Cell Biology and Genetics Notes

CELL BIOLOGY

Prokaryotic cell

Eukaryotic (plant cell and animal cell)

Cell

Discovered by Robert Hooke from Phellen of Cork described in book Micrographia

First living cell seen by AV Leewenhoek(called father of microscopy)

Cytology

Coined by Hertwig

Father of cytology Robert Hooke

Modern father Swanson (father of cell biology)

Cytogetics

Termed by Muller

Animal cell

  • Longest----------------->Nerve cell
  • Largest-----------------> Ostrich cell

Plant cell

  • Longest----------------->Ramie fibres
  • Largest-----------------> Acetabularia(umbrella shaped)

Cell theory

Omnis cellula e cellulae(cell lineage theory) + old cell theory by Schwann  and Schleidon

Cell wall

Discovered by Robert Hooke and called it diaphragm

Middle lamella is formed of Ca and Mg pectate.

Primary cell ----------------->Elastic, hemicelluloses

Secondary cell wall----------------->Inelastic due to lignin

Protoplast

Cell minus cell wall

Termed by Hanstein

Cell membrane

Outermost in animal cell and inside cell wall in plant cell

Discovered by Schwann

Termed by Nageli and Cramer

Termed as plasma membrane by Pfelffer

Termed as plasma lemma by Seifriz

Termed as cytoplasmic membrane by Singer and Nicholson

Models of cell membrane

  • Unit membrane model----------------->Robertson
  • Lipid model----------------->Overton
  • Sandwitch model----------------->Danellie and Davson
  • Fluid mosaic model----------------->Singer and Nicolson

Cell wall impermeable in Cork cell and Casperian stripe(due to deposition of suberin).

Cell membrane modification

  • Mesosome----------------->Bacteria----------------->Help in respiration
  • Lomasomes----------------->Fungi
  • Lamellosome----------------->BGA
  • Microvilli----------------->Intestine of animals

Protoplasm

= Cytoplasm + Nucleus

Termed by Purkinje

Observed by Alfosno de Corti

Termed as Sarcode by Dujardin

Huxley described protoplasm as physical basis of life.

Deutoplasm----------------->Non-living component

Cytoplasm minus cytoplasmic structure = Hyaloplasm

  • Largest Cell component ----------------->Nucleus
  • Largest cell organelle----------------->Plastid
  • Largest cell organelle in animal----------------->Mitochondria
  • Smallest cell organelle----------------->Ribosome, Perixosome
  • Smallest cell component----------------->Microtubules
  • Largest microbody----------------->Glyoxisome
  • Organelle of plant cell ----------------->Plastid, Glyoxisome

No membrane bound structure----------------->Microtubules, filaments, centrosome, ribosome, cilia and flagella

Triple membrane bound----------------->Transosome

Plastid

Kitchen of cell.

Discovered and termed by Haeckel

Types----------------->Leucoplast, Chromoplast, Chloroplast

Chromoplast contain Anthocyanin/Anthoxanthin----------------->Give water soluble plant colour

Chloroplast shapes

  • Spiral----------------->Spirogyra
  • Girdle----------------->Ulothrix
  • Star----------------->Zygnema
  • Cup----------------->Chlamydomonas
  • Reticulate----------------->Oedognima

In plastid there are two sites of reaction-----------------> Stroma(dark rxn site) and Grane(light rxn site)

Quantasomes combine----------------->Thylakoid----------------->stacked to form Grana

Thylakoid named by Menke.

Thylakoid if not staked called Chromatophores or Lamellar chloroplast.

Mitochondia

Power house of cell.

Absent in sieve tube, cancerous cell, mature RBC except camel and Llama

Yellowish colour of mitochondria due to riboflavin rich in Mn

Spermatids have mitochondria without cristae.

Cristae are finger like projections in mitochondria.

Cristae have elementary particles or oxysomes or Fernandez’s Morgan particle or Electron transport system.

About 70% of enzymes of cell found in mitochondria.

Together mitochondria of cell are called Chondriosome.

Oxysome has three parts----------------->Head(F1) has ATPase, Tail(F0) has proton channels of oxysome

Benda coined the term Mitochondrion.

Endoplasmic reticulum

Termed by Porter and Kallam

Three parts----------------->Cisternae,Tubules, Vesicles

Cisternae----------------->Unbranched, protein synthesis

Tubules----------------->branched, transport material inside cell

Vesicles----------------->Spherical, store synthesic materials

Isolated, fragmented to form microsomes.

Membrane factory of cell

Myeloid bodies----------------->Smooth Endoplasmic Reticulum

Nissl’s granules----------------->Rough Endoplasmic Reticulum

Golgi bodies

Traffic police of cell

Termed by Camilo Golgi

Discovered in Purkinje cells of cerebral cortex of bard owl

Dictyosome----------------->called in plants

@BaD Middle man to DIG

  • B----------------->Baker’s body
  • D----------------->Dictyosome
  • D----------------->Dalton complex
  • I----------------->Idiosome
  • G----------------->golgi body

Cis or forming face towards membrane, outer and convex

Trans or maturing face towards nucleus, concave  and inner

Acrosome or head of sperm and yolk derived from Golgi bodies

Form zymogen granules.

Three parts----------------->Tubules, vesicles, vacuoles

Tubules form complicated network between trans face and peripherals

Vesicles contain secretory substance

Vacuole function as lysosome

Ribosome

Termed by Robert

Termed by Claude as microsomes

Discovered by Palate

Protein factory/ engine of cell

Found in all cell except (RBC and sperm cell)

Types of RNA

  • rRNA-----------------> most abundant(80%)
  • mRNA-----------------> mol. Wt. highest, least abundant(5 to 10%)
  • tRNA----------------->smallest RNA, 10-15%

Types of r RNA

  • 80S----------------->60S + 40S
  • 70S----------------->50S + 30S

Lysososome

Suicidal bag

Discovered by de Duve from rat liver cell

types----------------->Primary, Secondary and residual bodies

Sphaerosome----------------->Also called plant lysosome(Oleosome) ----------------->discovered by Perner----------------->termed by Dangeard

Microbodies

----------------->Peroxisome, Glyoxysome

Peroxisome discovered by Rhodin from kidney cell

In plants, Tolbert and Yamazaki-----------------> discovered from germinating seed

 beta oxidation occur in animal in peoxisome

Termed by Beaufaytt and Berther

Glyoxysome----------------->Largest microbody found only in plant cell----------------->beta oxidation occur in plants in glyoxisome  

Lomasomes

In fungi.

Discovered by Moore and Mc Allister

Help in cell elongation

Transosome

Found in ovary follicle cells of birds

Helps in yolk formation or vitellogenesis

Microtubules

Discovered by Robertis and Franchi in nerve fibre

Has tubulin protein

Named by Slautterback

Basis structure of spindle apparatus, centrioles, chromosome factor

Microfilament

Protein filament made upof actin

Centriole

Membraneless

In animals except amoeba

Plants except red algae, gymno and angiosperms)

Centriole responsible for microtubules organization and spindle formation during cell division

Flagella

Basal granules/Blepharoplast is kinetic center of flagella lying in protoplasm

Prokaryotic flagella (flagellin protein), eukaryoticflagella (microtubules).

Vacuole

Tonoplasm(non-living)

living semipermeable tonoplast

Food vacuole----------------->protozoans----------------->food material associated

Gas vacuole----------------->prokaryotes  (gaseous exchange)

Contractile vacuole----------------->asmoregulation in protozoans

Sap vacuole----------------->higher plants----------------->turgidity

Nucleus

Robert brown from orchid root (discovered)

Director of cell (hammering) from grafting experiment on Acetabularia

Absent in sieve tube and mature mammalian RBC (except Camel and Llama)

Nuclear envelope(Karyotheca) ----------------->discovered Hertwig

Nucleoplasm-----------------> no cyclosis ----------------->rich in histone protein

Nucleolus-----------------> discovered by Fontana(named by Bowman) ----------------->Ribosome factory in eukaryotes

Chromatin fibre/ nuclear reticulum-----------------> discovered by Waldeyer

On the basis of stain----------------->Heterochromatin, Euchromatin

Heterochromatin----------------->thick, no active gene, inhibit crossing over

Euchromatin----------------->thin, active gene, take part in crossing over

Chromosome

Discovered by Strasburger

Coined by Waldeyer

Chromonemata----------------->2 chromatids

Chromosome with secondary constriction called SAT.

Shapes

I----------------->Telo

J----------------->Acro

V----------------->Meta

L----------------->Sub-meta

Cell inclusions

Non- living component of cell

Lipids, protein, fat


CELL DIVISION

GENETICS

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