KEY POINTS
Concept of cell theory
Robert Hook
v Robert Hook reported his work in his famous publication micrographic.
Lorenz Oken
v Lorenz Oken believed that all living beings originate from or consist of vesicles or sells.
Jean Baptist de-lamark
v Jean Baptist de-lamark said no body can have life if its constituents parts are not cellular tissue or one not formed by cellular tissue.
Robert Brown
v Robert Brown reported the presence of nucleus in the cell.
Schleiden and Schwann
v A German Zoologist Schwann and a German botanist Schleiden found that the cell consisted of three basic part i.e nueleus, cytoplasm and plasma membrane.
Rudolph Virchow
v Rudolph Virchow, a German physician hypothesized that new cells were formed only by the division of previously existing cell.
Louis Pasteur
v Louis Pasteur supplied experimental proof for Virchows hypothesis micro-organisms (bacteria) would be formed only from existing bacteria.
August Weismann
v August Weismann said “all presently living cells have a common origin because they have basic similarities in structure and molecules etc.
ORGANELLES WITHOUT MEMBRANE | ORGANELLES WITH SINGLE MEMBRANE | ORGANELLES WITH DOUBLE MEMBRANE |
v Ribosomes v Centrosomes | v Lysosome v Golgi Complex v Endiplasmic reticulum | v Mitochondria v Plastids v Nucleus |
ORGANISM | CELL WALL |
Bacteria | Peptidoglycan and lipopolysaccharides (lipoprotein complex) |
Blue green algae | Muramic acid |
Fungi | Chitin |
Algae and other plants | Mainly cellulose |
Cytoskeleton
v Microtubules and microfilament collectively form cytoskeleton.
v Chromatin material bounded by membrane is called nucleus.
v In all the cellular organelle, unit membrane model is present.
v The inner most boundary in most of the plant cells is cell wall.
v Cell wall is secreted by the protoplasm of the cell
v The primary wall is composed of cellular and some deposition of pectin and hemicellulose.
v Secondary wall is chemically composed of inorganic salts, silica, waxes cutin, lignin etc.
v Fungal cell wall contains chitin.
v The free floating cell organelles e.g. mitochondria move about in cytoplasm due to cytoplasm streaming movement which is an active mass movement of cytoplasm.
v The material present in Endoplasmic Reticulum in separated from the cytoplasm material by the spherical or tubular membranes celled cisternae.
v Endoplasmic Reticulum provides mechanical support to the cell so that its shape in maintained.
v Pavlove was the first person to study Ribosome.
v Eukaryotic Ribosome are composed of almost an equal amount of RNA and protein and are called Ribonucleoprotein particles
v The ribosomes are attached to m-RNA through smaller ribosomal subunit.
v The factory of Ribosome is mucleolus, while that of protein synthesis is the ribosome.
v Golgi Apparatus was found virtually in all the eukaryotic cell.
v In cisternae the outer convex surface in the forming face while the inner concave surface in the maturing face. Cisternae break up into vesicles from the latter.
v The most important function of Golgi apparatus is to modify the protein and lipids by adding carbohydrates and convert them into glycoproteins or glycolipids.
v The digestive vacuoles and autophagosomes are also known as secondary lysosomes.
v Through Autophagy materials of the cell may be recycled or the cell may be renewed.
v Several congenital diseases have been found to be due to accumulation within the cell of substances such as glycogen or various glycolpids.
v There are also called storage diseases and are produced by mutations that effect one of the lysosomal enzymes involved in the catabolism of certain substances.
v In glycogenosis type II disease liver and muscles appears filled with glycogen within membrane-bounded organelles.
v Tay- sach’s disease is because of the absence of an emzyme that is involved in the catabolism of lipids. The accumulation of lipids in the brain cells lead to mental retardation and even death.
v Peroxisomes are specifically involved in the formation and decomposition of Hydrogen peroxide in the cell.
v Peroxisomes are approximately 0.5 nm in diameter.
v Glyoxisomes are most abundant in plant seedling.
v Conversion of stored fatty acids to carbohydrates in the germinating seeds is achieved through glyoxylate cycle, the enzymes of which are located in the glyoxisomes.
v Glyoxisomes is present only during a short period of time in the germination of the lipid rich seed and is absent in lipid poor seed such as pea.
v Vacuoles are bounded by a single membrane.
v The main proteins that are present in cytoskeleton are tubulin (inmicrotubules) actin, myosin, tropomyosin and other which are also found in muscles.
v The movement of cyclosis and amoeboid movements are due to microfilaments whereas intermediate filaments are involved in determination of cell shape and integration of cellular compartments.
v Animal cells, and cells of some microorganisms and lower plants contain two centrioles located near the exterior surface of the nucleus.
v Centrioles play an important role in the location of furrowing during cell division and in the formation of cilia.
v Detailed studies have shown that mitochondria also contain DNA as well as Ribosomes.
v Mitochondria is a self replicating organelle.
v The inner surface of cristae in the mitochondrial matrix has small knob like structures called as F1 particles.
v A crista is made up of lipoprotein membrane containing different enzymes as well as F1 particles embedded in it.
v The main difference between chlorophyII and haem group is that the former contains Mg+2 and the later contains Fe12 as the central atom.
v Chloroplast vary in their shape and size with a diameter of about 4-6 um.
v Stroma covers most of the volume of the chloroplast.
v A granum appears to be a pile of thylakoids stacked on each other like coins. On average there are 50 or more thylakoids piled to form one granal (granum).
v Each granum is inter-connected with others by non-green part called intergranum.
v Membranes of the granum are the sites where sun light energy is trapped and where ATP is formed.
v Nucleus stands out as slightly darker than the surrounding cytoplasm.
v In animal cell, nucleus generally occupies the central position.
v The nuclear envelop composed of two envelops. The outer membrane is at places continuous with the endoplasmic reticulum. While the inner membrane encloses the nuclear contents.
v The rRNA is stored and synthesized in nucleolus.
v Nucleolus is composed of two regions, the peripheral granular area composed of precursors of ribosomal submits and the central fibrillar consisting of large molecular weight RNA and rDNA.
v Nucleus is often deeply stained with basic dyes because of the chromatin material.
v Chromatid is exact replica of the chromosome.
v Centromere is the place on the chromosome and Kinetochore is a place on Centromere where spindle fibres are attached during cell division.
PROKARYOTIC AND EUKARYOTIC CELL
DIFERENCE | PROKARYOTE | EUKARYOTE |
1) CELL TYPE | They are composed of prokaryotic cells. | They are composed of cukaryotic cells. |
2) NUCLEUS | Nucleus is absent in them. | They have well defined nucleus. |
3) DNA | DNA is without any nuclear membrane covering and is directly submerged in cytoplasm. | DNA is enclosed inside the Nucleus. |
4) MEMBRANE-BOUNDED STRUCTURES | Membrane-bounded structures are absent. | Membrane-bounded Structures are present. |
5) RIBOSOMES | They have small sized 70S ribosomes | They have large sized 80S ribosomes. |
6) CELL WALL | Their cell wall is composed of polysaccharide chain covalently bonded with shorter chains of amino acids forming Peptidoglycan or murein. | Cell wall of plants is generally composed of cellulose. |
7) CELL DIVISION | They reproduce by binary fission. | They reproduce by mitosis and meiosis. |
8) EXAMPLE | Bacteria and blue green algae | Multicellular animals and plants are examples |
After Some Time we changed these to :::
KEY POINTS
CONCEPT OF CELL THEORY
ROBERT HOOK
v Robert Hook reported his work in his famous publication micrographic.
LORENZ OKEN
v Lorenz Oken believed that all living beings originate from or consist of vesicles or sells.
JEAN BAPTIST DE-LAMARK
v Jean Baptist de-lamark said no body can have life if its constituents parts are not cellular tissue or one not formed by cellular tissue.
ROBERT BROWN
v Robert Brown reported the presence of nucleus in the cell.
SCHLEIDEN AND SCHWANN
v A German Zoologist Schwann and a German botanist Schleiden found that the cell consisted of three basic part i.e nueleus, cytoplasm and plasma membrane.
RUDOLPH VIRCHOW
v Rudolph Virchow, a German physician hypothesized that new cells were formed only by the division of previously existing cell.
LOUIS PASTEUR
v Louis Pasteur supplied experimental proof for Virchows hypothesis micro-organisms (bacteria) would be formed only from existing bacteria.
AUGUST WEISMANN
v August Weismann said “all presently living cells have a common origin because they have basic similarities in structure and molecules etc.
| ORGANELLES WITHOUT MEMBRANE | ORGANELLES WITH SINGLE MEMBRANE | ORGANELLES WITH DOUBLE MEMBRANE |
| v Ribosomes v Centrosomes | v Lysosome v Golgi Complex v Endiplasmic reticulum | v Mitochondria v Plastids v Nucleus |
| ORGANISM | CELL WALL |
| Bacteria | Peptidoglycan and lipopolysaccharides (lipoprotein complex) |
| Blue green algae | Muramic acid |
| Fungi | Chitin |
| Algae and other plants | Mainly cellulose |
CYTOSKELETON
v Microtubules and microfilament collectively form cytoskeleton.
CYTOPLASMIC STREAMING MOVEMENT
v The free floating cell organelles e.g. mitochondria move about in cytoplasm due to cytoplasm streaming movement which is an active mass movement of cytoplasm.
CISTERNAE
v The material present in Endoplasmic Reticulum in separated from the cytoplasm material by the spherical or tubular membranes celled cisternae.
RIBOSOME
v Eukaryotic Ribosome are composed of almost an equal amount of RNA and protein and are called Ribonucleoprotein particles
v The factory of Ribosome is mucleolus, while that of protein synthesis is the ribosome.
GOLGI APPARATUS
Golgi Appratus is concerened with cell secretion.
v The most important function of Golgi apparatus is to modify the protein and lipids by adding carbohydrates and convert them into glycoproteins or glycolipids.
AUTOPHAGOSOMES
v Lysosomes which eat parts of its own cell are known as autophagosomes.
v The digestive vacuoles and autophagosomes are also known as secondary lysosomes.
STORAGE DISEASES
v Storage diseases are produced by mutations that effect one of the lysosomal enzymes involved in the catabolism of certain substances.
GLYCOGENOSIS TYPE II
v In glycogenosis type II disease liver and muscles appears filled with glycogen within membrane-bounded organelles.
TAY- SACH’S DISEASE
v Tay- sach’s disease is because of the absence of an emzyme that is involved in the catabolism of lipids. The accumulation of lipids in the brain cells lead to mental retardation and even death.
PEROXISOMES
v Peroxisomes are specifically involved in the formation and decomposition of Hydrogen peroxide in the cell.
GLYOXISOMES
v Glyoxisomes are most abundant in plant seedling.
v Conversion of stored fatty acids to carbohydrates in the germinating seeds is achieved through glyoxylate cycle, the enzymes of which are located in the glyoxisomes.
MITOCHONDRIA
v Mitochondria is the power house of the cell.
CRISTAE
v The inner mitochondrial membrane forms infoldings called cristae.
F1 PARTICLES
v The inner surface of cristae in the mitochondrial matrix has small knob like structures called as F1 particles.
PLASTIDS
v Membrane bounded mostly pigment containing bodies present in the cells are called plastids.
TYPES OF PLASTIDS
1) Chloroplast
2) Chromoplast
3) Leucoplast
GRANUM
v A granum appears to be a pile of thylakoids stacked on each other like coins. On average there are 50 or more thylakoids piled to form one granal (granum).
v Nucleus stands out as slightly darker than the surrounding cytoplasm.
v In animal cell, nucleus generally occupies the central position.
v The nuclear envelop composed of two envelops. The outer membrane is at places continuous with the endoplasmic reticulum. While the inner membrane encloses the nuclear contents.
v The rRNA is stored and synthesized in nucleolus.
v Nucleolus is composed of two regions, the peripheral granular area composed of precursors of ribosomal submits and the central fibrillar consisting of large molecular weight RNA and rDNA.
v Nucleus is often deeply stained with basic dyes because of the chromatin material.
v Chromatid is exact replica of the chromosome.
v Centromere is the place on the chromosome and Kinetochore is a place on Centromere where spindle fibres are attached during cell division.
PROKARYOTIC AND EUKARYOTIC CELL
| DIFERENCE | PROKARYOTE | EUKARYOTE |
| 1) CELL TYPE | They are composed of prokaryotic cells. | They are composed of cukaryotic cells. |
| 2) NUCLEUS | Nucleus is absent in them. | They have well defined nucleus. |
| 3) DNA | DNA is without any nuclear membrane covering and is directly submerged in cytoplasm. | DNA is enclosed inside the Nucleus. |
| 4) MEMBRANE-BOUNDED STRUCTURES | Membrane-bounded structures are absent. | Membrane-bounded Structures are present. |
| 5) RIBOSOMES | They have small sized 70S ribosomes | They have large sized 80S ribosomes. |
| 6) CELL WALL | Their cell wall is composed of polysaccharide chain covalently bonded with shorter chains of amino acids forming Peptidoglycan or murein. | Cell wall of plants is generally composed of cellulose. |
| 7) CELL DIVISION | They reproduce by binary fission. | They reproduce by mitosis and meiosis. |
| 8) EXAMPLE | Bacteria and blue green algae | Multicellular animals and plants are examples |
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