Characters
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Prokaryotes
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Eukaryotes
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Groups where found
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Bacteria, Cyanobacteria, Archaea
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Algae, Fungi, Protoza, Plants and Animals
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Size
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1-2 by 1-4 m m or less
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Greater than 5 m m
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Cell wall
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Made up of peptidoglycan
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Made of cellulose in algae and plants, of fungal cellulose or chitin in fungi, absent in protozoan and animals
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Osmotic control
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Wall possesses mechanical strength necessary to counter balance turgor pressure of cytoplasm
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Maintained by contractile vacuole
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Plasma membrane
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Does not contain sterols except in Mycoplasma
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Sterol present
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Fatty acids, exclusively saturated or monounsaturated, except in cyanobacteria which are able to synthesize polyunsaturated fatty acids
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All lipids polyunsaturated
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No inter membrane structure is connected to plasma membrane
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Complex network of intermembrane connected with plasma membrane
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Plasma membrane is the only membrane
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Several cell organelles also covered by membrane (Unit mem-brane)
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Plasma membrane folded to form mesosomes.
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Mesosomes are absent, but in animal cells, it is folded to form finger like microvilli.
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Contains the respiratory machinery i.e. E.T.S., enzymes etc. and carries out respiration.
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E.T.S. is present on mitochondrial membrane.
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Photosynthetic machinery present on bacterial membrane. In cyanobacteria membrane forms vesicles which carry pigments.
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Photosynthetic pigments and ETS present in the chloroplast membrane.
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Cytoplasm
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Granular due to presence of ribosomes, fibrous cytoskeleton absent
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Fibrillar made up of fibrous proteins which form fibrous cytoskeleton
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Pinocytosis, Exocytosis, Endocytosis, Phagocytosis
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Absent, intracellular digestion.
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Present.
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Gas vacuoles
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Present
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Absent
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Ribosomes
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70S, freely distributed in cytoplasm
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80S free as well bounded to ER. 70S in mitochondria and chloroplast.
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Mitochondria
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Absent
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Present
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Chloroplast
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Absent, in cyanobacteria thylakoid vesicles present.
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Present in plant cells and absent in fungi, protozoa and animal cell.
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Golgi apparatus
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Absent
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Present
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Lysosomes
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Absent
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Present
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Endoplasmic Reticulum
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Absent
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Present
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Peroxisomes
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Absent
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Present
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Centrioles
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Absent
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Present
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Nucleolus
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Absent
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Present
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True vacuoles
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Absent
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Present
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Gas vesicles and carboxysomes
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Present
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Absent
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Flagella
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Made up of flagellin fibrils. Flagellin sub-units arranged in a ring helically around a central core.
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Made up of tubulin microtubules arranged in 9+2 formation
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Pili
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Present
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Absent
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Cilia
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Absent
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Present in protozoans
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Replication of DNA
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Through out cell cycle
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Only during ‘S’ phase
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Synthesis of histone proteins
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Absent
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Only during ‘S’ phase
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Cell growth, synthesis of RNA, membrane, macromolecules
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Through out cell cycle
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During Interphase
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Cell division
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Immediately after replication or simultaneously
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During mitosis (M) phase
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Meosis or reduction division
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Absent
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Present
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Chromosome number
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Usually 1
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Variable, 2 to many
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DNA
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Circular, single chromosome, single or double stranded, helically coiled, usually haploid chromosome.
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Single, linear, double stranded, helically coiled, chromosome diploid.
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Extranuclear DNA
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Present in bacteria (plasmid 0.1-5% of bacterial chromosome)
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Absent except in yeasts
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Histone proteins
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Absent
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Present
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DNA position, nuclear membrane
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Usually central, not surrounded by nuclear membrane
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Surrounded by nuclear membrane
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Chromosomal movement
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Unidirectional from donor to recipient at times only exchange of plasmids.
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Exchange of chromosome between two cells (gam etes)
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Structure of mRNA
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Polycistronic
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Monocistronic
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Photosynthesis
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Absent in most except cyanobacteria and autotrophic bacteria
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Present in plants. Absent in fungi, protozoa and animal cells.
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N2 fixation
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Present in some bacteria and cyanobacteria
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Absent
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Respiration (generation of energy)
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Performed by plasma membrane
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Performed by mitochondria
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Anerobic respiration
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Present in many bacteria
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Shown by some e.g. yeasts, few protozoans, muscle cells etc
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Aerobic respiration
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Present
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Present
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Locomotion
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Present in some bacteria, by flagella.
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Absent in plants, algae, fungi, except in zoospores and few unicellular algae and fungi, present in animals and protozoans. (flagellated, ciliary, amieboid, gliding)
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Reproduction
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Simple fragmentation or binary fission, no meosis, asexual spores produced in some.
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Complex, meosis present, also by fragmentation, binary fission and asexual spores in some plants. Algae and fungi and few protozoans.
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Genetic recombination
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Present in some but chromosomal cross over absent.
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By chromosomal cross over during meiosis.
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