Lab #2

Question 1

Parenchyma (7)

Answer 1

• make up ground tissue systems
• living at maturity
• fulfill metabolic functions
• polyhedral
• cell walls are thin (may be thickened)
• occurs in xylem & phloem
• intermediate size = phloem parenchyma cells

Question 2

Collenchyma (5)

Answer 2

• support of elongating leaves & stems, and mature herbaceous (non- woody) plants
• living at maturity
• unevenly thickened primary cell walls
• close to epidermis (never in pith or stem)
• absent from vascular bundles & roots

Question 3

Sclerenchyma (5)

Answer 3

• 2 kinds of cells: sclereids & fibers
• primary & secondary wall
• lignified
• cells are dead at maturity
• protect / support plant

Question 4

Sclerenchyma: Sclereids (2 + Ex.)

Answer 4

• variable in shape: short rounded vs branched
• protection of seeds (form hard protective layer that keeps out water & prevent damage to the seed)(soybean)

Ex: soybeans & pears

Question 5

Sclerenchyma: Fibers (3)

Answer 5

• support & protection (MATURE plant)
• dead at maturity
• found throughout plant (epidermis, ground tissues, vascular tissues of the root, stem, or leaf)

Question 6

Xylem (4 listed)

Answer 6

• consists of parenchyma, fibers, tracheids and vessel memebers

Question 7

Xylem: Tracheids (5)

Answer 7

• elongated cells
• thickened secodary walls
• have thin areas in their walls (pits)
• dead at maturity
• occur in ALL vascular plants

Question 8

Tracheids: Pit (Definition)

Answer 8

• Thin area, NOT a hole or perforation in the wall

Question 9

Xylem: Vessel Members (4)

Answer 9

• thick, lignified secondary walls
• pitted cell walls
• have true preferations in their end walls (are holes through cell wall)
• dead at maturity

Question 10

Xylem: Protoxylem (6)

Answer 10

• found in roots, stems, leaves
• first xylem that develops and matures
• matures before elongation of stems, leaves, and root is completed
• structure is compatible with this pattern of maturation
• extensibility
• located in the longitudinal sectiom of corn stem

Question 11

Phloem (4 listed)

Answer 11

• consists of parenchyma, fibers, sieve tube members, companion cells

Question 12

Phloem: Sieve Tube (7)

Answer 12

• relatively large cells that are clear in appearance
• thin, unlignified cell walls under high pressure
• extremely fragile
• sieve tube members are joined together, end to end to form long sieve tubes
• sieve plate
• lateral sieve areas are present on the sides of the cell
• difference between sieve plate & lateral sieve area = basis of pore size

Question 13

Sieve Tube: Pores (Definition)

Answer 13

• Tiny openings in the wall of the sieve tube member

Question 14

Companion Cells (4)

Answer 14

• relatively small cells which appear dark green because of their dense cytoplasm

• living cells
• loads sugar into sieve tube members from other parenchyma cells at a source of sugar (such as leaf)
• unloads sugar from sieve tube members and transfer it to other cells (such as parenchyma cells in a sotrage organ like a potato)

Question 15

Dicotyledons (5 Listed)

Answer 15

Ex:

• Okra
• Alfalfa
• Soybeans
• Sunflowers
• Crepe Myrtles

Question 16

Monocotyledons (5 Listed)

Answer 16

Ex:

• Corn
• Sorghum
• Palms
• Orchids
• Bananas