Cell Biology
(4 Lectures)
Prof. A.A.
Mahdi
Prof. A.A.
Mahdi
Department of Biochemistry
King George’s Medical University
Lucknow
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Cell biology is a branch of biology that studies the structure, function, and behavior of cells, which are the fundamental units of life, exploring how cells grow, divide, differentiate, and interact with each other to carry out various biological processes within an organism; it encompasses the study of cell components like organelles, membranes, and genetic material, and investigates how these parts contribute to cellular activities like metabolism, communication, and cell cycle regulation.
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Cell Biology
(4 Lectures) Prof. A.A.^
Mahdi
Prof. A.A.
Mahdi
Department of BiochemistryKing George’s Medical University
Lucknow
Water Atomic view^ Ice
Prof. A.A. Mahdi Department of Biochemistry
Prof. A.A. Mahdi Department of Biochemistry
Prof. A.A. Mahdi Department of Biochemistry
Biological Membranes Composed of mainly lipids and proteins Give cell its individuality and also compartmentalizeGive cell its individuality and also compartmentalize^ intracellular organelles. Biomembranes are thin films which are not rigid orimpermeable, rather highly mobile and dynamicstructures. They are gatekeepers of the cells. Control access to cell by inorganic ions, nutrients andbiological compounds.
Prof. A.A. Mahdi Department of Biochemistry
IMPORTANCE
Highly selective permeability barriers. Have specific receptors for external stimuli. Generate signals: chemical or electrical.Generate signals: chemical or electrical. Energy conservation processes occur in membranes.
COMMON FEATURES
Sheet like structures, form closed boundaries, thickness between^60 - 100 A
oo. 60 - 100 A.
Composed of lipids and proteins, ratio between 4:1 to 1:4. Non-covalent assemblies. Asymmetric. Fluid structure.
Prof. A.A. Mahdi Department of Biochemistry
Molecular structure
Name Stearic acid: saturated C18 Oleic acid: monounsaturated C18Linoleic acid: diunsaturated C18 γ-Linolenic acid: triunsaturated C18γ-Linolenic acid: triunsaturated C18 Arachidonic acid: tetraunsaturated C
(^20) Prof. A.A. Mahdi Department of Biochemistry
Prof. A.A. Mahdi Department of Biochemistry
+H
Respiratory Chain
IMS
H^ FeS^ N-2^ FeS^ N-1, N-3,N-4^ FMN
cyt c aa^3 CuB III FeS^ C^1 Q^0 b^ b^ Qi SDH
cyt c CoQ Succinate NADH^ Complex I^
Complex II^
Complex III^
MATRIXComplex IV
Prof. A.A. Mahdi Department of Biochemistry
Animal^
PC
Rat Liver^
Sheep liver
Sheep kidneys
Sheep heart
Sheep brain
RBCs^
C^ PL
Rat^
28%^ 60%
Rat^
28%^ 60%
Human^
25%^ 58%
Sheep^
28%^ 60%
Ox^
32%^ 55%
Prof. A.A. Mahdi Department of Biochemistry
Phospholipid composition of subcellular organelles prepared
from rat: PC PE
C^ CE
Whole mitochondria
45%^
40%^
-^ -
RER^
62%^
20%^
5%^ 1%
Golgi^
42%^
15%^
10%^ 2%
Plasma membrane
35%^
20%^
20%^ 1%
Inner Mito. Memb.
50%^
38%^
-^ -
Outer Mito. Memb.
55%^
32%^
-^ -^ Prof. A.A. Mahdi^ Department of Biochemistry
Proteins
Specific proteins mediate distinctive functions. Serve as pumps, gates, receptors, energy transducers andenzymes. Play most of the functions of the biological membranes. Not only structural components but also carry out membranetransport. Also act as recognizing sites for hormones. Distinguish between like and unlike cells.Distinguish between like and unlike cells.
Carbohydrates Some oligosaccharidic units present in the membrane playrole in cell-cell recognition
Prof. A.A. Mahdi Department of Biochemistry