CellsCells• Regions of cellsRegions of cells

– Middle lamella = pectinMiddle lamella = pectin• Bacteria/fungi break down causing fruit/vegetable rotBacteria/fungi break down causing fruit/vegetable rot

• Like “mortar” between two bricks!Like “mortar” between two bricks!

– Primary cell wall = cellulose and pectinPrimary cell wall = cellulose and pectin

– Secondary cell wall = cellulose and lignin (not always Secondary cell wall = cellulose and lignin (not always

present)present)

PectinPectin

Rot in fruitRot in fruit

CellsCells• Cell walls are NOT solid!Cell walls are NOT solid!

• Pierced by plasmodesmata Pierced by plasmodesmata (pores and strands that connect cells)(pores and strands that connect cells)

• Plasmamembrane = semipermeablePlasmamembrane = semipermeable

CellsCells• CytoplasmCytoplasm

– 85-90% water85-90% water– 10-15% organic(carbon-based) and 10-15% organic(carbon-based) and

inorganic substancesinorganic substances• Dissolved (salts and carbohydrates = CHO’s)Dissolved (salts and carbohydrates = CHO’s)

• Colloidal (proteins and fats)Colloidal (proteins and fats)

CellsCells– Similar to Jell-O®Similar to Jell-O®

• First made in 1897First made in 1897• Every four seconds, a box of JELL-O gelatin is Every four seconds, a box of JELL-O gelatin is

sold in the United States!sold in the United States!

– From the From the Chicago TribuneChicago Tribune of March 5th, 1997 of March 5th, 1997• Jell-O = "hide trimmings," animal tissue that is rendered, Jell-O = "hide trimmings," animal tissue that is rendered,

purified, filtered, and then purified again, leaving a protein purified, filtered, and then purified again, leaving a protein called collagencalled collagen

• ““The gelatin that is the building block of Jell-O is so The gelatin that is the building block of Jell-O is so purified that the FDA doesn't regard it as a meat product. purified that the FDA doesn't regard it as a meat product. Likewise, all but the strictest vegetarians find Jell-O Likewise, all but the strictest vegetarians find Jell-O acceptable”acceptable”

CellsCells• NucleusNucleus

– Contains chromosomes Contains chromosomes – DNA = deoxyribonucleic acidDNA = deoxyribonucleic acid

• mRNAmRNA– Relays genetic info. from nucleus to Relays genetic info. from nucleus to

ribosomes (often attached to the ER, where ribosomes (often attached to the ER, where proteins, such as enzymes, are made)proteins, such as enzymes, are made)

CellsCells• Plastids (in the cytoplasm)Plastids (in the cytoplasm)

– Leucoplasts (colorless) contain starchLeucoplasts (colorless) contain starch

– Chromoplasts (colored)Chromoplasts (colored)• Chloroplast = chromoplast that contains Chloroplast = chromoplast that contains

chlorophyll (20 - 100 chloroplasts per cell in a chlorophyll (20 - 100 chloroplasts per cell in a green leaf!)green leaf!)

– Where photosynthesis occursWhere photosynthesis occurs

– Grana = stacked like coins, contains chlorophyll, Grana = stacked like coins, contains chlorophyll, receive lightreceive light

– Stroma = surrounds grana where COStroma = surrounds grana where CO22 is converted to is converted to

CHO’sCHO’s

CellsCells• Mitochondria = power center for cellMitochondria = power center for cell

– Proteins and phospholipidsProteins and phospholipids– ATP (adenosine triphosphate) carries energyATP (adenosine triphosphate) carries energy

• Vacuoles = membrane-lined cavities in Vacuoles = membrane-lined cavities in the cytoplasm filled with cell sap (water, the cytoplasm filled with cell sap (water, salts, organic materials)salts, organic materials)– Helps control plant turgorHelps control plant turgor

Cell sapCell sap

90% water90% water8% sugars8% sugars2% minerals/AA/other2% minerals/AA/other

MitosisMitosis• Cell divisionCell division

• End up with the same # of chromosome End up with the same # of chromosome as your started with!as your started with!

• Can lead to plant growthCan lead to plant growth

MitosisMitosis

Mitosis in a blood lilyMitosis in a blood lily

Mitosis in an onion rootMitosis in an onion root

Cell enlargementCell enlargement• What causes plant growth!!What causes plant growth!!

• In a region just behind the area of cell In a region just behind the area of cell division (meristem)division (meristem)

Types of cellsTypes of cells• Parenchyma cellsParenchyma cells

– Juicy edible parts of fruits and veggiesJuicy edible parts of fruits and veggies– Thin walledThin walled– Contain lots of waterContain lots of water

Types of cellsTypes of cells• Collenchyma cellsCollenchyma cells

– Thick-walled cellsThick-walled cells– Coarse and “gritty”Coarse and “gritty”

Types of cellsTypes of cells• Sclerenchyma cellsSclerenchyma cells

– FibrousFibrous– For supportFor support

Types of cellsTypes of cells• Importance of middle lamellae in cookingImportance of middle lamellae in cooking

• ‘‘Russet Burbank’ potatoesRusset Burbank’ potatoes– Ideal for baking, mashing & processingIdeal for baking, mashing & processing– Middle lamellae breaks down easilyMiddle lamellae breaks down easily– Cells remain intactCells remain intact– Mealy textureMealy texture

• ‘‘Red Pontiac’ potatoesRed Pontiac’ potatoes– Ideal for boiling and fryingIdeal for boiling and frying– Middle lamellae does not break downMiddle lamellae does not break down

Middle lamellae comes apartMiddle lamellae comes apart

Middle lamellae Middle lamellae stays intactstays intact

RootsRoots• Why?Why?

– Anchor plantAnchor plant

– Absorb mineral nutrientsAbsorb mineral nutrients

– Absorb waterAbsorb water

– Store nutrients (CHO’s) and waterStore nutrients (CHO’s) and water

RootsRoots• Parts:Parts:

– Root capRoot cap

– MeristemMeristem

– Zone of elongationZone of elongation

– Maturation zoneMaturation zone