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Plant Decoding THE PLANT CELL
The Evaluation: Presence 10% (start from the week 3) Homework 20% Midterm exam 30% Final exam 30% Q and A10% (start from the week 3) Presentation (2 per group)10% (determined at the week 4) Maximum score98
Please check 1st-PPT on the Moodle for details
What are the features of plants?
Features of Plants1. Green plants are unique in the ability to
transfer solar energy (photosynthesis) to food for growth.
2. Plant are composed of a root, a stem, and a leaf
3. Mostly, plants are non-motile. Yet, they evolve the ability to grow toward essential resources, i.e. light, nutrients, and water.
4. Indeterminate growth: grow as much as they can during their lives
5. Plants vary in sizes and forms (1mm-100m), but share the basic physiology.
The smallest flower plantWolffia
~1 mm
http://waynesword.palomar.edu/ww0601.htm
Sugar frosting
The largest and smallest leaf
Giant Amazon water lily(Victoria amazonica),
diameter of up to 2.4 meters!!
Water fern (Azolloa filiculoides).
1 mm in length!
The highest plant The coast redwood Sequoia up to 115.2 m
http://waynesword.palomar.edu/ww0601.htm
An overview of the plant structureA typical dicot plant
All seed plants have the same body plan
A.Leaf-photosynthesis
B.Stem-support
C.Root-anchorage and absorption of water and nutrients
“Cell” From Latin cella, meaning store-room or chamber
1665, Robert Hooke describe the individual units of the honeycome- like structure of cork
1839 Schwann observed in animal
Hook’s microscope
Drawing of cork by Robert Hooke, discoverer of “cells”
Cells were first observed in plants.
Photograph of cork cells
Photo credit: ©David B. Fankhauser, Ph.D
A section of a plant leaf
All plants are made of cells
A plant cell is the simplest unit of a plant that can live independently
Many shapes, sizes, and functions
Compositions of a plant cell?
Compositions of a plant cell
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Compositions of a plant cell
Each organelle (胞器) is a “factory”
An organelle is a specialized subunit within a cell that has a specific function, and is usually separately enclosed within its own membrane (細胞膜) in a cell.
Cytoplasm -The contents in a cells, excluding nucleus and vacuole
* a watery fluid where the cell organelles are located
* many of the complex chemical reactions take place here
Each organelle is a “factory”
Cell walls provide protection and support-1st layer
• Make the shape of a cell!• While you have a skeleton to
hold you up, a 100-foot tall redwood tree uses the strong cell walls to maintain its shape.
• •made of cellulose (纖維素), hemicellulose, pectin (果膠),lignin (木質素) -complex carbohydrates(碳水化合物)
Cell wall
Cell walls provide protection and support-1st layer
• Primary cell wallsoutsideActively growing thin and flexible
• Secondary cell wallinsideMature and stop Contain more cellulose
(40-80%) than primary cell wall
Rigid
Cell walls
Photo credit: www.wpclipart.com/plants; Zhong, R., et al., (2008) Plant Cell 20:2763-2782 .
Primary plant cell walls are composed mainly of carbohydrates and proteins.
A portion of a cell wall from the green alga, showing how cellulose microfibrils are laid down.
Cell walls
Stain of switchgrasscell wallhttp://newscenter.lbl.gov/feature-stories/2009/07/08/fuels-from-biomass-ionic-liquids/
Cell walls used in our lives
copyright Russell Kightley
Windows b/t cells-Plasmodesmata (細胞間連絲)All plant cells are interconnected via plasmodesmata (singular: plasmodesma)Located between cellsSend signals and transport nutrientsc
The plasma membrane-2nd layer 2nd defense line Very thin (x12500 to a writing
paper) Surrounds the cells to form a
barrier that controls and filters nutrients
it is like a big plastic bag with some tiny holes. That bag holds all of the cell pieces and fluids inside the cell and keeps any nasty things outside the cell.
The plasma membrane-2nd layer
Questions? Take a break!
Each organelle is a specific “factory”
Nucleus (pl. Nuclei)
Nuclear envelope
Nucleolus (DNA) Nuclear pores
BOSS OF THE CELL! Like our brain! It controls all of the cell functions!Is surrounded by a double nuclear membraneonly found in EUKARYOTES (真核生物)
Biology breaks cell types into eukaryotic (those with a defined nucleus) and prokaryotic (those with no defined nucleus).
contains genetic materials (DNA) in the form of chromatins or chromosomes that control the activities of the cellTransfer DNA to RNA
Nucleus
Ribosomes•Are tiny bodies that are composed of two subunits of RNA and proteins•No bounding membranes; distributed in the cytoplasm•Bind special RNA to link amino acid together to construct the large and complex protein molecules that are basic part of all living organism
* a series of interconnecting channels associated with storage, synthesis, and transport of substances within the cell
* two types:A) rough--the 'ER' studded with ribosomes--for protein synthesis
B) smooth--the 'ER' without any ribosomes
Endoplasmic Reticulum (ER)
* Golgi Camillo 1906 win Nobel prize•a series of flattened sacs•Take products from ER for modification and ship them to the plasma membrane•post office of cells
Golgi complex or bodies
Cis
Trans
CisAccept products from ER
Trans golgi networkdeliver to others
Secretory (分泌)pathway: ER-Golgi network
Other subcellular organelles
Plasma membrane
fusion
Transport cargo
http://www.youtube.com/watch?v=MrHULUxAsGg&feature=related
biggest organelle?
Vacuole: up to 90% of the total volume•Latin root “ vacuus”-empty•There are one or two large central vacuoles in a mature plant cell; many and tiny in a new cell•They are bounded by vacuolar membranes•Filled with a watery acid fluid containing ions, pigments, enzymes •Cell enlargement is through an increase in vacuole volume
A mature cellA young cell
Energy and Food -producing organelles
Mitochondria and chloroplast
Mitochondria (singular: mitochodrion)•site of cellular respiration* POWERHOUSE OF A CELL!!! (make ATP) , where energy is released from nutrients* there are MANY in a single cell, 1-3 µm* has two layers, makes up a double membrane•Like cucumber, rods, or balls
thread granule
http://www.danforthcenter.org/science/core_facilities/integrated_microscopy/cells_main.asp
found in photosynthetic cells contains chlorophyll, a pigment that makes photosynthesis possible and greenComposed of double membranes; many (25~100) in one cell
Chloroplastgreen one form
Granum (grana)
ThylakoidThe membrane contains chlorophyll for photosynthesis
stroma
Microtubule Microfilament
The cytoskeleton•A network of filaments that forms a mechanical support system and in the cells (metal rack to build the house)•Important for movement in a cell (rail tracks in a cell) –cytoplasmic streaming
http://www.youtube.com/watch?v=pFsty-XyLZc
The cytoskeleton
Compositions of a plant cell
What make a plant cell different from a animal cell? -Q
http://understandingcells.blogspot.com/2008/10/key-differences-between-plant-and.html
Reference: http://www.goldiesroom.org/Note%20Packets/03%20Cytology/00%20Cytology--WHOLE.htm
Practice at http://www.cellsalive.com/cells/cell_model.htm
YouTube demo:
http://www.youtube.com/watch?v=gQW3sO_G0mU&feature=related
http://www.youtube.com/watch?v=2nqd9jYQEzw&feature=related
Help from internet!
Scientific units
1cm=10 mm
1mm (10 -3 m) =1000 µm
1µm (10 -6 m ) =1000 nm (10 -9 m)
The relative size of cells and cellular parts
eukaryotic cells: 10-100 µm
organelles: 1-10 µm bacteria: ~ 1 µm viruses: ~ 100 nm cell membrane thickness:
~ 10 nm molecules: ~ 1 nm
Biological instruments to observe cells
Microscopes allow us to observe beyond our bared eyes
Light microscope Electron microscope Fluorescence microscope
Light microscope: up to 2000x, color Exam life samples
A colorful section with staining
dye
Electron microscope (EM): Transmission (TEM) or Scanning (SEM)- B/W to 250,000X* can only show the image of dead organisms; the slides must
be coated in a special fashion
TEM microscope
TEM:--Details of cell contents
SEM microscope SEM scans the surface and is used to study
3D surface structure
Taro leaf structure, artificial colored SEM C009/0877 Rights Managed
Fluorescence microscopes Similar to light microscope, but adding excitation light. Use fluorescence proteins Stain cells in live
Roger Tsien's Nobel Prize research.
http://ucsdnews.ucsd.edu/thisweek/2008/10/13_tsien.asp
Wearing and drinking fluorescent juice!!
Fluorescence microscopesAdd chemicals
Observe instant reaction!
Flowers in spring!
Flowers in spring!
Homework 2
Please draw a cross section(橫切面) of a stem (2 points) and a root ( 2 points). Name three parts for each.
SEE YOU NEXT WEEKTISSUES, ROOTS, STEMS