following is NOT listed as a function of mesosomes?
Mesosomes help in cell wall formation, DNA replication and distribution to daughter cells, respiration, secretion processes, and to increase the surface area of the plasma membrane and enzymatic content. Ribosomes are the site of protein synthesis.
12. Bacteria can be classified into Gram positive and Gram negative based on differences in their:
Bacteria are classified into two groups based on differences in their cell envelopes and how they respond to the Gram staining procedure.
13. The outermost layer of the prokaryotic cell envelope, which can be a loose sheath (slime layer) or a thick and tough structure (capsule), is called the:
The cell envelope consists of the outermost glycocalyx, followed by the cell wall and then the plasma membrane. Glycocalyx can be a loose sheath (slime layer) or thick and tough (capsule).
14. Which of the following surface structures in bacteria are elongated tubular structures made of a special protein and are known to help attach bacteria to rocks or host tissues, but do not play a role in motility?
Pili are elongated tubular structures made of a special protein that help bacteria attach to rocks in streams and to host tissues. They do not play a role in motility, unlike flagella.
15. Prokaryotic ribosomes are about 15 nm by 20 nm in size and are made of two subunits. What is their Svedberg unit (S) value?
Prokaryotic ribosomes are made of two subunits - 50S and 30S units which when present together form 70S prokaryotic ribosomes.
16. Reserve material in prokaryotic cells are stored in the cytoplasm in the form of inclusion bodies. Which of these is NOT an example of an inclusion body?
Inclusion bodies are not bound by any membrane system and lie free in the cytoplasm, examples include phosphate granules, cyanophycean granules, and glycogen granules. Lysosomes are membrane-bound organelles found in eukaryotic cells.
17. Eukaryotic cells are characterized by extensive compartmentalization of cytoplasm and the presence of membrane-bound organelles. Which of the following is unique to animal cells and absent in almost all plant cells?
Plant cells possess cell walls, plastids and a large central vacuole which are absent in animal cells. On the other hand, animal cells have centrioles which are absent in almost all plant cells.
18. The fluid mosaic model of the plasma membrane, widely accepted in 1972, was proposed by:
An improved model of the structure of cell membrane was proposed by Singer and Nicolson (1972) widely accepted as the fluid mosaic model.
19. In human erythrocytes, what is the approximate percentage of protein and lipid in the cell membrane?
In human beings, the membrane of the erythrocyte has approximately 52 per cent protein and 40 per cent lipids.
20. Movement of molecules across the plasma membrane from a higher concentration to a lower concentration without the requirement of energy is called:
Many molecules can move briefly across the membrane without any requirement of energy and this is called the passive transport. Neutral solutes move by simple diffusion along concentration gradient.