Latest questions in this category.
Small size, rapid multiplication, naked DNA and absence of membrane-bound organelles identify X as prokaryotic. An organised nucleus and extensive compartmentalisation identify Y as eukaryotic. Eukaryotes include protists, plants, animals and fungi.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Prokaryotic ribosomes are approximately 15 nm by 20 nm, are associated with the plasma membrane and contain 50S and 30S subunits, forming a 70S ribosome. Several ribosomes on one mRNA constitute a polysome.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Mesosomes are extensions of the bacterial plasma membrane that occur as vesicles, tubules and lamellae. They are associated with cell-wall formation, DNA replication and distribution, respiration, secretion, and increased membrane surface area and enzymatic content.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Mycoplasmas are among the smallest cells, approximately 0.3 µm long, and lack a cell wall. Plasmids are small circular DNA molecules outside the bacterial genomic DNA. They can confer properties such as antibiotic resistance and help monitor transformation with foreign DNA.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
A plant cell possesses a cell wall, plastids and a large central vacuole. Centrioles are characteristic of animal cells and absent from almost all plant cells. Naked circular DNA and absence of membrane-bound organelles identify a prokaryotic cell.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Naked circular genomic DNA, 70S ribosomes, inclusion bodies and absence of membrane-bound organelles identify a prokaryotic cell. Pigment-containing membranous extensions are chromatophores found in some prokaryotes such as cyanobacteria.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
A mitochondrion is typically sausage-shaped or cylindrical. Its diameter is approximately 0.2–1.0 µm, with an average of about 0.5 µm, and its length is approximately 1.0–4.1 µm.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Pili are elongated tubular surface structures made of a special protein. Pili and fimbriae are bacterial surface structures, but they do not function as locomotory flagella.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Mitochondria divide by fission. They also possess circular DNA, RNA, 70S ribosomes and components needed for the synthesis of some proteins.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Gas vacuoles occur in blue-green bacteria and in purple and green photosynthetic bacteria. They are distinct from the non-membrane-bound granules that store reserve materials.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Microbodies are minute membrane-bound vesicles that contain various enzymes. They occur in both plant and animal cells.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Vibrio is the comma-shaped bacterial form. Bacillus is rod-like, coccus is spherical and spirillum is spiral in shape.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
