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Lectures on Plant Physiology

Prepared by

Prof Mohammed Naguib Abdel-Ghany Haseneen

Professor of Plant physiology For

Pre-Dental Students

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Contents

• Plant Cell– Plant Cell structure and function

• Different Bio-Physico-Chemical Phenomena– Colloids– Diffusion– Osmosis– Imbibitions

• The Enzymes– Structure– Mode of action– Inhibitors– Factors affecting enzymatic activity

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Cont.

• Metabolism• Respiration

– Glycolysis, TAC, Fermentation– Factors affecting rate of respiration

• Amino acid and protein metabolism• Biotechnology• -What is biotechnology?• Biotechnology benefit

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1- Plant Cell (Structure and Function)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.

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The CellThe 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 CellThe 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 CellThe 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 CellClick 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 CellClick 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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- Supports cells & plant- Controls cell growth & shape

Cell is a unit or module of plant organizationCell is a unit or module of plant organization

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Cell WallCell Wall

• 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 WallCell Wall

• Structural functions– Provides rigidity to plant– Determines size and shape of cell– Determines size and shape of plant

• Other functions– Absorption– Transport– Secretion– Cell-cell communication

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Structure of cell wallStructure 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 continuedStructure 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 continuedCell wall structure continued

• Secondary wall– 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 Cellulose threadsthreads

are woven in are woven in cell wallcell wall