I've no idea why I'm posting this. Anyhoo, read and understand.
Cell Structure
Cytology- study of cell and its structure and components as
seen under the microscope
Cell biology-study of all aspects of cell-structure,
biochemistry, development and physiology
Cytoplasm: living part of the cell lying outside the nucleus
but within the cell membrane.
Cell structures:
·
Cell membrane (Nageli and Kramer) –membrane covering
the protoplast
§
Structure: thin elastic skin like membrane
covering the cell.
Biochemical composition
a) phospholipids
a) phospholipids
b) Proteins
c) Carbohydrates-provide specificity
D) cholesterol-fluidity
§
Fluid Mosaic Model of plasma membrane –Singer and
Nicholson
a)Arrangement of lipids- phospholipid bilayer
a)Arrangement of lipids- phospholipid bilayer
b) Arrangement of proteins-
extrinsic- found on outer and inner side of bilayer
intrinsic- found inserted within the bilayer.
c) Arrangement of carbohydrates-attached to either lipids or proteins on the external surface only
extrinsic- found on outer and inner side of bilayer
intrinsic- found inserted within the bilayer.
c) Arrangement of carbohydrates-attached to either lipids or proteins on the external surface only
§
Function of plasma membrane:
a)Functions of membrane carbohydrates
b)Functions of membrane proteins
a)Functions of membrane carbohydrates
b)Functions of membrane proteins
c) Transport across Membranes
d) Passive Transport
a) Diffusion
b)Osmosis
d) Passive Transport
a) Diffusion
b)Osmosis
e) Active Transport
a) Bulk transport
b) Phagocytosis
c) Pinocytosis
a) Bulk transport
b) Phagocytosis
c) Pinocytosis
·
Endoplasmic Reticulum- (name given by Porter):
Biosynthetic Factory
1. Structure:
Composed of 3 types of units:
a)Cisternae
b)Vesicles
c)Tubules
2 types of ER:
1. Structure:
Composed of 3 types of units:
a)Cisternae
b)Vesicles
c)Tubules
2 types of ER:
o
Rough ER – With ribosomes and synthesizes
proteins
o
Smooth ER–Without ribosomes and synthesizes
steroids, lipids, carbohydrates and proteins
2.
Functions
§
Circulatory System of the cell
§
Protein Synthesis
§
Detoxification of drugs and other poisons
§
Membrane Factory
§
Storage of synthesized materials
§
Synthesis of molecules like bile acids,
phospholipids, cholesterol and hormones
·
Golgi Apparatus-(Named after its discoverer
Camillo Golgi) : Traffic Director
o
Function
§
Modification and packaging of proteins
§
Produces acrosome of sperm
§
Gives rise to lysosome
§
Helps in osmoregulation in one-celled fresh
water animals via contractile vacuole
o
Structure
§
Group of flattened sacs placed one over another
to form a pile/ stack.
§
Each stack is called a dictyosome
§
3 types of units in the Golgi Apparatus:
v
Cisternae
v
Tubules
v
Vacuole
·
Lysosomes- Discovered by Christian De Duve (Suicide
Bags)
o
Found only in eukaryotic cells.
o
Contain hydrolytic enzymes/hydrolases
o
4 functional stages are observed:
§
Primary
§
Secondary
§
Auto lysosome
§
Residual body
o
Functions:
§
Intracellular digestion
§
Apoptosis
§
Acrosome
§
Absence of lysosomal enzymes may lead to
Lysosomal storage diseases
·
Mitochondria – First seen by Kolliker (Powerhouses)
o
Structure:
§
2 membranes- inner is selectively permeable and
is produced into a large number of folds called cristae
§
F0F1 Particles: stalked
particles in cristae involved in ATP synthesis.
§
Mitochondrial Matrix
v
Mitochondrial DNA
v
Ribosomes
v
RNA
o
Functions:
§
Krebs Citric Acid Cycle
§
Electron Transport
·
Ribosomes (First seen by Albert Claude) ; RNA +
Proteins= Ribosomes
o
Not found in : Mature RBC, mature sperm, sieve tube
members of phloem in plants
o
S= Svedberg Unit or Sedimentation Coefficient
o
Prokaryotes: 70S
o
Eukaryotes: 80S
o
Mitochondrial Ribosomes: 55S to 80S
o
Chloroplast Ribosomes: 70S
o
Structure:
§
Composed of 2 units: Larger subunit and smaller
subunit.
o
Functions: Protein Synthesis
§
Ribosomes attached to ER: Secretory proteins
(mucus and digestive enzyme) synthesis
§
Free Ribosomes: Internal use proteins
(chlorophyll, haemoglobin) synthesis
·
Centrioles
o
Found only in Animal Cell
o
Centrioles of a pair occurring at right angles
to each other: Diplosome
o
Functions:
§
Microtubule organizing centre during cell
division
§
In animal and lower plant cells, centrioles give
rise to cilia and flagella. They’re called basal bodies.
·
Cytoskeleton
o
Microtubules
o
Microfilaments
o
Intermediate Filaments
·
Nucleus (Robert Brown) Master Organelle
o
Nuclear Envelope or Karyotheca
o
Nucleoplasm or Karyolymph
o
Chromatin (dispersed- -Eu, condensed –Hetero)
o
Nucleolus
o
Functions:
§
Responsible for the continuing of the life of
the cell
§
Carries hereditary information in its
chromosomes
§
Nucleolus: Ribosome Factory
Ultra structure of Plant Cell
§
Cell Wall
o
Middle Lamella- Calcium and Magnesium Pectate
o
Primary Wall-pectin and hemicellulose
o
Secondary Wall-High cellulose content
§
Plastids
o
Chloroplast
§
Stroma
§
Thylakoids
§
Stroma Lamellae
o
Leucoplast (Amylopast) : Formation and storage
of starch grains
o
Chromoplast: Plastids responsible for yellow,
red and orange color of many flowers and fruits
§
Vacuoles
o
Bubble like structure bound by a single membrane-Tonoplast
o
Contents of vacuole: Cell Sap
o
Functions:
§
Store organic compounds
§
Contain hydrolytic enzymes for macromolecule
digestion
§
Store inorganic ions like K+
and Cl-
§ Store
anthocyanin responsible for red and blue color in flowers
§ Helps
in increasing cell size
§ Ergastic
Substances
o Reserve
Food Materials
o Secretory
products
The End
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