Leaves And Leaf Structures

Question 1

Leaves are located where ?

Answer 1

Stem nodes, separated by internodes

Question 2

Leaf arrangement is based on the number of what

Answer 2

Based on the number of leaves per node

Question 3

Alternate

Answer 3

1 leaf per node

Question 4

Opposite

Answer 4

2 leaves per node

Question 5

Whorled

Answer 5

3 or more leaves per node

Question 6

Blade

Answer 6

Expanded light collecting surface

Question 7

Simple

Answer 7

Blade not divided into leaflets

Question 8

Compound

Answer 8

Blade divided into leaflets

Question 9

Pinnately compound

Answer 9

Leaflets connected to a rachis

Question 10

Palmately compound

Answer 10

Leaflets connected to the end of a petiole

Question 11

Blades will show a characteristics venation patterns like what?

Answer 11

Either netted (pinnately or palmately) or parallel

Question 12

Petiole

Answer 12

Stem like part connecting blade to node

Question 13

Petiole is flexible due to what

Answer 13

Collenchyma strands (also brings in CO2)

Question 14

Stipule

Answer 14

Accessory leaf like structure at base of petiole, may be deciduous or missing entirely

Question 15

Upper epidermis

Answer 15

Continues with stem surface compactly arranged cells covered by cuticle

Question 16

Mesophyll

Answer 16

Specialized for photosynthesis, thin walled for rapid diffusion of co2

Question 17

Lower epidermis

Answer 17

Stomata flanked by photosynthesis guard cells, trichromes for protection from herbivores or reflection of sunlight

Question 18

Palisade

Answer 18

Elongated cells oriented perpendicular to leaf surface

Question 19

Spongey

Answer 19

Loosely arranged oblong cells large air spaces for diffusion of gases

Question 20

Veins

Answer 20

Xylem always above the Phloem, surrounded by layers of endodermis- like bundle sheath

Question 21

Leaf Abscission

Answer 21

1. Formation of abscission zone at petiole
2. Cell walls of separation layer are allowed to weaken with no new fibers added
3. Siberin is added to walls on the stem side, forming a water repellent protective layer continuous with the bark
4. Enzymes then dissolve cell walls of separation layer and the leaf falls leaving a scar

Question 22

Bud scales

Answer 22

To protect apical meristems and delicate young leaves

Question 23

Cotyledons

Answer 23

“Seed leaves” to store nutrients for germination, monocots vs dicots