CELL is the structural and functional unit of all living organisms and of two types plant cell and animal cell.Its the basic building block of all organisms.Virus is the exception,it contains RNA/DNA surrounded …. Read More
- Prokaryotic cells lack well defined nucleus and has simplified internal organization.
- It consist of single closed compartment of cytosol and bounded by the plasma membrane.
- The genetic material DNA is condensed into the central region of cell.Most of or all of the genetic informations are stored in the single …. Read More
Prokaryotes are very small,some are larger than 50 micron.Eukaryotes are large range between 10 to 100 microns but some are larger than 1 mm …. Read More
Plant cell has outer rigid cell wall made of cellulose but cell wall is absent in animal cell and plasma membrane is the outermost covering …. Read More
The cells of all plants, bacteria and fungi have rigid,protective covering outside plasma membrane called “Cell wall”.Cell wall is present in plant cells but its absent in animal cells.The cell wall was first observed …. Read More
All prokaryotic and eukaryotic cells are enclosed by an elastic thin covering called Plasma membrane.It is selective permeable membrane because it only allows specific substances to pass through.Eukayotic cells in addition possess intracellular membranes …. Read More
Based on the permeability a membrane is said to be
- Permeable: Substances readily pass through the membrane
- Impermeable: Substances cannot pass through membrane.
- Selectively permeable: Membrane allows some of the substance to pass through but does not allow other substances to pass through. …. Read More
Endocytosis(into cells) and exocytosis(out of cells) are active processes involving bulk transport of materials through
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They are bounded by two membranes with the inner one extensively folded.Enzymes in inner mitochondrial membrane and central matrix carryout terminal stages of sugar and lipid oxidation coupled ATP synthesis.That’s why it is called as …. Read More
Nucleus is the largest organelle in eukaryotic cells.It is surrounded by two membranes.Each one is a phospholipid bilayer consist of different types of proteins.Inner nuclear membrane defines nucleus.Outer membrane of nucleus is continuous with rough …. Read More
Mitochondria is called as “Power house of the cell” because it stores and releases energy of the cell in the form of ATP(Adenosine Triphosphate).It is a principle site of energy production of aerobic cells …. Read More
Ribosomes are the site “Protein synthesis”.They are small sub-spherical granular organelles.It’s not enclosed by any membrane.They are composed of ribonucleoproteins and rRNA.They occur in large number each of 150-250 Angstroms in diameter and consists …. Read More
Plastids are the largest cell organelles bounded by double membrane.These are found in most of the plants cells.These are absent in prokaryotes and animal cells.It’s of three types.1.Chloroplasts 2.Chromoplasts and 3.Leucoplasts …. Read More
Chloroplast are of 10 microns long and 0.5 to 2.0 microns thick and it may vary based on size and type of the cells especially among algae.It is surrounded by outer and inner membrane.In addition chloroplasts consist of interconnected extensive sacs called Thylakoids …. Read More
Cell division or cell cycle is an important step of evolution,since each and every organisms in earth is evolved from single cell organisms(eg:Amoeba) to multicellular oragnisms(eg:Human) through cell-division …. Read More
Mitotic cell division is first described by W.flemming in 1882(in plant cell by Strasburger).Karyokinesis(DNA duplication followed by nuclear division) followed bycytokinesis(cytoplasm of single eukaryotic cell …. Read More
Meiotic cell division occurs in reproductive cells of plants and animals.Meiotic cell division is also known as “Reduction division” where diploid number of chromosomes are reduced to haploid …. Read More