Plant Structure- Roots, Stems, Leaves

Question 1

Roots

Answer 1

Epidermis
Cortex
Endodermis
Vascular Cylinder

Question 2

Epidermis of Root

Answer 2

Lines outside surface of root and produces root hairs in the zone of maturation to increase absorption

Root hairs die as the zone of maturation ages, requiring constant growth of the root to produce more

Question 3

Cortex of Root

Answer 3

Bulk of the roots

Stores starch

Question 4

Endodermis of Root

Answer 4

Ring at the inner cortex

Contains the casparian strip

Question 5

Casparian Strip

Answer 5

Band of fatty matterial (suberin)

Creates a water impermeable barrier between cells

Question 6

Result of Castrian Strip

Answer 6

Water passing through endodermis must pass through endodermal cells (not between cells)

Allows for endodermal cells to control movement of water into center of root (where vascular tissue resides) and prevent water movement back out to cortex

Question 7

Vascular Cylinder (Stele) of Root

Answer 7

Tissues inside endodermis

Question 8

Pericycle

Answer 8

Outer part of vascular cylinder

Where lateral roots arise from

Iside pericycle is the vascular tissue

Question 9

Structure of Stem

Answer 9

Similar to root, but no casparian strip or endodermis (specialized for water absorption, only happens in root)

Question 10

Epidermis of Stem

Answer 10

Contains epidermal cells covered with waxy cutin substance

Cutin forms the cuticle

Contains guard cells around stomata, and stinging cells

Question 11

Cortex of Stem

Answer 11

Ground tissue containing chloroplasts

Bulk of substance lying between epidermis and vascular cylinder

Question 12

Vascular Cylinder of Stem

Answer 12

Contains xylem, phloem, and pith

Single layer of cells between xylem and ploem may remain undifferntiated and later become the vascular cambium

Question 13

Structure of Leaf

Answer 13

Epidermis

Palisade mesophyll

Spongy mesophyll

Vascular bundle

Stomata

Question 14

Epidermis of Leaf

Answer 14

Protective covering

Covered by the cuticle, which reduces transpiration (water loss)

Specialized epidermal cells can contain trichomes

Question 15

Palisade Mesophyll

Answer 15

Parenchyma cells containing chloroplasts (sites of photosynthesis)

Question 16

Spongy Mesophyll

Answer 16

Parenchyma cells are more loosely arranged underneath the palisade mesophyll

Contains air chambers that can provide CO2 to photosynthesizing cells and O2 to respiring cells

Question 17

Vascular Bundles

Answer 17

Xylem and phloem tissue

Mesophyll cells (bundle sheath cells) surround these vascular bundles so that vascular tissue is not exposed to intercellular spaces (also provides anaerobic environment in C4 plants to fix CO2)

Question 18

Stomata

Answer 18

Opening and closing influences gas exchange, transpiration, ascent of sap, and photosynthesis

Closed= CO2 not available= No photosynthesis

Open= CO2 enters leaf, but plant risks desiccation from excessive transpiration

Question 19

Guard Cells

Answer 19

Each stomata has 2 guard cells surrounding it

Mechanism that controls opening and closing of stomata to optimize photosynthesis and minimize transpiration

Water diffuses into guard cell, causing it to expand, which causes thinner portion of cell wall to bulge out and open the stomata

Water diffusing out of guard cell closes stomata

Question 20

When Do Stomata Close

Answer 20

During high temperatures (to decrease water loss)

Also stops photosynthesis because CO2 can’t enter

At night to build up CO2 (lack of photosynthesis- no light, but respiration occurs)

Question 21

When Do Stomata Open

Answer 21

When CO2 is low in the leaf

During the day, uses CO2 for photosynthesis