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