Lectures on
Plant Physiology
Prepared by
Prof Mohammed Naguib Abdel-Ghany
Haseneen
Professor of Plant physiology
For
Pre-Dental Students
1
Contents
• Plant Cell
– Plant Cell structure and function
• Different Bio-Physico-Chemical Phenomena
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Colloids
Diffusion
Osmosis
Imbibitions
• The Enzymes
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Structure
Mode of action
Inhibitors
Factors affecting enzymatic activity
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Cont.
• Metabolism
• Respiration
– Glycolysis, TAC, Fermentation
– Factors affecting rate of respiration
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Amino acid and protein metabolism
Biotechnology
-What is biotechnology?
Biotechnology benefit
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1- Plant Cell (Structure and Function)
• Cells are the basic unit of life.
• Cells carryout all the necessary functions for
life such as: reproduction, taking in nutrients
and excreting wastes.
• Cells are made up of chemicals and
molecules. Human cells contain mostly
water.
4
The Cell
• Cells are classified as prokaryotic and
eukaryotic.
• Prokaryotic cells lack a well-defined nucleus
and many organelles. Bacteria are
prokaryotic cells.
• Eukaryotic cells include the protists, fungi,
plant and animal cells. We will study these
cells during this lab.
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The Cell
• Animal Cells
• Have centrioles
• Store glucose as
glycogen
• Do not have a cell wall
• Contain mitochondria
• Plant Cells
• Lack centrioles
• Store glucose as
cellulose or starch
• Have a cell wall
• Have large vacuoles
• Contain chloroplasts
as well as
mitochondria
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The Cell
• Animal Cell
• Click on the cell to
study it in more detail
• Plant Cell
• Click on the cell to
study it in more detail
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Animal Cell
Click on each organelle to learn its function. When you have finished click on the
arrow button to study the plant cell.
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Plant Cell
Click on each organelle to study its function. When you have finished click here to
study the animal cell or here to continue this lab.
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Cell is a unit or module of plant organization
- Supports cells & plant
- Controls cell growth &
shape
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Cell Wall
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Only found in plant cells
Surrounds cell membrane
Composed of lignin and cellulose
Function to strengthen and protect plant cells.
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Cell Wall
• Structural functions
– Provides rigidity to plant
– Determines size and shape of cell
– Determines size and shape of plant
• Other functions
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Absorption
Transport
Secretion
Cell-cell communication
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Structure of cell wall
• Cellulose is principal component
– Repeated monomers of glucose attached end to end
– Bundled into microfibrils
– Crystalline properties
• Cellulose matrix is embedded in matrix of
noncellulosic molecules
– Provide cross-links between cellulose microfibrils
– Pectins = hydophilic polysaccharides
– Glycoproteins- extensins
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Structure of cell wall continued
• Primary wall
– Formed first while cells growing and dividing
– Enriched in pectins and water (to allow expansion)
• Middle lamella
– Joins adjacent cells
– Mostly pectins
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Cell wall structure continued
• Secondary wall
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Not all cells form
Deposited after cell has stopped growing
Inside primary wall
More cellulose
Pectins lacking
Rigid
Formed by cells that provide strength or transport
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Cell walls (yellow) separated by middle
lamella (black)
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Middle lamella (black) separates walls from
2 different cells
Cell
membrane
contacts
inner part of
wall
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Cellulose is polymer of glucose that aggregates
into threads (microfibrils)
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Cellulose
threads
are woven in
cell wall
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