Cell Biology | CEE Academy

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CYTOLOGY AND CELL BIOLOGY

Table 1: Cytology vs Cell Biology

Feature	Cytology	Cell Biology / Modern Cytology
Study includes	Cell organelles + cell inclusions only	Cell organelles + cell inclusions + physiology + chemistry + genetics of cells
Main focus	Form + structure of cell	Structure + function of cell
Father	Robert Hooke	Swanson

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HISTORY OF CELL BIOLOGY

Table 1: Scientists and Contributions

Scientist	Contribution
Robert Hooke	Coined term cell in 1665
Robert Hooke	Observed cork from outer bark of Quercus suber
Robert Hooke	Actually observed dead attached cell walls
Robert Hooke	Published findings in Micrographia
A.V. Leeuwenhoek	Father of microscopy
A.V. Leeuwenhoek	Discovered living cells and free cells
Schleiden	German botanist; proposed cell theory with Schwann
Schwann	German zoologist; proposed cell theory with Schleiden
Dutrochet	First idea of cell theory; separated cells from Mimosa pudica leaf
Rudolf Virchow	Extended cell theory by law of cell lineage
Haberlandt	First idea of cellular totipotency
Steward	Experimentally proved cellular totipotency
Purkinje	Coined term protoplasm
Huxley	Defined protoplasm as physical basis of life
Robert Brown	Discovered nucleus from orchid root cells
Hammerling	Proved nucleus as control centre using Acetabularia
Fontana	Discovered nucleolus
Bowman	Gave term nucleolus
Flemming	Gave term chromatin
Waldeyer	Gave term chromosome
Sutton and Boveri	Proposed chromosome theory of inheritance
Palade	Discovered and named ribosomes
Kolliker	Discovered mitochondria in striated muscle of insects
Benda	Used term mitochondria
Altman	Called mitochondria bioplast
Haeckel	Discovered / gave term plastid
Sachs	Discovered chloroplast
Schimper	Named chloroplast
Porter	First observed endoplasmic reticulum
Camillo Golgi	Discovered Golgi body in nerve cell of cat and barn owl

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CELL THEORY

▢ Classical Cell Theory:

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All living beings consist of cells
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Cell = smallest structural + functional unit of life

▢ Cell Lineage:

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Proposed by Rudolf Virchow
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Statement: omnis cellula e cellula
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Meaning: all cells arise from pre-existing cells only by reproduction

▢ Modern / Modified Cell Theory: Cell theory + cell lineage

▢ Synonyms:

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Cell principle
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Cell doctrine
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Modern cell theory
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Modified cell theory

▢ Exceptions:

Table 1: Exceptions of Cell Theory

Exception	Reason
Virus	Obligate parasite; sub-cellular; major exception
Vaucheria	Multinucleated alga
Rhizopus	Multinucleated fungus
Mucor	Multinucleated fungus
Paramecium	Binucleate / multinucleated protist
Opalina	Multinucleated protist

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CELL SIZE

▢ Normal Cell Size: 0.2 μm to 20 μm

▢ Measurement Units:

Table 1: Units

Microscope	Unit
Light microscope	Micron / μm
Electron microscope	Angstrom / Å

▢ Factors Affecting Cell Size:

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Cell size ∝ chromosome number
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Cell size ∝ size of chromosome
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Cell size ∝ 1 / metabolic activity
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Cell size ∝ 1 / nucleocytoplasmic ratio
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Cell size ∝ 1 / surface area per unit volume

▢ Reasoning:

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Smaller cells are metabolically more active
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Smaller cells have greater surface area per unit volume
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Nucleocytoplasmic ratio is directly related to metabolic activity

▢ Smallest Cells:

Table 1: Smallest Cell Facts

Category	Answer
Smallest cell	Mycoplasma gallisepticum / PPLO
PPLO full form	Pleuro pneumonia like organism
Mycoplasma nickname	Joker of plant kingdom
Mycoplasma feature	Without cell wall
Smallest cell with cell wall	Bacterium Dialister pneumosintes
Smallest animal cell	Human sperm cell

▢ Mycoplasma Plant Diseases:

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Bunchy top of papaya
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Little leaf of brinjal
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Clover dwarf
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Mulberry dwarf

▢ Largest and Longest Cells:

Table 1: Largest / Longest Cell Facts

Category	Answer
Largest prokaryotic cell	Spirillum volutans
Largest animal cell	Ostrich egg cell
Longest animal cell	Nerve cell
Largest plant cell	Acetabularia
Longest plant cell	Fibre of Ramie / Boehmeria nivea

▢ Acetabularia:

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Unicellular
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Uninucleate
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Green alga
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Umbrella-shaped alga

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CELL DIVIDING CAPACITY

▢ Cellular Totipotency:

❖ Definition: Capacity of a single nucleated living vegetative plant cell to regenerate whole plant

❖ Word Meaning: Totus = all; potens = power

❖ Important Scientists:

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Idea first given by Haberlandt
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Experimentally proved by Steward and co-workers

❖ Steward Experiment:

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Used phloem tissue from carrot root as explant
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Used coconut milk as liquid medium
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Coconut milk contains cytokinin
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Cytokinin induces cell division

❖ Coconut Milk Factor:

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Cytokinin / zeatin / kinetin
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Rich in coconut milk
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Also rich in immature maize grain

▢ Pluripotency:

❖ Definition: Animal cell ability to develop into any type of body cell but not whole animal

❖ Important: Stem cells are totipotent in animals

▢ Cell Ghosts:

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Empty erythrocytes
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Difficult to observe under light microscope due to absence of contents
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When blood is placed in water, erythrocyte contents come out
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Rupture of RBC = haemolysis

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CELL TYPES BASED ON NUCLEUS

Table 1: Types

Type	Meaning / Feature	Examples
Akaryotic cell	Denucleated cell	Mature mammalian RBC, sieve tube cell
Prokaryotic cell	Nucleoid; no true nucleus	Bacteria, cyanobacteria, archaebacteria, mycoplasma, chlamydia, rickettsia
Mesokaryotic cell	Nuclear membrane present; histone protein absent; nucleolus absent; division by dinomitosis	Dinoflagellates
Eukaryotic cell	True nucleus with nuclear membrane, nucleoplasm and nucleolus	Fungi, protists, Euglena, plants, animals

▢ Prokaryotic vs Eukaryotic:

Table 1: Prokaryotic Cell vs Eukaryotic Cell

Feature	Prokaryotic Cell	Eukaryotic Cell
Nucleus	False nucleus / incipient nucleus / prokaryon / genophore / nucleoid	True well-organised nucleus
Nuclear membrane	Absent	Present
Nucleoplasm	Absent	Present
Nucleolus	Absent	Present
DNA location	Cytoplasm	Nucleoplasm
DNA type	Double-stranded circular DNA	Double-stranded linear DNA
DNA repetition	Non-repetitive	Repetitive
Histone protein	Absent	Present
DNA folding	With RNA + polyamines	With histone proteins
DNA:RNA ratio	1:2	1:1
A+T / G+C ratio	0.88; G+C higher	1.52; G+C lower
Cell wall	Non-cellulosic; peptidoglycan / murein + lipids	Cellulose or chitin
Respiration site	Mesosome / cell membrane	Mitochondria
Membrane-bound organelles	Absent	Present
Envelope system	Single envelope system	Double envelope system
Ribosome	70S	Both 70S and 80S; 80S main
Microtubules + spindle fibres	Absent	Present
Cilia / flagella	Single-stranded; flagellin protein	11-stranded; 2+9 arrangement; tubulin protein
Cell division	Amitosis common; mitosis and meiosis absent	Mitosis + meiosis present; amitosis rare in yeast
Examples	Monera, bacteria, cyanobacteria, archaebacteria, mycoplasma, chlamydia, rickettsia	Fungi, protists, Euglena, plants, animals

▢ Special Points:

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Most extensively studied prokaryote = E. coli
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Chlamydia and Rickettsia have both DNA and RNA
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Chlamydia and Rickettsia = connecting link between virus and bacteria
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Eukaryotic cells differ from prokaryotic cells by presence of cistrons

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PLANT CELL VS ANIMAL CELL

Table 1: Plant Cell vs Animal Cell

Feature	Plant Cell	Animal Cell
Cell wall	Present; main differentiating feature	Absent
Plastids	Present	Absent
Central vacuole	Large central vacuole	Usually small / absent
Centriole	Usually absent	Present
Lysosome	Usually absent	Present
Mitosis / meiosis	Anastral type	Astral / amphiastral type
Inorganic crystals	Common in cytoplasm	Not common
Special organelles	Sphaerosome, glyoxysome, lomasome	Absent
Cytokinesis	By cell plate	By furrowing
Reserve food	Starch	Glycogen
Hypotonic solution	Does not burst due to cell wall	RBC bursts because cell wall absent
Totipotency	All nucleated cells are totipotent	Fertilized egg + stem cells in blastocyst are totipotent

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CELL WALL

▢ Basic Features:

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Common in plants
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Also present in bacteria and cyanobacteria
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Non-living
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Porous
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Permeable
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Inert
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Hydrophilic
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Semitransparent
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Protective covering secreted by cytoplasm

▢ Constituents:

Table 1: Cell Wall Constituents

Organism / Cell	Cell Wall Material
Plant	Cellulose + hemicellulose + pectin
Bacteria and cyanobacteria	Murein / mucopeptide / peptidoglycan
Fungi	Chitin / fungal cellulose

Table 2: Important Monomers

Substance	Monomer / Components
Cellulose	β-D glucose
Hemicellulose	Arabinose, mannose, xylose, galactose etc.
Pectin	Galactose, galacturonic acid, arabinose
Peptidoglycan polysaccharide	NAG + NAM
Chitin	Polymer of N-acetyl glucosamine / NAG

▢ Plant Cells Without Cell Wall:

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Mycoplasma
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Gametes
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Zoospores
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Slime moulds / Myxomycetes

▢ Formation:

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Cell wall forms during cytokinesis
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Vesicles of ER + Golgi bodies participate
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Golgi vesicles + spindle proteins at equator = phragmoplast
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Phragmoplast → cell plate → cell wall

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LAYERS OF CELL WALL

Table 1: Cell Wall Layers

Layer	Position	Nature / Composition	Important Points
Middle lamella	Outermost / between two adjacent cells	Mainly calcium pectate + magnesium pectate	Cementing layer; joins adjacent cells
Primary cell wall	Inner to middle lamella	Cellulose + hemicellulose + pectin in roughly equal amount	Elastic; universal in cells with wall; common in parenchyma + meristematic cells
Secondary cell wall	Inner to primary wall	High cellulose + hemicellulose + cutin / suberin / pectin / lignin / wax / silica / mucilage	Thick, inelastic, mechanical strength
Tertiary cell wall	Sometimes S3 layer of secondary wall	Xylan + mannan	Thick warty wall; gymnosperm tracheids

▢ Middle Lamella:

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First layer formed during cytokinesis
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Cementing layer between adjacent plant cells
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Main cement = calcium pectate
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Retting of fibres due to dissolution of middle lamella
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Ripened fruit becomes soft due to dissolution of calcium pectate
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Pectinase enzyme dissolves pectin / calcium pectate
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Totally absent in unicellular plants and all fungi

▢ Primary Wall:

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Elastic
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Unipartite / single layer
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Lignin never found in primary cell wall
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May contain silica, wax, cutin etc.
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Growth by intussusception
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Starch is formed by α-D glucose

▢ Secondary Wall:

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Thick
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Inelastic
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Tripartite: S1 + S2 + S3
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S2 is thickest layer
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Developed by apposition
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Pits common
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Provides mechanical strength, stiffness and hardness

▢ Wall Deposition Substances:

Table 1: Secondary Wall Deposits

Substance	Site	Function / Point
Cutin	Epidermis; continuous layer = cuticle	Waxy substance
Suberin	Cork cells + endodermis	Makes cell impermeable; checks evaporation; fatty acid mixture
Pectin	Collenchyma	Elasticity
Lignin	Xylem vessels, tracheids, sclerenchyma	Highest rigidity; lignified cells thick-walled and dead
Wax	Floating leaves	Protection
Silica	Deposited on wall; Equisetum	Rough touch
Mucilage	Aloe vera, Hibiscus	Slimy, slippery; helps withstand extreme temperature

▢ Cuticle Thickness:

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Xerophytes: thick cuticle
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Mesophytes: thin cuticle
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Hydrophytes: cuticle absent

▢ Wall Growth:

Table 1: Cell Wall Growth

Type	Meaning
Intussusception	Primary wall stretched and new material inserted
Apposition	Secondary wall materials deposited as thin layers

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CELL TO CELL CONDUCTION SYSTEM

Table 1: Symplasm vs Apoplasm

Feature	Symplasm / Plasmodesmata	Apoplasm / Pits
Nature	Living system	Non-living system
Definition	Living cytoplasmic strands connecting adjacent plant cells	Unthickened wall area where secondary wall is absent
Connection	Links protoplasts into continuous living system	Dead cells interconnected through pits
Modification	Modification of cell membrane	Present in secondary wall
Found in	Only multicellular plants	Cells with secondary wall
Main structures	Plasmodesmata	Pit cavity + pit membrane

Table 2: Types of Pits

Pit Type	Feature	Common Site
Simple pit	Uniform diameter; lacks pit chamber and torus	Angiosperms; companion cells; sieve tubes
Bordered pit	Flask-shaped cavity; has pit chamber and torus	Gymnosperms; vessels; tracheids
Aspirated pit	Non-functional pit; aperture permanently blocked by torus	Gymnosperms

▢ Pit Membrane:

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Middle lamella + primary wall
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Mainly primary wall

▢ Torus:

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Swollen portion of pit membrane
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Acts as valve

▢ Special Point: Sclerenchyma fibre may have simple pits as well as bordered pits

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CELL WALL CONSTITUENTS AND UNITS

▢ Important Facts:

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Cellulose = most abundant carbohydrate of biosphere
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Cotton contains highest amount of cellulose, about 90%
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Chitin = second most abundant carbohydrate

▢ Cellulose Organization: β-D glucose → cellulose → micelle → microfibril → macrofibril

▢ Structural Units:

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Micelle
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Microfibril
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Macrofibril

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CELL COAT / GLYCOCALYX

▢ Definition: Outermost covering of animal cell because cell wall is absent

▢ Composition:

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Oligosaccharides
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Glycoproteins
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Glycolipids

▢ Important Points:

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Terminal sugar of oligosaccharide = sialic acid
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Oligosaccharide layer helps in cell-to-cell recognition
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Glycocalyx = glycoprotein + glycolipid
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Glycoprotein + glycolipid help in site recognition
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Glycocalyx = site of cell recognition
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Glycocalyx makes cell membrane asymmetric
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In cell recognition: oligosaccharide > glycoprotein + glycolipid

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PLASMA MEMBRANE

▢ Synonyms:

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Cell membrane
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Plasmalemma

▢ Features:

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Thin
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Elastic
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Living
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Selectively / differentially permeable

▢ Composition:

Table 1: Membrane Components

Component	Forms / Points
Lipid	Phospholipid, glycolipid, cholesterol
Protein	Extrinsic / peripheral = 25%; intrinsic / integral = 75%
Carbohydrate	Glycolipid + glycoprotein
Phospholipid	Framework molecule; amphipathic; bilayered
Myelin sheath	Lipid 75% > protein 25%
Amino acids	Arginine and lysine found in cytoplasmic membrane

▢ Phospholipid:

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Head = hydrophilic
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Tail = hydrophobic
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Amphipathic molecule
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Shows hydrophilic + hydrophobic properties
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Always bilayered

▢ Thickness: About 75 Å

▢ Biological Membrane: Plasma membrane + organelle membrane

▢ Membrane Fluidity: Depends mainly on lipids

▢ Membrane Models:

Table 1: Cell Membrane Models

Model	Scientist	Main Point
Trilamellar / Sandwich model	Danielli and Davson	3 layers: protein outside + phospholipid bilayer middle + protein inside; sequence P-L-L-P
Unit membrane model	Robertson	Similar to trilamellar model; protein fibrillar type; sequence P-L-L-P
Fluid Mosaic Model	Singer and Nicolson	Latest and most accepted; protein iceberg in sea of lipid

▢ Fluid Mosaic Model:

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Based on freeze-etching / freeze-fracture technique
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Differs by arrangement of proteins
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Lipids form continuous layer
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Protein molecules randomly arranged
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Proteins: extrinsic, tunnel, intrinsic
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All carrier proteins are intrinsic proteins
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Lipids and proteins held by hydrophobic attraction
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Rotational movement of lipid molecule = flip-flop mechanism

▢ Functions:

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Controls passage of materials in and out of cell with help of Ca2+ and cAMP
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Exchange of gases like O2 and CO2
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Bulk transport
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Active transport needs energy + carrier protein
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Passive transport needs neither energy nor carrier protein
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Exception: facilitated diffusion is passive but requires carrier protein

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JUNCTION COMPLEX

▢ Definition: Cell adhesion structures found in multicellular organisms

Table 1: Junction Complex Types

Type	Feature
Plasmodesmata	Living cytoplasmic strands connecting adjacent plant cells
Desmosome	Spot weld between two adjacent animal cells
Tight junction	Water-tight seal between adjacent animal cells
Gap junction	Channels between adjacent animal cells
Interdigitation	Interwoven processes
Terminal bar	Group of junctional complexes attaching adjacent epithelial cells laterally

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MODIFICATIONS OF CELL MEMBRANE

Table 1: Membrane Modifications

Modification	Found In	Feature / Function
Mesosome	Gram-positive bacteria	Infoldings of cell membrane; respiration + cell division
Lomasome	Fungi	Between cell membrane and cell wall; extracellular cell organelle; cell wall proliferation + elongation
Lamellosome	Blue-green algae	Infolding of cell membrane; helps expansion of cell wall
Microvilli	Digestive tract cells	Finger-like outfolds; absorption of liquids

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PROTOPLASM

▢ Definition and Features:

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Term coined by Purkinje
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Huxley called it physical basis of life
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All life processes occur in protoplasm
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Best material to study protoplasm = slime moulds due to absence of cell wall
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Highly organised and most active chemical system of nature
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Maximum energy conversion occurs in protoplasm
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Living beings differ from non-living by presence of protoplasm

▢ Composition:

Table 1: Protoplasm Composition

Component	Value / Point
Water	75–85%; highest percentage
Major inorganic constituent	Water
Oxygen	62%; highest element by weight
Carbon	20%
Hydrogen	10%
Nitrogen	3%; lowest among major elements
Inorganic:organic ratio	1:9

▢ Sol-Gel State:

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Protoplasm exists as sol and gel
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Inner sol = endoplast / plasmasol
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Outer gel = ectoplast / plasmagel
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Sol-gel interconversion due to colloidal nature
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Conversion of plasmasol into plasmagel = physicochemical phenomenon
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Cyclosis occurs in endoplast region

▢ Cyclosis:

Table 1: Types of Cyclosis

Type	Movement	Examples
Rotation	Movement in one direction around vacuole	Hydrilla, Vallisneria
Circulation	Movement in different directions around vacuole	Tradescantia

▢ Colloidal Nature Effects:

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Brownian movement
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Tyndall effect
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Cyclosis
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Amoeboid movement

▢ Temperature / Chemicals:

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Protoplasm coagulates above 60°C
•
Protoplasm coagulates with concentrated acids / bases
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Enzymes denature at high temperature
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Enzymes inactivated at very low temperature
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Optimum temperature required for enzyme function

▢ Deutoplasm: Non-living substance formed by protoplasm during metabolism, e.g., lipid droplets, yolk

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CYTOPLASM

▢ Parts:

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Cell organelles
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Cell inclusions
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Cytosol

▢ Cytosol:

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Clear optically homogeneous fluid portion after removing organelles and inclusions
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Also called cytoplasmic matrix / hyaloplasm / ground plasm
•
Ribosome-containing ground substance = ergastoplasm

▢ Cell Inclusions:

Table 1: Cell Inclusions

Type	Examples
Reserve food	Carbohydrates, fats, proteins
Secretory substances	Colouring matter, enzymes, nectar, pigments
Excretory substances	Alkaloids, glucosides, tannins, gum, resins

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CELL ORGANELLES BY MEMBRANE

Table 1: Organelles by Membrane Covering

Category	Organelles
Triple membrane	Transosomes
Double membrane	Plastids, mitochondria
Single membrane	Endoplasmic reticulum, Golgi bodies, vacuoles, lysosome, peroxisome, glyoxysome, sphaerosome, lomasome
Without membrane	Ribosomes, centrioles, cytoskeleton, nucleolus, chromosomes

▢ Transosome:

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Found in ovarian follicle of bird
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Takes part in yolk synthesis / vitellogenesis
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In other animals, vitellogenesis mainly by Golgi bodies + ER + microfilaments

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PLASTIDS

▢ Basic Features:

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Double-membrane organelles
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Discovered / named by Haeckel
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Mainly found in plants and some protists
•
Absent in fungi
•
Involved in formation and storage of carbohydrates
•
Usually 3 types based on pigment: leucoplast, chromoplast, chloroplast

▢ Leucoplast:

❖ Features:

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Largest plastid
•
Usually found in underground parts
•
Storage of reserve food

Table 1: Types of Leucoplast

Type	Stores	Examples
Amyloplast	Starch	Potato, rice, wheat
Proteinoplast / Aleuronoplast	Protein	Maize
Elaioplast / Oleosome / Lipoplast	Oil / fat	Ricinus / castor seed

▢ Chromoplast:

❖ Features:

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Second largest plastid
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Coloured plastid other than green
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Contains fat-soluble carotenoids
•
Provides colour to fruits, seeds and flowers

❖ Formation:

•
From chloroplast by replacement of chlorophyll by coloured pigment
•
Green tomato → red tomato due to lycopene
•
Green chilli → red chilli due to capsanthin
•
From leucoplast by development of coloured pigment, e.g., carrot

❖ Other Coloured Plastids:

Table 1: Other Plastids

Plastid	Colour	Example
Phaeoplast	Brown	Brown algae
Rhodoplast	Red	Red algae

▢ Chloroplast:

❖ Features:

•
Discovered by Sachs
•
Named chloroplast by Schimper
•
Green plastid
•
Forms carbohydrates
•
Stores starch temporarily
•
Called kitchen of cell, photosynthetic apparatus, autoplast
•
Present in photosynthetic organisms except photosynthetic bacteria and cyanobacteria
•
In photosynthetic bacteria and cyanobacteria, pigments occur in chromatophores / scattered thylakoids

❖ Shapes:

Table 1: Chloroplast Shapes

Shape	Example
Discoid / oval / tablet / biconvex	General
Cup-shaped	Chlamydomonas
Spherical	Chlorella
Spiral / ribbon / scalariform	Spirogyra
Girdle / ring / collar / horse-shoe	Ulothrix
Reticulate / net-like	Oedogonium
Stellate / star-shaped	Zygnema
Discoid	Vaucheria, Chara

❖ Number:

•
Single chloroplast: Chlamydomonas and Chlorella
•
Single chloroplast per cell: Ulothrix
•
Double chloroplast per cell: Zygnema
•
Maximum chloroplasts: mesophyll cells of leaf

❖ Structure:

Table 1: Chloroplast Structure

Part	Feature / Function
Grana	Site of light reaction
Thylakoids	Structural unit of chloroplast
Quantasomes	Functional unit of chloroplast
Stroma lamellae / fret membrane	Connect grana
Stroma	Ground substance
Matrix of stroma	Contains dark reaction / CO2 fixation enzymes
Stroma DNA + ribosome	Semi-autonomous feature

❖ Quantasome:

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Photosynthetic pigments present in thylakoid membrane at quantasomes
•
One quantasome has about 280 pigments
•
Eukaryotic quantasome: 230 chlorophyll molecules + 50 carotenoids
•
230 chlorophyll = 160 chlorophyll-a + 70 chlorophyll-b
•
Prokaryotic quantasome: about 50 chlorophyll molecules

❖ Agranal Chloroplast:

•
Common in algae
•
Present in bundle sheath chloroplast of C4 plants
•
If thylakoids are not stacked, called lamellar chloroplast

❖ Blue Green Algae: Lacks chloroplast; photosynthesis site = photosynthetic lamellae

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MITOCHONDRIA

▢ Names:

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Power house of cell
•
Electric house of cell
•
Cellular furnace
•
ATP mills

▢ History:

•
Discovered by Kolliker in striated muscle of insects
•
Term mitochondria used by Benda
•
Altman called it bioplast

▢ Occurrence:

•
Size: 0.5 to 1 μm
•
Absent in all prokaryotes
•
Absent in anaerobic eukaryotes
•
Present in aerobic eukaryotes except mature mammalian RBC, cancerous cell and sieve tube of phloem
•
Mature RBC obtains energy by glycolysis

▢ Membranes:

Table 1: Mitochondrial Membranes

Part	Feature
Outer membrane	Permeable due to porins
Outer chamber	Contains adenylate kinase
Inner membrane	Less permeable; has cristae / tubuli
Cristae	Site of oxidation-reduction
Inner membrane / cristae	Carries ETS + oxysomes

▢ Oxysomes:

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Tennis-racket-like particles on inner mitochondrial membrane
•
Functional unit of mitochondria
•
Head = F1 particle
•
F1 contains ATPase
•
ATPase helps final step of ATP synthesis
•
Base = Fo particle
•
Fo has proton channels
•
ETS occurs at Fo / inner membrane
•
Old concept: 2 protons → 1 ATP
•
New accepted concept in note: 3 protons → 1 ATP

▢ Matrix:

•
Contains about 70% of total cell enzymes
•
Krebs cycle enzymes present in matrix
•
Exception: succinic dehydrogenase bound to inner membrane
•
Fatty acid synthesis enzymes and amino acid synthesis enzymes present
•
Exceptions: ATPase and cytochrome oxidase located in inner membrane
•
Matrix rich in Mn

▢ Functions and Special Points:

•
ATP synthesis process = oxidative phosphorylation
•
Oxidative phosphorylation is O2-dependent and light-independent
•
All mitochondria of a cell collectively = chondriome
•
Mitochondria without outer membrane = mitoplast
•
Acristate mitochondria found in spermatid
•
Petite character in yeast due to mitochondrial inheritance
•
Helps in elongation of fatty acid
•
Forms middle piece of sperm

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ENDOPLASMIC RETICULUM

▢ Basic Features:

•
First observed by Porter from liver cells
•
Single-membrane organelle
•
Unit membrane / trilaminar lipoprotein membrane
•
Not visible under light microscope
•
Continues from nuclear membrane to cell membrane
•
ER connection between cells through plasmodesmata = desmotubule
•
Forms more than 50% of eukaryotic cell membranes
•
Occupies about 10% of total cell volume

▢ Names:

•
Working bench of cell
•
Pipeline of cell
•
Endoskeleton
•
Membrane factory
•
Organelle of detoxification

▢ Well Developed In:

•
Pancreas
•
Liver
•
Digestive gland
•
Fibroblast

▢ Poor / Absent In:

•
All prokaryotic cells
•
Mammalian RBC
•
Egg
•
Embryonic cell
•
Monocyte
•
Poorly developed in sperms and meristematic cells

▢ Components:

•
Cisternae = flattened sacs
•
Tubules
•
Vesicles
•
Cisternae are not parallel in ER but parallel in Golgi bodies

▢ RER vs SER:

Table 1: Rough ER vs Smooth ER

Feature	RER	SER
Amount	2/3 of total ER	1/3 of total ER
Ribosomes	80S ribosomes attached by large subunit via ribophorin	No ribosomes
Main structure	Cisternae + few tubules	Network of tubules + vesicles
Origin	Nuclear membrane	RER
Function	Protein synthesis + glycosylation	Lipid metabolism

▢ Special Terms:

•
Broken RER during ultracentrifugation = microsome
•
Basophilic cytoplasm due to RER / ribosome = ergastoplasm
•
Nissl granules = modification of RER / ribosome
•
Nissl granules rich in RNA followed by protein
•
RER without ribosomes = transitional ER
•
SER in retinal epithelial cells = myeloid bodies
•
Annulate lamellae = precursor of ER
•
Special ER in skeletal muscle = sarcoplasmic reticulum
•
Sarcoplasmic reticulum releases Ca2+
•
Ca2+ helps muscle contraction and vesicle fusion
•
Sphaerosomes formed by SER
•
RER + Golgi complex gives rise to lysosome

▢ Functions:

•
Mechanical support due to microtubules; endoskeleton of cell
•
Intracellular and intercellular transport
•
Keeps cell organelles in position
•
Formation of nuclear membrane and cell membrane
•
Formation of vacuoles, lysosomes, glyoxysome, Golgi bodies, exine of pollen grain and zymogen
•
Detoxification of toxic substances
•
SER in liver helps detoxification
•
SER in liver helps glycogenesis and glycogenolysis
•
Major phospholipid synthesized in ER = lecithin / phosphatidylcholine

📚

GOLGI BODIES

▢ Names:

•
Idiosome
•
Dalton complex
•
Middle man of cell
•
Baker's bodies
•
Dictyosome in plant cell

▢ History:

•
Discovered by Camillo Golgi from nerve cell of cat and barn owl
•
First stained with Sudan III
•
Therefore called Baker's bodies

▢ Absent In:

•
All prokaryotic cells
•
RBCs
•
Sieve tube
•
Sperm of bryophytes and pteridophytes
•
Cells of fungi

▢ Origin and Structure:

•
Formed from vesicles of SER
•
Consists of parallel cisternae, tubules and vesicles
•
New cisternae constantly formed by budding from SER and fusion of vesicles
•
Outside convex side = forming face
•
Microtubules never found in Golgi body
•
Maximum Golgi bodies in rhizoidal cell of Chara

▢ Functions:

•
Secretion and storage of secretions
•
Chemical modification and transport of materials
•
Cell plate formation during cytokinesis
•
Formation of lysosomes
•
Formation of acrosome in sperm
•
Acrosome helps penetration
•
Secretion of mucilage in root tip
•
Mucilage helps lubrication
•
Formation of sialic acid in cell membrane
•
Formation of yolk, melanin granules, hemicellulose and galactose
•
Glycosidation and glycosylation
•
Protein packaging
•
All complex carbohydrates except glycogen are synthesized by Golgi body

▢ Macromolecular Traffic: Golgi apparatus = principal director of macromolecular traffic in cell

▢ Glycosidation and Glycosylation:

•
Lipid + carbohydrate → glycolipid = glycosidation
•
Protein + carbohydrate → glycoprotein = glycosylation
•
Glycosidation and glycosylation start in ER

▢ Common Enzyme Points:

Table 1: ER and Golgi Enzymes

Organelle	Main Enzyme
RER	Peptidyl transferase
Golgi body	Glycosyl transferase

📚

MICROBODIES AND SINGLE MEMBRANE ORGANELLES

Table 1: Microbodies

Organelle	Important Point
Lysosome	Marker enzyme = acid phosphatase
Lysosome	Produced by Golgi bodies; eats vacuoles; associates with ER for excretion
Peroxisome	Photorespiration
Glyoxysome	Important in plant fat metabolism / germinating seeds
Sphaerosome	Plant lysosome
Lomasome	Found in fungi

▢ Smallest Membrane-Bound Organelle: Lysosome

📚

RIBOSOMES

▢ Names:

•
Palade particles
•
Engine of cell
•
Protein factory of cell
•
RNP / ribonucleoprotein particle

▢ Features:

•
Discovered and named by Palade
•
Smallest unmembranous organelle
•
Electron microscopic organelle
•
Most abundant cytoplasmic organelle
•
Made of rRNA + protein
•
rRNA synthesized in nucleolus
•
Protein synthesized in cytoplasm
•
Ribosomes formed inside nucleolus
•
Nucleolus = ribosomal factory
•
Unit = Svedberg unit / S
•
S = sedimentation coefficient
•
1S = 10^-13 sec
•
Isolated by fractionation and ultracentrifugation
•
Function = protein synthesis
•
Present in prokaryotes and eukaryotes except RBC and sperms

▢ Types:

Table 1: 70S vs 80S Ribosome

Feature	70S Ribosome	80S Ribosome
Found in	Prokaryotes; mitochondria and chloroplast of eukaryotes	Eukaryotic cytoplasm
Subunits	30S + 50S	40S + 60S
rRNA	30S has 1 rRNA; 50S has 2 rRNA	40S has 1 rRNA; 60S has 3 rRNA
Total rRNA	3	4
Total proteins	55	80
Function note	Prokaryotic protein synthesis	Free: non-secretory proteins; RER-bound: secretory/export proteins

▢ Special Points:

•
Mammalian mitochondria have 55S ribosome, not 70S
•
55S ribosome subunits = 35S + 25S
•
Two ribosomal subunits joined by Mg2+
•
High Mg2+ concentration can combine two ribosomes into dimer
•
6 to 8 ribosomes attached to mRNA during protein synthesis = polysome / polyribosome / ergasome
•
During protein synthesis, smaller ribosomal subunit attaches to mRNA
•
Ribosomes present inside mitochondria, plastids and nucleus
•
Therefore called organelle within organelle
•
DNA and RNA are observed by X-ray crystallography, not ordinary microscopy

📚

NUCLEUS

▢ Basic Points:

•
Discovered by Robert Brown from orchid root cells
•
Hammerling proved nucleus as control centre using Acetabularia
•
Not considered a cell organelle
•
Largest extracytoplasmic component
•
Controls heredity and cellular activities

▢ Names:

•
Controlling centre of cell
•
Brain of cell
•
Director of cell
•
Apparatus of heredity

▢ Number of Nuclei:

Table 1: Nucleus Number in Cells

Type	Meaning	Examples
Uninucleated	One nucleus; common	Most cells
Binucleated	Two nuclei	Paramecium; secondary mycelium of Ascomycetes and Basidiomycetes
Syncyte	Multinucleated due to fusion of many cells	Bone marrow, striated muscle, Ascaris epidermis
Coenocyte	Multinucleated due to repeated nuclear division without cytoplasmic division	Phycomycete hyphae, Vaucheria, Botrydium, latex cells
Anucleated	Cell without nucleus	Mature sieve tube, mammalian RBC

▢ Exception: Camel and llama RBC are exception among mammalian RBCs

📚

NUCLEAR STRUCTURE

▢ Nuclear Envelope / Karyotheca:

•
Double-layered
•
Lipoproteinaceous
•
Inner nuclear membrane is smooth because ribosomes absent
•
Separates nucleoplasm from cytoplasm
•
Space between two nuclear membranes = perinuclear space
•
Perinuclear space = 50–70 Å
•
Nuclear pore complex is octagonal
•
Gates in pore = annulus
•
Annulus allows selective transport through nuclear pore

▢ Nucleoplasm:

•
Also called nuclear sap, karyoplasm, karyolymph
•
Contains nucleotides and ions like Mn2+ and Mg2+
•
Cyclosis absent because viscosity not constant

▢ Nucleolus:

•
Discovered by Fontana
•
Term given by Bowman
•
Membraneless structure
•
Ribosomal factory of cell
•
Largest part of nucleus
•
Colloidal mass
•
Contains rRNA and non-histone acidic proteins
•
No DNA
•
Shape maintained by Ca2+ and Mg2+
•
Biogenesis at secondary constriction-I of SAT chromosome

▢ Chromatin:

•
Term chromatin given by Flemming
•
Chromosome name given by Waldeyer
•
Made of DNA and histone proteins
•
DNA is acidic and negatively charged
•
Histone is basic and positively charged
•
Ultrastructure appears as beads on a string

📚

CHROMATIN AND CHROMOSOME

▢ Nucleosome:

•
Beaded structure of chromatin
•
Each nucleosome has 8 histone molecules
•
Histone octamer = 2 copies each of H2A, H2B, H3, H4
•
Double-stranded DNA coils around histone octamer
•
Histone core = Nu body
•
Two nucleosomes joined by linker DNA

▢ Chromatin Stain:

•
Feulgen stain = basic fuchsin
•
Feulgen stain reacts with deoxyribose
•
Specific for DNA / chromatin / chromosome

▢ Euchromatin vs Heterochromatin:

Table 1: Euchromatin vs Heterochromatin

Feature	Euchromatin	Heterochromatin
Staining	Light stain	Dark stain
DNA state	Decondensed	Condensed
Gene activity	Active genes	Inactive genes
Replication	Early in S-phase	Late in S-phase

▢ Chromosome Basics:

•
Condensed chromatin = chromosome
•
Meiotic chromosome with beaded structure = chromomere
•
Haploid set of chromosomes = genome
•
Chromosome = physical basis of inheritance
•
DNA = chemical basis of inheritance
•
Chromosomes carry genes; vehicle / bearer of genes
•
Karyotype = morphological features of chromosomes of a species
•
Idiogram = diagrammatic representation of karyotype in descending order
•
Heteropycnosis = differential staining due to differential thickening
•
Saliva test in Olympic games related to X-chromosome / Barr body

▢ Chromosome Number:

Table 1: Chromosome Number Extremes

Category	Organism
Smallest chromosome number	Haplopappus gracilis
Largest chromosome number	Ophioglossum

📚

CHROMOSOME ULTRASTRUCTURE

Table 1: Parts of Chromosome

Part	Meaning / Function
Pellicle	Sheath / covering of chromosome
Matrix	Ground substance
Chromonemata	Coiled threads forming bulk of chromosome
Primary constriction / centromere	Narrow non-stainable region where chromatids attach
Kinetochore	Protein complex on centromere for spindle attachment
Secondary constriction-I	NOR; forms nucleolus; contains rRNA genes
Secondary constriction-II	Contains tRNA genes
Satellite / trabant	Knob-like structure near secondary constriction-I
SAT chromosome	Chromosome bearing satellite
Telomere	Terminal end / sealed end of chromosome

▢ Centromere vs Kinetochore:

•
Centromere = DNA region
•
Kinetochore = assembling protein complex on centromere
•
Centrosome = microtubule-organising centre of animal cell

▢ Types Based on Centromere:

Table 1: Chromosome Types by Centromere Position

Type	Centromere Position	Anaphase Shape / Feature
Acentric	No centromere	No proper spindle attachment
Metacentric	Middle / centre	V-shaped; arms equal
Submetacentric	Submedian / near centre	L-shaped
Acrocentric	Subterminal / near top	J-shaped
Telocentric	Terminal	I-shaped / rod-like; one arm
Holocentric / polycentric / diffuse centric	Whole surface acts as centromere	Example: Luzula

▢ Study Stage:

•
Chromosome shape best studied in anaphase
•
Structure, morphology, size and number best studied in late prophase and metaphase
•
Most appropriate stage for chromosome study = metaphase
•
Centromeric index = ratio of lengths of two chromosome arms

▢ SAT Chromosome:

•
Satellite = knob-like structure near secondary constriction-I
•
Chromosome with satellite = SAT chromosome
•
SAT chromosome with secondary satellite = tandem SAT
•
At least 2 SAT chromosomes per diploid nucleus

📚

OTHER NON-MEMBRANOUS ORGANELLES

Table 1: Non-Membranous Organelles

Organelle	Important Point
Centriole	Related to spindle formation in animal cells
Cytoskeleton	Microtubules + microfilaments + intermediate filaments
Microtubules	Cytoskeletal support; spindle fibres
Microfilaments	Smallest cell component
Intermediate filaments	Cytoskeletal support
Nucleolus	Ribosomal factory; membraneless
Chromosomes	Physical basis of inheritance

📚

SKELETONS OF CELL

Table 1: Cell Skeletons

Type	Structure
Exoskeleton	Cell wall
Endoskeleton	Endoplasmic reticulum
Cytoskeleton	Microtubules, microfilaments, intermediate filaments

📚

SIZE-BASED NOTES

Table 1: Largest and Smallest Components

Category	Answer
Largest cell component	Nucleus
Largest cell organelle in plant	Chloroplast
Largest cell organelle in animal	Mitochondria
Second largest cell organelle in plant	Mitochondria
Smallest cell organelle	Ribosome
Smallest membrane-bound organelle	Lysosome
Smallest cell component	Microfilament

📚

SEMI-AUTONOMOUS ORGANELLES

▢ Examples:

•
Mitochondria
•
Plastids

▢ Features:

•
Contain DNA, RNA and ribosomes
•
DNA is simple, circular and double-stranded
•
Ribosomes are 70S type
•
Replicate independent of nuclear DNA

▢ Plastids:

•
Plastid carrying genetic information = plastidome

▢ Mitochondria:

•
Endosymbionts of cell
•
Prokaryotic cell within eukaryotic cell
•
Cell within cell
•
Divide by binary fission due to own DNA
•
Apoptosis = programmed cell death caused by mitochondrial DNA

Q1.

The catabolic enzymes are found in

Q2.

Thylakoids are associated with

Q3.

"Cells arise from pre-existing cells only reproduction." This theory was given by

Q4.

Who first discovered living cell?

Q5.

Aerobic respiration inside the cell occurs in:

Q6.

Energy is stored in the cell in

Q7.

“Who first observed and named the cell?”:

Q8.

The protein tubulin is found in

Q9.

The extranuclear cell organelles which posses hereditary materials are

Q10.

The site for protein synthesis is:

Q11.

All of the following are membrane bound except

Q12.

Which of the following structure is not possessed by in eukaryotic cell?

Q13.

Enzymes that take part in glycolysis are present in:

Q14.

Which of the following is true for prokaryotic cells?

Q15.

Genetic material of eukaryotic organism is:

Q16.

Which thin delicate membrane surrounds the central vacuole and is in contact with the cytoplasm

Q17.

Which of the following is correct?

Q18.

The layer found between cell wall of two cells is

Q19.

Control centre of the cell is

Q20.

The sugar present in fruits, honey and nectar is:

Q21.

In nucleic acids, nucleotides are joined by:

Q22.

Metabolic event taking place in cell is:

Q23.

Which is not a lipid?

Q24.

The amino acid 'Glycine' is found:

Q25.

All proteins are:

Q26.

Which is true about lipids?

Q27.

Lipids are:

Q28.

Which of the following is correct?

Q29.

All nucleic acids are made of:

Q30.

The aspect of protein structure to which the genes most directly relates:

Q31.

Protein that gives off amino acids only on hydrolysis

Q32.

which one of the following is not a part of nucleotides:

Q33.

Molecular formula of cholorophyll is:

Q34.

As the size of protein increases:

Q35.

X-ray crystallography is used to study:

Q36.

Pyrenoids are found in:

Q37.

Ribosome in prokaryotes is:

Q38.

Large number of grana occurs in:

Q39.

A thin membrane that envelops the structure chromosome is known as:

Q40.

The cell wall is interrupted by minute pores called:

Q41.

Which of the following occurs in mitochondria:

Q42.

The process by which all organells are separated from cell is:

Q43.

Which microscope would you use to examine a culture of living cells?

Q44.

When all organelles are removed from a cell, the remaining fluid like portion left is called:

Q45.

The temperature at which protoplasm coagulates is:

Q46.

Which process occurs in chloroplast?

Q47.

What is wrong about mitochondria?

Q48.

What is wrong about golgi bodies:

Q49.

Chloroplast are green due to presence of:

Q50.

Eukaryotic cells differ from prokaryotic cells in

Q51.

Endoplasmic reticulum is made up of:

Q52.

Which is wrong?

Q53.

Description correctly matching corresponding junction type is:

Q54.

The cell and the corresponding substances stored in storage parenchyma:

Q55.

Chromosomes at anaphase are of various shapes due to position of centromere. It is J-shaped when centromere is at:

Q56.

In histology, the details of tissue structure observed through a definite technique, when involves treatment of tissues in an order. The correct sequence is:

Q57.

A tissue is a group of cells which are:

Q58.

Cell drinking is referred to:

Q59.

Which organelle contains maximum enzyme of cell?

Q60.

Prokaryotic genetic system has:

Q61.

The term "suicidal bag" is used for:

Q62.

Which of the following structure other than nucleus contains DNA?

Q63.

Proteins are synthesized by:

Q64.

A light microscope has a magnification of about:

Q65.

The protein embedded in the lipid in the cell membrane is:

Q66.

Enzymes for various functions are found in complex form in

Q67.

Mitochondria are found in

Q68.

Animal cells inter junctions are called

Q69.

Lysosomes contain enzymes which are:

Q70.

The polypeptide assembly can be found on:

Q71.

Beet roots are coloured due to presence of

Q72.

Lysosomes are called suicidal bags because they have

Q73.

Lipid bilayer is impermeable to

Q74.

Plant cells connected by channels through their walls called:

Q75.

Main component of endoplasmic reticulum is

Q76.

The most prime component of cell wall is

Q77.

Who coined the term cell?

Q78.

Function of golgi bodies is

Q79.

Which of the following lack nucleus?

Q80.

Bacterial and eukaryotic cell have similar

Q81.

Cellular totipotency is demonstrated by

Q82.

Spindle fibre is made up of protein:

Q83.

Core element of chlorophyll is

Q84.

Protein synthesis takes place in:

Q85.

The most common character between prokaryotes and eukaryotes is

Q86.

Glycosylation is carried out by

Q87.

Chromoplasts are modified plastids, rhodoplast is mainly consists of pigment.

Q88.

If 'G' represents gametophytec generation and 's' sporophytic generation in plant, the sequence in their life cycle is

Q89.

Nucleus of cell was discovered by

Q90.

Red colour of tomato is due to

Q91.

The filaments of cilia and flagella are composed of:

Q92.

The point which provides the site for the spindle attachment is called

Q93.

Which of the following is common to prokaryotes and eukaryotes?

Q94.

The layer of the cell wall that is formed soon after the cell division and is composed of calcium pectate is

Q95.

Oxysomes is present in

Q96.

Largest cell organelle is

Q97.

Which one of the following is the largest cell component?

Q98.

ATP synthesis takes place in

Q99.

ATP is formed inside mitochondria at

Q100.

Which one of the following in a cell is non-living?

Q101.

Which one of the following has single membrane structure?

Q102.

Which of the following in a cell is non-living?

Q103.

The prokaryotes have

Q104.

Centromere is a part of

Q105.

Chiasma formation occurs during

Q106.

Which of the following part of a cell is non-living?

Q107.

Nucleolus in plant cell is involved in the synthesis of

📚

ADDITION

Q1.

Thylakoids are associated with...

📅MOE 2059

Q2.

Glycosylation of lipids and proteins is carried out by the...

📅BPKIHS 2016

Q3.

Who coined the term 'Cell'?

📅BPKIHS 2013

Q4.

Who first discovered the living cell?

📅MOE 2059

Q5.

The nucleus of a cell was discovered by...

📅BPKIHS 2014

Q6.

The sugar present in fruits, honey, and nectar is...

📅IOM 2001

Q7.

Which of the following is NOT a lipid?

📅BPKIHS 2002

Q8.

All nucleic acids are made of...

📅BPKIHS 2002

Q9.

Prokaryotes differ from eukaryotes in...

📅IOM 2017

Q10.

Prokaryotic genetic system has...

📅BPKIHS 2006

Q11.

What is common between prokaryotes and eukaryotes?

📅IOM 2014

Q12.

Which microscope would you use to examine a culture of living cells?

📅IOM 1996

Q13.

A light microscope has a magnification of about...

📅BPKIHS 2007

Q14.

X-ray crystallography is used to study the...

📅BPKIHS 2007

Q15.

The control centre of the cell is the...

📅MOE 2055

Q16.

Plant cells are connected with each other by...

📅CEE 2022

Q17.

The main component of the Endoplasmic Reticulum is...

📅BPKIHS 2016

Q18.

Which organelle is known as the 'Engine of the Cell'?

Q19.

Aerobic respiration inside the cell occurs in the...

Q20.

The marker enzyme of mitochondria is...

Q21.

The protein embedded in the lipid bilayer of the cell membrane is called...

Q22.

Lipid bilayer is impermeable to...

Q23.

'Cell drinking' is referred to as...

Q24.

The most prime component of the plant cell wall is...

Q25.

The layer found between the cell walls of two plant cells is called the...

Q26.

Maximum cellulose is found in the...

Q27.

The genetic material of a eukaryotic organism is...

Q28.

Which of the following structures, other than the nucleus, contains DNA?

Q29.

Ribosomes are synthesized in the...

Q30.

Chloroplasts are green due to the presence of...

Q31.

The red colour of a tomato is due to the...

Q32.

The core element of chlorophyll is...

Q33.

Enzymes that take part in glycolysis are present in the...

Q34.

The metabolic event taking place in a cell is best described as...

Q35.

Which process occurs in the chloroplast?

Q36.

Spindle fibre is made up of the protein...

Q37.

The point which provides the site for spindle attachment is called the...

Q38.

The filaments of cilia and flagella are composed of...

Q39.

Who proposed that 'Cells arise from pre-existing cells only by reproduction'?

Q40.

In mitochondria, protons accumulate in the...

Q41.

The largest cell organelle in a plant cell is generally the...

Q42.

Which one of the following in a cell is non-living?

Q43.

Which one of the following has a single membrane structure?

Q44.

Cellular totipotency is demonstrated by...

Q45.

The prokaryotes have...

Q46.

Centrioles are made up of...

Q47.

Cristae are associated with...

Q48.

Which structure in bacteria is responsible for motility?

Q49.

Which organelle is called the 'ribosome factory'?

Q50.

Which of the following is called 'suicide bag'?

Q51.

Which one is known as 'cell sap'?

Q52.

Who discovered the cell?

Q53.

The power house of cell is...

Q54.

The extranuclear cell organelles which possess hereditary materials are...

Q55.

ATP synthesis in mitochondria takes place...

Q56.

Which of the following is a function of the Golgi body?

Q57.

The organelle that helps in cell plate formation is the...

Q58.

The nucleolus has maximum size during...

Q59.

The main component of the middle lamella is...

Q60.

Which of the following is the non-living part of a plant cell?

Q61.

The prokaryotic cell differs from a higher plant cell wall in having...

Q62.

The structure present outer to the plasma membrane but inner to the cell wall is the...

Q63.

The organelle performing a similar function in both plant and animal cells is the...

Q64.

The term 'Microsome' refers to...

Q65.

The simplest amino acid is...

Q66.

β-oxidation of fatty acids occurs in the...

Q67.

The organelle responsible for the origin of plasmodesmata is the...

Q68.

Chromosomes consist of...

Q69.

The branch of biology dealing with the structure and function of the cell is...

Q70.

Who demonstrated totipotency in plant cells?

Table 1: Cytology vs Cell Biology

Table 1: Scientists and Contributions

Table 1: Exceptions of Cell Theory

Table 1: Units

Table 1: Smallest Cell Facts

Table 1: Largest / Longest Cell Facts

Table 1: Types

Table 1: Prokaryotic Cell vs Eukaryotic Cell

Table 1: Plant Cell vs Animal Cell

Table 1: Cell Wall Constituents

Table 2: Important Monomers

Table 1: Cell Wall Layers

Table 1: Secondary Wall Deposits

Table 1: Cell Wall Growth

Table 1: Symplasm vs Apoplasm

Table 2: Types of Pits

Table 1: Membrane Components

Table 1: Cell Membrane Models

Table 1: Junction Complex Types

Table 1: Membrane Modifications

Table 1: Protoplasm Composition

Table 1: Types of Cyclosis

Table 1: Cell Inclusions

Table 1: Organelles by Membrane Covering

Table 1: Types of Leucoplast

Table 1: Other Plastids

Table 1: Chloroplast Shapes

Table 1: Chloroplast Structure

Table 1: Mitochondrial Membranes

Table 1: Rough ER vs Smooth ER

Table 1: ER and Golgi Enzymes

Table 1: Microbodies

Table 1: 70S vs 80S Ribosome

Table 1: Nucleus Number in Cells

Table 1: Euchromatin vs Heterochromatin

Table 1: Chromosome Number Extremes

Table 1: Parts of Chromosome

Table 1: Chromosome Types by Centromere Position

Table 1: Non-Membranous Organelles

Table 1: Cell Skeletons

Table 1: Largest and Smallest Components

More CEE preparation resources