Chapter 1 Plant Cells

8/10/2019 Chapter 1 Plant Cells

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Plant Anatomy and Physiology(BIO3602)

Dr. Ng Lee Chuen PPSTMTel: 09-668 5050 Email: [email protected]



Plant Anatomy and Physiology?



Plant Anatomy

• ANATOMY: study the structure of organisms.

looking at cells, tissues and organs

• Internal structure of plants, especially at themicrosco ic level histolo .

Morphology: Study of the physical form andexternal structure of plants.

• Plant morphology is useful in the visual

identification of plants.

Histology: Study of the microscopic anatomy ofcell and tissue of plants.



Plant physiology• The study of the plant function and processes occur in

plant.• Plant physiology is a study of the plant way of life,

which include various aspects of the plant lifestyle and, ,

nutrition, development, movement, irritability (responseto the environment), organization, growth, and transportprocesses.

• The study from the moment of conception, zygote, untilthe plant’s death.



Chapter 1: Introduction to

Plant Cell

Learning goal

• Understand the cells, tissues and organs in plant

in relation to their functions in plant.

Learning outcomes

1. Describe the anatomy of plant in detail.

2. Explain the processes that involve by each cell

structure in plant.



Plants- What are they?



Plants• Photosynthetic eukaryotes.

• Is autotrophic.• Existed possibly as long as 1.6 billion years

.

• Is non-motile (grow toward essentialresources eg: light, water and mineralnutrients).

• Include angiosperms (flowering plants),gymnosperms (cone-bearing plants), ferns,

and bryophytes (mosses & liverworts).



From smallest to largest

plants

Individual plants of Wolffia arrhiza

(atermeal!, 1"2mm #ide

$ymnosperms% the tallest, larges and the

long"lived tress





verv ew

of PlantStructure



Plant Cell Animal cell



contains DNA

storage:

pigments,

acids,

respiration

transport &

modification

cell recognition,

structural support

storage high energy

carbs.

protein synthesis &

transport ofmaterials

photosynthesis

transport



A

B

CD

!

"

#

$



Organelles in plant cells

Cell wall

primary cell #all " cellulose, hemicellulose, and pectin.

secondary cell #all " inside primary cell #all, cellulose,

hemicellulose, and lignin (complex alcohol polymer!.

&ell #all is mainly cellulose% beta"1,'"glucopyranoside





Organelles in plant cellsCell wall



Cell %all




• Cell Wall is a rigid, non-living structurethat surrounds the plant cell.

• It provides physical support for thecell.

• It determines the cell's shape.• It protects the cell from osmotic

expansion.

Cell %all


• Its most important components arecellulose (very strong), hemicelluloses(link together the cellulose fibers) andpectin (a gelatinous matrix).

• All plant cells have a "primary wall,"some produce a stronger "secondary

wall" as well.



Cell %allmiddle lamella


'iddle lamella is an adhesive gelatinous unction bet#een the t#oprimary #alls of t#o plant cells. It is cooperatively secreted by

adoining cells.



• Small tubes that connect plant

cells to each other, establishingliving bridges between cells.

– Allow certain molecules to pass

directl from one cell to another.


Cell %all plasmodesma

– These channels, penetrate thecell wall and are lined withplasma membrane, uniting all

connected cells with essentially

one continuous cell membrane.



Plasma membrane


)protects the cell

)regulates transport in and out of the cell

)provides anchoring for other cell parts

)allo#s cell recognition

)allo# for signal transfers

)provide a site for binding #ith other cells



&hloroplast

*esophyll

+ m

Chloroplasts – are the organelles in which photosynthesis

occurs. – absorb light energy and convert it to

chemical energy.


Chloroplast

-uter

membrane

Intermembrane

space

Innermembrane

hyla/oid

space

hyla/oid

$ranum0troma

1 m

–

grana (stacks of thylakoids)

hyla/oid

◦ he membrane is impregnated #ith

photosynthetic pigments

(chlorophylls,carotenoids!.

◦ &hlorophyll is the green pigment that

captures light for photosynthesis.





lastids that capture light energy from the sun to ma/e food34

contain chlorophyll

Chloroplast


•he plamid is a maor

organelle.

•lasmids are the site of

manufacture and storage of

important chemical compoundsused by the cell.



Leucoplasts

• Colorless plastidsthat store starch oroil


• Found in tubers(e.g., Irish potatoes),roots, leaves, grains,

fruits, and seeds.



Chromoplasts

• Plastids that make & store

carotenoid pigments.

• Found in red & yellow


peppers, oma oes, owerpetals.

• Carotenoid pigments are

not water soluble, but it isfat soluble.






Mitochondria

• Power-house of the cell - energyproduction – Cells re uirin lar e amounts of ener have

numerous mitochondria. – Generates ATP from the oxidation of food

molecules.

– Requires oxygen and gives off carbondioxide, called cellular respiration• With oxygen – aerobic

• Without oxygen - anaerobic






Nucleus• Usually the most prominent organelle.

• Contains the genetic material of the cell – DNA. – Chromatin is a complex of DNA and protein that

is diffusely distributed in the nucleus.

– DNA can be seen as chromosomes only duringcell division.

• Contains the nucleolus.

– Nucleolar organizing area.

– Contains the RNA molecules and proteinsnecessary for formation of ribosomes.





Ribosome• Sites of protein

synthesis (translation).• Two subunits; one largeand the other small.


-organelles.

• Some free, someattached to the

endoplasmid reticulum(ER).





Vacuoles


• 80 -90% volume of cell.

• Surrounded by vacuolarmembrane: tonoplast (vacuolar

membrane!

• on a n: norgan c ons, organ cacids, sugars, enzymes andsecondary metabolites.

• Hydrolytic enzymes: protease,

ribonucleases, glycosidases• Specialized protein storing

vacuoles – protein bodies in seeds

• Hydrolytic enzymes stored in lyticvacuoles



Cytoplasma / cytosol• Extends bet#een cell

membrane, tonoplast and

nuclear membrane• Includes metabolically active

as #ell as inactive particles


– -rganelles 6 the smallmembrane"boundcomponents of the cell thatallo# it to function

– &ytosol 6 the a8ueous part ofthe cytoplasm outside of theother membrane boundorganelles







(!) differs from )!) in the follo%ing aspects:

Smooth ER Rough ER

No ribosome, devoid ofpores

Bears ribosomes and pores

Smooth Rou h

Peripheral, may beconnected to plasmamembrane

Internal, may be connectedto nuclear membrane

Synthesis glycogen, lipidsand steroids

Synthesis protein

Has vesicles and tubules Cisternae and a few tubules



Golgi apparatus• Most abundant in meristematic

and secretory cells.

• Produce materials for export(secretion).

• Polarity-


trans – exports vesicles).

• Site of processing and packagingcellular components.

• Vesiclesgolgi (cis-side)release processed sortedpackaged re-released (transface).

• Active in synthesizing many cellcomponent (carbohydrate).



'C)*B*D!(• Microbodies are a diverse group of organelles that are found

in the cytoplasm of almost all cells, roughly spherical, and

bound by a single membrane.• Two main type: peroxisomes and glyoxysomes

• Peroxisomes: found in C3 and CAM lants, sites of


photorespiration, removal of hydrogen from organicsubstrate, consuming oxygen.

• RH2 + O2 R + H2O2

• Glyoxysomes: present in oil-storing seed

• Glyoxylate cycle enzymes; convert stored fatty acid intosugar

O ll i l ll



Oleosomes

• Oil accumulate in – oleosomes.

• Also called lipid bodies or spherosomes.

• Surrounded b half-unit membrane:


phospholipid monolayer.

9ipid bodies stained #ith 0udan. 0ome cells may contain

large amounts of storage lipids in vacuoles large : small.

hese stain red #ith 0udan III.



The Cytoskeleton

• Elaborate network of filaments that function to

give strength, shape and movement to cells.

• Play fundamental role in:

– mitosis,

– meiosis,

– cytokinesis,

– wall deposition, – maintenance of cell shape and

– cell differentiation





Microfilaments

• Solid, 7 nm diameter, globular actin or G-

protein.• Compose of single polypeptide ~ 42 000

daltons.

• Consist of two chain polymerized actin subunit – intertwine in a helical fashion.

Intermediate Filaments

• Helically wound fibrous elements, 10 nmdiameter.

• Linear polypeptide monomer various types.



;unction of



;unction of

*icrotubules and *icrofilaments

Cytos+eleton fleible tubular scaffold of microfilaments.

• maintains cell shape and pro-ides support.

• anchors organelles & enymes to specific regions of the cell.

• contractility and mo-ement /amoeboid mo-ement0.

• ntracellular transport trac+s for -esicle and organelle mo-ement by.

Cytos+eleton components:

• 'icrofilaments

– solid protein /actin0 %hich is assembled at one end anddisassembled at the other end.

• ntermediate filaments ropeli+e fibrous proteins.

– pro-ide structural reinforcement

– anchor organelles

– +eep nucleus in place





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Chapter 1 Plant Cells